fix CCE

Signed-off-by: Devan-Kerman <devan@cleverpath.com>

README.md

@@ -1,75 +1,7 @@
-# ![CC: Tweaked](logo.png)
-[![Current build status](https://travis-ci.org/SquidDev-CC/CC-Tweaked.svg?branch=master)](https://travis-ci.org/SquidDev-CC/CC-Tweaked "Current build status") [![Download CC: Tweaked on CurseForge](https://cf.way2muchnoise.eu/title/cc-tweaked.svg)](https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked on CurseForge")
+# CC:T for Fabric
 
-CC: Tweaked is a fork of [ComputerCraft](https://github.com/dan200/ComputerCraft), adding programmable computers,
-turtles and more to Minecraft.
+* [Download on CurseForge](https://www.curseforge.com/minecraft/mc-mods/cc-restitched)
 
-## What?
-ComputerCraft has always held a fond place in my heart: it's the mod which really got me into Minecraft, and it's the
-mod which has kept me playing it for many years. However, development of the original mod has slowed, as the original
-developers have had less time to work on the mod, and moved onto other projects and commitments.
+A fork of [CC: Tweaked](https://github.com/SquidDev-CC/CC-Tweaked) for use with the latest Fabric.
 
-CC: Tweaked (or CC:T for short) is an attempt to continue ComputerCraft's legacy. It's not intended to be a competitor
-to CC, nor do I want to take it in a vastly different direction to the original mod. Instead, CC:T focuses on making the
-ComputerCraft experience as _solid_ as possible, ironing out any wrinkles that may have developed over time.
-
-## Features
-CC: Tweaked contains all the features of the latest version of ComputerCraft, as well as numerous fixes, performance
-improvements and several nifty additions. I'd recommend checking out [the releases page](https://github.com/SquidDev-CC/CC-Tweaked/releases)
-to see the full set of changes, but here's a couple of the more interesting additions:
-
- - Improvements to the `http` library, including websockets, support for other HTTP methods (`PUT`, `DELETE`, etc...)
-   and configurable limits on HTTP usage.
- - Full-block wired modems, allowing one to wrap non-solid peripherals (such as turtles, or chests if Plethora is
-   installed).
- - Pocket computers can be held like maps, allowing you to view the screen without entering a GUI.
- - Printed pages and books can be placed in item frames and held like maps.
- - Several profiling and administration tools for server owners, via the `/computercraft` command. This allows operators
-   to track which computers are hogging resources, turn on and shutdown multiple computers at once and interact with
-   computers remotely.
- - Closer emulation of standard Lua, adding the `debug` and `io` libraries. This also enables seeking within binary
-   files, meaning you don't need to read large files into memory.
- - Allow running multiple computers on multiple threads, reducing latency on worlds with many computers.
-
-## Relation to CCTweaks?
-This mod has nothing to do with CCTweaks, though there is no denying the name is a throwback to it. That being said,
-several features have been included, such as full block modems, the Cobalt runtime and map-like rendering for pocket
-computers.
-
-## Contributing
-Any contribution is welcome, be that using the mod, reporting bugs or contributing code. In order to start helping
-develop CC:T, you'll need to follow these steps:
-
- - **Clone the repository:** `git clone https://github.com/SquidDev-CC/CC-Tweaked.git && cd CC-Tweaked`
- - **Setup Forge:** `./gradlew setupDecompWorkspace`
- - **Test your changes:** `./gradlew runClient` (or run the `GradleStart` class from your IDE).
-
-If you want to run CC:T in a normal Minecraft instance, run `./gradlew build` and copy the `.jar` from `build/libs`.
-
-## Community
-If you need help getting started with CC: Tweaked, want to show off your latest project, or just want to chat about
-ComputerCraft we have a [forum](https://forums.computercraft.cc/) and [Discord guild](https://discord.gg/H2UyJXe)!
-There's also a fairly populated, albeit quiet [IRC channel](http://webchat.esper.net/?channels=#computercraft), if
-that's more your cup of tea.
-
-I'd generally recommend you don't contact me directly (email, DM, etc...) unless absolutely necessary (i.e. in order to
-report exploits). You'll get a far quicker response if you ask the whole community!
-
-## Using
-If you want to depend on CC: Tweaked, we have a maven repo. However, you should be wary that some functionality is only
-exposed by CC:T's API and not vanilla ComputerCraft. If you wish to support all variations of ComputerCraft, I recommend
-using [cc.crzd.me's maven](https://cc.crzd.me/maven/) instead.
-
-```groovy
-dependencies {
-  maven { url 'https://squiddev.cc/maven/' }
-}
-
-dependencies {
-  implementation "org.squiddev:cc-tweaked-${mc_version}:${cct_version}"
-}
-```
-
-You should also be careful to only use classes within the `dan200.computercraft.api` package. Non-API classes are
-subject to change at any point. If you depend on functionality outside the API, file an issue, and we can look into
-exposing more features.
+NOTE: This project is currently in alpha stage. It may not be well-tested and stable, so use it at your own peril!

build.gradle

@@ -1,417 +1,117 @@
-buildscript {
-    repositories {
-        jcenter()
-        mavenCentral()
-        maven {
-            name = "forge"
-            url = "http://files.minecraftforge.net/maven"
-        }
-    }
-    dependencies {
-        classpath 'com.google.code.gson:gson:2.8.1'
-        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.117'
-        classpath 'net.sf.proguard:proguard-gradle:6.1.0beta2'
-        classpath 'org.ajoberstar.grgit:grgit-gradle:3.0.0'
-    }
-}
-
 plugins {
-    id 'com.matthewprenger.cursegradle' version '1.2.0'
-    id "com.github.breadmoirai.github-release" version "2.2.4"
+    id 'fabric-loom' version '0.5-SNAPSHOT'
+    id 'maven-publish'
 }
 
-apply plugin: 'net.minecraftforge.gradle'
-apply plugin: 'org.ajoberstar.grgit'
-apply plugin: 'maven-publish'
-apply plugin: 'maven'
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
 
 version = mod_version
 
-group = "org.squiddev"
-archivesBaseName = "cc-tweaked-${mc_version}"
-
-minecraft {
-    runs {
-        client {
-            workingDirectory project.file('run')
-            property 'forge.logging.markers', 'REGISTRIES'
-            property 'forge.logging.console.level', 'debug'
-
-            mods {
-                computercraft {
-                    source sourceSets.main
-                }
-            }
-        }
-
-        server {
-            workingDirectory project.file('run')
-            property 'forge.logging.markers', 'SCAN,REGISTRIES,REGISTRYDUMP'
-            property 'forge.logging.console.level', 'debug'
-
-            mods {
-                computercraft {
-                    source sourceSets.main
-                }
-            }
-        }
-    }
-
-    mappings channel: 'snapshot', version: "${mappings_version}".toString()
-
-    accessTransformer file('src/main/resources/META-INF/accesstransformer.cfg')
-}
+group = "dan200.computercraft"
+archivesBaseName = "cc-tweaked-fabric-${mc_version}"
 
 repositories {
-    maven {
-        name "JEI"
-        url  "http://dvs1.progwml6.com/files/maven"
-    }
+    mavenCentral()
     maven {
         name "SquidDev"
         url "https://squiddev.cc/maven"
     }
-    ivy {
-        name "Charset"
-        artifactPattern "https://asie.pl/files/mods/Charset/LibOnly/[module]-[revision](-[classifier]).[ext]"
-    }
-    maven {
-        name "Amadornes"
-        url "http://maven.amadornes.com/"
-    }
 }
 
 configurations {
-    shade
     compile.extendsFrom shade
-    deployerJars
 }
 
 dependencies {
-    minecraft "net.minecraftforge:forge:${mc_version}-${forge_version}"
+    minecraft "com.mojang:minecraft:${mc_version}"
+    mappings "net.fabricmc:yarn:${mc_version}+build.${mappings_version}:v2"
+    modImplementation "net.fabricmc:fabric-loader:${fabric_loader_version}"
+    modImplementation "net.fabricmc.fabric-api:fabric-api:${fabric_api_version}"
 
-    compileOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20:api")
-    // deobfProvided "pl.asie:Charset-Lib:0.5.4.6"
-    // deobfProvided "MCMultiPart2:MCMultiPart:2.5.3"
+    modImplementation "me.shedaniel.cloth:config-2:${cloth_config_version}"
+    modImplementation "io.github.prospector:modmenu:${modmenu_version}"
 
-    runtimeOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20")
+    modApi "me.shedaniel.cloth.api:cloth-utils-v1:${project.cloth_api_version}"
+    include "me.shedaniel.cloth.api:cloth-utils-v1:${project.cloth_api_version}"
 
-    shade 'org.squiddev:Cobalt:0.5.0-SNAPSHOT'
+    implementation "blue.endless:jankson:${jankson_version}"
+    implementation 'com.google.code.findbugs:jsr305:3.0.2'
+
+    include "me.shedaniel.cloth:config-2:${cloth_config_version}"
+    include "blue.endless:jankson:${jankson_version}"
+    include 'javax.vecmath:vecmath:1.5.2'
+
+    compile 'javax.vecmath:vecmath:1.5.2'
+
+    shade 'org.squiddev:Cobalt:0.5.1-SNAPSHOT'
 
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.1.0'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.1.0'
 
-    deployerJars "org.apache.maven.wagon:wagon-ssh:3.0.0"
+    modRuntime "me.shedaniel:RoughlyEnoughItems-api:5.2.10"
+    modRuntime "me.shedaniel:RoughlyEnoughItems:5.2.10"
 }
 
 sourceSets {
     main {
         java {
-            exclude 'dan200/computercraft/shared/integration/mcmp'
-            exclude 'dan200/computercraft/shared/integration/charset'
+            exclude 'dan200/computercraft/shared/integration'
         }
     }
 }
 
-javadoc {
-    include "dan200/computercraft/api/**/*.java"
+processResources {
+    inputs.property "version", project.version
+
+    from(sourceSets.main.resources.srcDirs) {
+        include "fabric.mod.json"
+        expand "version": project.version
+    }
+
+    from(sourceSets.main.resources.srcDirs) {
+        exclude "fabric.mod.json"
+    }
+}
+
+// ensure that the encoding is set to UTF-8, no matter what the system default is
+// this fixes some edge cases with special characters not displaying correctly
+// see http://yodaconditions.net/blog/fix-for-java-file-encoding-problems-with-gradle.html
+tasks.withType(JavaCompile) {
+    options.encoding = "UTF-8"
+}
+
+// Loom will automatically attach sourcesJar to a RemapSourcesJar task and to the "build" task
+// if it is present.
+// If you remove this task, sources will not be generated.
+task sourcesJar(type: Jar, dependsOn: classes) {
+    classifier = "sources"
+    from sourceSets.main.allSource
 }
 
 jar {
-    dependsOn javadoc
-
-    manifest {
-        attributes(["Specification-Title": "computercraft",
-                    "Specification-Vendor": "SquidDev",
-                    "Specification-Version": "25.0",
-                    "Implementation-Title": "CC: Tweaked",
-                    "Implementation-Version": "${mod_version}",
-                    "Implementation-Vendor" :"SquidDev",
-                    "Implementation-Timestamp": new Date().format("yyyy-MM-dd'T'HH:mm:ssZ")])
-    }
-
-    from (sourceSets.main.allSource) {
-        include "dan200/computercraft/api/**/*.java"
-    }
+    from "LICENSE"
 
     from configurations.shade.collect { it.isDirectory() ? it : zipTree(it) }
 }
 
-import java.nio.charset.StandardCharsets
-import java.nio.file.*
-import java.util.zip.*
-
-import com.google.gson.GsonBuilder
-import com.google.gson.JsonElement
-import org.ajoberstar.grgit.Grgit
-import proguard.gradle.ProGuardTask
-
-task proguard(type: ProGuardTask, dependsOn: jar) {
-    description "Removes unused shadowed classes from the jar"
-    group "compact"
-
-    injars jar.archivePath
-    outjars "${jar.archivePath.absolutePath.replace(".jar", "")}-min.jar"
-
-    // Add the main runtime jar and all non-shadowed dependencies
-    libraryjars "${System.getProperty('java.home')}/lib/rt.jar"
-    doFirst {
-        sourceSets.main.compileClasspath
-            .filter { !it.name.contains("Cobalt") }
-            .each { libraryjars it }
-    }
-
-    // We want to avoid as much obfuscation as possible. We're only doing this to shrink code size.
-    dontobfuscate; dontoptimize; keepattributes; keepparameternames
-
-    // Proguard will remove directories by default, but that breaks JarMount.
-    keepdirectories 'data/computercraft/lua**'
-
-    // Preserve ComputerCraft classes - we only want to strip shadowed files.
-    keep 'class dan200.computercraft.** { *; }'
-
-    // Preserve the constructors in Cobalt library class, as we init them via reflection
-    keepclassmembers 'class org.squiddev.cobalt.lib.** { <init>(...); }'
-
-    // LWJGL and Apache bundle Java 9 versions, which is great, but rather breaks Proguard
-    dontwarn 'module-info'
-    dontwarn 'org.apache.**,org.lwjgl.**'
-}
-
-task proguardMove(dependsOn: proguard) {
-    description "Replace the original jar with the minified version"
-    group "compact"
-
-    doLast {
-        Files.move(
-            file("${jar.archivePath.absolutePath.replace(".jar", "")}-min.jar").toPath(),
-            file(jar.archivePath).toPath(),
-            StandardCopyOption.REPLACE_EXISTING
-        )
-    }
-}
-
-
-
-processResources {
-    inputs.property "version", mod_version
-    inputs.property "mcversion", mc_version
-
-    def hash = 'none'
-    Set<String> contributors = []
-    try {
-        def grgit = Grgit.open(dir: '.')
-        hash = grgit.head().id
-
-        def blacklist = ['GitHub', 'dan200', 'Daniel Ratcliffe']
-        grgit.log().each {
-            if (!blacklist.contains(it.author.name)) contributors.add(it.author.name)
-            if (!blacklist.contains(it.committer.name)) contributors.add(it.committer.name)
-        }
-    } catch(Exception ignored) { }
-
-    inputs.property "commithash", hash
-
-    from(sourceSets.main.resources.srcDirs) {
-        include 'META-INF/mods.toml'
-        include 'data/computercraft/lua/rom/help/credits.txt'
-
-        expand 'version': mod_version,
-               'mcversion': mc_version,
-               'gitcontributors': contributors.sort(false, String.CASE_INSENSITIVE_ORDER).join('\n')
-    }
-
-    from(sourceSets.main.resources.srcDirs) {
-        exclude 'META-INF/mods.toml'
-        exclude 'data/computercraft/lua/rom/help/credits.txt'
-    }
-}
-
-task compressJson(dependsOn: jar) {
-    group "compact"
-    description "Minifies all JSON files, stripping whitespace"
-
-    def jarPath = file(jar.archivePath)
-
-    def tempPath = File.createTempFile("input", ".jar", temporaryDir)
-    tempPath.deleteOnExit()
-
-    def gson = new GsonBuilder().create()
-
-    doLast {
-        // Copy over all files in the current jar to the new one, running json files from GSON. As pretty printing
-        // is turned off, they should be minified.
-        new ZipFile(jarPath).withCloseable { inJar ->
-            new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(tempPath))).withCloseable { outJar ->
-                inJar.entries().each { entry ->
-                    if(entry.directory) {
-                        outJar.putNextEntry(entry)
-                    } else if(!entry.name.endsWith(".json")) {
-                        outJar.putNextEntry(entry)
-                        inJar.getInputStream(entry).withCloseable { outJar << it }
-                    } else {
-                        ZipEntry newEntry = new ZipEntry(entry.name)
-                        newEntry.setTime(entry.time)
-                        outJar.putNextEntry(newEntry)
-
-                        def element = inJar.getInputStream(entry).withCloseable { gson.fromJson(it.newReader("UTF8"), JsonElement.class) }
-                        outJar.write(gson.toJson(element).getBytes(StandardCharsets.UTF_8))
-                    }
-                }
-
-            }
-        }
-
-        // And replace the original jar again
-        Files.move(tempPath.toPath(), jarPath.toPath(), StandardCopyOption.REPLACE_EXISTING)
-    }
-}
-
-assemble.dependsOn compressJson
-
-task checkRelease {
-    group "upload"
-    description "Verifies that everything is ready for a release"
-
-    inputs.property "version", mod_version
-    inputs.file("src/main/resources/data/computercraft/lua/rom/help/changelog.txt")
-    inputs.file("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt")
-
-    doLast {
-        def ok = true
-
-        // Check we're targetting the current version
-        def whatsnew = new File("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt").readLines()
-        if (whatsnew[0] != "New features in CC: Tweaked $mod_version") {
-            ok = false
-            project.logger.error("Expected `whatsnew.txt' to target $mod_version.")
-        }
-
-        // Check "read more" exists and trim it
-        def idx = whatsnew.findIndexOf { it == 'Type "help changelog" to see the full version history.' }
-        if (idx == -1) {
-            ok = false
-            project.logger.error("Must mention the changelog in whatsnew.txt")
-        } else {
-            whatsnew = whatsnew.getAt(0 ..< idx)
-        }
-
-        // Check whatsnew and changelog match.
-        def versionChangelog = "# " + whatsnew.join("\n")
-        def changelog = new File("src/main/resources/data/computercraft/lua/rom/help/changelog.txt").getText()
-        if (!changelog.startsWith(versionChangelog)) {
-            ok = false
-            project.logger.error("whatsnew and changelog are not in sync")
-        }
-
-        if (!ok) throw new IllegalStateException("Could not check release")
-    }
-}
-
-
-curseforge {
-    apiKey = project.hasProperty('curseForgeApiKey') ? project.curseForgeApiKey : ''
-    project {
-        id = '282001'
-        releaseType = 'release'
-        changelog = "Release notes can be found on the GitHub repository (https://github.com/SquidDev-CC/CC-Tweaked/releases/tag/v${mc_version}-${mod_version})."
-
-        relations {
-            incompatible "computercraft"
-        }
-    }
-}
-
+// configure the maven publication
 publishing {
     publications {
         mavenJava(MavenPublication) {
-            from components.java
-            // artifact sourceJar
-        }
-    }
-}
-
-uploadArchives {
-    repositories {
-        if(project.hasProperty('mavenUploadUrl')) {
-            mavenDeployer {
-                configuration = configurations.deployerJars
-
-                repository(url: project.property('mavenUploadUrl')) {
-                    authentication(
-                        userName: project.property('mavenUploadUser'),
-                        privateKey: project.property('mavenUploadKey'))
-                }
-
-                pom.project {
-                    name 'CC: Tweaked'
-                    packaging 'jar'
-                    description 'CC: Tweaked is a fork of ComputerCraft, adding programmable computers, turtles and more to Minecraft.'
-                    url 'https://github.com/SquidDev-CC/CC-Tweaked'
-
-                    scm {
-                        url 'https://github.com/SquidDev-CC/CC-Tweaked.git'
-                    }
-
-                    issueManagement {
-                        system 'github'
-                        url 'https://github.com/SquidDev-CC/CC-Tweaked/issues'
-                    }
-
-                    licenses {
-                        license {
-                            name 'ComputerCraft Public License, Version 1.0'
-                            url 'https://github.com/SquidDev-CC/CC-Tweaked/blob/master/LICENSE'
-                            distribution 'repo'
-                        }
-                    }
-                }
-
-                pom.whenConfigured { pom ->
-                    pom.dependencies.clear()
-                }
+            // add all the jars that should be included when publishing to maven
+            artifact(remapJar) {
+                builtBy remapJar
+            }
+            artifact(sourcesJar) {
+                builtBy remapSourcesJar
             }
         }
     }
-}
 
-githubRelease {
-    token project.hasProperty('githubApiKey') ? project.githubApiKey : ''
-    owner 'SquidDev-CC'
-    repo 'CC-Tweaked'
-    targetCommitish { Grgit.open(dir: '.').branch.current().name }
-
-    tagName "v${mc_version}-${mod_version}"
-    releaseName "[${mc_version}] ${mod_version}"
-    body {
-        "## " + new File("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt")
-            .readLines()
-            .takeWhile { it != 'Type "help changelog" to see the full version history.' }
-            .join("\n").trim()
-    }
-    prerelease false
-}
-
-def uploadTasks = ["uploadArchives", "curseforge", "githubRelease"]
-uploadTasks.forEach { tasks.getByName(it).dependsOn checkRelease }
-
-task uploadAll(dependsOn: uploadTasks) {
-    group "upload"
-    description "Uploads to all repositories (Maven, Curse, GitHub release)"
-}
-
-test {
-    useJUnitPlatform()
-    testLogging {
-        events "passed", "skipped", "failed"
+    // select the repositories you want to publish to
+    repositories {
+        // uncomment to publish to the local maven
+        // mavenLocal()
     }
 }
-
-gradle.projectsEvaluated {
-    reobfJar.dependsOn proguardMove
-
-    tasks.withType(JavaCompile) {
-        options.compilerArgs << "-Xlint" << "-Xlint:-processing" // Causes Forge build to fail << "-Werror"
-    }
-}
-

gradle.properties

@@ -1,7 +1,17 @@
+# Done to increase the memory available to gradle.
+org.gradle.jvmargs=-Xmx1G
+
 # Mod properties
-mod_version=1.83.1
+mod_version=1.91.1
 
 # Minecraft properties
-mc_version=1.13.2
-forge_version=25.0.219
-mappings_version=20190530-1.13.2
+mc_version=1.16.2
+mappings_version=31
+
+# Dependencies
+cloth_config_version=4.8.1
+fabric_api_version=0.19.0+build.398-1.16
+fabric_loader_version=0.9.2+build.206
+jankson_version=1.2.0
+modmenu_version=1.14.6+
+cloth_api_version=1.4.5

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
+#Tue Jul 07 13:15:43 EDT 2020
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.6.1-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-bin.zip
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME

settings.gradle

@@ -1 +1,12 @@
-rootProject.name = "cc-tweaked-${mc_version}"
+pluginManagement {
+    repositories {
+        jcenter()
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+        gradlePluginPortal()
+    }
+}
+
+rootProject.name = "cc-tweaked-fabric-${mc_version}"

src/main/java/dan200/computercraft/ComputerCraft.java

@@ -1,67 +1,99 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft;
 
-import dan200.computercraft.api.filesystem.IMount;
+import static dan200.computercraft.shared.ComputerCraftRegistry.ModBlocks;
+import static dan200.computercraft.shared.ComputerCraftRegistry.init;
+
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 import dan200.computercraft.api.turtle.event.TurtleAction;
 import dan200.computercraft.core.apis.AddressPredicate;
+import dan200.computercraft.core.apis.http.options.Action;
+import dan200.computercraft.core.apis.http.options.AddressRule;
 import dan200.computercraft.core.apis.http.websocket.Websocket;
-import dan200.computercraft.core.filesystem.ResourceMount;
-import dan200.computercraft.shared.Config;
-import dan200.computercraft.shared.computer.blocks.BlockComputer;
+import dan200.computercraft.shared.common.ColourableRecipe;
 import dan200.computercraft.shared.computer.core.ClientComputerRegistry;
 import dan200.computercraft.shared.computer.core.ServerComputerRegistry;
-import dan200.computercraft.shared.computer.items.ItemComputer;
-import dan200.computercraft.shared.media.items.ItemDisk;
-import dan200.computercraft.shared.media.items.ItemPrintout;
-import dan200.computercraft.shared.media.items.ItemTreasureDisk;
-import dan200.computercraft.shared.peripheral.diskdrive.BlockDiskDrive;
-import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
-import dan200.computercraft.shared.peripheral.modem.wired.BlockWiredModemFull;
-import dan200.computercraft.shared.peripheral.modem.wired.ItemBlockCable;
-import dan200.computercraft.shared.peripheral.modem.wireless.BlockWirelessModem;
-import dan200.computercraft.shared.peripheral.monitor.BlockMonitor;
-import dan200.computercraft.shared.peripheral.printer.BlockPrinter;
-import dan200.computercraft.shared.peripheral.speaker.BlockSpeaker;
-import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
+import dan200.computercraft.shared.computer.recipe.ComputerUpgradeRecipe;
+import dan200.computercraft.shared.data.BlockNamedEntityLootCondition;
+import dan200.computercraft.shared.data.HasComputerIdLootCondition;
+import dan200.computercraft.shared.data.PlayerCreativeLootCondition;
+import dan200.computercraft.shared.media.recipes.DiskRecipe;
+import dan200.computercraft.shared.media.recipes.PrintoutRecipe;
+import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
 import dan200.computercraft.shared.pocket.peripherals.PocketModem;
 import dan200.computercraft.shared.pocket.peripherals.PocketSpeaker;
-import dan200.computercraft.shared.turtle.blocks.BlockTurtle;
-import dan200.computercraft.shared.turtle.items.ItemTurtle;
-import dan200.computercraft.shared.turtle.upgrades.*;
-import net.minecraft.resources.IReloadableResourceManager;
-import net.minecraft.util.ResourceLocation;
-import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.server.ServerLifecycleHooks;
+import dan200.computercraft.shared.pocket.recipes.PocketComputerUpgradeRecipe;
+import dan200.computercraft.shared.proxy.ComputerCraftProxyCommon;
+import dan200.computercraft.shared.turtle.recipes.TurtleRecipe;
+import dan200.computercraft.shared.turtle.recipes.TurtleUpgradeRecipe;
+import dan200.computercraft.shared.turtle.upgrades.TurtleAxe;
+import dan200.computercraft.shared.turtle.upgrades.TurtleCraftingTable;
+import dan200.computercraft.shared.turtle.upgrades.TurtleHoe;
+import dan200.computercraft.shared.turtle.upgrades.TurtleModem;
+import dan200.computercraft.shared.turtle.upgrades.TurtleShovel;
+import dan200.computercraft.shared.turtle.upgrades.TurtleSpeaker;
+import dan200.computercraft.shared.turtle.upgrades.TurtleSword;
+import dan200.computercraft.shared.turtle.upgrades.TurtleTool;
+import dan200.computercraft.shared.util.Config;
+import dan200.computercraft.shared.util.ImpostorRecipe;
+import dan200.computercraft.shared.util.ImpostorShapelessRecipe;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.EnumSet;
-import java.util.concurrent.TimeUnit;
+import net.minecraft.item.ItemGroup;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.registry.Registry;
 
-@Mod( ComputerCraft.MOD_ID )
-public final class ComputerCraft
-{
+import net.fabricmc.api.ModInitializer;
+import net.fabricmc.fabric.api.client.itemgroup.FabricItemGroupBuilder;
+import net.fabricmc.loader.api.FabricLoader;
+
+public final class ComputerCraft implements ModInitializer {
     public static final String MOD_ID = "computercraft";
-
-    public static final int DATAFIXER_VERSION = 0;
-
     // Configuration options
-    public static final String[] DEFAULT_HTTP_WHITELIST = new String[] { "*" };
+    public static final String[] DEFAULT_HTTP_WHITELIST = new String[] {"*"};
     public static final String[] DEFAULT_HTTP_BLACKLIST = new String[] {
         "127.0.0.0/8",
         "10.0.0.0/8",
         "172.16.0.0/12",
         "192.168.0.0/16",
         "fd00::/8",
-    };
-
+        };
+    public static final int terminalWidth_computer = 51;
+    public static final int terminalHeight_computer = 19;
+    public static final int terminalWidth_turtle = 39;
+    public static final int terminalHeight_turtle = 13;
+    public static final int terminalWidth_pocketComputer = 26;
+    public static final int terminalHeight_pocketComputer = 20;
+    // Registries
+    public static final ClientComputerRegistry clientComputerRegistry = new ClientComputerRegistry();
+    public static final ServerComputerRegistry serverComputerRegistry = new ServerComputerRegistry();
+    // Logging
+    public static final Logger log = LogManager.getLogger(MOD_ID);
+    public static ItemGroup MAIN_GROUP = FabricItemGroupBuilder.build(new Identifier(MOD_ID, "main"), () -> new ItemStack(ModBlocks.COMPUTER_NORMAL));
+    public static List<AddressRule> httpRules = Collections.unmodifiableList(Stream.concat(Stream.of(DEFAULT_HTTP_BLACKLIST)
+                                                                                                 .map(x -> AddressRule.parse(x, Action.DENY.toPartial()))
+                                                                                                 .filter(Objects::nonNull),
+                                                                                           Stream.of(DEFAULT_HTTP_WHITELIST)
+                                                                                                 .map(x -> AddressRule.parse(x, Action.ALLOW.toPartial()))
+                                                                                                 .filter(Objects::nonNull))
+                                                                                   .collect(Collectors.toList()));
+    public static boolean commandRequireCreative = false;
+    public static MonitorRenderer monitorRenderer = MonitorRenderer.BEST;
     public static int computerSpaceLimit = 1000 * 1000;
     public static int floppySpaceLimit = 125 * 1000;
     public static int maximumFilesOpen = 128;
@@ -69,148 +101,57 @@ public final class ComputerCraft
     public static String default_computer_settings = "";
     public static boolean debug_enable = true;
     public static boolean logPeripheralErrors = false;
-
     public static int computer_threads = 1;
-    public static long maxMainGlobalTime = TimeUnit.MILLISECONDS.toNanos( 10 );
-    public static long maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos( 5 );
-
+    public static long maxMainGlobalTime = TimeUnit.MILLISECONDS.toNanos(10);
+    public static long maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos(5);
     public static boolean http_enable = true;
     public static boolean http_websocket_enable = true;
-    public static AddressPredicate http_whitelist = new AddressPredicate( DEFAULT_HTTP_WHITELIST );
-    public static AddressPredicate http_blacklist = new AddressPredicate( DEFAULT_HTTP_BLACKLIST );
-
+    public static AddressPredicate http_whitelist = new AddressPredicate(DEFAULT_HTTP_WHITELIST);
+    public static AddressPredicate http_blacklist = new AddressPredicate(DEFAULT_HTTP_BLACKLIST);
     public static int httpTimeout = 30000;
     public static int httpMaxRequests = 16;
     public static long httpMaxDownload = 16 * 1024 * 1024;
     public static long httpMaxUpload = 4 * 1024 * 1024;
     public static int httpMaxWebsockets = 4;
     public static int httpMaxWebsocketMessage = Websocket.MAX_MESSAGE_SIZE;
-
     public static boolean enableCommandBlock = false;
     public static int modem_range = 64;
     public static int modem_highAltitudeRange = 384;
     public static int modem_rangeDuringStorm = 64;
     public static int modem_highAltitudeRangeDuringStorm = 384;
     public static int maxNotesPerTick = 8;
-
     public static boolean turtlesNeedFuel = true;
     public static int turtleFuelLimit = 20000;
     public static int advancedTurtleFuelLimit = 100000;
     public static boolean turtlesObeyBlockProtection = true;
     public static boolean turtlesCanPush = true;
-    public static EnumSet<TurtleAction> turtleDisabledActions = EnumSet.noneOf( TurtleAction.class );
+    public static EnumSet<TurtleAction> turtleDisabledActions = EnumSet.noneOf(TurtleAction.class);
+    public static int monitorWidth = 8;
+    public static int monitorHeight = 6;
+    public static double monitorDistanceSq = 4096;
 
-    public static final int terminalWidth_computer = 51;
-    public static final int terminalHeight_computer = 19;
-
-    public static final int terminalWidth_turtle = 39;
-    public static final int terminalHeight_turtle = 13;
-
-    public static final int terminalWidth_pocketComputer = 26;
-    public static final int terminalHeight_pocketComputer = 20;
-
-    // Blocks and Items
-    public static final class Blocks
-    {
-        public static BlockComputer computerNormal;
-        public static BlockComputer computerAdvanced;
-        public static BlockComputer computerCommand;
-
-        public static BlockTurtle turtleNormal;
-        public static BlockTurtle turtleAdvanced;
-
-        public static BlockSpeaker speaker;
-        public static BlockDiskDrive diskDrive;
-        public static BlockPrinter printer;
-
-        public static BlockMonitor monitorNormal;
-        public static BlockMonitor monitorAdvanced;
-
-        public static BlockWirelessModem wirelessModemNormal;
-        public static BlockWirelessModem wirelessModemAdvanced;
-
-        public static BlockWiredModemFull wiredModemFull;
-        public static BlockCable cable;
+    @Override
+    public void onInitialize() {
+        Config.load(Paths.get(FabricLoader.getInstance()
+                                          .getConfigDir()
+                                          .toFile()
+                                          .getPath(), MOD_ID + ".json5"));
+        ComputerCraftProxyCommon.init();
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "colour"), ColourableRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "computer_upgrade"), ComputerUpgradeRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER,
+                          new Identifier(ComputerCraft.MOD_ID, "pocket_computer_upgrade"),
+                          PocketComputerUpgradeRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "disk"), DiskRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "printout"), PrintoutRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "turtle"), TurtleRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "turtle_upgrade"), TurtleUpgradeRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "impostor_shaped"), ImpostorRecipe.SERIALIZER);
+        Registry.register(Registry.RECIPE_SERIALIZER, new Identifier(ComputerCraft.MOD_ID, "impostor_shapeless"), ImpostorShapelessRecipe.SERIALIZER);
+        Registry.register(Registry.LOOT_CONDITION_TYPE, new Identifier(ComputerCraft.MOD_ID, "block_named"), BlockNamedEntityLootCondition.TYPE);
+        Registry.register(Registry.LOOT_CONDITION_TYPE, new Identifier(ComputerCraft.MOD_ID, "player_creative"), PlayerCreativeLootCondition.TYPE);
+        Registry.register(Registry.LOOT_CONDITION_TYPE, new Identifier(ComputerCraft.MOD_ID, "has_id"), HasComputerIdLootCondition.TYPE);
+        init();
     }
 
-    public static final class Items
-    {
-        public static ItemComputer computerNormal;
-        public static ItemComputer computerAdvanced;
-        public static ItemComputer computerCommand;
-
-        public static ItemPocketComputer pocketComputerNormal;
-        public static ItemPocketComputer pocketComputerAdvanced;
-
-        public static ItemTurtle turtleNormal;
-        public static ItemTurtle turtleAdvanced;
-
-        public static ItemDisk disk;
-        public static ItemTreasureDisk treasureDisk;
-
-        public static ItemPrintout printedPage;
-        public static ItemPrintout printedPages;
-        public static ItemPrintout printedBook;
-
-        public static ItemBlockCable.Cable cable;
-        public static ItemBlockCable.WiredModem wiredModem;
-    }
-
-    public static final class TurtleUpgrades
-    {
-        public static TurtleModem wirelessModemNormal;
-        public static TurtleModem wirelessModemAdvanced;
-        public static TurtleSpeaker speaker;
-
-        public static TurtleCraftingTable craftingTable;
-        public static TurtleSword diamondSword;
-        public static TurtleShovel diamondShovel;
-        public static TurtleTool diamondPickaxe;
-        public static TurtleAxe diamondAxe;
-        public static TurtleHoe diamondHoe;
-    }
-
-    public static final class PocketUpgrades
-    {
-        public static PocketModem wirelessModemNormal;
-        public static PocketModem wirelessModemAdvanced;
-        public static PocketSpeaker speaker;
-    }
-
-    // Registries
-    public static final ClientComputerRegistry clientComputerRegistry = new ClientComputerRegistry();
-    public static final ServerComputerRegistry serverComputerRegistry = new ServerComputerRegistry();
-
-    // Logging
-    public static final Logger log = LogManager.getLogger( MOD_ID );
-
-    public ComputerCraft()
-    {
-        Config.load();
-    }
-
-    public static String getVersion()
-    {
-        return "${version}";
-    }
-
-    static IMount createResourceMount( String domain, String subPath )
-    {
-        IReloadableResourceManager manager = ServerLifecycleHooks.getCurrentServer().getResourceManager();
-        ResourceMount mount = new ResourceMount( domain, subPath, manager );
-        return mount.exists( "" ) ? mount : null;
-    }
-
-    public static InputStream getResourceFile( String domain, String subPath )
-    {
-        IReloadableResourceManager manager = ServerLifecycleHooks.getCurrentServer().getResourceManager();
-        try
-        {
-            return manager.getResource( new ResourceLocation( domain, subPath ) ).getInputStream();
-        }
-        catch( IOException ignored )
-        {
-            return null;
-        }
-    }
 }

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -1,11 +1,18 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft;
 
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import dan200.computercraft.api.ComputerCraftAPI.IComputerCraftAPI;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -20,122 +27,148 @@ import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.core.apis.ApiFactories;
 import dan200.computercraft.core.filesystem.FileMount;
-import dan200.computercraft.shared.*;
+import dan200.computercraft.core.filesystem.ResourceMount;
+import dan200.computercraft.mixin.MinecraftServerAccess;
+import dan200.computercraft.shared.BundledRedstone;
+import dan200.computercraft.shared.MediaProviders;
+import dan200.computercraft.shared.Peripherals;
+import dan200.computercraft.shared.PocketUpgrades;
+import dan200.computercraft.shared.TurtleUpgrades;
+import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
+import dan200.computercraft.shared.peripheral.modem.wired.TileWiredModemFull;
 import dan200.computercraft.shared.peripheral.modem.wireless.WirelessNetwork;
 import dan200.computercraft.shared.util.IDAssigner;
-import dan200.computercraft.shared.wired.CapabilityWiredElement;
 import dan200.computercraft.shared.wired.WiredNode;
-import net.minecraft.tileentity.TileEntity;
-import net.minecraft.util.EnumFacing;
+import me.shedaniel.cloth.api.utils.v1.GameInstanceUtils;
+
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.resource.ReloadableResourceManager;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.Identifier;
 import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.IBlockReader;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.BlockView;
 import net.minecraft.world.World;
-import net.minecraftforge.common.util.LazyOptional;
 
-import javax.annotation.Nonnull;
-import java.io.File;
+import net.fabricmc.loader.api.FabricLoader;
 
-public final class ComputerCraftAPIImpl implements IComputerCraftAPI
-{
+public final class ComputerCraftAPIImpl implements IComputerCraftAPI {
     public static final ComputerCraftAPIImpl INSTANCE = new ComputerCraftAPIImpl();
 
-    private ComputerCraftAPIImpl()
-    {
+    private String version;
+
+    private ComputerCraftAPIImpl() {
+    }
+
+    public static InputStream getResourceFile(String domain, String subPath) {
+        MinecraftServer server = GameInstanceUtils.getServer();
+        if (server != null) {
+            ReloadableResourceManager manager = (ReloadableResourceManager) ((MinecraftServerAccess)server).getServerResourceManager().getResourceManager();
+            try {
+                return manager.getResource(new Identifier(domain, subPath))
+                              .getInputStream();
+            } catch (IOException ignored) {
+                return null;
+            }
+        }
+        return null;
     }
 
     @Nonnull
     @Override
-    public String getInstalledVersion()
-    {
-        return "${version}";
-    }
-
-    @Override
-    public int createUniqueNumberedSaveDir( @Nonnull World world, @Nonnull String parentSubPath )
-    {
-        return IDAssigner.getNextId( parentSubPath );
-    }
-
-    @Override
-    public IWritableMount createSaveDirMount( @Nonnull World world, @Nonnull String subPath, long capacity )
-    {
-        try
-        {
-            return new FileMount( new File( IDAssigner.getDir(), subPath ), capacity );
+    public String getInstalledVersion() {
+        if (this.version != null) {
+            return this.version;
         }
-        catch( Exception e )
-        {
+        return this.version = FabricLoader.getInstance()
+                                          .getModContainer(ComputerCraft.MOD_ID)
+                                          .map(x -> x.getMetadata()
+                                                .getVersion()
+                                                .toString())
+                                          .orElse("unknown");
+    }
+
+    @Override
+    public int createUniqueNumberedSaveDir(@Nonnull World world, @Nonnull String parentSubPath) {
+        return IDAssigner.getNextId(parentSubPath);
+    }
+
+    @Override
+    public IWritableMount createSaveDirMount(@Nonnull World world, @Nonnull String subPath, long capacity) {
+        try {
+            return new FileMount(new File(IDAssigner.getDir(), subPath), capacity);
+        } catch (Exception e) {
             return null;
         }
     }
 
     @Override
-    public IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath )
-    {
-        return ComputerCraft.createResourceMount( domain, subPath );
+    public IMount createResourceMount(@Nonnull String domain, @Nonnull String subPath) {
+        MinecraftServer server = GameInstanceUtils.getServer();
+        if (server != null) {
+            ReloadableResourceManager manager = (ReloadableResourceManager) ((MinecraftServerAccess)server).getServerResourceManager().getResourceManager();
+            ResourceMount mount = ResourceMount.get(domain, subPath, manager);
+            return mount.exists("") ? mount : null;
+        }
+        return null;
     }
 
     @Override
-    public void registerPeripheralProvider( @Nonnull IPeripheralProvider provider )
-    {
-        Peripherals.register( provider );
+    public void registerPeripheralProvider(@Nonnull IPeripheralProvider provider) {
+        Peripherals.register(provider);
     }
 
     @Override
-    public void registerTurtleUpgrade( @Nonnull ITurtleUpgrade upgrade )
-    {
-        TurtleUpgrades.register( upgrade );
+    public void registerTurtleUpgrade(@Nonnull ITurtleUpgrade upgrade) {
+        TurtleUpgrades.register(upgrade);
     }
 
     @Override
-    public void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider )
-    {
-        BundledRedstone.register( provider );
+    public void registerBundledRedstoneProvider(@Nonnull IBundledRedstoneProvider provider) {
+        BundledRedstone.register(provider);
     }
 
     @Override
-    public int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
-    {
-        return BundledRedstone.getDefaultOutput( world, pos, side );
+    public int getBundledRedstoneOutput(@Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side) {
+        return BundledRedstone.getDefaultOutput(world, pos, side);
     }
 
     @Override
-    public void registerMediaProvider( @Nonnull IMediaProvider provider )
-    {
-        MediaProviders.register( provider );
+    public void registerMediaProvider(@Nonnull IMediaProvider provider) {
+        MediaProviders.register(provider);
     }
 
     @Override
-    public void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade )
-    {
-        PocketUpgrades.register( upgrade );
+    public void registerPocketUpgrade(@Nonnull IPocketUpgrade upgrade) {
+        PocketUpgrades.register(upgrade);
     }
 
     @Nonnull
     @Override
-    public IPacketNetwork getWirelessNetwork()
-    {
+    public IPacketNetwork getWirelessNetwork() {
         return WirelessNetwork.getUniversal();
     }
 
     @Override
-    public void registerAPIFactory( @Nonnull ILuaAPIFactory factory )
-    {
-        ApiFactories.register( factory );
+    public void registerAPIFactory(@Nonnull ILuaAPIFactory factory) {
+        ApiFactories.register(factory);
     }
 
     @Nonnull
     @Override
-    public IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )
-    {
-        return new WiredNode( element );
+    public IWiredNode createWiredNodeForElement(@Nonnull IWiredElement element) {
+        return new WiredNode(element);
     }
 
-    @Nonnull
+    @Nullable
     @Override
-    public LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
-    {
-        TileEntity tile = world.getTileEntity( pos );
-        return tile == null ? LazyOptional.empty() : tile.getCapability( CapabilityWiredElement.CAPABILITY, side );
+    public IWiredElement getWiredElementAt(@Nonnull BlockView world, @Nonnull BlockPos pos, @Nonnull Direction side) {
+        BlockEntity tile = world.getBlockEntity(pos);
+        if (tile instanceof TileCable) {
+            return ((TileCable) tile).getElement(side);
+        } else if (tile instanceof TileWiredModemFull) {
+            return ((TileWiredModemFull) tile).getElement();
+        }
+        return null;
     }
 }

src/main/java/dan200/computercraft/api/AbstractTurtleUpgrade.java

@@ -1,80 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.api;
-
-import dan200.computercraft.api.turtle.ITurtleUpgrade;
-import dan200.computercraft.api.turtle.TurtleUpgradeType;
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.IItemProvider;
-import net.minecraft.util.ResourceLocation;
-import net.minecraft.util.Util;
-
-import javax.annotation.Nonnull;
-
-/**
- * A base class for {@link ITurtleUpgrade}s.
- *
- * One does not have to use this, but it does provide a convenient template.
- */
-public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade
-{
-    private final ResourceLocation id;
-    private final TurtleUpgradeType type;
-    private final String adjective;
-    private final ItemStack stack;
-
-    protected AbstractTurtleUpgrade( ResourceLocation id, TurtleUpgradeType type, String adjective, ItemStack stack )
-    {
-        this.id = id;
-        this.type = type;
-        this.adjective = adjective;
-        this.stack = stack;
-    }
-
-    protected AbstractTurtleUpgrade( ResourceLocation id, TurtleUpgradeType type, String adjective, IItemProvider item )
-    {
-        this( id, type, adjective, new ItemStack( item ) );
-    }
-
-    protected AbstractTurtleUpgrade( ResourceLocation id, TurtleUpgradeType type, ItemStack stack )
-    {
-        this( id, type, Util.makeTranslationKey( "upgrade", id ) + ".adjective", stack );
-    }
-
-    protected AbstractTurtleUpgrade( ResourceLocation id, TurtleUpgradeType type, IItemProvider item )
-    {
-        this( id, type, new ItemStack( item ) );
-    }
-
-    @Nonnull
-    @Override
-    public final ResourceLocation getUpgradeID()
-    {
-        return id;
-    }
-
-    @Nonnull
-    @Override
-    public final String getUnlocalisedAdjective()
-    {
-        return adjective;
-    }
-
-    @Nonnull
-    @Override
-    public final TurtleUpgradeType getType()
-    {
-        return type;
-    }
-
-    @Nonnull
-    @Override
-    public final ItemStack getCraftingItem()
-    {
-        return stack;
-    }
-}

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -1,11 +1,14 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.ILuaAPIFactory;
@@ -20,32 +23,44 @@ import dan200.computercraft.api.peripheral.IPeripheralProvider;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.IBlockReader;
-import net.minecraft.world.World;
-import net.minecraftforge.common.util.LazyOptional;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.BlockView;
+import net.minecraft.world.World;
 
 /**
  * The static entry point to the ComputerCraft API.
- * Members in this class must be called after mod_ComputerCraft has been initialised,
- * but may be called before it is fully loaded.
+ *
+ * Members in this class must be called after mod_ComputerCraft has been initialised, but may be called before it is fully loaded.
  */
-public final class ComputerCraftAPI
-{
+public final class ComputerCraftAPI {
+    private static IComputerCraftAPI instance;
+
     @Nonnull
-    public static String getInstalledVersion()
-    {
+    @Deprecated
+    public static String getAPIVersion() {
+        return getInstalledVersion();
+    }
+
+    @Nonnull
+    public static String getInstalledVersion() {
         return getInstance().getInstalledVersion();
     }
 
     @Nonnull
-    public static String getAPIVersion()
-    {
-        return "${version}";
+    private static IComputerCraftAPI getInstance() {
+        if (instance != null) {
+            return instance;
+        }
+
+        try {
+            return instance = (IComputerCraftAPI) Class.forName("dan200.computercraft.ComputerCraftAPIImpl")
+                                                       .getField("INSTANCE")
+                                                       .get(null);
+        } catch (ReflectiveOperationException e) {
+            throw new IllegalStateException("Cannot find ComputerCraft API", e);
+        }
     }
 
     /**
@@ -53,31 +68,29 @@ public final class ComputerCraftAPI
      *
      * Use in conjunction with createSaveDirMount() to create a unique place for your peripherals or media items to store files.
      *
-     * @param world         The world for which the save dir should be created. This should be the server side world object.
+     * @param world The world for which the save dir should be created. This should be the server side world object.
      * @param parentSubPath The folder path within the save directory where the new directory should be created. eg: "computercraft/disk"
      * @return The numerical value of the name of the new folder, or -1 if the folder could not be created for some reason.
      *
-     * eg: if createUniqueNumberedSaveDir( world, "computer/disk" ) was called returns 42, then "computer/disk/42" is now
-     * available for writing.
+     *     eg: if createUniqueNumberedSaveDir( world, "computer/disk" ) was called returns 42, then "computer/disk/42" is now available for writing.
      * @see #createSaveDirMount(World, String, long)
      */
-    public static int createUniqueNumberedSaveDir( @Nonnull World world, @Nonnull String parentSubPath )
-    {
-        return getInstance().createUniqueNumberedSaveDir( world, parentSubPath );
+    public static int createUniqueNumberedSaveDir(@Nonnull World world, @Nonnull String parentSubPath) {
+        return getInstance().createUniqueNumberedSaveDir(world, parentSubPath);
     }
 
     /**
      * Creates a file system mount that maps to a subfolder of the save directory for a given world, and returns it.
      *
-     * Use in conjunction with IComputerAccess.mount() or IComputerAccess.mountWritable() to mount a folder from the
-     * users save directory onto a computers file system.
+     * Use in conjunction with IComputerAccess.mount() or IComputerAccess.mountWritable() to mount a folder from the users save directory onto a computers
+     * file system.
      *
-     * @param world    The world for which the save dir can be found. This should be the server side world object.
-     * @param subPath  The folder path within the save directory that the mount should map to. eg: "computer/disk/42".
-     *                 Use createUniqueNumberedSaveDir() to create a new numbered folder to use.
+     * @param world The world for which the save dir can be found. This should be the server side world object.
+     * @param subPath The folder path within the save directory that the mount should map to. eg: "computer/disk/42". Use createUniqueNumberedSaveDir()
+     *     to create a new numbered folder to use.
      * @param capacity The amount of data that can be stored in the directory before it fills up, in bytes.
-     * @return The mount, or null if it could be created for some reason. Use IComputerAccess.mount() or IComputerAccess.mountWritable()
-     * to mount this on a Computers' file system.
+     * @return The mount, or null if it could be created for some reason. Use IComputerAccess.mount() or IComputerAccess.mountWritable() to mount this on a
+     *     Computers' file system.
      * @see #createUniqueNumberedSaveDir(World, String)
      * @see IComputerAccess#mount(String, IMount)
      * @see IComputerAccess#mountWritable(String, IWritableMount)
@@ -85,21 +98,19 @@ public final class ComputerCraftAPI
      * @see IWritableMount
      */
     @Nullable
-    public static IWritableMount createSaveDirMount( @Nonnull World world, @Nonnull String subPath, long capacity )
-    {
-        return getInstance().createSaveDirMount( world, subPath, capacity );
+    public static IWritableMount createSaveDirMount(@Nonnull World world, @Nonnull String subPath, long capacity) {
+        return getInstance().createSaveDirMount(world, subPath, capacity);
     }
 
     /**
      * Creates a file system mount to a resource folder, and returns it.
      *
-     * Use in conjunction with {@link IComputerAccess#mount} or {@link IComputerAccess#mountWritable} to mount a
-     * resource folder onto a computer's file system.
+     * Use in conjunction with {@link IComputerAccess#mount} or {@link IComputerAccess#mountWritable} to mount a resource folder onto a computer's file
+     * system.
      *
-     * The files in this mount will be a combination of files in all mod jar, and data packs that contain
-     * resources with the same domain and path.
+     * The files in this mount will be a combination of files in all mod jar, and data packs that contain resources with the same domain and path.
      *
-     * @param domain  The domain under which to look for resources. eg: "mymod".
+     * @param domain The domain under which to look for resources. eg: "mymod".
      * @param subPath The subPath under which to look for resources. eg: "lua/myfiles".
      * @return The mount, or {@code null} if it could be created for some reason.
      * @see IComputerAccess#mount(String, IMount)
@@ -107,34 +118,8 @@ public final class ComputerCraftAPI
      * @see IMount
      */
     @Nullable
-    public static IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath )
-    {
-        return getInstance().createResourceMount( domain, subPath );
-    }
-
-    /**
-     * Creates a file system mount to a resource folder, and returns it.
-     *
-     * Use in conjunction with {@link IComputerAccess#mount} or {@link IComputerAccess#mountWritable} to mount a
-     * resource folder onto a computer's file system.
-     *
-     * The files in this mount will be a combination of files in all mod jar, and data packs that contain
-     * resources with the same domain and path.
-     *
-     * @param klass   The mod class to which the files belong.
-     * @param domain  The domain under which to look for resources. eg: "mymod".
-     * @param subPath The subPath under which to look for resources. eg: "lua/myfiles".
-     * @return The mount, or {@code null} if it could be created for some reason.
-     * @see IComputerAccess#mount(String, IMount)
-     * @see IComputerAccess#mountWritable(String, IWritableMount)
-     * @see IMount
-     * @deprecated Use {@link #createResourceMount(String, String)} instead.
-     */
-    @Nullable
-    @Deprecated
-    public static IMount createResourceMount( Class<?> klass, @Nonnull String domain, @Nonnull String subPath )
-    {
-        return getInstance().createResourceMount( domain, subPath );
+    public static IMount createResourceMount(@Nonnull String domain, @Nonnull String subPath) {
+        return getInstance().createResourceMount(domain, subPath);
     }
 
     /**
@@ -144,22 +129,19 @@ public final class ComputerCraftAPI
      * @see IPeripheral
      * @see IPeripheralProvider
      */
-    public static void registerPeripheralProvider( @Nonnull IPeripheralProvider provider )
-    {
-        getInstance().registerPeripheralProvider( provider );
+    public static void registerPeripheralProvider(@Nonnull IPeripheralProvider provider) {
+        getInstance().registerPeripheralProvider(provider);
     }
 
     /**
-     * Registers a new turtle turtle for use in ComputerCraft. After calling this,
-     * users should be able to craft Turtles with your new turtle. It is recommended to call
-     * this during the load() method of your mod.
+     * Registers a new turtle turtle for use in ComputerCraft. After calling this, users should be able to craft Turtles with your new turtle. It is
+     * recommended to call this during the load() method of your mod.
      *
      * @param upgrade The turtle upgrade to register.
      * @see ITurtleUpgrade
      */
-    public static void registerTurtleUpgrade( @Nonnull ITurtleUpgrade upgrade )
-    {
-        getInstance().registerTurtleUpgrade( upgrade );
+    public static void registerTurtleUpgrade(@Nonnull ITurtleUpgrade upgrade) {
+        getInstance().registerTurtleUpgrade(upgrade);
     }
 
     /**
@@ -168,40 +150,36 @@ public final class ComputerCraftAPI
      * @param provider The bundled redstone provider to register.
      * @see IBundledRedstoneProvider
      */
-    public static void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider )
-    {
-        getInstance().registerBundledRedstoneProvider( provider );
+    public static void registerBundledRedstoneProvider(@Nonnull IBundledRedstoneProvider provider) {
+        getInstance().registerBundledRedstoneProvider(provider);
     }
 
     /**
      * If there is a Computer or Turtle at a certain position in the world, get it's bundled redstone output.
      *
      * @param world The world this block is in.
-     * @param pos   The position this block is at.
-     * @param side  The side to extract the bundled redstone output from.
-     * @return If there is a block capable of emitting bundled redstone at the location, it's signal (0-65535) will be returned.
-     * If there is no block capable of emitting bundled redstone at the location, -1 will be returned.
+     * @param pos The position this block is at.
+     * @param side The side to extract the bundled redstone output from.
+     * @return If there is a block capable of emitting bundled redstone at the location, it's signal (0-65535) will be returned. If there is no block
+     *     capable of emitting bundled redstone at the location, -1 will be returned.
      * @see IBundledRedstoneProvider
      */
-    public static int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
-    {
-        return getInstance().getBundledRedstoneOutput( world, pos, side );
+    public static int getBundledRedstoneOutput(@Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side) {
+        return getInstance().getBundledRedstoneOutput(world, pos, side);
     }
 
     /**
-     * Registers a media provider to provide {@link IMedia} implementations for Items
+     * Registers a media provider to provide {@link IMedia} implementations for Items.
      *
      * @param provider The media provider to register.
      * @see IMediaProvider
      */
-    public static void registerMediaProvider( @Nonnull IMediaProvider provider )
-    {
-        getInstance().registerMediaProvider( provider );
+    public static void registerMediaProvider(@Nonnull IMediaProvider provider) {
+        getInstance().registerMediaProvider(provider);
     }
 
-    public static void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade )
-    {
-        getInstance().registerPocketUpgrade( upgrade );
+    public static void registerPocketUpgrade(@Nonnull IPocketUpgrade upgrade) {
+        getInstance().registerPocketUpgrade(upgrade);
     }
 
     /**
@@ -209,96 +187,73 @@ public final class ComputerCraftAPI
      *
      * @return The global wireless network, or {@code null} if it could not be fetched.
      */
-    public static IPacketNetwork getWirelessNetwork()
-    {
+    public static IPacketNetwork getWirelessNetwork() {
         return getInstance().getWirelessNetwork();
     }
 
-    public static void registerAPIFactory( @Nonnull ILuaAPIFactory factory )
-    {
-        getInstance().registerAPIFactory( factory );
+    public static void registerAPIFactory(@Nonnull ILuaAPIFactory factory) {
+        getInstance().registerAPIFactory(factory);
     }
 
     /**
-     * Construct a new wired node for a given wired element
+     * Construct a new wired node for a given wired element.
      *
      * @param element The element to construct it for
      * @return The element's node
      * @see IWiredElement#getNode()
      */
     @Nonnull
-    public static IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )
-    {
-        return getInstance().createWiredNodeForElement( element );
+    public static IWiredNode createWiredNodeForElement(@Nonnull IWiredElement element) {
+        return getInstance().createWiredNodeForElement(element);
     }
 
     /**
-     * Get the wired network element for a block in world
+     * Get the wired network element for a block in world.
      *
      * @param world The world the block exists in
-     * @param pos   The position the block exists in
-     * @param side  The side to extract the network element from
+     * @param pos The position the block exists in
+     * @param side The side to extract the network element from
      * @return The element's node
      * @see IWiredElement#getNode()
      */
-    @Nonnull
-    public static LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
-    {
-        return getInstance().getWiredElementAt( world, pos, side );
+    @Nullable
+    public static IWiredElement getWiredElementAt(@Nonnull BlockView world, @Nonnull BlockPos pos, @Nonnull Direction side) {
+        return getInstance().getWiredElementAt(world, pos, side);
     }
 
-    private static IComputerCraftAPI instance;
-
-    @Nonnull
-    private static IComputerCraftAPI getInstance()
-    {
-        if( instance != null ) return instance;
-
-        try
-        {
-            return instance = (IComputerCraftAPI) Class.forName( "dan200.computercraft.ComputerCraftAPIImpl" )
-                .getField( "INSTANCE" ).get( null );
-        }
-        catch( ReflectiveOperationException e )
-        {
-            throw new IllegalStateException( "Cannot find ComputerCraft API", e );
-        }
-    }
-
-    public interface IComputerCraftAPI
-    {
+    public interface IComputerCraftAPI {
         @Nonnull
         String getInstalledVersion();
 
-        int createUniqueNumberedSaveDir( @Nonnull World world, @Nonnull String parentSubPath );
+        int createUniqueNumberedSaveDir(@Nonnull World world, @Nonnull String parentSubPath);
 
         @Nullable
-        IWritableMount createSaveDirMount( @Nonnull World world, @Nonnull String subPath, long capacity );
+        IWritableMount createSaveDirMount(@Nonnull World world, @Nonnull String subPath, long capacity);
 
         @Nullable
-        IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath );
+        IMount createResourceMount(@Nonnull String domain, @Nonnull String subPath);
 
-        void registerPeripheralProvider( @Nonnull IPeripheralProvider provider );
+        void registerPeripheralProvider(@Nonnull IPeripheralProvider provider);
 
-        void registerTurtleUpgrade( @Nonnull ITurtleUpgrade upgrade );
+        void registerTurtleUpgrade(@Nonnull ITurtleUpgrade upgrade);
 
-        void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider );
+        void registerBundledRedstoneProvider(@Nonnull IBundledRedstoneProvider provider);
 
-        int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+        int getBundledRedstoneOutput(@Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side);
 
-        void registerMediaProvider( @Nonnull IMediaProvider provider );
+        void registerMediaProvider(@Nonnull IMediaProvider provider);
 
-        void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade );
+        void registerPocketUpgrade(@Nonnull IPocketUpgrade upgrade);
 
         @Nonnull
         IPacketNetwork getWirelessNetwork();
 
-        void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
+        void registerAPIFactory(@Nonnull ILuaAPIFactory factory);
 
         @Nonnull
-        IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
+        IWiredNode createWiredNodeForElement(@Nonnull IWiredElement element);
 
-        @Nonnull
-        LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+        @Nullable
+        IWiredElement getWiredElementAt(@Nonnull BlockView world, @Nonnull BlockPos pos, @Nonnull Direction side);
     }
 }

src/main/java/dan200/computercraft/api/client/TransformedModel.java

@@ -0,0 +1,83 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.client;
+
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.mixin.AffineTransformationAccess;
+
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.BakedModelManager;
+import net.minecraft.client.util.ModelIdentifier;
+import net.minecraft.client.util.math.AffineTransformation;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.item.ItemStack;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+/**
+ * A model to render, combined with a transformation matrix to apply.
+ */
+@Environment (EnvType.CLIENT)
+public final class TransformedModel {
+    private final BakedModel model;
+    private final AffineTransformation matrix;
+
+    public TransformedModel(@Nonnull BakedModel model, @Nonnull AffineTransformation matrix) {
+        this.model = Objects.requireNonNull(model);
+        this.matrix = Objects.requireNonNull(matrix);
+    }
+
+    public TransformedModel(@Nonnull BakedModel model) {
+        this.model = Objects.requireNonNull(model);
+        this.matrix = AffineTransformation.identity();
+    }
+
+    public static TransformedModel of(@Nonnull ModelIdentifier location) {
+        BakedModelManager modelManager = MinecraftClient.getInstance()
+                                                        .getBakedModelManager();
+        return new TransformedModel(modelManager.getModel(location));
+    }
+
+    public static TransformedModel of(@Nonnull ItemStack item, @Nonnull AffineTransformation transform) {
+        BakedModel model = MinecraftClient.getInstance()
+                                          .getItemRenderer()
+                                          .getModels()
+                                          .getModel(item);
+        return new TransformedModel(model, transform);
+    }
+
+    @Nonnull
+    public BakedModel getModel() {
+        return this.model;
+    }
+
+    @Nonnull
+    public AffineTransformation getMatrix() {
+        return this.matrix;
+    }
+
+    public void push(MatrixStack matrixStack) {
+        matrixStack.push();
+
+        AffineTransformationAccess access = (AffineTransformationAccess) (Object) this.matrix;
+        if (access.getTranslation() != null)
+            matrixStack.translate(access.getTranslation().getX(), access.getTranslation().getY(), access.getTranslation().getZ());
+
+        matrixStack.multiply(this.matrix.getRotation2());
+
+        if (access.getScale() != null)
+            matrixStack.scale(access.getScale().getX(), access.getScale().getY(), access.getScale().getZ());
+
+        if (access.getRotation1() != null)
+            matrixStack.multiply(access.getRotation1());
+    }
+}

src/main/java/dan200/computercraft/api/filesystem/FileAttributes.java

@@ -0,0 +1,71 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.filesystem;
+
+import java.nio.file.attribute.BasicFileAttributes;
+import java.nio.file.attribute.FileTime;
+import java.time.Instant;
+
+/**
+ * A simple version of {@link BasicFileAttributes}, which provides what information a {@link IMount} already exposes.
+ */
+final class FileAttributes implements BasicFileAttributes {
+    private static final FileTime EPOCH = FileTime.from(Instant.EPOCH);
+
+    private final boolean isDirectory;
+    private final long size;
+
+    FileAttributes(boolean isDirectory, long size) {
+        this.isDirectory = isDirectory;
+        this.size = size;
+    }
+
+    @Override
+    public FileTime lastModifiedTime() {
+        return EPOCH;
+    }
+
+    @Override
+    public FileTime lastAccessTime() {
+        return EPOCH;
+    }
+
+    @Override
+    public FileTime creationTime() {
+        return EPOCH;
+    }
+
+    @Override
+    public boolean isRegularFile() {
+        return !this.isDirectory;
+    }
+
+    @Override
+    public boolean isDirectory() {
+        return this.isDirectory;
+    }
+
+    @Override
+    public boolean isSymbolicLink() {
+        return false;
+    }
+
+    @Override
+    public boolean isOther() {
+        return false;
+    }
+
+    @Override
+    public long size() {
+        return this.size;
+    }
+
+    @Override
+    public Object fileKey() {
+        return null;
+    }
+}

src/main/java/dan200/computercraft/api/filesystem/FileOperationException.java

@@ -0,0 +1,39 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.filesystem;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * An {@link IOException} which occurred on a specific file.
+ *
+ * This may be thrown from a {@link IMount} or {@link IWritableMount} to give more information about a failure.
+ */
+public class FileOperationException extends IOException {
+    private static final long serialVersionUID = -8809108200853029849L;
+
+    private final String filename;
+
+    public FileOperationException(@Nullable String filename, @Nonnull String message) {
+        super(Objects.requireNonNull(message, "message cannot be null"));
+        this.filename = filename;
+    }
+
+    public FileOperationException(@Nonnull String message) {
+        super(Objects.requireNonNull(message, "message cannot be null"));
+        this.filename = null;
+    }
+
+    @Nullable
+    public String getFilename() {
+        return this.filename;
+    }
+}

src/main/java/dan200/computercraft/api/filesystem/IFileSystem.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -13,32 +13,31 @@ import java.io.IOException;
  *
  * This exists for use by various APIs - one should not attempt to mount it.
  */
-public interface IFileSystem extends IWritableMount
-{
+public interface IFileSystem extends IWritableMount {
     /**
      * Combine two paths together, reducing them into a normalised form.
      *
-     * @param path  The main path.
+     * @param path The main path.
      * @param child The path to append.
      * @return The combined, normalised path.
      */
-    String combine( String path, String child );
+    String combine(String path, String child);
 
     /**
      * Copy files from one location to another.
      *
      * @param from The location to copy from.
-     * @param to   The location to copy to. This should not exist.
+     * @param to The location to copy to. This should not exist.
      * @throws IOException If the copy failed.
      */
-    void copy( String from, String to ) throws IOException;
+    void copy(String from, String to) throws IOException;
 
     /**
      * Move files from one location to another.
      *
      * @param from The location to move from.
-     * @param to   The location to move to. This should not exist.
+     * @param to The location to move to. This should not exist.
      * @throws IOException If the move failed.
      */
-    void move( String from, String to ) throws IOException;
+    void move(String from, String to) throws IOException;
 }

src/main/java/dan200/computercraft/api/filesystem/IMount.java

@@ -1,37 +1,70 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.filesystem;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-import dan200.computercraft.api.peripheral.IComputerAccess;
-import net.minecraft.world.World;
-
-import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
-import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.peripheral.IComputerAccess;
+
+import net.minecraft.world.World;
+
 /**
- * Represents a read only part of a virtual filesystem that can be mounted onto a computer using
- * {@link IComputerAccess#mount(String, IMount)}
+ * Represents a read only part of a virtual filesystem that can be mounted onto a computer using {@link IComputerAccess#mount(String, IMount)}.
  *
- * Ready made implementations of this interface can be created using
- * {@link ComputerCraftAPI#createSaveDirMount(World, String, long)} or
- * {@link ComputerCraftAPI#createResourceMount(Class, String, String)}, or you're free to implement it yourselves!
+ * Ready made implementations of this interface can be created using {@link ComputerCraftAPI#createSaveDirMount(World, String, long)} or {@link
+ * ComputerCraftAPI#createResourceMount(String, String)}, or you're free to implement it yourselves!
  *
  * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
- * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+ * @see ComputerCraftAPI#createResourceMount(String, String)
  * @see IComputerAccess#mount(String, IMount)
  * @see IWritableMount
  */
-public interface IMount
-{
+public interface IMount {
+    /**
+     * Returns the file names of all the files in a directory.
+     *
+     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprograms".
+     * @param contents A list of strings. Add all the file names to this list.
+     * @throws IOException If the file was not a directory, or could not be listed.
+     */
+    void list(@Nonnull String path, @Nonnull List<String> contents) throws IOException;
+
+    /**
+     * Opens a file with a given path, and returns an {@link ReadableByteChannel} representing its contents.
+     *
+     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
+     * @return A channel representing the contents of the file. If the channel implements {@link java.nio.channels.SeekableByteChannel}, one will be able to
+     *     seek to arbitrary positions when using binary mode.
+     * @throws IOException If the file does not exist, or could not be opened.
+     */
+    @Nonnull
+    ReadableByteChannel openForRead(@Nonnull String path) throws IOException;
+
+    /**
+     * Get attributes about the given file.
+     *
+     * @param path The path to query.
+     * @return File attributes for the given file.
+     * @throws IOException If the file does not exist, or attributes could not be fetched.
+     */
+    @Nonnull
+    default BasicFileAttributes getAttributes(@Nonnull String path) throws IOException {
+        if (!this.exists(path)) {
+            throw new FileOperationException(path, "No such file");
+        }
+        return new FileAttributes(this.isDirectory(path), this.getSize(path));
+    }
+
     /**
      * Returns whether a file with a given path exists or not.
      *
@@ -39,7 +72,7 @@ public interface IMount
      * @return If the file exists.
      * @throws IOException If an error occurs when checking the existence of the file.
      */
-    boolean exists( @Nonnull String path ) throws IOException;
+    boolean exists(@Nonnull String path) throws IOException;
 
     /**
      * Returns whether a file with a given path is a directory or not.
@@ -48,51 +81,14 @@ public interface IMount
      * @return If the file exists and is a directory
      * @throws IOException If an error occurs when checking whether the file is a directory.
      */
-    boolean isDirectory( @Nonnull String path ) throws IOException;
+    boolean isDirectory(@Nonnull String path) throws IOException;
 
     /**
-     * Returns the file names of all the files in a directory.
-     *
-     * @param path     A file path in normalised format, relative to the mount location. ie: "programs/myprograms".
-     * @param contents A list of strings. Add all the file names to this list.
-     * @throws IOException If the file was not a directory, or could not be listed.
-     */
-    void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException;
-
-    /**
-     * Returns the size of a file with a given path, in bytes
+     * Returns the size of a file with a given path, in bytes.
      *
      * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
      * @return The size of the file, in bytes.
      * @throws IOException If the file does not exist, or its size could not be determined.
      */
-    long getSize( @Nonnull String path ) throws IOException;
-
-    /**
-     * Opens a file with a given path, and returns an {@link InputStream} representing its contents.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream representing the contents of the file.
-     * @throws IOException If the file does not exist, or could not be opened.
-     * @deprecated Use {@link #openChannelForRead(String)} instead
-     */
-    @Nonnull
-    @Deprecated
-    InputStream openForRead( @Nonnull String path ) throws IOException;
-
-    /**
-     * Opens a file with a given path, and returns an {@link ReadableByteChannel} representing its contents.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A channel representing the contents of the file. If the channel implements
-     * {@link java.nio.channels.SeekableByteChannel}, one will be able to seek to arbitrary positions when using binary
-     * mode.
-     * @throws IOException If the file does not exist, or could not be opened.
-     */
-    @Nonnull
-    @SuppressWarnings( "deprecation" )
-    default ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForRead( path ) );
-    }
+    long getSize(@Nonnull String path) throws IOException;
 }

src/main/java/dan200/computercraft/api/filesystem/IWritableMount.java

@@ -1,42 +1,43 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.filesystem;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-import dan200.computercraft.api.peripheral.IComputerAccess;
-import net.minecraft.world.World;
-
-import javax.annotation.Nonnull;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.channels.Channels;
 import java.nio.channels.WritableByteChannel;
+import java.util.OptionalLong;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.peripheral.IComputerAccess;
+
+import net.minecraft.world.World;
 
 /**
- * Represents a part of a virtual filesystem that can be mounted onto a computer using {@link IComputerAccess#mount(String, IMount)}
- * or {@link IComputerAccess#mountWritable(String, IWritableMount)}, that can also be written to.
+ * Represents a part of a virtual filesystem that can be mounted onto a computer using {@link IComputerAccess#mount(String, IMount)} or {@link
+ * IComputerAccess#mountWritable(String, IWritableMount)}, that can also be written to.
  *
- * Ready made implementations of this interface can be created using
- * {@link ComputerCraftAPI#createSaveDirMount(World, String, long)}, or you're free to implement it yourselves!
+ * Ready made implementations of this interface can be created using {@link ComputerCraftAPI#createSaveDirMount(World, String, long)}, or you're free to
+ * implement it yourselves!
  *
  * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
  * @see IComputerAccess#mount(String, IMount)
  * @see IComputerAccess#mountWritable(String, IWritableMount)
  * @see IMount
  */
-public interface IWritableMount extends IMount
-{
+public interface IWritableMount extends IMount {
     /**
      * Creates a directory at a given path inside the virtual file system.
      *
      * @param path A file path in normalised format, relative to the mount location. ie: "programs/mynewprograms".
      * @throws IOException If the directory already exists or could not be created.
      */
-    void makeDirectory( @Nonnull String path ) throws IOException;
+    void makeDirectory(@Nonnull String path) throws IOException;
 
     /**
      * Deletes a directory at a given path inside the virtual file system.
@@ -44,68 +45,46 @@ public interface IWritableMount extends IMount
      * @param path A file path in normalised format, relative to the mount location. ie: "programs/myoldprograms".
      * @throws IOException If the file does not exist or could not be deleted.
      */
-    void delete( @Nonnull String path ) throws IOException;
+    void delete(@Nonnull String path) throws IOException;
 
     /**
      * Opens a file with a given path, and returns an {@link OutputStream} for writing to it.
      *
      * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to
-     * @throws IOException If the file could not be opened for writing.
-     * @deprecated Use {@link #openChannelForWrite(String)} instead.
-     */
-    @Nonnull
-    @Deprecated
-    OutputStream openForWrite( @Nonnull String path ) throws IOException;
-
-    /**
-     * Opens a file with a given path, and returns an {@link OutputStream} for writing to it.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to. If the channel implements {@link java.nio.channels.SeekableByteChannel}, one
-     * will be able to seek to arbitrary positions when using binary mode.
+     * @return A stream for writing to. If the channel implements {@link java.nio.channels.SeekableByteChannel}, one will be able to seek to arbitrary
+     *     positions when using binary mode.
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    @SuppressWarnings( "deprecation" )
-    default WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForWrite( path ) );
-    }
+    WritableByteChannel openForWrite(@Nonnull String path) throws IOException;
 
     /**
      * Opens a file with a given path, and returns an {@link OutputStream} for appending to it.
      *
      * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to.
-     * @throws IOException If the file could not be opened for writing.
-     * @deprecated Use {@link #openChannelForAppend(String)} instead.
-     */
-    @Nonnull
-    @Deprecated
-    OutputStream openForAppend( @Nonnull String path ) throws IOException;
-
-    /**
-     * Opens a file with a given path, and returns an {@link OutputStream} for appending to it.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to. If the channel implements {@link java.nio.channels.SeekableByteChannel}, one
-     * will be able to seek to arbitrary positions when using binary mode.
+     * @return A stream for writing to. If the channel implements {@link java.nio.channels.SeekableByteChannel}, one will be able to seek to arbitrary
+     *     positions when using binary mode.
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    @SuppressWarnings( "deprecation" )
-    default WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForAppend( path ) );
-    }
+    WritableByteChannel openForAppend(@Nonnull String path) throws IOException;
 
     /**
-     * Get the amount of free space on the mount, in bytes. You should decrease this value as the user writes to the
-     * mount, and write operations should fail once it reaches zero.
+     * Get the amount of free space on the mount, in bytes. You should decrease this value as the user writes to the mount, and write operations should fail
+     * once it reaches zero.
      *
      * @return The amount of free space, in bytes.
      * @throws IOException If the remaining space could not be computed.
      */
     long getRemainingSpace() throws IOException;
+
+    /**
+     * Get the capacity of this mount. This should be equal to the size of all files/directories on this mount, minus the {@link #getRemainingSpace()}.
+     *
+     * @return The capacity of this mount, in bytes.
+     */
+    @Nonnull
+    default OptionalLong getCapacity() {
+        return OptionalLong.empty();
+    }
 }

src/main/java/dan200/computercraft/api/lua/IArguments.java

@@ -0,0 +1,418 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import static dan200.computercraft.api.lua.LuaValues.checkFinite;
+
+import java.nio.ByteBuffer;
+import java.util.Map;
+import java.util.Optional;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * The arguments passed to a function.
+ */
+public interface IArguments {
+    /**
+     * Drop a number of arguments. The returned arguments instance will access arguments at position {@code i + count}, rather than {@code i}. However,
+     * errors will still use the given argument index.
+     *
+     * @param count The number of arguments to drop.
+     * @return The new {@link IArguments} instance.
+     */
+    IArguments drop(int count);
+
+    default Object[] getAll() {
+        Object[] result = new Object[this.count()];
+        for (int i = 0; i < result.length; i++) {
+            result[i] = this.get(i);
+        }
+        return result;
+    }
+
+    /**
+     * Get the number of arguments passed to this function.
+     *
+     * @return The number of passed arguments.
+     */
+    int count();
+
+    /**
+     * Get the argument at the specific index. The returned value must obey the following conversion rules:
+     *
+     * <ul>
+     *   <li>Lua values of type "string" will be represented by a {@link String}.</li>
+     *   <li>Lua values of type "number" will be represented by a {@link Number}.</li>
+     *   <li>Lua values of type "boolean" will be represented by a {@link Boolean}.</li>
+     *   <li>Lua values of type "table" will be represented by a {@link Map}.</li>
+     *   <li>Lua values of any other type will be represented by a {@code null} value.</li>
+     * </ul>
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@code null} if not present.
+     */
+    @Nullable
+    Object get(int index);
+
+    /**
+     * Get an argument as an integer.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not an integer.
+     */
+    default int getInt(int index) throws LuaException {
+        return (int) this.getLong(index);
+    }
+
+    /**
+     * Get an argument as a long.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a long.
+     */
+    default long getLong(int index) throws LuaException {
+        Object value = this.get(index);
+        if (!(value instanceof Number)) {
+            throw LuaValues.badArgumentOf(index, "number", value);
+        }
+        return LuaValues.checkFiniteNum(index, (Number) value)
+                        .longValue();
+    }
+
+    /**
+     * Get an argument as a finite number (not infinite or NaN).
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not finite.
+     */
+    default double getFiniteDouble(int index) throws LuaException {
+        return checkFinite(index, this.getDouble(index));
+    }
+
+    /**
+     * Get an argument as a double.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a number.
+     * @see #getFiniteDouble(int) if you require this to be finite (i.e. not infinite or NaN).
+     */
+    default double getDouble(int index) throws LuaException {
+        Object value = this.get(index);
+        if (!(value instanceof Number)) {
+            throw LuaValues.badArgumentOf(index, "number", value);
+        }
+        return ((Number) value).doubleValue();
+    }
+
+    /**
+     * Get an argument as a boolean.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a boolean.
+     */
+    default boolean getBoolean(int index) throws LuaException {
+        Object value = this.get(index);
+        if (!(value instanceof Boolean)) {
+            throw LuaValues.badArgumentOf(index, "boolean", value);
+        }
+        return (Boolean) value;
+    }
+
+    /**
+     * Get a string argument as a byte array.
+     *
+     * @param index The argument number.
+     * @return The argument's value. This is a <em>read only</em> buffer.
+     * @throws LuaException If the value is not a string.
+     */
+    @Nonnull
+    default ByteBuffer getBytes(int index) throws LuaException {
+        return LuaValues.encode(this.getString(index));
+    }
+
+    /**
+     * Get an argument as a string.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a string.
+     */
+    @Nonnull
+    default String getString(int index) throws LuaException {
+        Object value = this.get(index);
+        if (!(value instanceof String)) {
+            throw LuaValues.badArgumentOf(index, "string", value);
+        }
+        return (String) value;
+    }
+
+    /**
+     * Get a string argument as an enum value.
+     *
+     * @param index The argument number.
+     * @param klass The type of enum to parse.
+     * @param <T> The type of enum to parse.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a string or not a valid option for this enum.
+     */
+    @Nonnull
+    default <T extends Enum<T>> T getEnum(int index, Class<T> klass) throws LuaException {
+        return LuaValues.checkEnum(index, klass, this.getString(index));
+    }
+
+    /**
+     * Get an argument as a table.
+     *
+     * @param index The argument number.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a table.
+     */
+    @Nonnull
+    default Map<?, ?> getTable(int index) throws LuaException {
+        Object value = this.get(index);
+        if (!(value instanceof Map)) {
+            throw LuaValues.badArgumentOf(index, "table", value);
+        }
+        return (Map<?, ?>) value;
+    }
+
+    /**
+     * Get a string argument as a byte array.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present. This is a <em>read only</em> buffer.
+     * @throws LuaException If the value is not a string.
+     */
+    default Optional<ByteBuffer> optBytes(int index) throws LuaException {
+        return this.optString(index).map(LuaValues::encode);
+    }
+
+    /**
+     * Get an argument as a string.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a string.
+     */
+    default Optional<String> optString(int index) throws LuaException {
+        Object value = this.get(index);
+        if (value == null) {
+            return Optional.empty();
+        }
+        if (!(value instanceof String)) {
+            throw LuaValues.badArgumentOf(index, "string", value);
+        }
+        return Optional.of((String) value);
+    }
+
+    /**
+     * Get a string argument as an enum value.
+     *
+     * @param index The argument number.
+     * @param klass The type of enum to parse.
+     * @param <T> The type of enum to parse.
+     * @return The argument's value.
+     * @throws LuaException If the value is not a string or not a valid option for this enum.
+     */
+    @Nonnull
+    default <T extends Enum<T>> Optional<T> optEnum(int index, Class<T> klass) throws LuaException {
+        Optional<String> str = this.optString(index);
+        return str.isPresent() ? Optional.of(LuaValues.checkEnum(index, klass, str.get())) : Optional.empty();
+    }
+
+    /**
+     * Get an argument as a double.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a number.
+     */
+    default double optDouble(int index, double def) throws LuaException {
+        return this.optDouble(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a double.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a number.
+     */
+    @Nonnull
+    default Optional<Double> optDouble(int index) throws LuaException {
+        Object value = this.get(index);
+        if (value == null) {
+            return Optional.empty();
+        }
+        if (!(value instanceof Number)) {
+            throw LuaValues.badArgumentOf(index, "number", value);
+        }
+        return Optional.of(((Number) value).doubleValue());
+    }
+
+    /**
+     * Get an argument as an int.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a number.
+     */
+    default int optInt(int index, int def) throws LuaException {
+        return this.optInt(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as an int.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a number.
+     */
+    @Nonnull
+    default Optional<Integer> optInt(int index) throws LuaException {
+        return this.optLong(index).map(Long::intValue);
+    }
+
+    /**
+     * Get an argument as a long.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a number.
+     */
+    default Optional<Long> optLong(int index) throws LuaException {
+        Object value = this.get(index);
+        if (value == null) {
+            return Optional.empty();
+        }
+        if (!(value instanceof Number)) {
+            throw LuaValues.badArgumentOf(index, "number", value);
+        }
+        return Optional.of(LuaValues.checkFiniteNum(index, (Number) value)
+                                    .longValue());
+    }
+
+    /**
+     * Get an argument as a long.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a number.
+     */
+    default long optLong(int index, long def) throws LuaException {
+        return this.optLong(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a finite number (not infinite or NaN).
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not finite.
+     */
+    default double optFiniteDouble(int index, double def) throws LuaException {
+        return this.optFiniteDouble(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a finite number (not infinite or NaN).
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not finite.
+     */
+    default Optional<Double> optFiniteDouble(int index) throws LuaException {
+        Optional<Double> value = this.optDouble(index);
+        if (value.isPresent()) {
+            LuaValues.checkFiniteNum(index, value.get());
+        }
+        return value;
+    }
+
+    /**
+     * Get an argument as a boolean.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a boolean.
+     */
+    default boolean optBoolean(int index, boolean def) throws LuaException {
+        return this.optBoolean(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a boolean.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a boolean.
+     */
+    default Optional<Boolean> optBoolean(int index) throws LuaException {
+        Object value = this.get(index);
+        if (value == null) {
+            return Optional.empty();
+        }
+        if (!(value instanceof Boolean)) {
+            throw LuaValues.badArgumentOf(index, "boolean", value);
+        }
+        return Optional.of((Boolean) value);
+    }
+
+    /**
+     * Get an argument as a string.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a string.
+     */
+    default String optString(int index, String def) throws LuaException {
+        return this.optString(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a table.
+     *
+     * @param index The argument number.
+     * @param def The default value, if this argument is not given.
+     * @return The argument's value, or {@code def} if none was provided.
+     * @throws LuaException If the value is not a table.
+     */
+    default Map<?, ?> optTable(int index, Map<Object, Object> def) throws LuaException {
+        return this.optTable(index).orElse(def);
+    }
+
+    /**
+     * Get an argument as a table.
+     *
+     * @param index The argument number.
+     * @return The argument's value, or {@link Optional#empty()} if not present.
+     * @throws LuaException If the value is not a table.
+     */
+    default Optional<Map<?, ?>> optTable(int index) throws LuaException {
+        Object value = this.get(index);
+        if (value == null) {
+            return Optional.empty();
+        }
+        if (!(value instanceof Map)) {
+            throw LuaValues.badArgumentOf(index, "map", value);
+        }
+        return Optional.of((Map<?, ?>) value);
+    }
+}

src/main/java/dan200/computercraft/api/lua/IComputerSystem.java

@@ -1,22 +1,20 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.lua;
 
+import javax.annotation.Nullable;
+
 import dan200.computercraft.api.filesystem.IFileSystem;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 
-import javax.annotation.Nullable;
-
 /**
- * An interface passed to {@link ILuaAPIFactory} in order to provide additional information
- * about a computer.
+ * An interface passed to {@link ILuaAPIFactory} in order to provide additional information about a computer.
  */
-public interface IComputerSystem extends IComputerAccess
-{
+public interface IComputerSystem extends IComputerAccess {
     /**
      * Get the file system for this computer.
      *
@@ -26,7 +24,7 @@ public interface IComputerSystem extends IComputerAccess
     IFileSystem getFileSystem();
 
     /**
-     * Get the label for this computer
+     * Get the label for this computer.
      *
      * @return This computer's label, or {@code null} if it is not set.
      */

src/main/java/dan200/computercraft/api/lua/IDynamicLuaObject.java

@@ -0,0 +1,40 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.peripheral.IDynamicPeripheral;
+
+/**
+ * An interface for representing custom objects returned by peripherals or other Lua objects.
+ *
+ * Generally, one does not need to implement this type - it is sufficient to return an object with some methods annotated with {@link LuaFunction}. {@link
+ * IDynamicLuaObject} is useful when you wish your available methods to change at runtime.
+ */
+public interface IDynamicLuaObject {
+    /**
+     * Get the names of the methods that this object implements. This should not change over the course of the object's lifetime.
+     *
+     * @return The method names this object provides.
+     * @see IDynamicPeripheral#getMethodNames()
+     */
+    @Nonnull
+    String[] getMethodNames();
+
+    /**
+     * Called when a user calls one of the methods that this object implements.
+     *
+     * @param context The context of the currently running lua thread. This can be used to wait for events or otherwise yield.
+     * @param method An integer identifying which method index from {@link #getMethodNames()} the computer wishes to call.
+     * @param arguments The arguments for this method.
+     * @return The result of this function. Either an immediate value ({@link MethodResult#of(Object...)} or an instruction to yield.
+     * @throws LuaException If the function threw an exception.
+     */
+    @Nonnull
+    MethodResult callMethod(@Nonnull ILuaContext context, int method, @Nonnull IArguments arguments) throws LuaException;
+}

src/main/java/dan200/computercraft/api/lua/ILuaAPI.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -9,16 +9,16 @@ package dan200.computercraft.api.lua;
 import dan200.computercraft.api.ComputerCraftAPI;
 
 /**
- * Represents a {@link ILuaObject} which is stored as a global variable on computer startup.
+ * Represents a Lua object which is stored as a global variable on computer startup. This must either provide {@link LuaFunction} annotated functions or
+ * implement {@link IDynamicLuaObject}.
  *
- * Before implementing this interface, consider alternative methods of providing methods. It is generally preferred
- * to use peripherals to provide functionality to users.
+ * Before implementing this interface, consider alternative methods of providing methods. It is generally preferred to use peripherals to provide
+ * functionality to users.
  *
  * @see ILuaAPIFactory
  * @see ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
  */
-public interface ILuaAPI extends ILuaObject
-{
+public interface ILuaAPI {
     /**
      * Get the globals this API will be assigned to. This will override any other global, so you should
      *
@@ -31,15 +31,13 @@ public interface ILuaAPI extends ILuaObject
      *
      * One should only interact with the file system.
      */
-    default void startup()
-    {
+    default void startup() {
     }
 
     /**
      * Called every time the computer is ticked. This can be used to process various.
      */
-    default void update()
-    {
+    default void update() {
     }
 
     /**
@@ -47,7 +45,6 @@ public interface ILuaAPI extends ILuaObject
      *
      * This should reset the state of the object, disposing any remaining file handles, or other resources.
      */
-    default void shutdown()
-    {
+    default void shutdown() {
     }
 }

src/main/java/dan200/computercraft/api/lua/ILuaAPIFactory.java

@@ -1,16 +1,16 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.lua;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import dan200.computercraft.api.ComputerCraftAPI;
+
 /**
  * Construct an {@link ILuaAPI} for a specific computer.
  *
@@ -18,8 +18,7 @@ import javax.annotation.Nullable;
  * @see ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
  */
 @FunctionalInterface
-public interface ILuaAPIFactory
-{
+public interface ILuaAPIFactory {
     /**
      * Create a new API instance for a given computer.
      *
@@ -27,5 +26,5 @@ public interface ILuaAPIFactory
      * @return The created API, or {@code null} if one should not be injected.
      */
     @Nullable
-    ILuaAPI create( @Nonnull IComputerSystem computer );
+    ILuaAPI create(@Nonnull IComputerSystem computer);
 }

src/main/java/dan200/computercraft/api/lua/ILuaCallback.java

@@ -0,0 +1,26 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import javax.annotation.Nonnull;
+
+/**
+ * A continuation which is called when this coroutine is resumed.
+ *
+ * @see MethodResult#yield(Object[], ILuaCallback)
+ */
+public interface ILuaCallback {
+    /**
+     * Resume this coroutine.
+     *
+     * @param args The result of resuming this coroutine. These will have the same form as described in {@link LuaFunction}.
+     * @return The result of this continuation. Either the result to return to the callee, or another yield.
+     * @throws LuaException On an error.
+     */
+    @Nonnull
+    MethodResult resume(Object[] args) throws LuaException;
+}

src/main/java/dan200/computercraft/api/lua/ILuaContext.java

@@ -1,105 +1,29 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.lua;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 
 /**
- * An interface passed to peripherals and {@link ILuaObject}s by computers or turtles, providing methods
- * that allow the peripheral call to wait for events before returning, just like in lua. This is very useful if you need
- * to signal work to be performed on the main thread, and don't want to return until the work has been completed.
+ * An interface passed to peripherals and {@link IDynamicLuaObject}s by computers or turtles, providing methods that allow the peripheral call to interface
+ * with the computer.
  */
-public interface ILuaContext
-{
+public interface ILuaContext {
     /**
-     * Wait for an event to occur on the computer, suspending the thread until it arises. This method is exactly
-     * equivalent to {@code os.pullEvent()} in lua.
+     * Queue a task to be executed on the main server thread at the beginning of next tick, but do not wait for it to complete. This should be used when you
+     * need to interact with the world in a thread-safe manner but do not care about the result or you wish to run asynchronously.
      *
-     * @param filter A specific event to wait for, or null to wait for any event.
-     * @return An object array containing the name of the event that occurred, and any event parameters.
-     * @throws LuaException         If the user presses CTRL+T to terminate the current program while pullEvent() is
-     *                              waiting for an event, a "Terminated" exception will be thrown here.
-     *
-     *                              Do not attempt to catch this exception. You should use {@link #pullEventRaw(String)}
-     *                              should you wish to disable termination.
-     * @throws InterruptedException If the user shuts down or reboots the computer while pullEvent() is waiting for an
-     *                              event, InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.
-     */
-    @Nonnull
-    default Object[] pullEvent( @Nullable String filter ) throws LuaException, InterruptedException
-    {
-        Object[] results = pullEventRaw( filter );
-        if( results.length >= 1 && results[0].equals( "terminate" ) ) throw new LuaException( "Terminated", 0 );
-        return results;
-    }
-
-    /**
-     * The same as {@link #pullEvent(String)}, except "terminated" events are ignored. Only use this if you want to
-     * prevent program termination, which is not recommended. This method is exactly equivalent to
-     * {@code os.pullEventRaw()} in lua.
-     *
-     * @param filter A specific event to wait for, or null to wait for any event.
-     * @return An object array containing the name of the event that occurred, and any event parameters.
-     * @throws InterruptedException If the user shuts down or reboots the computer while pullEventRaw() is waiting for
-     *                              an event, InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.
-     * @see #pullEvent(String)
-     */
-    @Nonnull
-    default Object[] pullEventRaw( @Nullable String filter ) throws InterruptedException
-    {
-        return yield( new Object[] { filter } );
-    }
-
-    /**
-     * Yield the current coroutine with some arguments until it is resumed. This method is exactly equivalent to
-     * {@code coroutine.yield()} in lua. Use {@code pullEvent()} if you wish to wait for events.
-     *
-     * @param arguments An object array containing the arguments to pass to coroutine.yield()
-     * @return An object array containing the return values from coroutine.yield()
-     * @throws InterruptedException If the user shuts down or reboots the computer the coroutine is suspended,
-     *                              InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.
-     * @see #pullEvent(String)
-     */
-    @Nonnull
-    Object[] yield( @Nullable Object[] arguments ) throws InterruptedException;
-
-    /**
-     * Queue a task to be executed on the main server thread at the beginning of next tick, waiting for it to complete.
-     * This should be used when you need to interact with the world in a thread-safe manner.
-     *
-     * Note that the return values of your task are handled as events, meaning more complex objects such as maps or
-     * {@link ILuaObject} will not preserve their identities.
-     *
-     * @param task The task to execute on the main thread.
-     * @return The objects returned by {@code task}.
-     * @throws LuaException         If the task could not be queued, or if the task threw an exception.
-     * @throws InterruptedException If the user shuts down or reboots the computer the coroutine is suspended,
-     *                              InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.
-     */
-    @Nullable
-    Object[] executeMainThreadTask( @Nonnull ILuaTask task ) throws LuaException, InterruptedException;
-
-    /**
-     * Queue a task to be executed on the main server thread at the beginning of next tick, but do not wait for it to
-     * complete. This should be used when you need to interact with the world in a thread-safe manner but do not care
-     * about the result or you wish to run asynchronously.
-     *
-     * When the task has finished, it will enqueue a {@code task_completed} event, which takes the task id, a success
-     * value and the return values, or an error message if it failed. If you need to wait on this event, it may be
-     * better to use {@link #executeMainThreadTask(ILuaTask)}.
+     * When the task has finished, it will enqueue a {@code task_completed} event, which takes the task id, a success value and the return values, or an
+     * error message if it failed.
      *
      * @param task The task to execute on the main thread.
      * @return The "id" of the task. This will be the first argument to the {@code task_completed} event.
      * @throws LuaException If the task could not be queued.
+     * @see LuaFunction#mainThread() To run functions on the main thread and return their results synchronously.
      */
-    long issueMainThreadTask( @Nonnull ILuaTask task ) throws LuaException;
+    long issueMainThreadTask(@Nonnull ILuaTask task) throws LuaException;
 }

src/main/java/dan200/computercraft/api/lua/ILuaFunction.java

@@ -0,0 +1,29 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import javax.annotation.Nonnull;
+
+/**
+ * A function, which can be called from Lua. If you need to return a table of functions, it is recommended to use an object with {@link LuaFunction}
+ * methods, or implement {@link IDynamicLuaObject}.
+ *
+ * @see MethodResult#of(Object)
+ */
+@FunctionalInterface
+public interface ILuaFunction {
+    /**
+     * Call this function with a series of arguments. Note, this will <em>always</em> be called on the computer thread, and so its implementation must be
+     * thread-safe.
+     *
+     * @param arguments The arguments for this function
+     * @return The result of calling this function.
+     * @throws LuaException Upon Lua errors.
+     */
+    @Nonnull
+    MethodResult call(@Nonnull IArguments arguments) throws LuaException;
+}

src/main/java/dan200/computercraft/api/lua/ILuaObject.java

@@ -6,51 +6,13 @@
 
 package dan200.computercraft.api.lua;
 
-import dan200.computercraft.api.peripheral.IComputerAccess;
-import dan200.computercraft.api.peripheral.IPeripheral;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-/**
- * An interface for representing custom objects returned by {@link IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])}
- * calls.
- *
- * Return objects implementing this interface to expose objects with methods to lua.
- */
-public interface ILuaObject
-{
-    /**
-     * Get the names of the methods that this object implements. This works the same as {@link IPeripheral#getMethodNames()}.
-     * See that method for detailed documentation.
-     *
-     * @return The method names this object provides.
-     * @see IPeripheral#getMethodNames()
-     */
+public interface ILuaObject {
     @Nonnull
     String[] getMethodNames();
 
-    /**
-     * Called when a user calls one of the methods that this object implements. This works the same as
-     * {@link IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])}}. See that method for detailed
-     * documentation.
-     *
-     * @param context   The context of the currently running lua thread. This can be used to wait for events
-     *                  or otherwise yield.
-     * @param method    An integer identifying which of the methods from getMethodNames() the computercraft
-     *                  wishes to call. The integer indicates the index into the getMethodNames() table
-     *                  that corresponds to the string passed into peripheral.call()
-     * @param arguments The arguments for this method. See {@link IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])}
-     *                  the possible values and conversion rules.
-     * @return An array of objects, representing the values you wish to return to the Lua program.
-     * See {@link IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])} for the valid values and
-     * conversion rules.
-     * @throws LuaException         If the task could not be queued, or if the task threw an exception.
-     * @throws InterruptedException If the user shuts down or reboots the computer the coroutine is suspended,
-     *                              InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.w
-     * @see IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])
-     */
     @Nullable
-    Object[] callMethod( @Nonnull ILuaContext context, int method, @Nonnull Object[] arguments ) throws LuaException, InterruptedException;
+    Object[] callMethod(@Nonnull ILuaContext context, int method, @Nonnull Object[] arguments) throws LuaException, InterruptedException;
 }

src/main/java/dan200/computercraft/api/lua/ILuaTask.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -9,24 +9,19 @@ package dan200.computercraft.api.lua;
 import javax.annotation.Nullable;
 
 /**
- * A task which can be executed via {@link ILuaContext#executeMainThreadTask(ILuaTask)} or
- * {@link ILuaContext#issueMainThreadTask(ILuaTask)}. This will be run on the main thread, at the beginning of the
- * next tick.
+ * A task which can be executed via {@link ILuaContext#issueMainThreadTask(ILuaTask)} This will be run on the main thread, at the beginning of the next
+ * tick.
  *
- * @see ILuaContext#executeMainThreadTask(ILuaTask)
  * @see ILuaContext#issueMainThreadTask(ILuaTask)
  */
 @FunctionalInterface
-public interface ILuaTask
-{
+public interface ILuaTask {
     /**
      * Execute this task.
      *
-     * @return The arguments to add to the {@code task_completed} event. These will be returned by
-     * {@link ILuaContext#executeMainThreadTask(ILuaTask)}.
-     * @throws LuaException If you throw any exception from this function, a lua error will be raised with the
-     *                      same message as your exception. Use this to throw appropriate errors if the wrong
-     *                      arguments are supplied to your method.
+     * @return The arguments to add to the {@code task_completed} event.
+     * @throws LuaException If you throw any exception from this function, a lua error will be raised with the same message as your exception. Use this
+     *     to throw appropriate errors if the wrong arguments are supplied to your method.
      */
     @Nullable
     Object[] execute() throws LuaException;

src/main/java/dan200/computercraft/api/lua/LuaException.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -11,35 +11,38 @@ import javax.annotation.Nullable;
 /**
  * An exception representing an error in Lua, like that raised by the {@code error()} function.
  */
-public class LuaException extends Exception
-{
+public class LuaException extends Exception {
     private static final long serialVersionUID = -6136063076818512651L;
+    private final boolean hasLevel;
     private final int level;
 
-    public LuaException()
-    {
-        this( "error", 1 );
+    public LuaException(@Nullable String message) {
+        super(message);
+        this.hasLevel = false;
+        this.level = 1;
     }
 
-    public LuaException( @Nullable String message )
-    {
-        this( message, 1 );
-    }
-
-    public LuaException( @Nullable String message, int level )
-    {
-        super( message );
+    public LuaException(@Nullable String message, int level) {
+        super(message);
+        this.hasLevel = true;
         this.level = level;
     }
 
     /**
-     * The level this error is raised at. Level 1 is the function's caller, level 2 is that function's caller, and so
-     * on.
+     * Whether a level was explicitly specified when constructing. This is used to determine
+     *
+     * @return Whether this has an explicit level.
+     */
+    public boolean hasLevel() {
+        return this.hasLevel;
+    }
+
+    /**
+     * The level this error is raised at. Level 1 is the function's caller, level 2 is that function's caller, and so on.
      *
      * @return The level to raise the error at.
      */
-    public int getLevel()
-    {
-        return level;
+    public int getLevel() {
+        return this.level;
     }
 }

src/main/java/dan200/computercraft/api/lua/LuaFunction.java

@@ -0,0 +1,61 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.util.Map;
+import java.util.Optional;
+
+import dan200.computercraft.api.peripheral.IComputerAccess;
+import dan200.computercraft.api.peripheral.IPeripheral;
+
+/**
+ * Used to mark a Java function which is callable from Lua.
+ *
+ * Methods annotated with {@link LuaFunction} must be public final instance methods. They can have any number of parameters, but they must be of the
+ * following types:
+ *
+ * <ul>
+ *   <li>{@link ILuaContext} (and {@link IComputerAccess} if on a {@link IPeripheral})</li>
+ *   <li>{@link IArguments}: The arguments supplied to this function.</li>
+ *   <li>
+ *     Alternatively, one may specify the desired arguments as normal parameters and the argument parsing code will
+ *     be generated automatically.
+ *
+ *     Each parameter must be one of the given types supported by {@link IArguments} (for instance, {@link int} or
+ *     {@link Map}). Optional values are supported by accepting a parameter of type {@link Optional}.
+ *   </li>
+ * </ul>
+ *
+ * This function may return {@link MethodResult}. However, if you simply return a value (rather than having to yield),
+ * you may return {@code void}, a single value (either an object or a primitive like {@code int}) or array of objects.
+ * These will be treated the same as {@link MethodResult#of()}, {@link MethodResult#of(Object)} and
+ * {@link MethodResult#of(Object...)}.
+ */
+@Documented
+@Retention (RetentionPolicy.RUNTIME)
+@Target (ElementType.METHOD)
+public @interface LuaFunction {
+    /**
+     * Explicitly specify the method names of this function. If not given, it uses the name of the annotated method.
+     *
+     * @return This function's name(s).
+     */
+    String[] value() default {};
+
+    /**
+     * Run this function on the main server thread. This should be specified for any method which interacts with Minecraft in a thread-unsafe manner.
+     *
+     * @return Whether this functi
+     * @see ILuaContext#issueMainThreadTask(ILuaTask)
+     */
+    boolean mainThread() default false;
+}

src/main/java/dan200/computercraft/api/lua/LuaValues.java

@@ -0,0 +1,163 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import java.nio.ByteBuffer;
+import java.util.Map;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Various utility functions for operating with Lua values.
+ *
+ * @see IArguments
+ */
+public final class LuaValues {
+    private LuaValues() {
+    }
+
+    /**
+     * Encode a Lua string into a read-only {@link ByteBuffer}.
+     *
+     * @param string The string to encode.
+     * @return The encoded string.
+     */
+    @Nonnull
+    public static ByteBuffer encode(@Nonnull String string) {
+        byte[] chars = new byte[string.length()];
+        for (int i = 0; i < chars.length; i++) {
+            char c = string.charAt(i);
+            chars[i] = c < 256 ? (byte) c : 63;
+        }
+
+        return ByteBuffer.wrap(chars)
+                         .asReadOnlyBuffer();
+    }
+
+    /**
+     * Construct a "bad argument" exception, from an expected type and the actual value provided.
+     *
+     * @param index The argument number, starting from 0.
+     * @param expected The expected type for this argument.
+     * @param actual The actual value provided for this argument.
+     * @return The constructed exception, which should be thrown immediately.
+     */
+    @Nonnull
+    public static LuaException badArgumentOf(int index, @Nonnull String expected, @Nullable Object actual) {
+        return badArgument(index, expected, getType(actual));
+    }
+
+    /**
+     * Construct a "bad argument" exception, from an expected and actual type.
+     *
+     * @param index The argument number, starting from 0.
+     * @param expected The expected type for this argument.
+     * @param actual The provided type for this argument.
+     * @return The constructed exception, which should be thrown immediately.
+     */
+    @Nonnull
+    public static LuaException badArgument(int index, @Nonnull String expected, @Nonnull String actual) {
+        return new LuaException("bad argument #" + (index + 1) + " (" + expected + " expected, got " + actual + ")");
+    }
+
+    /**
+     * Get a string representation of the given value's type.
+     *
+     * @param value The value whose type we are trying to compute.
+     * @return A string representation of the given value's type, in a similar format to that provided by Lua's {@code type} function.
+     */
+    @Nonnull
+    public static String getType(@Nullable Object value) {
+        if (value == null) {
+            return "nil";
+        }
+        if (value instanceof String) {
+            return "string";
+        }
+        if (value instanceof Boolean) {
+            return "boolean";
+        }
+        if (value instanceof Number) {
+            return "number";
+        }
+        if (value instanceof Map) {
+            return "table";
+        }
+        return "userdata";
+    }
+
+    /**
+     * Ensure a numeric argument is finite (i.e. not infinite or {@link Double#NaN}.
+     *
+     * @param index The argument index to check.
+     * @param value The value to check.
+     * @return The input {@code value}.
+     * @throws LuaException If this is not a finite number.
+     */
+    public static Number checkFiniteNum(int index, Number value) throws LuaException {
+        checkFinite(index, value.doubleValue());
+        return value;
+    }
+
+    /**
+     * Ensure a numeric argument is finite (i.e. not infinite or {@link Double#NaN}.
+     *
+     * @param index The argument index to check.
+     * @param value The value to check.
+     * @return The input {@code value}.
+     * @throws LuaException If this is not a finite number.
+     */
+    public static double checkFinite(int index, double value) throws LuaException {
+        if (!Double.isFinite(value)) {
+            throw badArgument(index, "number", getNumericType(value));
+        }
+        return value;
+    }
+
+    /**
+     * Returns a more detailed representation of this number's type. If this is finite, it will just return "number", otherwise it returns whether it is
+     * infinite or NaN.
+     *
+     * @param value The value to extract the type for.
+     * @return This value's numeric type.
+     */
+    @Nonnull
+    public static String getNumericType(double value) {
+        if (Double.isNaN(value)) {
+            return "nan";
+        }
+        if (value == Double.POSITIVE_INFINITY) {
+            return "inf";
+        }
+        if (value == Double.NEGATIVE_INFINITY) {
+            return "-inf";
+        }
+        return "number";
+    }
+
+    /**
+     * Ensure a string is a valid enum value.
+     *
+     * @param index The argument index to check.
+     * @param klass The class of the enum instance.
+     * @param value The value to extract.
+     * @param <T> The type of enum we are extracting.
+     * @return The parsed enum value.
+     * @throws LuaException If this is not a known enum value.
+     */
+    public static <T extends Enum<T>> T checkEnum(int index, Class<T> klass, String value) throws LuaException {
+        for (T possibility : klass.getEnumConstants()) {
+            if (possibility.name()
+                           .equalsIgnoreCase(value)) {
+                return possibility;
+            }
+        }
+
+        throw new LuaException("bad argument #" + (index + 1) + " (unknown option " + value + ")");
+    }
+}

src/main/java/dan200/computercraft/api/lua/MethodResult.java

@@ -0,0 +1,162 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import java.nio.ByteBuffer;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import dan200.computercraft.api.peripheral.IComputerAccess;
+
+/**
+ * The result of invoking a Lua method.
+ *
+ * Method results either return a value immediately ({@link #of(Object...)} or yield control to the parent coroutine. When the current coroutine is resumed,
+ * we invoke the provided {@link ILuaCallback#resume(Object[])} callback.
+ */
+public final class MethodResult {
+    private static final MethodResult empty = new MethodResult(null, null);
+
+    private final Object[] result;
+    private final ILuaCallback callback;
+    private final int adjust;
+
+    private MethodResult(Object[] arguments, ILuaCallback callback) {
+        this.result = arguments;
+        this.callback = callback;
+        this.adjust = 0;
+    }
+
+    private MethodResult(Object[] arguments, ILuaCallback callback, int adjust) {
+        this.result = arguments;
+        this.callback = callback;
+        this.adjust = adjust;
+    }
+
+    /**
+     * Return no values immediately.
+     *
+     * @return A method result which returns immediately with no values.
+     */
+    @Nonnull
+    public static MethodResult of() {
+        return empty;
+    }
+
+    /**
+     * Return a single value immediately.
+     *
+     * Integers, doubles, floats, strings, booleans, {@link Map}, {@link Collection}s, arrays and {@code null} will be converted to their corresponding Lua
+     * type. {@code byte[]} and {@link ByteBuffer} will be treated as binary strings. {@link ILuaFunction} will be treated as a function.
+     *
+     * In order to provide a custom object with methods, one may return a {@link IDynamicLuaObject}, or an arbitrary class with {@link LuaFunction}
+     * annotations. Anything else will be converted to {@code nil}.
+     *
+     * @param value The value to return to the calling Lua function.
+     * @return A method result which returns immediately with the given value.
+     */
+    @Nonnull
+    public static MethodResult of(@Nullable Object value) {
+        return new MethodResult(new Object[] {value}, null);
+    }
+
+    /**
+     * Return any number of values immediately.
+     *
+     * @param values The values to return. See {@link #of(Object)} for acceptable values.
+     * @return A method result which returns immediately with the given values.
+     */
+    @Nonnull
+    public static MethodResult of(@Nullable Object... values) {
+        return values == null || values.length == 0 ? empty : new MethodResult(values, null);
+    }
+
+    /**
+     * Wait for an event to occur on the computer, suspending the thread until it arises. This method is exactly equivalent to {@code os.pullEvent()} in
+     * lua.
+     *
+     * @param filter A specific event to wait for, or null to wait for any event.
+     * @param callback The callback to resume with the name of the event that occurred, and any event parameters.
+     * @return The method result which represents this yield.
+     * @see IComputerAccess#queueEvent(String, Object[])
+     */
+    @Nonnull
+    public static MethodResult pullEvent(@Nullable String filter, @Nonnull ILuaCallback callback) {
+        Objects.requireNonNull(callback, "callback cannot be null");
+        return new MethodResult(new Object[] {filter}, results -> {
+            if (results.length >= 1 && results[0].equals("terminate")) {
+                throw new LuaException("Terminated", 0);
+            }
+            return callback.resume(results);
+        });
+    }
+
+    /**
+     * The same as {@link #pullEvent(String, ILuaCallback)}, except "terminated" events are ignored. Only use this if you want to prevent program
+     * termination, which is not recommended. This method is exactly equivalent to {@code os.pullEventRaw()} in Lua.
+     *
+     * @param filter A specific event to wait for, or null to wait for any event.
+     * @param callback The callback to resume with the name of the event that occurred, and any event parameters.
+     * @return The method result which represents this yield.
+     * @see #pullEvent(String, ILuaCallback)
+     */
+    @Nonnull
+    public static MethodResult pullEventRaw(@Nullable String filter, @Nonnull ILuaCallback callback) {
+        Objects.requireNonNull(callback, "callback cannot be null");
+        return new MethodResult(new Object[] {filter}, callback);
+    }
+
+    /**
+     * Yield the current coroutine with some arguments until it is resumed. This method is exactly equivalent to {@code coroutine.yield()} in lua. Use
+     * {@code pullEvent()} if you wish to wait for events.
+     *
+     * @param arguments An object array containing the arguments to pass to coroutine.yield()
+     * @param callback The callback to resume with an array containing the return values from coroutine.yield()
+     * @return The method result which represents this yield.
+     * @see #pullEvent(String, ILuaCallback)
+     */
+    @Nonnull
+    public static MethodResult yield(@Nullable Object[] arguments, @Nonnull ILuaCallback callback) {
+        Objects.requireNonNull(callback, "callback cannot be null");
+        return new MethodResult(arguments, callback);
+    }
+
+    @Nullable
+    public Object[] getResult() {
+        return this.result;
+    }
+
+    @Nullable
+    public ILuaCallback getCallback() {
+        return this.callback;
+    }
+
+    public int getErrorAdjust() {
+        return this.adjust;
+    }
+
+    /**
+     * Increase the Lua error by a specific amount. One should never need to use this function - it largely exists for some CC internal code.
+     *
+     * @param adjust The amount to increase the level by.
+     * @return The new {@link MethodResult} with an adjusted error. This has no effect on immediate results.
+     */
+    @Nonnull
+    public MethodResult adjustError(int adjust) {
+        if (adjust < 0) {
+            throw new IllegalArgumentException("cannot adjust by a negative amount");
+        }
+        if (adjust == 0 || this.callback == null) {
+            return this;
+        }
+        return new MethodResult(this.result, this.callback, this.adjust + adjust);
+    }
+}

src/main/java/dan200/computercraft/api/lua/ObjectArguments.java

@@ -0,0 +1,66 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.lua;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+import javax.annotation.Nullable;
+
+/**
+ * An implementation of {@link IArguments} which wraps an array of {@link Object}.
+ */
+public final class ObjectArguments implements IArguments {
+    private static final IArguments EMPTY = new ObjectArguments();
+    private final List<Object> args;
+
+    @Deprecated
+    @SuppressWarnings ("unused")
+    public ObjectArguments(IArguments arguments) {
+        throw new IllegalStateException();
+    }
+
+    public ObjectArguments(Object... args) {
+        this.args = Arrays.asList(args);
+    }
+
+    public ObjectArguments(List<Object> args) {
+        this.args = Objects.requireNonNull(args);
+    }
+
+    @Override
+    public IArguments drop(int count) {
+        if (count < 0) {
+            throw new IllegalStateException("count cannot be negative");
+        }
+        if (count == 0) {
+            return this;
+        }
+        if (count >= this.args.size()) {
+            return EMPTY;
+        }
+
+        return new ObjectArguments(this.args.subList(count, this.args.size()));
+    }
+
+    @Override
+    public Object[] getAll() {
+        return this.args.toArray();
+    }
+
+    @Override
+    public int count() {
+        return this.args.size();
+    }
+
+    @Nullable
+    @Override
+    public Object get(int index) {
+        return index >= this.args.size() ? null : this.args.get(index);
+    }
+}

src/main/java/dan200/computercraft/api/media/IMedia.java

@@ -1,28 +1,27 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.media;
 
-import dan200.computercraft.api.filesystem.IMount;
-import net.minecraft.item.Item;
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.SoundEvent;
-import net.minecraft.world.World;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import dan200.computercraft.api.filesystem.IMount;
+
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+import net.minecraft.sound.SoundEvent;
+import net.minecraft.world.World;
+
 /**
  * Represents an item that can be placed in a disk drive and used by a Computer.
  *
- * Implement this interface on your {@link Item} class to allow it to be used in the drive. Alternatively, register
- * a {@link IMediaProvider}.
+ * Implement this interface on your {@link Item} class to allow it to be used in the drive. Alternatively, register a {@link IMediaProvider}.
  */
-public interface IMedia
-{
+public interface IMedia {
     /**
      * Get a string representing the label of this item. Will be called via {@code disk.getLabel()} in lua.
      *
@@ -30,7 +29,7 @@ public interface IMedia
      * @return The label. ie: "Dan's Programs".
      */
     @Nullable
-    String getLabel( @Nonnull ItemStack stack );
+    String getLabel(@Nonnull ItemStack stack);
 
     /**
      * Set a string representing the label of this item. Will be called vi {@code disk.setLabel()} in lua.
@@ -39,21 +38,18 @@ public interface IMedia
      * @param label The string to set the label to.
      * @return true if the label was updated, false if the label may not be modified.
      */
-    default boolean setLabel( @Nonnull ItemStack stack, @Nullable String label )
-    {
+    default boolean setLabel(@Nonnull ItemStack stack, @Nullable String label) {
         return false;
     }
 
     /**
-     * If this disk represents an item with audio (like a record), get the readable name of the audio track. ie:
-     * "Jonathan Coulton - Still Alive"
+     * If this disk represents an item with audio (like a record), get the readable name of the audio track. ie: "Jonathan Coulton - Still Alive"
      *
      * @param stack The {@link ItemStack} to modify.
      * @return The name, or null if this item does not represent an item with audio.
      */
     @Nullable
-    default String getAudioTitle( @Nonnull ItemStack stack )
-    {
+    default String getAudioTitle(@Nonnull ItemStack stack) {
         return null;
     }
 
@@ -64,27 +60,25 @@ public interface IMedia
      * @return The name, or null if this item does not represent an item with audio.
      */
     @Nullable
-    default SoundEvent getAudio( @Nonnull ItemStack stack )
-    {
+    default SoundEvent getAudio(@Nonnull ItemStack stack) {
         return null;
     }
 
     /**
-     * If this disk represents an item with data (like a floppy disk), get a mount representing it's contents. This will
-     * be mounted onto the filesystem of the computer while the media is in the disk drive.
+     * If this disk represents an item with data (like a floppy disk), get a mount representing it's contents. This will be mounted onto the filesystem of
+     * the computer while the media is in the disk drive.
      *
      * @param stack The {@link ItemStack} to modify.
      * @param world The world in which the item and disk drive reside.
-     * @return The mount, or null if this item does not represent an item with data. If the mount returned also
-     * implements {@link dan200.computercraft.api.filesystem.IWritableMount}, it will mounted using mountWritable()
+     * @return The mount, or null if this item does not represent an item with data. If the mount returned also implements {@link
+     *     dan200.computercraft.api.filesystem.IWritableMount}, it will mounted using mountWritable()
      * @see IMount
      * @see dan200.computercraft.api.filesystem.IWritableMount
      * @see dan200.computercraft.api.ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see dan200.computercraft.api.ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see dan200.computercraft.api.ComputerCraftAPI#createResourceMount(String, String)
      */
     @Nullable
-    default IMount createDataMount( @Nonnull ItemStack stack, @Nonnull World world )
-    {
+    default IMount createDataMount(@Nonnull ItemStack stack, @Nonnull World world) {
         return null;
     }
 }

src/main/java/dan200/computercraft/api/media/IMediaProvider.java

@@ -1,24 +1,23 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.media;
 
-import net.minecraft.item.ItemStack;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import net.minecraft.item.ItemStack;
+
 /**
  * This interface is used to provide {@link IMedia} implementations for {@link ItemStack}.
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerMediaProvider(IMediaProvider)
  */
 @FunctionalInterface
-public interface IMediaProvider
-{
+public interface IMediaProvider {
     /**
      * Produce an IMedia implementation from an ItemStack.
      *
@@ -27,5 +26,5 @@ public interface IMediaProvider
      * @see dan200.computercraft.api.ComputerCraftAPI#registerMediaProvider(IMediaProvider)
      */
     @Nullable
-    IMedia getMedia( @Nonnull ItemStack stack );
+    IMedia getMedia(@Nonnull ItemStack stack);
 }

src/main/java/dan200/computercraft/api/network/IPacketNetwork.java

@@ -1,8 +1,9 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
+
 package dan200.computercraft.api.network;
 
 import javax.annotation.Nonnull;
@@ -13,21 +14,20 @@ import javax.annotation.Nonnull;
  * @see Packet
  * @see IPacketReceiver
  */
-public interface IPacketNetwork
-{
+public interface IPacketNetwork {
     /**
      * Add a receiver to the network.
      *
      * @param receiver The receiver to register to the network.
      */
-    void addReceiver( @Nonnull IPacketReceiver receiver );
+    void addReceiver(@Nonnull IPacketReceiver receiver);
 
     /**
      * Remove a receiver from the network.
      *
      * @param receiver The device to remove from the network.
      */
-    void removeReceiver( @Nonnull IPacketReceiver receiver );
+    void removeReceiver(@Nonnull IPacketReceiver receiver);
 
     /**
      * Determine whether this network is wireless.
@@ -37,23 +37,23 @@ public interface IPacketNetwork
     boolean isWireless();
 
     /**
-     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it
-     * to all receivers within range (or any interdimensional ones).
+     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it to all receivers within range (or any
+     * interdimensional ones).
      *
      * @param packet The packet to send.
-     * @param range  The maximum distance this packet will be sent.
+     * @param range The maximum distance this packet will be sent.
      * @see #transmitInterdimensional(Packet)
      * @see IPacketReceiver#receiveSameDimension(Packet, double)
      */
-    void transmitSameDimension( @Nonnull Packet packet, double range );
+    void transmitSameDimension(@Nonnull Packet packet, double range);
 
     /**
-     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it
-     * to all receivers across all dimensions.
+     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it to all receivers across all
+     * dimensions.
      *
      * @param packet The packet to send.
      * @see #transmitSameDimension(Packet, double)
      * @see IPacketReceiver#receiveDifferentDimension(Packet)
      */
-    void transmitInterdimensional( @Nonnull Packet packet );
+    void transmitInterdimensional(@Nonnull Packet packet);
 }

src/main/java/dan200/computercraft/api/network/IPacketReceiver.java

@@ -1,20 +1,20 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
+
 package dan200.computercraft.api.network;
 
+import javax.annotation.Nonnull;
+
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
-import javax.annotation.Nonnull;
-
 /**
  * An object on an {@link IPacketNetwork}, capable of receiving packets.
  */
-public interface IPacketReceiver
-{
+public interface IPacketReceiver {
     /**
      * Get the world in which this packet receiver exists.
      *
@@ -34,9 +34,8 @@ public interface IPacketReceiver
     /**
      * Get the maximum distance this receiver can send and receive messages.
      *
-     * When determining whether a receiver can receive a message, the largest distance of the packet and receiver is
-     * used - ensuring it is within range. If the packet or receiver is inter-dimensional, then the packet will always
-     * be received.
+     * When determining whether a receiver can receive a message, the largest distance of the packet and receiver is used - ensuring it is within range. If
+     * the packet or receiver is inter-dimensional, then the packet will always be received.
      *
      * @return The maximum distance this device can send and receive messages.
      * @see #isInterdimensional()
@@ -60,25 +59,25 @@ public interface IPacketReceiver
     /**
      * Receive a network packet from the same dimension.
      *
-     * @param packet   The packet to receive. Generally you should check that you are listening on the given channel and,
-     *                 if so, queue the appropriate modem event.
+     * @param packet The packet to receive. Generally you should check that you are listening on the given channel and, if so, queue the appropriate
+     *     modem event.
      * @param distance The distance this packet has travelled from the source.
      * @see Packet
      * @see #getRange()
      * @see IPacketNetwork#transmitSameDimension(Packet, double)
      * @see IPacketNetwork#transmitInterdimensional(Packet)
      */
-    void receiveSameDimension( @Nonnull Packet packet, double distance );
+    void receiveSameDimension(@Nonnull Packet packet, double distance);
 
     /**
      * Receive a network packet from a different dimension.
      *
-     * @param packet The packet to receive. Generally you should check that you are listening on the given channel and,
-     *               if so, queue the appropriate modem event.
+     * @param packet The packet to receive. Generally you should check that you are listening on the given channel and, if so, queue the appropriate
+     *     modem event.
      * @see Packet
      * @see IPacketNetwork#transmitInterdimensional(Packet)
      * @see IPacketNetwork#transmitSameDimension(Packet, double)
      * @see #isInterdimensional()
      */
-    void receiveDifferentDimension( @Nonnull Packet packet );
+    void receiveDifferentDimension(@Nonnull Packet packet);
 }

src/main/java/dan200/computercraft/api/network/IPacketSender.java

@@ -1,20 +1,20 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
+
 package dan200.computercraft.api.network;
 
+import javax.annotation.Nonnull;
+
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
-import javax.annotation.Nonnull;
-
 /**
  * An object on a {@link IPacketNetwork}, capable of sending packets.
  */
-public interface IPacketSender
-{
+public interface IPacketSender {
     /**
      * Get the world in which this packet sender exists.
      *
@@ -32,8 +32,8 @@ public interface IPacketSender
     Vec3d getPosition();
 
     /**
-     * Get some sort of identification string for this sender. This does not strictly need to be unique, but you
-     * should be able to extract some identifiable information from it.
+     * Get some sort of identification string for this sender. This does not strictly need to be unique, but you should be able to extract some identifiable
+     * information from it.
      *
      * @return This device's id.
      */

src/main/java/dan200/computercraft/api/network/Packet.java

@@ -1,13 +1,15 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
+
 package dan200.computercraft.api.network;
 
+import java.util.Objects;
+
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Objects;
 
 /**
  * Represents a packet which may be sent across a {@link IPacketNetwork}.
@@ -18,8 +20,7 @@ import java.util.Objects;
  * @see IPacketReceiver#receiveDifferentDimension(Packet)
  * @see IPacketReceiver#receiveSameDimension(Packet, double)
  */
-public class Packet
-{
+public class Packet {
     private final int channel;
     private final int replyChannel;
     private final Object payload;
@@ -29,16 +30,14 @@ public class Packet
     /**
      * Create a new packet, ready for transmitting across the network.
      *
-     * @param channel      The channel to send the packet along. Receiving devices should only process packets from on
-     *                     channels they are listening to.
+     * @param channel The channel to send the packet along. Receiving devices should only process packets from on channels they are listening to.
      * @param replyChannel The channel to reply on.
-     * @param payload      The contents of this packet. This should be a "valid" Lua object, safe for queuing as an
-     *                     event or returning from a peripheral call.
-     * @param sender       The object which sent this packet.
+     * @param payload The contents of this packet. This should be a "valid" Lua object, safe for queuing as an event or returning from a peripheral
+     *     call.
+     * @param sender The object which sent this packet.
      */
-    public Packet( int channel, int replyChannel, @Nullable Object payload, @Nonnull IPacketSender sender )
-    {
-        Objects.requireNonNull( sender, "sender cannot be null" );
+    public Packet(int channel, int replyChannel, @Nullable Object payload, @Nonnull IPacketSender sender) {
+        Objects.requireNonNull(sender, "sender cannot be null");
 
         this.channel = channel;
         this.replyChannel = replyChannel;
@@ -47,14 +46,12 @@ public class Packet
     }
 
     /**
-     * Get the channel this packet is sent along. Receivers should generally only process packets from on channels they
-     * are listening to.
+     * Get the channel this packet is sent along. Receivers should generally only process packets from on channels they are listening to.
      *
      * @return This packet's channel.
      */
-    public int getChannel()
-    {
-        return channel;
+    public int getChannel() {
+        return this.channel;
     }
 
     /**
@@ -62,21 +59,18 @@ public class Packet
      *
      * @return This channel to reply on.
      */
-    public int getReplyChannel()
-    {
-        return replyChannel;
+    public int getReplyChannel() {
+        return this.replyChannel;
     }
 
     /**
-     * The actual data of this packet. This should be a "valid" Lua object, safe for queuing as an
-     * event or returning from a peripheral call.
+     * The actual data of this packet. This should be a "valid" Lua object, safe for queuing as an event or returning from a peripheral call.
      *
      * @return The packet's payload
      */
     @Nullable
-    public Object getPayload()
-    {
-        return payload;
+    public Object getPayload() {
+        return this.payload;
     }
 
     /**
@@ -85,33 +79,40 @@ public class Packet
      * @return The sending object.
      */
     @Nonnull
-    public IPacketSender getSender()
-    {
-        return sender;
+    public IPacketSender getSender() {
+        return this.sender;
     }
 
     @Override
-    public boolean equals( Object o )
-    {
-        if( this == o ) return true;
-        if( o == null || getClass() != o.getClass() ) return false;
+    public int hashCode() {
+        int result;
+        result = this.channel;
+        result = 31 * result + this.replyChannel;
+        result = 31 * result + (this.payload != null ? this.payload.hashCode() : 0);
+        result = 31 * result + this.sender.hashCode();
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || this.getClass() != o.getClass()) {
+            return false;
+        }
 
         Packet packet = (Packet) o;
 
-        if( channel != packet.channel ) return false;
-        if( replyChannel != packet.replyChannel ) return false;
-        if( !Objects.equals( payload, packet.payload ) ) return false;
-        return sender.equals( packet.sender );
-    }
-
-    @Override
-    public int hashCode()
-    {
-        int result;
-        result = channel;
-        result = 31 * result + replyChannel;
-        result = 31 * result + (payload != null ? payload.hashCode() : 0);
-        result = 31 * result + sender.hashCode();
-        return result;
+        if (this.channel != packet.channel) {
+            return false;
+        }
+        if (this.replyChannel != packet.replyChannel) {
+            return false;
+        }
+        if (!Objects.equals(this.payload, packet.payload)) {
+            return false;
+        }
+        return this.sender.equals(packet.sender);
     }
 }

src/main/java/dan200/computercraft/api/network/wired/IWiredElement.java

@@ -1,35 +1,31 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.network.wired;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-
 import javax.annotation.Nonnull;
 
+import dan200.computercraft.api.ComputerCraftAPI;
+
 /**
  * An object which may be part of a wired network.
  *
- * Elements should construct a node using {@link ComputerCraftAPI#createWiredNodeForElement(IWiredElement)}. This acts
- * as a proxy for all network objects. Whilst the node may change networks, an element's node should remain constant
- * for its lifespan.
+ * Elements should construct a node using {@link ComputerCraftAPI#createWiredNodeForElement(IWiredElement)}. This acts as a proxy for all network objects.
+ * Whilst the node may change networks, an element's node should remain constant for its lifespan.
  *
- * Elements are generally tied to a block or tile entity in world. In such as case, one should provide the
- * {@link IWiredElement} capability for the appropriate sides.
+ * Elements are generally tied to a block or tile entity in world. In such as case, one should provide the {@link IWiredElement} capability for the
+ * appropriate sides.
  */
-public interface IWiredElement extends IWiredSender
-{
+public interface IWiredElement extends IWiredSender {
     /**
-     * Called when objects on the network change. This may occur when network nodes are added or removed, or when
-     * peripherals change.
+     * Called when objects on the network change. This may occur when network nodes are added or removed, or when peripherals change.
      *
      * @param change The change which occurred.
      * @see IWiredNetworkChange
      */
-    default void networkChanged( @Nonnull IWiredNetworkChange change )
-    {
+    default void networkChanged(@Nonnull IWiredNetworkChange change) {
     }
 }

src/main/java/dan200/computercraft/api/network/wired/IWiredNetwork.java

@@ -1,53 +1,51 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.network.wired;
 
-import dan200.computercraft.api.peripheral.IPeripheral;
-
-import javax.annotation.Nonnull;
 import java.util.Map;
 
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.peripheral.IPeripheral;
+
 /**
- * A wired network is composed of one of more {@link IWiredNode}s, a set of connections between them, and a series
- * of peripherals.
+ * A wired network is composed of one of more {@link IWiredNode}s, a set of connections between them, and a series of peripherals.
  *
- * Networks from a connected graph. This means there is some path between all nodes on the network. Further more, if
- * there is some path between two nodes then they must be on the same network. {@link IWiredNetwork} will automatically
- * handle the merging and splitting of networks (and thus changing of available nodes and peripherals) as connections
- * change.
+ * Networks from a connected graph. This means there is some path between all nodes on the network. Further more, if there is some path between two nodes
+ * then they must be on the same network. {@link IWiredNetwork} will automatically handle the merging and splitting of networks (and thus changing of
+ * available nodes and peripherals) as connections change.
  *
- * This does mean one can not rely on the network remaining consistent between subsequent operations. Consequently,
- * it is generally preferred to use the methods provided by {@link IWiredNode}.
+ * This does mean one can not rely on the network remaining consistent between subsequent operations. Consequently, it is generally preferred to use the
+ * methods provided by {@link IWiredNode}.
  *
  * @see IWiredNode#getNetwork()
  */
-public interface IWiredNetwork
-{
+public interface IWiredNetwork {
     /**
      * Create a connection between two nodes.
      *
      * This should only be used on the server thread.
      *
-     * @param left  The first node to connect
+     * @param left The first node to connect
      * @param right The second node to connect
      * @return {@code true} if a connection was created or {@code false} if the connection already exists.
-     * @throws IllegalStateException    If neither node is on the network.
+     * @throws IllegalStateException If neither node is on the network.
      * @throws IllegalArgumentException If {@code left} and {@code right} are equal.
      * @see IWiredNode#connectTo(IWiredNode)
      * @see IWiredNetwork#connect(IWiredNode, IWiredNode)
      */
-    boolean connect( @Nonnull IWiredNode left, @Nonnull IWiredNode right );
+    boolean connect(@Nonnull IWiredNode left, @Nonnull IWiredNode right);
 
     /**
      * Destroy a connection between this node and another.
      *
      * This should only be used on the server thread.
      *
-     * @param left  The first node in the connection.
+     * @param left The first node in the connection.
      * @param right The second node in the connection.
      * @return {@code true} if a connection was destroyed or {@code false} if no connection exists.
      * @throws IllegalArgumentException If either node is not on the network.
@@ -55,32 +53,29 @@ public interface IWiredNetwork
      * @see IWiredNode#disconnectFrom(IWiredNode)
      * @see IWiredNetwork#connect(IWiredNode, IWiredNode)
      */
-    boolean disconnect( @Nonnull IWiredNode left, @Nonnull IWiredNode right );
+    boolean disconnect(@Nonnull IWiredNode left, @Nonnull IWiredNode right);
 
     /**
      * Sever all connections this node has, removing it from this network.
      *
-     * This should only be used on the server thread. You should only call this on nodes
-     * that your network element owns.
+     * This should only be used on the server thread. You should only call this on nodes that your network element owns.
      *
      * @param node The node to remove
-     * @return Whether this node was removed from the network. One cannot remove a node from a network where it is the
-     * only element.
+     * @return Whether this node was removed from the network. One cannot remove a node from a network where it is the only element.
      * @throws IllegalArgumentException If the node is not in the network.
      * @see IWiredNode#remove()
      */
-    boolean remove( @Nonnull IWiredNode node );
+    boolean remove(@Nonnull IWiredNode node);
 
     /**
      * Update the peripherals a node provides.
      *
-     * This should only be used on the server thread. You should only call this on nodes
-     * that your network element owns.
+     * This should only be used on the server thread. You should only call this on nodes that your network element owns.
      *
-     * @param node        The node to attach peripherals for.
+     * @param node The node to attach peripherals for.
      * @param peripherals The new peripherals for this node.
      * @throws IllegalArgumentException If the node is not in the network.
      * @see IWiredNode#updatePeripherals(Map)
      */
-    void updatePeripherals( @Nonnull IWiredNode node, @Nonnull Map<String, IPeripheral> peripherals );
+    void updatePeripherals(@Nonnull IWiredNode node, @Nonnull Map<String, IPeripheral> peripherals);
 }

src/main/java/dan200/computercraft/api/network/wired/IWiredNetworkChange.java

@@ -1,26 +1,26 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.network.wired;
 
-import dan200.computercraft.api.peripheral.IPeripheral;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
-import java.util.Map;
+
+import dan200.computercraft.api.peripheral.IPeripheral;
 
 /**
  * Represents a change to the objects on a wired network.
  *
  * @see IWiredElement#networkChanged(IWiredNetworkChange)
  */
-public interface IWiredNetworkChange
-{
+public interface IWiredNetworkChange {
     /**
-     * A set of peripherals which have been removed. Note that there may be entries with the same name
-     * in the added and removed set, but with a different peripheral.
+     * A set of peripherals which have been removed. Note that there may be entries with the same name in the added and removed set, but with a different
+     * peripheral.
      *
      * @return The set of removed peripherals.
      */
@@ -28,8 +28,8 @@ public interface IWiredNetworkChange
     Map<String, IPeripheral> peripheralsRemoved();
 
     /**
-     * A set of peripherals which have been added. Note that there may be entries with the same name
-     * in the added and removed set, but with a different peripheral.
+     * A set of peripherals which have been added. Note that there may be entries with the same name in the added and removed set, but with a different
+     * peripheral.
      *
      * @return The set of added peripherals.
      */

src/main/java/dan200/computercraft/api/network/wired/IWiredNode.java

@@ -1,32 +1,31 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.network.wired;
 
-import dan200.computercraft.api.network.IPacketNetwork;
-import dan200.computercraft.api.peripheral.IPeripheral;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
-import java.util.Map;
+
+import dan200.computercraft.api.network.IPacketNetwork;
+import dan200.computercraft.api.peripheral.IPeripheral;
 
 /**
  * Wired nodes act as a layer between {@link IWiredElement}s and {@link IWiredNetwork}s.
  *
- * Firstly, a node acts as a packet network, capable of sending and receiving modem messages to connected nodes. These
- * methods may be safely used on any thread.
+ * Firstly, a node acts as a packet network, capable of sending and receiving modem messages to connected nodes. These methods may be safely used on any
+ * thread.
  *
- * When sending a packet, the system will attempt to find the shortest path between the two nodes based on their
- * element's position. Note that packet senders and receivers can have different locations from their associated
- * element: the distance between the two will be added to the total packet's distance.
+ * When sending a packet, the system will attempt to find the shortest path between the two nodes based on their element's position. Note that packet
+ * senders and receivers can have different locations from their associated element: the distance between the two will be added to the total packet's
+ * distance.
  *
- * Wired nodes also provide several convenience methods for interacting with a wired network. These should only ever
- * be used on the main server thread.
+ * Wired nodes also provide several convenience methods for interacting with a wired network. These should only ever be used on the main server thread.
  */
-public interface IWiredNode extends IPacketNetwork
-{
+public interface IWiredNode extends IPacketNetwork {
     /**
      * The associated element for this network node.
      *
@@ -35,17 +34,6 @@ public interface IWiredNode extends IPacketNetwork
     @Nonnull
     IWiredElement getElement();
 
-    /**
-     * The network this node is currently connected to. Note that this may change
-     * after any network operation, so it should not be cached.
-     *
-     * This should only be used on the server thread.
-     *
-     * @return This node's network.
-     */
-    @Nonnull
-    IWiredNetwork getNetwork();
-
     /**
      * Create a connection from this node to another.
      *
@@ -56,11 +44,20 @@ public interface IWiredNode extends IPacketNetwork
      * @see IWiredNetwork#connect(IWiredNode, IWiredNode)
      * @see IWiredNode#disconnectFrom(IWiredNode)
      */
-    default boolean connectTo( @Nonnull IWiredNode node )
-    {
-        return getNetwork().connect( this, node );
+    default boolean connectTo(@Nonnull IWiredNode node) {
+        return this.getNetwork().connect(this, node);
     }
 
+    /**
+     * The network this node is currently connected to. Note that this may change after any network operation, so it should not be cached.
+     *
+     * This should only be used on the server thread.
+     *
+     * @return This node's network.
+     */
+    @Nonnull
+    IWiredNetwork getNetwork();
+
     /**
      * Destroy a connection between this node and another.
      *
@@ -72,38 +69,32 @@ public interface IWiredNode extends IPacketNetwork
      * @see IWiredNetwork#disconnect(IWiredNode, IWiredNode)
      * @see IWiredNode#connectTo(IWiredNode)
      */
-    default boolean disconnectFrom( @Nonnull IWiredNode node )
-    {
-        return getNetwork().disconnect( this, node );
+    default boolean disconnectFrom(@Nonnull IWiredNode node) {
+        return this.getNetwork().disconnect(this, node);
     }
 
     /**
      * Sever all connections this node has, removing it from this network.
      *
-     * This should only be used on the server thread. You should only call this on nodes
-     * that your network element owns.
+     * This should only be used on the server thread. You should only call this on nodes that your network element owns.
      *
-     * @return Whether this node was removed from the network. One cannot remove a node from a network where it is the
-     * only element.
+     * @return Whether this node was removed from the network. One cannot remove a node from a network where it is the only element.
      * @throws IllegalArgumentException If the node is not in the network.
      * @see IWiredNetwork#remove(IWiredNode)
      */
-    default boolean remove()
-    {
-        return getNetwork().remove( this );
+    default boolean remove() {
+        return this.getNetwork().remove(this);
     }
 
     /**
      * Mark this node's peripherals as having changed.
      *
-     * This should only be used on the server thread. You should only call this on nodes
-     * that your network element owns.
+     * This should only be used on the server thread. You should only call this on nodes that your network element owns.
      *
      * @param peripherals The new peripherals for this node.
      * @see IWiredNetwork#updatePeripherals(IWiredNode, Map)
      */
-    default void updatePeripherals( @Nonnull Map<String, IPeripheral> peripherals )
-    {
-        getNetwork().updatePeripherals( this, peripherals );
+    default void updatePeripherals(@Nonnull Map<String, IPeripheral> peripherals) {
+        this.getNetwork().updatePeripherals(this, peripherals);
     }
 }

src/main/java/dan200/computercraft/api/network/wired/IWiredSender.java

@@ -1,28 +1,25 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.network.wired;
 
-import dan200.computercraft.api.network.IPacketSender;
-
 import javax.annotation.Nonnull;
 
+import dan200.computercraft.api.network.IPacketSender;
+
 /**
  * An object on a {@link IWiredNetwork} capable of sending packets.
  *
- * Unlike a regular {@link IPacketSender}, this must be associated with the node you are attempting to
- * to send the packet from.
+ * Unlike a regular {@link IPacketSender}, this must be associated with the node you are attempting to to send the packet from.
  */
-public interface IWiredSender extends IPacketSender
-{
+public interface IWiredSender extends IPacketSender {
     /**
      * The node in the network representing this object.
      *
-     * This should be used as a proxy for the main network. One should send packets
-     * and register receivers through this object.
+     * This should be used as a proxy for the main network. One should send packets and register receivers through this object.
      *
      * @return The node for this element.
      */

src/main/java/dan200/computercraft/api/peripheral/IComputerAccess.java

@@ -1,169 +1,160 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.peripheral;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-import dan200.computercraft.api.filesystem.IMount;
-import dan200.computercraft.api.filesystem.IWritableMount;
-import dan200.computercraft.api.lua.ILuaContext;
-import dan200.computercraft.api.lua.ILuaTask;
-import net.minecraft.world.World;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Collections;
-import java.util.Map;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.filesystem.IMount;
+import dan200.computercraft.api.filesystem.IWritableMount;
+import dan200.computercraft.api.lua.ILuaCallback;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaTask;
+import dan200.computercraft.api.lua.MethodResult;
+
+import net.minecraft.world.World;
 
 /**
- * The interface passed to peripherals by computers or turtles, providing methods
- * that they can call. This should not be implemented by your classes. Do not interact
- * with computers except via this interface.
+ * The interface passed to peripherals by computers or turtles, providing methods that they can call. This should not be implemented by your classes. Do not
+ * interact with computers except via this interface.
  */
-public interface IComputerAccess
-{
+public interface IComputerAccess {
     /**
      * Mount a mount onto the computer's file system in a read only mode.
      *
      * @param desiredLocation The location on the computer's file system where you would like the mount to be mounted.
-     * @param mount           The mount object to mount on the computer.
-     * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a
-     * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @param mount The mount object to mount on the computer.
+     * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a file in the desired location.
+     *     Store this value if you wish to unmount the mount later.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount, String)
      * @see #mountWritable(String, IWritableMount)
      * @see #unmount(String)
      * @see IMount
      */
     @Nullable
-    default String mount( @Nonnull String desiredLocation, @Nonnull IMount mount )
-    {
-        return mount( desiredLocation, mount, getAttachmentName() );
+    default String mount(@Nonnull String desiredLocation, @Nonnull IMount mount) {
+        return this.mount(desiredLocation, mount, this.getAttachmentName());
     }
 
     /**
      * Mount a mount onto the computer's file system in a read only mode.
      *
      * @param desiredLocation The location on the computer's file system where you would like the mount to be mounted.
-     * @param mount           The mount object to mount on the computer.
-     * @param driveName       A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
-     * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a
-     * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @param mount The mount object to mount on the computer.
+     * @param driveName A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
+     * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a file in the desired location.
+     *     Store this value if you wish to unmount the mount later.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #mountWritable(String, IWritableMount)
      * @see #unmount(String)
      * @see IMount
      */
     @Nullable
-    String mount( @Nonnull String desiredLocation, @Nonnull IMount mount, @Nonnull String driveName );
+    String mount(@Nonnull String desiredLocation, @Nonnull IMount mount, @Nonnull String driveName);
+
+    /**
+     * Get a string, unique to the computer, by which the computer refers to this peripheral. For directly attached peripherals this will be
+     * "left","right","front","back",etc, but for peripherals attached remotely it will be different. It is good practice to supply this string when raising
+     * events to the computer, so that the computer knows from which peripheral the event came.
+     *
+     * @return A string unique to the computer, but not globally.
+     * @throws NotAttachedException If the peripheral has been detached.
+     */
+    @Nonnull
+    String getAttachmentName();
 
     /**
      * Mount a mount onto the computer's file system in a writable mode.
      *
      * @param desiredLocation The location on the computer's file system where you would like the mount to be mounted.
-     * @param mount           The mount object to mount on the computer.
-     * @return The location on the computer's file system where you the mount mounted, or null if there was already a
-     * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @param mount The mount object to mount on the computer.
+     * @return The location on the computer's file system where you the mount mounted, or null if there was already a file in the desired location. Store
+     *     this value if you wish to unmount the mount later.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #unmount(String)
      * @see IMount
      */
     @Nullable
-    default String mountWritable( @Nonnull String desiredLocation, @Nonnull IWritableMount mount )
-    {
-        return mountWritable( desiredLocation, mount, getAttachmentName() );
+    default String mountWritable(@Nonnull String desiredLocation, @Nonnull IWritableMount mount) {
+        return this.mountWritable(desiredLocation, mount, this.getAttachmentName());
     }
 
     /**
      * Mount a mount onto the computer's file system in a writable mode.
      *
      * @param desiredLocation The location on the computer's file system where you would like the mount to be mounted.
-     * @param mount           The mount object to mount on the computer.
-     * @param driveName       A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
-     * @return The location on the computer's file system where you the mount mounted, or null if there was already a
-     * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @param mount The mount object to mount on the computer.
+     * @param driveName A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
+     * @return The location on the computer's file system where you the mount mounted, or null if there was already a file in the desired location. Store
+     *     this value if you wish to unmount the mount later.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #unmount(String)
      * @see IMount
      */
-    String mountWritable( @Nonnull String desiredLocation, @Nonnull IWritableMount mount, @Nonnull String driveName );
+    String mountWritable(@Nonnull String desiredLocation, @Nonnull IWritableMount mount, @Nonnull String driveName);
 
     /**
-     * Unmounts a directory previously mounted onto the computers file system by {@link #mount(String, IMount)}
-     * or {@link #mountWritable(String, IWritableMount)}.
+     * Unmounts a directory previously mounted onto the computers file system by {@link #mount(String, IMount)} or {@link #mountWritable(String,
+     * IWritableMount)}.
      *
-     * When a directory is unmounted, it will disappear from the computers file system, and the user will no longer be
-     * able to access it. All directories mounted by a mount or mountWritable are automatically unmounted when the
-     * peripheral is attached if they have not been explicitly unmounted.
+     * When a directory is unmounted, it will disappear from the computers file system, and the user will no longer be able to access it. All directories
+     * mounted by a mount or mountWritable are automatically unmounted when the peripheral is attached if they have not been explicitly unmounted.
      *
      * Note that you cannot unmount another peripheral's mounts.
      *
-     * @param location The desired location in the computers file system of the directory to unmount.
-     *                 This must be the location of a directory previously mounted by {@link #mount(String, IMount)} or
-     *                 {@link #mountWritable(String, IWritableMount)}, as indicated by their return value.
-     * @throws RuntimeException If the peripheral has been detached.
-     * @throws RuntimeException If the mount does not exist, or was mounted by another peripheral.
+     * @param location The desired location in the computers file system of the directory to unmount. This must be the location of a directory
+     *     previously mounted by {@link #mount(String, IMount)} or {@link #mountWritable(String, IWritableMount)}, as indicated by their return value.
+     * @throws NotAttachedException If the peripheral has been detached.
+     * @throws IllegalStateException If the mount does not exist, or was mounted by another peripheral.
      * @see #mount(String, IMount)
      * @see #mountWritable(String, IWritableMount)
      */
-    void unmount( @Nullable String location );
+    void unmount(@Nullable String location);
 
     /**
      * Returns the numerical ID of this computer.
      *
-     * This is the same number obtained by calling {@code os.getComputerID()} or running the "id" program from lua,
-     * and is guaranteed unique. This number will be positive.
+     * This is the same number obtained by calling {@code os.getComputerID()} or running the "id" program from lua, and is guaranteed unique. This number
+     * will be positive.
      *
      * @return The identifier.
      */
     int getID();
 
     /**
-     * Causes an event to be raised on this computer, which the computer can respond to by calling
-     * {@code os.pullEvent()}. This can be used to notify the computer when things happen in the world or to
-     * this peripheral.
+     * Causes an event to be raised on this computer, which the computer can respond to by calling {@code os.pullEvent()}. This can be used to notify the
+     * computer when things happen in the world or to this peripheral.
      *
-     * @param event     A string identifying the type of event that has occurred, this will be
-     *                  returned as the first value from {@code os.pullEvent()}. It is recommended that you
-     *                  you choose a name that is unique, and recognisable as originating from your
-     *                  peripheral. eg: If your peripheral type is "button", a suitable event would be
-     *                  "button_pressed".
-     * @param arguments In addition to a name, you may pass an array of extra arguments to the event, that will
-     *                  be supplied as extra return values to os.pullEvent(). Objects in the array will be converted
-     *                  to lua data types in the same fashion as the return values of IPeripheral.callMethod().
+     * @param event A string identifying the type of event that has occurred, this will be returned as the first value from {@code os.pullEvent()}. It
+     *     is recommended that you you choose a name that is unique, and recognisable as originating from your peripheral. eg: If your peripheral type is
+     *     "button", a suitable event would be "button_pressed".
+     * @param arguments In addition to a name, you may pass an array of extra arguments to the event, that will be supplied as extra return values to
+     *     os.pullEvent(). Objects in the array will be converted to lua data types in the same fashion as the return values of IPeripheral.callMethod().
      *
-     *                  You may supply {@code null} to indicate that no arguments are to be supplied.
-     * @throws RuntimeException If the peripheral has been detached.
-     * @see IPeripheral#callMethod
+     *     You may supply {@code null} to indicate that no arguments are to be supplied.
+     * @throws NotAttachedException If the peripheral has been detached.
+     * @see MethodResult#pullEvent(String, ILuaCallback)
      */
-    void queueEvent( @Nonnull String event, @Nullable Object[] arguments );
-
-    /**
-     * Get a string, unique to the computer, by which the computer refers to this peripheral.
-     * For directly attached peripherals this will be "left","right","front","back",etc, but
-     * for peripherals attached remotely it will be different. It is good practice to supply
-     * this string when raising events to the computer, so that the computer knows from
-     * which peripheral the event came.
-     *
-     * @return A string unique to the computer, but not globally.
-     * @throws RuntimeException If the peripheral has been detached.
-     */
-    @Nonnull
-    String getAttachmentName();
+    void queueEvent(@Nonnull String event, @Nullable Object... arguments);
 
     /**
      * Get a set of peripherals that this computer access can "see", along with their attachment name.
@@ -171,45 +162,36 @@ public interface IComputerAccess
      * This may include other peripherals on the wired network or peripherals on other sides of the computer.
      *
      * @return All reachable peripherals
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see #getAttachmentName()
      * @see #getAvailablePeripheral(String)
      */
     @Nonnull
-    default Map<String, IPeripheral> getAvailablePeripherals()
-    {
-        return Collections.emptyMap();
-    }
+    Map<String, IPeripheral> getAvailablePeripherals();
 
     /**
-     * Get a reachable peripheral with the given attachment name. This is a equivalent to
-     * {@link #getAvailablePeripherals()}{@code .get(name)}, though may be more efficient.
+     * Get a reachable peripheral with the given attachment name. This is a equivalent to {@link #getAvailablePeripherals()}{@code .get(name)}, though may
+     * be more efficient.
      *
      * @param name The peripheral's attached name
      * @return The reachable peripheral, or {@code null} if none can be found.
      * @see #getAvailablePeripherals()
      */
     @Nullable
-    default IPeripheral getAvailablePeripheral( @Nonnull String name )
-    {
-        return null;
-    }
+    IPeripheral getAvailablePeripheral(@Nonnull String name);
 
     /**
      * Get a {@link IWorkMonitor} for tasks your peripheral might execute on the main (server) thread.
      *
-     * This should be used to ensure your peripheral integrates with ComputerCraft's monitoring and limiting of how much
-     * server time each computer consumes. You should not need to use this if you use
-     * {@link ILuaContext#issueMainThreadTask(ILuaTask)} - this is intended for mods with their own system for running
-     * work on the main thread.
+     * This should be used to ensure your peripheral integrates with ComputerCraft's monitoring and limiting of how much server time each computer consumes.
+     * You should not need to use this if you use {@link ILuaContext#issueMainThreadTask(ILuaTask)} - this is intended for mods with their own system for
+     * running work on the main thread.
      *
-     * Please note that the returned implementation is <em>not</em> thread-safe, and should only be used from the main
-     * thread.
+     * Please note that the returned implementation is <em>not</em> thread-safe, and should only be used from the main thread.
      *
      * @return The work monitor for the main thread, or {@code null} if this computer does not have one.
+     * @throws NotAttachedException If the peripheral has been detached.
      */
-    @Nullable
-    default IWorkMonitor getMainThreadMonitor()
-    {
-        return null;
-    }
+    @Nonnull
+    IWorkMonitor getMainThreadMonitor();
 }

src/main/java/dan200/computercraft/api/peripheral/IDynamicPeripheral.java

@@ -0,0 +1,53 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.peripheral;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.lua.IArguments;
+import dan200.computercraft.api.lua.IDynamicLuaObject;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.LuaFunction;
+import dan200.computercraft.api.lua.MethodResult;
+
+/**
+ * A peripheral whose methods are not known at runtime.
+ *
+ * This behaves similarly to {@link IDynamicLuaObject}, though also accepting the current {@link IComputerAccess}. Generally one may use {@link LuaFunction}
+ * instead of implementing this interface.
+ */
+public interface IDynamicPeripheral extends IPeripheral {
+    /**
+     * Should return an array of strings that identify the methods that this peripheral exposes to Lua. This will be called once before each attachment, and
+     * should not change when called multiple times.
+     *
+     * @return An array of strings representing method names.
+     * @see #callMethod
+     */
+    @Nonnull
+    String[] getMethodNames();
+
+    /**
+     * This is called when a lua program on an attached computer calls {@code peripheral.call()} with one of the methods exposed by {@link
+     * #getMethodNames()}.
+     *
+     * Be aware that this will be called from the ComputerCraft Lua thread, and must be thread-safe when interacting with Minecraft objects.
+     *
+     * @param computer The interface to the computer that is making the call. Remember that multiple computers can be attached to a peripheral at once.
+     * @param context The context of the currently running lua thread. This can be used to wait for events or otherwise yield.
+     * @param method An integer identifying which of the methods from getMethodNames() the computercraft wishes to call. The integer indicates the index
+     *     into the getMethodNames() table that corresponds to the string passed into peripheral.call()
+     * @param arguments The arguments for this method.
+     * @return A {@link MethodResult} containing the values to return or the action to perform.
+     * @throws LuaException If you throw any exception from this function, a lua error will be raised with the same message as your exception. Use this
+     *     to throw appropriate errors if the wrong arguments are supplied to your method.
+     * @see #getMethodNames()
+     */
+    @Nonnull
+    MethodResult callMethod(@Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull IArguments arguments) throws LuaException;
+}

src/main/java/dan200/computercraft/api/peripheral/IPeripheral.java

@@ -1,142 +1,84 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.peripheral;
 
-import dan200.computercraft.api.lua.ILuaContext;
-import dan200.computercraft.api.lua.LuaException;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import dan200.computercraft.api.lua.LuaFunction;
+
 /**
- * The interface that defines a peripheral. See {@link IPeripheralProvider} for how to associate blocks with peripherals.
+ * The interface that defines a peripheral.
+ *
+ * In order to expose a peripheral for your block or tile entity, you register a {@link IPeripheralProvider}. This <em>cannot</em> be implemented {@link
+ * IPeripheral} directly on the tile.
+ *
+ * Peripherals should provide a series of methods to the user, either using {@link LuaFunction} or by implementing {@link IDynamicPeripheral}.
  */
-public interface IPeripheral
-{
+public interface IPeripheral {
     /**
-     * Should return a string that uniquely identifies this type of peripheral.
-     * This can be queried from lua by calling {@code peripheral.getType()}
+     * Should return a string that uniquely identifies this type of peripheral. This can be queried from lua by calling {@code peripheral.getType()}
      *
      * @return A string identifying the type of peripheral.
      */
     @Nonnull
     String getType();
 
-    /**
-     * Should return an array of strings that identify the methods that this
-     * peripheral exposes to Lua. This will be called once before each attachment,
-     * and should not change when called multiple times.
-     *
-     * @return An array of strings representing method names.
-     * @see #callMethod
-     */
-    @Nonnull
-    String[] getMethodNames();
-
-    /**
-     * This is called when a lua program on an attached computer calls {@code peripheral.call()} with
-     * one of the methods exposed by {@link #getMethodNames()}.
-     *
-     * Be aware that this will be called from the ComputerCraft Lua thread, and must be thread-safe when interacting
-     * with Minecraft objects.
-     *
-     * @param computer  The interface to the computer that is making the call. Remember that multiple
-     *                  computers can be attached to a peripheral at once.
-     * @param context   The context of the currently running lua thread. This can be used to wait for events
-     *                  or otherwise yield.
-     * @param method    An integer identifying which of the methods from getMethodNames() the computercraft
-     *                  wishes to call. The integer indicates the index into the getMethodNames() table
-     *                  that corresponds to the string passed into peripheral.call()
-     * @param arguments An array of objects, representing the arguments passed into {@code peripheral.call()}.<br>
-     *                  Lua values of type "string" will be represented by Object type String.<br>
-     *                  Lua values of type "number" will be represented by Object type Double.<br>
-     *                  Lua values of type "boolean" will be represented by Object type Boolean.<br>
-     *                  Lua values of type "table" will be represented by Object type Map.<br>
-     *                  Lua values of any other type will be represented by a null object.<br>
-     *                  This array will be empty if no arguments are passed.
-     * @return An array of objects, representing values you wish to return to the lua program. Integers, Doubles, Floats,
-     * Strings, Booleans, Maps and ILuaObject and null be converted to their corresponding lua type. All other types
-     * will be converted to nil.
-     *
-     * You may return null to indicate no values should be returned.
-     * @throws LuaException         If you throw any exception from this function, a lua error will be raised with the
-     *                              same message as your exception. Use this to throw appropriate errors if the wrong
-     *                              arguments are supplied to your method.
-     * @throws InterruptedException If the user shuts down or reboots the computer the coroutine is suspended,
-     *                              InterruptedException will be thrown. This exception must not be caught or
-     *                              intercepted, or the computer will leak memory and end up in a broken state.
-     * @see #getMethodNames
-     */
-    @Nullable
-    Object[] callMethod( @Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull Object[] arguments ) throws LuaException, InterruptedException;
-
     /**
      * Is called when when a computer is attaching to the peripheral.
      *
-     * This will occur when a peripheral is placed next to an active computer, when a computer is turned on next to a
-     * peripheral, when a turtle travels into a square next to a peripheral, or when a wired modem adjacent to this
-     * peripheral is does any of the above.
+     * This will occur when a peripheral is placed next to an active computer, when a computer is turned on next to a peripheral, when a turtle travels into
+     * a square next to a peripheral, or when a wired modem adjacent to this peripheral is does any of the above.
      *
-     * Between calls to attach and {@link #detach}, the attached computer can make method calls on the peripheral using
-     * {@code peripheral.call()}. This method can be used to keep track of which computers are attached to the
-     * peripheral, or to take action when attachment occurs.
+     * Between calls to attach and {@link #detach}, the attached computer can make method calls on the peripheral using {@code peripheral.call()}. This
+     * method can be used to keep track of which computers are attached to the peripheral, or to take action when attachment occurs.
      *
-     * Be aware that will be called from both the server thread and ComputerCraft Lua thread, and so must be thread-safe
-     * and reentrant.
+     * Be aware that will be called from both the server thread and ComputerCraft Lua thread, and so must be thread-safe and reentrant.
      *
-     * @param computer The interface to the computer that is being attached. Remember that multiple computers can be
-     *                 attached to a peripheral at once.
+     * @param computer The interface to the computer that is being attached. Remember that multiple computers can be attached to a peripheral at once.
      * @see #detach
      */
-    default void attach( @Nonnull IComputerAccess computer )
-    {
+    default void attach(@Nonnull IComputerAccess computer) {
     }
 
     /**
      * Called when a computer is detaching from the peripheral.
      *
-     * This will occur when a computer shuts down, when the peripheral is removed while attached to computers, when a
-     * turtle moves away from a block attached to a peripheral, or when a wired modem adjacent to this peripheral is
-     * detached.
+     * This will occur when a computer shuts down, when the peripheral is removed while attached to computers, when a turtle moves away from a block
+     * attached to a peripheral, or when a wired modem adjacent to this peripheral is detached.
      *
-     * This method can be used to keep track of which computers are attached to the peripheral, or to take action when
-     * detachment occurs.
+     * This method can be used to keep track of which computers are attached to the peripheral, or to take action when detachment occurs.
      *
-     * Be aware that this will be called from both the server and ComputerCraft Lua thread, and must be thread-safe
-     * and reentrant.
+     * Be aware that this will be called from both the server and ComputerCraft Lua thread, and must be thread-safe and reentrant.
      *
-     * @param computer The interface to the computer that is being detached. Remember that multiple computers can be
-     *                 attached to a peripheral at once.
+     * @param computer The interface to the computer that is being detached. Remember that multiple computers can be attached to a peripheral at once.
      * @see #attach
      */
-    default void detach( @Nonnull IComputerAccess computer )
-    {
+    default void detach(@Nonnull IComputerAccess computer) {
     }
 
     /**
-     * Get the object that this peripheral provides methods for. This will generally be the tile entity
-     * or block, but may be an inventory, entity, etc...
+     * Get the object that this peripheral provides methods for. This will generally be the tile entity or block, but may be an inventory, entity, etc...
      *
      * @return The object this peripheral targets
      */
-    @Nonnull
-    default Object getTarget()
-    {
-        return this;
+    @Nullable
+    default Object getTarget() {
+        return null;
     }
 
     /**
      * Determine whether this peripheral is equivalent to another one.
      *
-     * The minimal example should at least check whether they are the same object. However, you may wish to check if
-     * they point to the same block or tile entity.
+     * The minimal example should at least check whether they are the same object. However, you may wish to check if they point to the same block or tile
+     * entity.
      *
      * @param other The peripheral to compare against. This may be {@code null}.
      * @return Whether these peripherals are equivalent.
      */
-    boolean equals( @Nullable IPeripheral other );
+    boolean equals(@Nullable IPeripheral other);
 }

src/main/java/dan200/computercraft/api/peripheral/IPeripheralProvider.java

@@ -1,38 +1,38 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.peripheral;
 
-import net.minecraft.tileentity.TileEntity;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.World;
+import java.util.Optional;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
+
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.World;
 
 /**
  * This interface is used to create peripheral implementations for blocks.
  *
- * If you have a {@link TileEntity} which acts as a peripheral, you may alternatively implement {@link IPeripheralTile}.
+ * If you have a {@link BlockEntity} which acts as a peripheral, you may alternatively expose the {@link IPeripheral} capability.
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerPeripheralProvider(IPeripheralProvider)
  */
 @FunctionalInterface
-public interface IPeripheralProvider
-{
+public interface IPeripheralProvider {
     /**
      * Produce an peripheral implementation from a block location.
      *
      * @param world The world the block is in.
-     * @param pos   The position the block is at.
-     * @param side  The side to get the peripheral from.
-     * @return A peripheral, or {@code null} if there is not a peripheral here you'd like to handle.
+     * @param pos The position the block is at.
+     * @param side The side to get the peripheral from.
+     * @return A peripheral, or {@link Optional#empty()} if there is not a peripheral here you'd like to handle.
      * @see dan200.computercraft.api.ComputerCraftAPI#registerPeripheralProvider(IPeripheralProvider)
      */
-    @Nullable
-    IPeripheral getPeripheral( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+    @Nonnull
+    IPeripheral getPeripheral(@Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side);
 }

src/main/java/dan200/computercraft/api/peripheral/IPeripheralTile.java

@@ -3,30 +3,29 @@
  * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-package dan200.computercraft.api.peripheral;
 
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.World;
+package dan200.computercraft.api.peripheral;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.World;
+
 /**
- * A {@link net.minecraft.tileentity.TileEntity} which may act as a peripheral.
+ * A {@link net.minecraft.block.entity.BlockEntity} which may act as a peripheral.
  *
- * If you need more complex capabilities (such as handling TEs not belonging to your mod), you should use
- * {@link IPeripheralProvider}.
+ * If you need more complex capabilities (such as handling TEs not belonging to your mod), you should use {@link IPeripheralProvider}.
  */
-public interface IPeripheralTile
-{
+public interface IPeripheralTile {
     /**
      * Get the peripheral on the given {@code side}.
      *
      * @param side The side to get the peripheral from.
      * @return A peripheral, or {@code null} if there is not a peripheral here.
-     * @see IPeripheralProvider#getPeripheral(World, BlockPos, EnumFacing)
+     * @see IPeripheralProvider#getPeripheral(World, BlockPos, Direction)
      */
     @Nullable
-    IPeripheral getPeripheral( @Nonnull EnumFacing side );
+    IPeripheral getPeripheral(@Nonnull Direction side);
 }

src/main/java/dan200/computercraft/api/peripheral/IWorkMonitor.java

@@ -1,32 +1,63 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.peripheral;
 
-import javax.annotation.Nonnull;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
+import javax.annotation.Nonnull;
+
 /**
- * Monitors "work" associated with a computer, keeping track of how much a computer has done, and ensuring every
- * computer receives a fair share of any processing time.
+ * Monitors "work" associated with a computer, keeping track of how much a computer has done, and ensuring every computer receives a fair share of any
+ * processing time.
  *
- * This is primarily intended for work done by peripherals on the main thread (such as on a tile entity's tick), but
- * could be used for other purposes (such as complex computations done on another thread).
+ * This is primarily intended for work done by peripherals on the main thread (such as on a tile entity's tick), but could be used for other purposes (such
+ * as complex computations done on another thread).
  *
- * Before running a task, one should call {@link #canWork()} to determine if the computer is currently allowed to
- * execute work. If that returns true, you should execute the task and use {@link #trackWork(long, TimeUnit)} to inform
- * the monitor how long that task took.
+ * Before running a task, one should call {@link #canWork()} to determine if the computer is currently allowed to execute work. If that returns true, you
+ * should execute the task and use {@link #trackWork(long, TimeUnit)} to inform the monitor how long that task took.
  *
  * Alternatively, use {@link #runWork(Runnable)} to run and keep track of work.
  *
  * @see IComputerAccess#getMainThreadMonitor()
  */
-public interface IWorkMonitor
-{
+public interface IWorkMonitor {
+    /**
+     * If the owning computer is currently allowed to execute work, and has ample time to do so.
+     *
+     * This is effectively a more restrictive form of {@link #canWork()}. One should use that in order to determine if you may do an initial piece of work,
+     * and shouldWork to determine if any additional task may be performed.
+     *
+     * @return If we should execute work right now.
+     */
+    boolean shouldWork();
+
+    /**
+     * Run a task if possible, and inform the monitor of how long it took.
+     *
+     * @param runnable The task to run.
+     * @return If the task was actually run (namely, {@link #canWork()} returned {@code true}).
+     */
+    default boolean runWork(@Nonnull Runnable runnable) {
+        Objects.requireNonNull(runnable, "runnable should not be null");
+        if (!this.canWork()) {
+            return false;
+        }
+
+        long start = System.nanoTime();
+        try {
+            runnable.run();
+        } finally {
+            this.trackWork(System.nanoTime() - start, TimeUnit.NANOSECONDS);
+        }
+
+        return true;
+    }
+
     /**
      * If the owning computer is currently allowed to execute work.
      *
@@ -34,45 +65,11 @@ public interface IWorkMonitor
      */
     boolean canWork();
 
-    /**
-     * If the owning computer is currently allowed to execute work, and has ample time to do so.
-     *
-     * This is effectively a more restrictive form of {@link #canWork()}. One should use that in order to determine if
-     * you may do an initial piece of work, and shouldWork to determine if any additional task may be performed.
-     *
-     * @return If we should execute work right now.
-     */
-    boolean shouldWork();
-
     /**
      * Inform the monitor how long some piece of work took to execute.
      *
      * @param time The time some task took to run
      * @param unit The unit that {@code time} was measured in.
      */
-    void trackWork( long time, @Nonnull TimeUnit unit );
-
-    /**
-     * Run a task if possible, and inform the monitor of how long it took.
-     *
-     * @param runnable The task to run.
-     * @return If the task was actually run (namely, {@link #canWork()} returned {@code true}).
-     */
-    default boolean runWork( @Nonnull Runnable runnable )
-    {
-        Objects.requireNonNull( runnable, "runnable should not be null" );
-        if( !canWork() ) return false;
-
-        long start = System.nanoTime();
-        try
-        {
-            runnable.run();
-        }
-        finally
-        {
-            trackWork( System.nanoTime() - start, TimeUnit.NANOSECONDS );
-        }
-
-        return true;
-    }
+    void trackWork(long time, @Nonnull TimeUnit unit);
 }

src/main/java/dan200/computercraft/api/peripheral/NotAttachedException.java

@@ -0,0 +1,22 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.peripheral;
+
+/**
+ * Thrown when performing operations on {@link IComputerAccess} when the current peripheral is no longer attached to the computer.
+ */
+public class NotAttachedException extends IllegalStateException {
+    private static final long serialVersionUID = 1221244785535553536L;
+
+    public NotAttachedException() {
+        super("You are not attached to this computer");
+    }
+
+    public NotAttachedException(String s) {
+        super(s);
+    }
+}

src/main/java/dan200/computercraft/api/pocket/AbstractPocketUpgrade.java

@@ -1,64 +1,60 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.pocket;
 
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.IItemProvider;
-import net.minecraft.util.ResourceLocation;
-import net.minecraft.util.Util;
-
 import javax.annotation.Nonnull;
 
+import net.minecraft.item.ItemConvertible;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.Util;
+
 /**
  * A base class for {@link IPocketUpgrade}s.
  *
  * One does not have to use this, but it does provide a convenient template.
  */
-public abstract class AbstractPocketUpgrade implements IPocketUpgrade
-{
-    private final ResourceLocation id;
+public abstract class AbstractPocketUpgrade implements IPocketUpgrade {
+    private final Identifier id;
     private final String adjective;
     private final ItemStack stack;
 
-    protected AbstractPocketUpgrade( ResourceLocation id, String adjective, ItemStack stack )
-    {
+    protected AbstractPocketUpgrade(Identifier id, ItemConvertible item) {
+        this(id, Util.createTranslationKey("upgrade", id) + ".adjective", item);
+    }
+
+    protected AbstractPocketUpgrade(Identifier id, String adjective, ItemConvertible item) {
+        this.id = id;
+        this.adjective = adjective;
+        this.stack = new ItemStack(item);
+    }
+
+    protected AbstractPocketUpgrade(Identifier id, String adjective, ItemStack stack) {
         this.id = id;
         this.adjective = adjective;
         this.stack = stack;
     }
 
-    protected AbstractPocketUpgrade( ResourceLocation id, String adjective, IItemProvider item )
-    {
-        this( id, adjective, new ItemStack( item ) );
-    }
 
-    protected AbstractPocketUpgrade( ResourceLocation id, IItemProvider item )
-    {
-        this( id, Util.makeTranslationKey( "upgrade", id ) + ".adjective", new ItemStack( item ) );
+    @Nonnull
+    @Override
+    public final Identifier getUpgradeID() {
+        return this.id;
     }
 
     @Nonnull
     @Override
-    public final ResourceLocation getUpgradeID()
-    {
-        return id;
+    public final String getUnlocalisedAdjective() {
+        return this.adjective;
     }
 
     @Nonnull
     @Override
-    public final String getUnlocalisedAdjective()
-    {
-        return adjective;
-    }
-
-    @Nonnull
-    @Override
-    public final ItemStack getCraftingItem()
-    {
-        return stack;
+    public final ItemStack getCraftingItem() {
+        return this.stack;
     }
 }

src/main/java/dan200/computercraft/api/pocket/IPocketAccess.java

@@ -1,25 +1,26 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.pocket;
 
-import dan200.computercraft.api.peripheral.IPeripheral;
-import net.minecraft.entity.Entity;
-import net.minecraft.nbt.NBTTagCompound;
-import net.minecraft.util.ResourceLocation;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Map;
+
+import dan200.computercraft.api.peripheral.IPeripheral;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.util.Identifier;
 
 /**
- * Wrapper class for pocket computers
+ * Wrapper class for pocket computers.
  */
-public interface IPocketAccess
-{
+public interface IPocketAccess {
     /**
      * Gets the entity holding this item.
      *
@@ -33,8 +34,7 @@ public interface IPocketAccess
     /**
      * Get the colour of this pocket computer as a RGB number.
      *
-     * @return The colour this pocket computer is. This will be a RGB colour between {@code 0x000000} and
-     * {@code 0xFFFFFF} or -1 if it has no colour.
+     * @return The colour this pocket computer is. This will be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or -1 if it has no colour.
      * @see #setColour(int)
      */
     int getColour();
@@ -42,17 +42,16 @@ public interface IPocketAccess
     /**
      * Set the colour of the pocket computer to a RGB number.
      *
-     * @param colour The colour this pocket computer should be changed to. This should be a RGB colour between
-     *               {@code 0x000000} and {@code 0xFFFFFF} or -1 to reset to the default colour.
+     * @param colour The colour this pocket computer should be changed to. This should be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or
+     *     -1 to reset to the default colour.
      * @see #getColour()
      */
-    void setColour( int colour );
+    void setColour(int colour);
 
     /**
      * Get the colour of this pocket computer's light as a RGB number.
      *
-     * @return The colour this light is. This will be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or
-     * -1 if it has no colour.
+     * @return The colour this light is. This will be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or -1 if it has no colour.
      * @see #setLight(int)
      */
     int getLight();
@@ -60,11 +59,11 @@ public interface IPocketAccess
     /**
      * Set the colour of the pocket computer's light to a RGB number.
      *
-     * @param colour The colour this modem's light will be changed to. This should be a RGB colour between
-     *               {@code 0x000000} and {@code 0xFFFFFF} or -1 to reset to the default colour.
+     * @param colour The colour this modem's light will be changed to. This should be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or -1
+     *     to reset to the default colour.
      * @see #getLight()
      */
-    void setLight( int colour );
+    void setLight(int colour);
 
     /**
      * Get the upgrade-specific NBT.
@@ -75,7 +74,7 @@ public interface IPocketAccess
      * @see #updateUpgradeNBTData()
      */
     @Nonnull
-    NBTTagCompound getUpgradeNBTData();
+    CompoundTag getUpgradeNBTData();
 
     /**
      * Mark the upgrade-specific NBT as dirty.
@@ -95,5 +94,5 @@ public interface IPocketAccess
      * @return A collection of all upgrade names.
      */
     @Nonnull
-    Map<ResourceLocation, IPeripheral> getUpgrades();
+    Map<Identifier, IPeripheral> getUpgrades();
 }

src/main/java/dan200/computercraft/api/pocket/IPocketUpgrade.java

@@ -1,42 +1,41 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.pocket;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.ResourceLocation;
-import net.minecraft.world.World;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Identifier;
+import net.minecraft.world.World;
 
 /**
  * Additional peripherals for pocket computers.
  *
  * This is similar to {@link ITurtleUpgrade}.
  */
-public interface IPocketUpgrade
-{
+public interface IPocketUpgrade {
 
     /**
-     * Gets a unique identifier representing this type of turtle upgrade. eg: "computercraft:wireless_modem" or
-     * "my_mod:my_upgrade".
+     * Gets a unique identifier representing this type of turtle upgrade. eg: "computercraft:wireless_modem" or "my_mod:my_upgrade".
      *
-     * You should use a unique resource domain to ensure this upgrade is uniquely identified. The upgrade will fail
-     * registration if an already used ID is specified.
+     * You should use a unique resource domain to ensure this upgrade is uniquely identified. The upgrade will fail registration if an already used ID is
+     * specified.
      *
      * @return The upgrade's id.
      * @see IPocketUpgrade#getUpgradeID()
      * @see ComputerCraftAPI#registerPocketUpgrade(IPocketUpgrade)
      */
     @Nonnull
-    ResourceLocation getUpgradeID();
+    Identifier getUpgradeID();
 
     /**
      * Return an unlocalised string to describe the type of pocket computer this upgrade provides.
@@ -50,12 +49,11 @@ public interface IPocketUpgrade
     String getUnlocalisedAdjective();
 
     /**
-     * Return an item stack representing the type of item that a pocket computer must be crafted with to create a
-     * pocket computer which holds this upgrade. This item stack is also used to determine the upgrade given by
-     * {@code pocket.equip()}/{@code pocket.unequip()}.
+     * Return an item stack representing the type of item that a pocket computer must be crafted with to create a pocket computer which holds this upgrade.
+     * This item stack is also used to determine the upgrade given by {@code pocket.equip()}/{@code pocket.unequip()}.
      *
-     * Ideally this should be constant over a session. It is recommended that you cache
-     * the item too, in order to prevent constructing it every time the method is called.
+     * Ideally this should be constant over a session. It is recommended that you cache the item too, in order to prevent constructing it every time the
+     * method is called.
      *
      * @return The item stack used for crafting. This can be {@link ItemStack#EMPTY} if crafting is disabled.
      */
@@ -65,41 +63,37 @@ public interface IPocketUpgrade
     /**
      * Creates a peripheral for the pocket computer.
      *
-     * The peripheral created will be stored for the lifetime of the upgrade, will be passed an argument to
-     * {@link #update(IPocketAccess, IPeripheral)} and will be attached, detached and have methods called in the same
-     * manner as an ordinary peripheral.
+     * The peripheral created will be stored for the lifetime of the upgrade, will be passed an argument to {@link #update(IPocketAccess, IPeripheral)} and
+     * will be attached, detached and have methods called in the same manner as an ordinary peripheral.
      *
      * @param access The access object for the pocket item stack.
      * @return The newly created peripheral.
      * @see #update(IPocketAccess, IPeripheral)
      */
     @Nullable
-    IPeripheral createPeripheral( @Nonnull IPocketAccess access );
+    IPeripheral createPeripheral(@Nonnull IPocketAccess access);
 
     /**
      * Called when the pocket computer item stack updates.
      *
-     * @param access     The access object for the pocket item stack.
+     * @param access The access object for the pocket item stack.
      * @param peripheral The peripheral for this upgrade.
      * @see #createPeripheral(IPocketAccess)
      */
-    default void update( @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral )
-    {
+    default void update(@Nonnull IPocketAccess access, @Nullable IPeripheral peripheral) {
     }
 
     /**
      * Called when the pocket computer is right clicked.
      *
-     * @param world      The world the computer is in.
-     * @param access     The access object for the pocket item stack.
+     * @param world The world the computer is in.
+     * @param access The access object for the pocket item stack.
      * @param peripheral The peripheral for this upgrade.
-     * @return {@code true} to stop the GUI from opening, otherwise false. You should always provide some code path
-     * which returns {@code false}, such as requiring the player to be sneaking - otherwise they will be unable to
-     * access the GUI.
+     * @return {@code true} to stop the GUI from opening, otherwise false. You should always provide some code path which returns {@code false}, such as
+     *     requiring the player to be sneaking - otherwise they will be unable to access the GUI.
      * @see #createPeripheral(IPocketAccess)
      */
-    default boolean onRightClick( @Nonnull World world, @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral )
-    {
+    default boolean onRightClick(@Nonnull World world, @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral) {
         return false;
     }
 }

src/main/java/dan200/computercraft/api/redstone/IBundledRedstoneProvider.java

@@ -1,34 +1,32 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.redstone;
 
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.World;
-
 import javax.annotation.Nonnull;
 
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.World;
+
 /**
  * This interface is used to provide bundled redstone output for blocks.
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerBundledRedstoneProvider(IBundledRedstoneProvider)
  */
 @FunctionalInterface
-public interface IBundledRedstoneProvider
-{
+public interface IBundledRedstoneProvider {
     /**
      * Produce an bundled redstone output from a block location.
      *
      * @param world The world this block is in.
-     * @param pos   The position this block is at.
-     * @param side  The side to extract the bundled redstone output from.
-     * @return A number in the range 0-65535 to indicate this block is providing output, or -1 if you do not wish to
-     * handle this block.
+     * @param pos The position this block is at.
+     * @param side The side to extract the bundled redstone output from.
+     * @return A number in the range 0-65535 to indicate this block is providing output, or -1 if you do not wish to handle this block.
      * @see dan200.computercraft.api.ComputerCraftAPI#registerBundledRedstoneProvider(IBundledRedstoneProvider)
      */
-    int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+    int getBundledRedstoneOutput(@Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side);
 }

src/main/java/dan200/computercraft/api/turtle/AbstractTurtleUpgrade.java

@@ -0,0 +1,70 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+package dan200.computercraft.api.turtle;
+
+import javax.annotation.Nonnull;
+
+import net.minecraft.item.ItemConvertible;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.Util;
+
+/**
+ * A base class for {@link ITurtleUpgrade}s.
+ *
+ * One does not have to use this, but it does provide a convenient template.
+ */
+public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade {
+    private final Identifier id;
+    private final TurtleUpgradeType type;
+    private final String adjective;
+    private final ItemStack stack;
+
+    protected AbstractTurtleUpgrade(Identifier id, TurtleUpgradeType type, String adjective, ItemConvertible item) {
+        this(id, type, adjective, new ItemStack(item));
+    }
+
+    protected AbstractTurtleUpgrade(Identifier id, TurtleUpgradeType type, String adjective, ItemStack stack) {
+        this.id = id;
+        this.type = type;
+        this.adjective = adjective;
+        this.stack = stack;
+    }
+
+    protected AbstractTurtleUpgrade(Identifier id, TurtleUpgradeType type, ItemConvertible item) {
+        this(id, type, new ItemStack(item));
+    }
+
+    protected AbstractTurtleUpgrade(Identifier id, TurtleUpgradeType type, ItemStack stack) {
+        this(id, type, Util.createTranslationKey("upgrade", id) + ".adjective", stack);
+    }
+
+
+    @Nonnull
+    @Override
+    public final Identifier getUpgradeID() {
+        return this.id;
+    }
+
+    @Nonnull
+    @Override
+    public final String getUnlocalisedAdjective() {
+        return this.adjective;
+    }
+
+    @Nonnull
+    @Override
+    public final TurtleUpgradeType getType() {
+        return this.type;
+    }
+
+    @Nonnull
+    @Override
+    public final ItemStack getCraftingItem() {
+        return this.stack;
+    }
+}

src/main/java/dan200/computercraft/api/turtle/FakePlayer.java

@@ -0,0 +1,266 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2018. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.api.turtle;
+
+import java.util.Collection;
+import java.util.OptionalInt;
+import java.util.UUID;
+
+import javax.annotation.Nullable;
+import javax.crypto.SecretKey;
+
+import com.mojang.authlib.GameProfile;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.GenericFutureListener;
+
+import net.minecraft.block.entity.CommandBlockBlockEntity;
+import net.minecraft.block.entity.SignBlockEntity;
+import net.minecraft.command.argument.EntityAnchorArgumentType;
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.damage.DamageSource;
+import net.minecraft.entity.effect.StatusEffectInstance;
+import net.minecraft.entity.passive.HorseBaseEntity;
+import net.minecraft.inventory.Inventory;
+import net.minecraft.item.ItemStack;
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.MessageType;
+import net.minecraft.network.NetworkSide;
+import net.minecraft.network.NetworkState;
+import net.minecraft.network.Packet;
+import net.minecraft.network.packet.c2s.play.RequestCommandCompletionsC2SPacket;
+import net.minecraft.network.packet.c2s.play.VehicleMoveC2SPacket;
+import net.minecraft.recipe.Recipe;
+import net.minecraft.screen.NamedScreenHandlerFactory;
+import net.minecraft.screen.ScreenHandler;
+import net.minecraft.server.network.ServerPlayNetworkHandler;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.server.network.ServerPlayerInteractionManager;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.sound.SoundCategory;
+import net.minecraft.sound.SoundEvent;
+import net.minecraft.text.Text;
+import net.minecraft.util.Hand;
+import net.minecraft.util.collection.DefaultedList;
+import net.minecraft.util.math.ChunkPos;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.village.TraderOfferList;
+import net.minecraft.world.GameMode;
+
+/**
+ * A wrapper for {@link ServerPlayerEntity} which denotes a "fake" player.
+ *
+ * Please note that this does not implement any of the traditional fake player behaviour. It simply exists to prevent me passing in normal players.
+ */
+public class FakePlayer extends ServerPlayerEntity {
+    public FakePlayer(ServerWorld world, GameProfile gameProfile) {
+        super(world.getServer(), world, gameProfile, new ServerPlayerInteractionManager(world));
+        this.networkHandler = new FakeNetHandler(this);
+    }
+
+    // region Direct networkHandler access
+    @Override
+    public void enterCombat() { }
+
+    @Override
+    public void endCombat() { }
+
+    @Override
+    public void tick() { }
+
+    @Override
+    public void playerTick() { }
+
+    @Override
+    public void onDeath(DamageSource damage) { }
+
+    @Override
+    public Entity moveToWorld(ServerWorld destination) {
+        return this;
+    }
+
+    @Override
+    public void wakeUp(boolean bl, boolean updateSleepingPlayers) {
+
+    }
+
+    @Override
+    public boolean startRiding(Entity entity, boolean flag) {
+        return false;
+    }
+
+    @Override
+    public void stopRiding() { }
+
+    @Override
+    public void openEditSignScreen(SignBlockEntity tile) { }
+
+    @Override
+    public OptionalInt openHandledScreen(@Nullable NamedScreenHandlerFactory container) {
+        return OptionalInt.empty();
+    }
+
+    @Override
+    public void sendTradeOffers(int id, TraderOfferList list, int level, int experience, boolean levelled, boolean refreshable) { }
+
+    @Override
+    public void openHorseInventory(HorseBaseEntity horse, Inventory inventory) { }
+
+    @Override
+    public void openEditBookScreen(ItemStack stack, Hand hand) { }
+
+    @Override
+    public void openCommandBlockScreen(CommandBlockBlockEntity block) { }
+
+    @Override
+    public void onSlotUpdate(ScreenHandler container, int slot, ItemStack stack) { }
+
+    @Override
+    public void onHandlerRegistered(ScreenHandler container, DefaultedList<ItemStack> defaultedList) { }
+
+    @Override
+    public void onPropertyUpdate(ScreenHandler container, int key, int value) { }
+
+    @Override
+    public void closeHandledScreen() { }
+
+    @Override
+    public void updateCursorStack() { }
+
+    @Override
+    public int unlockRecipes(Collection<Recipe<?>> recipes) {
+        return 0;
+    }
+
+    // Indirect
+    @Override
+    public int lockRecipes(Collection<Recipe<?>> recipes) {
+        return 0;
+    }
+
+    @Override
+    public void sendMessage(Text textComponent, boolean status) { }
+
+    @Override
+    protected void consumeItem() { }
+
+    @Override
+    public void lookAt(EntityAnchorArgumentType.EntityAnchor anchor, Vec3d vec3d) {}
+
+    @Override
+    public void method_14222(EntityAnchorArgumentType.EntityAnchor self, Entity entity, EntityAnchorArgumentType.EntityAnchor target) { }
+
+    @Override
+    protected void onStatusEffectApplied(StatusEffectInstance statusEffectInstance) { }
+
+    @Override
+    protected void onStatusEffectUpgraded(StatusEffectInstance statusEffectInstance, boolean particles) { }
+
+    @Override
+    protected void onStatusEffectRemoved(StatusEffectInstance statusEffectInstance) { }
+
+    @Override
+    public void requestTeleport(double x, double y, double z) { }
+
+    @Override
+    public void setGameMode(GameMode gameMode) { }
+
+    @Override
+    public void sendMessage(Text message, MessageType type, UUID senderUuid) {
+
+    }
+
+    @Override
+    public String getIp() {
+        return "[Fake Player]";
+    }
+
+    @Override
+    public void sendResourcePackUrl(String url, String hash) { }
+
+    @Override
+    public void onStoppedTracking(Entity entity) { }
+
+    @Override
+    public void setCameraEntity(Entity entity) { }
+
+    @Override
+    public void teleport(ServerWorld serverWorld, double x, double y, double z, float pitch, float yaw) { }
+
+    @Override
+    public void sendInitialChunkPackets(ChunkPos chunkPos, Packet<?> packet, Packet<?> packet2) { }
+
+    @Override
+    public void sendUnloadChunkPacket(ChunkPos chunkPos) { }
+
+    @Override
+    public void playSound(SoundEvent soundEvent, SoundCategory soundCategory, float volume, float pitch) { }
+
+    private static class FakeNetHandler extends ServerPlayNetworkHandler {
+        FakeNetHandler(ServerPlayerEntity player) {
+            super(player.server, new FakeConnection(), player);
+        }
+
+        @Override
+        public void disconnect(Text message) { }
+
+        @Override
+        public void onVehicleMove(VehicleMoveC2SPacket move) { }
+
+        @Override
+        public void onRequestCommandCompletions(RequestCommandCompletionsC2SPacket packet) { }
+
+        @Override
+        public void sendPacket(Packet<?> packet, @Nullable GenericFutureListener<? extends Future<? super Void>> listener) { }
+    }
+
+    private static class FakeConnection extends ClientConnection {
+        FakeConnection() {
+            super(NetworkSide.CLIENTBOUND);
+        }
+
+        @Override
+        public void channelActive(ChannelHandlerContext active) {
+        }
+
+        @Override
+        public void setState(NetworkState state) {
+        }
+
+        @Override
+        public void exceptionCaught(ChannelHandlerContext context, Throwable err) {
+        }
+
+        @Override
+        protected void channelRead0(ChannelHandlerContext context, Packet<?> packet) {
+        }
+
+        @Override
+        public void send(Packet<?> packet, @Nullable GenericFutureListener<? extends Future<? super Void>> listener) {
+        }
+
+        @Override
+        public void tick() {
+        }
+
+        @Override
+        public void disconnect(Text message) {
+        }
+
+        @Override
+        public void setupEncryption(SecretKey key) {
+        }
+
+        @Override
+        public void disableAutoRead() {
+        }
+
+        @Override
+        public void setCompressionThreshold(int size) {
+        }
+    }
+}

src/main/java/dan200/computercraft/api/turtle/ITurtleAccess.java

@@ -1,34 +1,33 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle;
 
-import com.mojang.authlib.GameProfile;
-import dan200.computercraft.api.lua.ILuaContext;
-import dan200.computercraft.api.lua.LuaException;
-import dan200.computercraft.api.peripheral.IPeripheral;
-import net.minecraft.inventory.IInventory;
-import net.minecraft.nbt.NBTTagCompound;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.Vec3d;
-import net.minecraft.world.World;
-import net.minecraftforge.items.IItemHandlerModifiable;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import com.mojang.authlib.GameProfile;
+import dan200.computercraft.api.lua.ILuaCallback;
+import dan200.computercraft.api.lua.MethodResult;
+import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.shared.util.ItemStorage;
+
+import net.minecraft.inventory.Inventory;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
+
 /**
  * The interface passed to turtle by turtles, providing methods that they can call.
  *
- * This should not be implemented by your classes. Do not interact with turtles except via this interface and
- * {@link ITurtleUpgrade}.
+ * This should not be implemented by your classes. Do not interact with turtles except via this interface and {@link ITurtleUpgrade}.
  */
-public interface ITurtleAccess
-{
+public interface ITurtleAccess {
     /**
      * Returns the world in which the turtle resides.
      *
@@ -48,27 +47,25 @@ public interface ITurtleAccess
     /**
      * Attempt to move this turtle to a new position.
      *
-     * This will preserve the turtle's internal state, such as it's inventory, computer and upgrades. It should
-     * be used before playing a movement animation using {@link #playAnimation(TurtleAnimation)}.
+     * This will preserve the turtle's internal state, such as it's inventory, computer and upgrades. It should be used before playing a movement animation
+     * using {@link #playAnimation(TurtleAnimation)}.
      *
      * @param world The new world to move it to
-     * @param pos   The new position to move it to.
-     * @return Whether the movement was successful. It may fail if the block was not loaded or the block placement
-     * was cancelled.
+     * @param pos The new position to move it to.
+     * @return Whether the movement was successful. It may fail if the block was not loaded or the block placement was cancelled.
      * @throws UnsupportedOperationException When attempting to teleport on the client side.
      */
-    boolean teleportTo( @Nonnull World world, @Nonnull BlockPos pos );
+    boolean teleportTo(@Nonnull World world, @Nonnull BlockPos pos);
 
     /**
-     * Returns a vector containing the floating point co-ordinates at which the turtle is rendered.
-     * This will shift when the turtle is moving.
+     * Returns a vector containing the floating point co-ordinates at which the turtle is rendered. This will shift when the turtle is moving.
      *
      * @param f The subframe fraction.
      * @return A vector containing the floating point co-ordinates at which the turtle resides.
      * @see #getVisualYaw(float)
      */
     @Nonnull
-    Vec3d getVisualPosition( float f );
+    Vec3d getVisualPosition(float f);
 
     /**
      * Returns the yaw the turtle is facing when it is rendered.
@@ -77,25 +74,25 @@ public interface ITurtleAccess
      * @return The yaw the turtle is facing.
      * @see #getVisualPosition(float)
      */
-    float getVisualYaw( float f );
+    float getVisualYaw(float f);
 
     /**
      * Returns the world direction the turtle is currently facing.
      *
      * @return The world direction the turtle is currently facing.
-     * @see #setDirection(EnumFacing)
+     * @see #setDirection(Direction)
      */
     @Nonnull
-    EnumFacing getDirection();
+    Direction getDirection();
 
     /**
-     * Set the direction the turtle is facing. Note that this will not play a rotation animation, you will also need to
-     * call {@link #playAnimation(TurtleAnimation)} to do so.
+     * Set the direction the turtle is facing. Note that this will not play a rotation animation, you will also need to call {@link
+     * #playAnimation(TurtleAnimation)} to do so.
      *
      * @param dir The new direction to set. This should be on either the x or z axis (so north, south, east or west).
      * @see #getDirection()
      */
-    void setDirection( @Nonnull EnumFacing dir );
+    void setDirection(@Nonnull Direction dir);
 
     /**
      * Get the currently selected slot in the turtle's inventory.
@@ -109,32 +106,30 @@ public interface ITurtleAccess
     /**
      * Set the currently selected slot in the turtle's inventory.
      *
-     * @param slot The slot to set. This must be greater or equal to 0 and less than the inventory size. Otherwise no
-     *             action will be taken.
+     * @param slot The slot to set. This must be greater or equal to 0 and less than the inventory size. Otherwise no action will be taken.
      * @throws UnsupportedOperationException When attempting to change the slot on the client side.
      * @see #getInventory()
      * @see #getSelectedSlot()
      */
-    void setSelectedSlot( int slot );
-
-    /**
-     * Set the colour of the turtle to a RGB number.
-     *
-     * @param colour The colour this turtle should be changed to. This should be a RGB colour between {@code 0x000000}
-     *               and {@code 0xFFFFFF} or -1 to reset to the default colour.
-     * @see #getColour()
-     */
-    void setColour( int colour );
+    void setSelectedSlot(int slot);
 
     /**
      * Get the colour of this turtle as a RGB number.
      *
-     * @return The colour this turtle is. This will be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or
-     * -1 if it has no colour.
+     * @return The colour this turtle is. This will be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or -1 if it has no colour.
      * @see #setColour(int)
      */
     int getColour();
 
+    /**
+     * Set the colour of the turtle to a RGB number.
+     *
+     * @param colour The colour this turtle should be changed to. This should be a RGB colour between {@code 0x000000} and {@code 0xFFFFFF} or -1 to
+     *     reset to the default colour.
+     * @see #getColour()
+     */
+    void setColour(int colour);
+
     /**
      * Get the player who owns this turtle, namely whoever placed it.
      *
@@ -143,26 +138,6 @@ public interface ITurtleAccess
     @Nonnull
     GameProfile getOwningPlayer();
 
-    /**
-     * Get the inventory of this turtle
-     *
-     * @return This turtle's inventory
-     * @see #getItemHandler()
-     */
-    @Nonnull
-    IInventory getInventory();
-
-    /**
-     * Get the inventory of this turtle as an {@link IItemHandlerModifiable}.
-     *
-     * @return This turtle's inventory
-     * @see #getInventory()
-     * @see IItemHandlerModifiable
-     * @see net.minecraftforge.items.CapabilityItemHandler#ITEM_HANDLER_CAPABILITY
-     */
-    @Nonnull
-    IItemHandlerModifiable getItemHandler();
-
     /**
      * Determine whether this turtle will require fuel when performing actions.
      *
@@ -182,8 +157,7 @@ public interface ITurtleAccess
     int getFuelLevel();
 
     /**
-     * Set the fuel level to a new value. It is generally preferred to use {@link #consumeFuel(int)}} or {@link #addFuel(int)}
-     * instead.
+     * Set the fuel level to a new value. It is generally preferred to use {@link #consumeFuel(int)}} or {@link #addFuel(int)} instead.
      *
      * @param fuel The new amount of fuel. This must be between 0 and the fuel limit.
      * @see #getFuelLevel()
@@ -191,7 +165,7 @@ public interface ITurtleAccess
      * @see #addFuel(int)
      * @see #consumeFuel(int)
      */
-    void setFuelLevel( int fuel );
+    void setFuelLevel(int fuel);
 
     /**
      * Get the maximum amount of fuel a turtle can hold.
@@ -204,11 +178,11 @@ public interface ITurtleAccess
      * Removes some fuel from the turtles fuel supply. Negative numbers can be passed in to INCREASE the fuel level of the turtle.
      *
      * @param fuel The amount of fuel to consume.
-     * @return Whether the turtle was able to consume the amount of fuel specified. Will return false if you supply a number
-     * greater than the current fuel level of the turtle. No fuel will be consumed if {@code false} is returned.
+     * @return Whether the turtle was able to consume the amount of fuel specified. Will return false if you supply a number greater than the current fuel
+     *     level of the turtle. No fuel will be consumed if {@code false} is returned.
      * @throws UnsupportedOperationException When attempting to consume fuel on the client side.
      */
-    boolean consumeFuel( int fuel );
+    boolean consumeFuel(int fuel);
 
     /**
      * Increase the turtle's fuel level by the given amount.
@@ -216,40 +190,31 @@ public interface ITurtleAccess
      * @param fuel The amount to refuel with.
      * @throws UnsupportedOperationException When attempting to refuel on the client side.
      */
-    void addFuel( int fuel );
+    void addFuel(int fuel);
 
     /**
-     * Adds a custom command to the turtles command queue. Unlike peripheral methods, these custom commands will be executed
-     * on the main thread, so are guaranteed to be able to access Minecraft objects safely, and will be queued up
-     * with the turtles standard movement and tool commands. An issued command will return an unique integer, which will
-     * be supplied as a parameter to a "turtle_response" event issued to the turtle after the command has completed. Look at the
-     * lua source code for "rom/apis/turtle" for how to build a lua wrapper around this functionality.
+     * Adds a custom command to the turtles command queue. Unlike peripheral methods, these custom commands will be executed on the main thread, so are
+     * guaranteed to be able to access Minecraft objects safely, and will be queued up with the turtles standard movement and tool commands. An issued
+     * command will return an unique integer, which will be supplied as a parameter to a "turtle_response" event issued to the turtle after the command has
+     * completed. Look at the lua source code for "rom/apis/turtle" for how to build a lua wrapper around this functionality.
      *
-     * @param context The Lua context to pull events from.
      * @param command An object which will execute the custom command when its point in the queue is reached
-     * @return The objects the command returned when executed. you should probably return these to the player
-     * unchanged if called from a peripheral method.
+     * @return The objects the command returned when executed. you should probably return these to the player unchanged if called from a peripheral method.
      * @throws UnsupportedOperationException When attempting to execute a command on the client side.
-     * @throws LuaException                  If the user presses CTRL+T to terminate the current program while {@code executeCommand()} is
-     *                                       waiting for an event, a "Terminated" exception will be thrown here.
-     * @throws InterruptedException          If the user shuts down or reboots the computer while pullEvent() is waiting for an
-     *                                       event, InterruptedException will be thrown. This exception must not be caught or
-     *                                       intercepted, or the computer will leak memory and end up in a broken state.
      * @see ITurtleCommand
-     * @see ILuaContext#pullEvent(String)
+     * @see MethodResult#pullEvent(String, ILuaCallback)
      */
     @Nonnull
-    Object[] executeCommand( @Nonnull ILuaContext context, @Nonnull ITurtleCommand command ) throws LuaException, InterruptedException;
+    MethodResult executeCommand(@Nonnull ITurtleCommand command);
 
     /**
-     * Start playing a specific animation. This will prevent other turtle commands from executing until
-     * it is finished.
+     * Start playing a specific animation. This will prevent other turtle commands from executing until it is finished.
      *
      * @param animation The animation to play.
      * @throws UnsupportedOperationException When attempting to execute play an animation on the client side.
      * @see TurtleAnimation
      */
-    void playAnimation( @Nonnull TurtleAnimation animation );
+    void playAnimation(@Nonnull TurtleAnimation animation);
 
     /**
      * Returns the turtle on the specified side of the turtle, if there is one.
@@ -259,16 +224,16 @@ public interface ITurtleAccess
      * @see #setUpgrade(TurtleSide, ITurtleUpgrade)
      */
     @Nullable
-    ITurtleUpgrade getUpgrade( @Nonnull TurtleSide side );
+    ITurtleUpgrade getUpgrade(@Nonnull TurtleSide side);
 
     /**
      * Set the upgrade for a given side, resetting peripherals and clearing upgrade specific data.
      *
-     * @param side    The side to set the upgrade on.
+     * @param side The side to set the upgrade on.
      * @param upgrade The upgrade to set, may be {@code null} to clear.
      * @see #getUpgrade(TurtleSide)
      */
-    void setUpgrade( @Nonnull TurtleSide side, @Nullable ITurtleUpgrade upgrade );
+    void setUpgrade(@Nonnull TurtleSide side, @Nullable ITurtleUpgrade upgrade);
 
     /**
      * Returns the peripheral created by the upgrade on the specified side of the turtle, if there is one.
@@ -277,27 +242,40 @@ public interface ITurtleAccess
      * @return The peripheral created by the upgrade on the specified side of the turtle, {@code null} if none exists.
      */
     @Nullable
-    IPeripheral getPeripheral( @Nonnull TurtleSide side );
+    IPeripheral getPeripheral(@Nonnull TurtleSide side);
 
     /**
      * Get an upgrade-specific NBT compound, which can be used to store arbitrary data.
      *
-     * This will be persisted across turtle restarts and chunk loads, as well as being synced to the client. You must
-     * call {@link #updateUpgradeNBTData(TurtleSide)} after modifying it.
+     * This will be persisted across turtle restarts and chunk loads, as well as being synced to the client. You must call {@link
+     * #updateUpgradeNBTData(TurtleSide)} after modifying it.
      *
      * @param side The side to get the upgrade data for.
      * @return The upgrade-specific data.
      * @see #updateUpgradeNBTData(TurtleSide)
      */
     @Nonnull
-    NBTTagCompound getUpgradeNBTData( @Nullable TurtleSide side );
+    CompoundTag getUpgradeNBTData(@Nullable TurtleSide side);
 
     /**
-     * Mark the upgrade-specific data as dirty on a specific side. This is required for the data to be synced to the
-     * client and persisted.
+     * Mark the upgrade-specific data as dirty on a specific side. This is required for the data to be synced to the client and persisted.
      *
      * @param side The side to mark dirty.
      * @see #updateUpgradeNBTData(TurtleSide)
      */
-    void updateUpgradeNBTData( @Nonnull TurtleSide side );
+    void updateUpgradeNBTData(@Nonnull TurtleSide side);
+
+    default ItemStorage getItemHandler() {
+        return ItemStorage.wrap(this.getInventory());
+    }
+
+    /**
+     * Get the inventory of this turtle.
+     *
+     * Note: this inventory should only be accessed and modified on the server thread.
+     *
+     * @return This turtle's inventory
+     */
+    @Nonnull
+    Inventory getInventory();
 }

src/main/java/dan200/computercraft/api/turtle/ITurtleCommand.java

@@ -1,36 +1,33 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle;
 
-import dan200.computercraft.api.lua.ILuaContext;
-
 import javax.annotation.Nonnull;
 
 /**
- * An interface for objects executing custom turtle commands, used with {@link ITurtleAccess#executeCommand(ILuaContext, ITurtleCommand)}.
+ * An interface for objects executing custom turtle commands, used with {@link ITurtleAccess#executeCommand(ITurtleCommand)}.
  *
- * @see ITurtleAccess#executeCommand(ILuaContext, ITurtleCommand)
+ * @see ITurtleAccess#executeCommand(ITurtleCommand)
  */
 @FunctionalInterface
-public interface ITurtleCommand
-{
+public interface ITurtleCommand {
     /**
      * Will be called by the turtle on the main thread when it is time to execute the custom command.
      *
-     * The handler should either perform the work of the command, and return success, or return
-     * failure with an error message to indicate the command cannot be executed at this time.
+     * The handler should either perform the work of the command, and return success, or return failure with an error message to indicate the command cannot
+     * be executed at this time.
      *
      * @param turtle Access to the turtle for whom the command was issued.
      * @return A result, indicating whether this action succeeded or not.
-     * @see ITurtleAccess#executeCommand(ILuaContext, ITurtleCommand)
+     * @see ITurtleAccess#executeCommand(ITurtleCommand)
      * @see TurtleCommandResult#success()
      * @see TurtleCommandResult#failure(String)
      * @see TurtleCommandResult
      */
     @Nonnull
-    TurtleCommandResult execute( @Nonnull ITurtleAccess turtle );
+    TurtleCommandResult execute(@Nonnull ITurtleAccess turtle);
 }

src/main/java/dan200/computercraft/api/turtle/ITurtleUpgrade.java

@@ -1,48 +1,40 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle;
 
-import dan200.computercraft.api.ComputerCraftAPI;
-import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.api.turtle.event.TurtleAttackEvent;
-import dan200.computercraft.api.turtle.event.TurtleBlockEvent;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.ModelResourceLocation;
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.ResourceLocation;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.api.distmarker.OnlyIn;
-import net.minecraftforge.event.entity.player.AttackEntityEvent;
-import net.minecraftforge.event.world.BlockEvent;
-import org.apache.commons.lang3.tuple.Pair;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import javax.vecmath.Matrix4f;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.client.TransformedModel;
+import dan200.computercraft.api.peripheral.IPeripheral;
+
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.math.Direction;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
 
 /**
- * The primary interface for defining an update for Turtles. A turtle update
- * can either be a new tool, or a new peripheral.
+ * The primary interface for defining an update for Turtles. A turtle update can either be a new tool, or a new peripheral.
  *
  * @see ComputerCraftAPI#registerTurtleUpgrade(ITurtleUpgrade)
  */
-public interface ITurtleUpgrade
-{
+public interface ITurtleUpgrade {
     /**
-     * Gets a unique identifier representing this type of turtle upgrade. eg: "computercraft:wireless_modem" or "my_mod:my_upgrade".
-     * You should use a unique resource domain to ensure this upgrade is uniquely identified.
-     * The turtle will fail registration if an already used ID is specified.
+     * Gets a unique identifier representing this type of turtle upgrade. eg: "computercraft:wireless_modem" or "my_mod:my_upgrade". You should use a unique
+     * resource domain to ensure this upgrade is uniquely identified. The turtle will fail registration if an already used ID is specified.
      *
      * @return The unique ID for this upgrade.
      * @see ComputerCraftAPI#registerTurtleUpgrade(ITurtleUpgrade)
      */
     @Nonnull
-    ResourceLocation getUpgradeID();
+    Identifier getUpgradeID();
 
     /**
      * Return an unlocalised string to describe this type of turtle in turtle item names.
@@ -64,12 +56,11 @@ public interface ITurtleUpgrade
     TurtleUpgradeType getType();
 
     /**
-     * Return an item stack representing the type of item that a turtle must be crafted
-     * with to create a turtle which holds this upgrade. This item stack is also used
-     * to determine the upgrade given by {@code turtle.equip()}
+     * Return an item stack representing the type of item that a turtle must be crafted with to create a turtle which holds this upgrade. This item stack is
+     * also used to determine the upgrade given by {@code turtle.equip()}
      *
-     * Ideally this should be constant over a session. It is recommended that you cache
-     * the item too, in order to prevent constructing it every time the method is called.
+     * Ideally this should be constant over a session. It is recommended that you cache the item too, in order to prevent constructing it every time the
+     * method is called.
      *
      * @return The item stack to craft with, or {@link ItemStack#EMPTY} if it cannot be crafted.
      */
@@ -79,68 +70,52 @@ public interface ITurtleUpgrade
     /**
      * Will only be called for peripheral upgrades. Creates a peripheral for a turtle being placed using this upgrade.
      *
-     * The peripheral created will be stored for the lifetime of the upgrade and will be passed as an argument to
-     * {@link #update(ITurtleAccess, TurtleSide)}. It will be attached, detached and have methods called in the same
-     * manner as a Computer peripheral.
+     * The peripheral created will be stored for the lifetime of the upgrade and will be passed as an argument to {@link #update(ITurtleAccess,
+     * TurtleSide)}. It will be attached, detached and have methods called in the same manner as a Computer peripheral.
      *
      * @param turtle Access to the turtle that the peripheral is being created for.
-     * @param side   Which side of the turtle (left or right) that the upgrade resides on.
-     * @return The newly created peripheral. You may return {@code null} if this upgrade is a Tool
-     * and this method is not expected to be called.
+     * @param side Which side of the turtle (left or right) that the upgrade resides on.
+     * @return The newly created peripheral. You may return {@code null} if this upgrade is a Tool and this method is not expected to be called.
      */
     @Nullable
-    default IPeripheral createPeripheral( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side )
-    {
+    default IPeripheral createPeripheral(@Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side) {
         return null;
     }
 
     /**
-     * Will only be called for Tool turtle. Called when turtle.dig() or turtle.attack() is called
-     * by the turtle, and the tool is required to do some work.
+     * Will only be called for Tool turtle. Called when turtle.dig() or turtle.attack() is called by the turtle, and the tool is required to do some work.
      *
-     * Conforming implementations should fire {@link BlockEvent.BreakEvent} and {@link TurtleBlockEvent.Dig}for digging,
-     * {@link AttackEntityEvent} and {@link TurtleAttackEvent} for attacking.
-     *
-     * @param turtle    Access to the turtle that the tool resides on.
-     * @param side      Which side of the turtle (left or right) the tool resides on.
-     * @param verb      Which action (dig or attack) the turtle is being called on to perform.
-     * @param direction Which world direction the action should be performed in, relative to the turtles
-     *                  position. This will either be up, down, or the direction the turtle is facing, depending on
-     *                  whether dig, digUp or digDown was called.
-     * @return Whether the turtle was able to perform the action, and hence whether the {@code turtle.dig()}
-     * or {@code turtle.attack()} lua method should return true. If true is returned, the tool will perform
-     * a swinging animation. You may return {@code null} if this turtle is a Peripheral  and this method is not expected
-     * to be called.
+     * @param turtle Access to the turtle that the tool resides on.
+     * @param side Which side of the turtle (left or right) the tool resides on.
+     * @param verb Which action (dig or attack) the turtle is being called on to perform.
+     * @param direction Which world direction the action should be performed in, relative to the turtles position. This will either be up, down, or the
+     *     direction the turtle is facing, depending on whether dig, digUp or digDown was called.
+     * @return Whether the turtle was able to perform the action, and hence whether the {@code turtle.dig()} or {@code turtle.attack()} lua method should
+     *     return true. If true is returned, the tool will perform a swinging animation. You may return {@code null} if this turtle is a Peripheral  and
+     *     this method is not expected to be called.
      */
     @Nonnull
-    default TurtleCommandResult useTool( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side, @Nonnull TurtleVerb verb, @Nonnull EnumFacing direction )
-    {
+    default TurtleCommandResult useTool(@Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side, @Nonnull TurtleVerb verb, @Nonnull Direction direction) {
         return TurtleCommandResult.failure();
     }
 
     /**
      * Called to obtain the model to be used when rendering a turtle peripheral.
      *
-     * This can be obtained from {@link net.minecraft.client.renderer.ItemModelMesher#getItemModel(ItemStack)},
-     * {@link net.minecraft.client.renderer.model.ModelManager#getModel(ModelResourceLocation)} or any other
-     * source.
-     *
      * @param turtle Access to the turtle that the upgrade resides on. This will be null when getting item models!
-     * @param side   Which side of the turtle (left or right) the upgrade resides on.
-     * @return The model that you wish to be used to render your upgrade, and a transformation to apply to it. Returning
-     * a transformation of {@code null} has the same effect as the identify matrix.
+     * @param side Which side of the turtle (left or right) the upgrade resides on.
+     * @return The model that you wish to be used to render your upgrade.
      */
     @Nonnull
-    @OnlyIn( Dist.CLIENT )
-    Pair<IBakedModel, Matrix4f> getModel( @Nullable ITurtleAccess turtle, @Nonnull TurtleSide side );
+    @Environment (EnvType.CLIENT)
+    TransformedModel getModel(@Nullable ITurtleAccess turtle, @Nonnull TurtleSide side);
 
     /**
      * Called once per tick for each turtle which has the upgrade equipped.
      *
      * @param turtle Access to the turtle that the upgrade resides on.
-     * @param side   Which side of the turtle (left or right) the upgrade resides on.
+     * @param side Which side of the turtle (left or right) the upgrade resides on.
      */
-    default void update( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side )
-    {
+    default void update(@Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side) {
     }
 }

src/main/java/dan200/computercraft/api/turtle/TurtleAnimation.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -13,75 +13,70 @@ package dan200.computercraft.api.turtle;
  *
  * @see ITurtleAccess#playAnimation(TurtleAnimation)
  */
-public enum TurtleAnimation
-{
+public enum TurtleAnimation {
     /**
      * An animation which does nothing. This takes no time to complete.
      *
-     * @see #Wait
-     * @see #ShortWait
+     * @see #WAIT
+     * @see #SHORT_WAIT
      */
-    None,
+    NONE,
 
     /**
-     * Make the turtle move forward. Note that the animation starts from the block <em>behind</em> it, and
-     * moves into this one.
+     * Make the turtle move forward. Note that the animation starts from the block <em>behind</em> it, and moves into this one.
      */
-    MoveForward,
+    MOVE_FORWARD,
 
     /**
-     * Make the turtle move backwards. Note that the animation starts from the block <em>in front</em> it, and
-     * moves into this one.
+     * Make the turtle move backwards. Note that the animation starts from the block <em>in front</em> it, and moves into this one.
      */
-    MoveBack,
+    MOVE_BACK,
 
     /**
-     * Make the turtle move backwards. Note that the animation starts from the block <em>above</em> it, and
-     * moves into this one.
+     * Make the turtle move backwards. Note that the animation starts from the block <em>above</em> it, and moves into this one.
      */
-    MoveUp,
+    MOVE_UP,
 
     /**
-     * Make the turtle move backwards. Note that the animation starts from the block <em>below</em> it, and
-     * moves into this one.
+     * Make the turtle move backwards. Note that the animation starts from the block <em>below</em> it, and moves into this one.
      */
-    MoveDown,
+    MOVE_DOWN,
 
     /**
-     * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and
-     * the turtle turns to face in the current direction.
+     * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and the turtle turns to face in the current
+     * direction.
      */
-    TurnLeft,
+    TURN_LEFT,
 
     /**
-     * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and
-     * the turtle turns to face in the current direction.
+     * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and the turtle turns to face in the current
+     * direction.
      */
-    TurnRight,
+    TURN_RIGHT,
 
     /**
      * Swing the tool on the left.
      */
-    SwingLeftTool,
+    SWING_LEFT_TOOL,
 
     /**
      * Swing the tool on the right.
      */
-    SwingRightTool,
+    SWING_RIGHT_TOOL,
 
     /**
      * Wait until the animation has finished, performing no movement.
      *
-     * @see #ShortWait
-     * @see #None
+     * @see #SHORT_WAIT
+     * @see #NONE
      */
-    Wait,
+    WAIT,
 
     /**
      * Wait until the animation has finished, performing no movement. This takes 4 ticks to complete.
      *
-     * @see #Wait
-     * @see #None
+     * @see #WAIT
+     * @see #NONE
      */
-    ShortWait,
+    SHORT_WAIT,
 }

src/main/java/dan200/computercraft/api/turtle/TurtleCommandResult.java

@@ -1,13 +1,11 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle;
 
-import net.minecraft.util.EnumFacing;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
@@ -15,12 +13,20 @@ import javax.annotation.Nullable;
  * Used to indicate the result of executing a turtle command.
  *
  * @see ITurtleCommand#execute(ITurtleAccess)
- * @see ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, EnumFacing)
+ * @see ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, Direction)
  */
-public final class TurtleCommandResult
-{
-    private static final TurtleCommandResult EMPTY_SUCCESS = new TurtleCommandResult( true, null, null );
-    private static final TurtleCommandResult EMPTY_FAILURE = new TurtleCommandResult( false, null, null );
+public final class TurtleCommandResult {
+    private static final TurtleCommandResult EMPTY_SUCCESS = new TurtleCommandResult(true, null, null);
+    private static final TurtleCommandResult EMPTY_FAILURE = new TurtleCommandResult(false, null, null);
+    private final boolean success;
+    private final String errorMessage;
+    private final Object[] results;
+
+    private TurtleCommandResult(boolean success, String errorMessage, Object[] results) {
+        this.success = success;
+        this.errorMessage = errorMessage;
+        this.results = results;
+    }
 
     /**
      * Create a successful command result with no result.
@@ -28,8 +34,7 @@ public final class TurtleCommandResult
      * @return A successful command result with no values.
      */
     @Nonnull
-    public static TurtleCommandResult success()
-    {
+    public static TurtleCommandResult success() {
         return EMPTY_SUCCESS;
     }
 
@@ -40,10 +45,11 @@ public final class TurtleCommandResult
      * @return A successful command result with the given values.
      */
     @Nonnull
-    public static TurtleCommandResult success( @Nullable Object[] results )
-    {
-        if( results == null || results.length == 0 ) return EMPTY_SUCCESS;
-        return new TurtleCommandResult( true, null, results );
+    public static TurtleCommandResult success(@Nullable Object[] results) {
+        if (results == null || results.length == 0) {
+            return EMPTY_SUCCESS;
+        }
+        return new TurtleCommandResult(true, null, results);
     }
 
     /**
@@ -52,8 +58,7 @@ public final class TurtleCommandResult
      * @return A failed command result with no message.
      */
     @Nonnull
-    public static TurtleCommandResult failure()
-    {
+    public static TurtleCommandResult failure() {
         return EMPTY_FAILURE;
     }
 
@@ -64,21 +69,11 @@ public final class TurtleCommandResult
      * @return A failed command result with a message.
      */
     @Nonnull
-    public static TurtleCommandResult failure( @Nullable String errorMessage )
-    {
-        if( errorMessage == null ) return EMPTY_FAILURE;
-        return new TurtleCommandResult( false, errorMessage, null );
-    }
-
-    private final boolean success;
-    private final String errorMessage;
-    private final Object[] results;
-
-    private TurtleCommandResult( boolean success, String errorMessage, Object[] results )
-    {
-        this.success = success;
-        this.errorMessage = errorMessage;
-        this.results = results;
+    public static TurtleCommandResult failure(@Nullable String errorMessage) {
+        if (errorMessage == null) {
+            return EMPTY_FAILURE;
+        }
+        return new TurtleCommandResult(false, errorMessage, null);
     }
 
     /**
@@ -86,9 +81,8 @@ public final class TurtleCommandResult
      *
      * @return If the command was successful.
      */
-    public boolean isSuccess()
-    {
-        return success;
+    public boolean isSuccess() {
+        return this.success;
     }
 
     /**
@@ -97,9 +91,8 @@ public final class TurtleCommandResult
      * @return The command's error message, or {@code null} if it was a success.
      */
     @Nullable
-    public String getErrorMessage()
-    {
-        return errorMessage;
+    public String getErrorMessage() {
+        return this.errorMessage;
     }
 
     /**
@@ -108,8 +101,7 @@ public final class TurtleCommandResult
      * @return The command's result, or {@code null} if it was a failure.
      */
     @Nullable
-    public Object[] getResults()
-    {
-        return results;
+    public Object[] getResults() {
+        return this.results;
     }
 }

src/main/java/dan200/computercraft/api/turtle/TurtleSide.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -9,15 +9,14 @@ package dan200.computercraft.api.turtle;
 /**
  * An enum representing the two sides of the turtle that a turtle turtle might reside.
  */
-public enum TurtleSide
-{
+public enum TurtleSide {
     /**
-     * The turtle's left side (where the pickaxe usually is on a Wireless Mining Turtle)
+     * The turtle's left side (where the pickaxe usually is on a Wireless Mining Turtle).
      */
-    Left,
+    LEFT,
 
     /**
-     * The turtle's right side (where the modem usually is on a Wireless Mining Turtle)
+     * The turtle's right side (where the modem usually is on a Wireless Mining Turtle).
      */
-    Right,
+    RIGHT,
 }

src/main/java/dan200/computercraft/api/turtle/TurtleUpgradeType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -11,34 +11,30 @@ package dan200.computercraft.api.turtle;
  *
  * @see ITurtleUpgrade#getType()
  */
-public enum TurtleUpgradeType
-{
+public enum TurtleUpgradeType {
     /**
-     * A tool is rendered as an item on the side of the turtle, and responds to the {@code turtle.dig()}
-     * and {@code turtle.attack()} methods (Such as pickaxe or sword on Mining and Melee turtles).
+     * A tool is rendered as an item on the side of the turtle, and responds to the {@code turtle.dig()} and {@code turtle.attack()} methods (Such as
+     * pickaxe or sword on Mining and Melee turtles).
      */
-    Tool,
+    TOOL,
 
     /**
-     * A peripheral adds a special peripheral which is attached to the side of the turtle,
-     * and can be interacted with the {@code peripheral} API (Such as the modem on Wireless Turtles).
+     * A peripheral adds a special peripheral which is attached to the side of the turtle, and can be interacted with the {@code peripheral} API (Such as
+     * the modem on Wireless Turtles).
      */
-    Peripheral,
+    PERIPHERAL,
 
     /**
-     * An upgrade which provides both a tool and a peripheral. This can be used when you wish
-     * your upgrade to also provide methods. For example, a pickaxe could provide methods
-     * determining whether it can break the given block or not.
+     * An upgrade which provides both a tool and a peripheral. This can be used when you wish your upgrade to also provide methods. For example, a pickaxe
+     * could provide methods determining whether it can break the given block or not.
      */
-    Both;
+    BOTH;
 
-    public boolean isTool()
-    {
-        return this == Tool || this == Both;
+    public boolean isTool() {
+        return this == TOOL || this == BOTH;
     }
 
-    public boolean isPeripheral()
-    {
-        return this == Peripheral || this == Both;
+    public boolean isPeripheral() {
+        return this == PERIPHERAL || this == BOTH;
     }
 }

src/main/java/dan200/computercraft/api/turtle/TurtleVerb.java

@@ -1,29 +1,25 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle;
 
-import net.minecraft.util.EnumFacing;
-
 /**
- * An enum representing the different actions that an {@link ITurtleUpgrade} of type Tool may be called on to perform by
- * a turtle.
+ * An enum representing the different actions that an {@link ITurtleUpgrade} of type Tool may be called on to perform by a turtle.
  *
  * @see ITurtleUpgrade#getType()
- * @see ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, EnumFacing)
+ * @see ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, Direction)
  */
-public enum TurtleVerb
-{
+public enum TurtleVerb {
     /**
-     * The turtle called {@code turtle.dig()}, {@code turtle.digUp()} or {@code turtle.digDown()}
+     * The turtle called {@code turtle.dig()}, {@code turtle.digUp()} or {@code turtle.digDown()}.
      */
-    Dig,
+    DIG,
 
     /**
-     * The turtle called {@code turtle.attack()}, {@code turtle.attackUp()} or {@code turtle.attackDown()}
+     * The turtle called {@code turtle.attack()}, {@code turtle.attackUp()} or {@code turtle.attackDown()}.
      */
-    Attack,
+    ATTACK,
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleAction.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
@@ -11,8 +11,7 @@ package dan200.computercraft.api.turtle.event;
  *
  * @see TurtleActionEvent
  */
-public enum TurtleAction
-{
+public enum TurtleAction {
     /**
      * A turtle moves to a new position.
      *
@@ -71,7 +70,7 @@ public enum TurtleAction
     EQUIP,
 
     /**
-     * Inspect a block in world
+     * Inspect a block in world.
      *
      * @see TurtleBlockEvent.Inspect
      */

src/main/java/dan200/computercraft/api/turtle/event/TurtleActionEvent.java

@@ -1,39 +1,36 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import dan200.computercraft.api.turtle.TurtleCommandResult;
-import net.minecraftforge.eventbus.api.Cancelable;
+import java.util.Objects;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Objects;
+
+import dan200.computercraft.api.turtle.ITurtleAccess;
+import dan200.computercraft.api.turtle.TurtleCommandResult;
 
 /**
  * An event fired when a turtle is performing a known action.
  */
-@Cancelable
-public class TurtleActionEvent extends TurtleEvent
-{
+public class TurtleActionEvent extends TurtleEvent {
     private final TurtleAction action;
     private String failureMessage;
+    private boolean cancelled = false;
 
-    public TurtleActionEvent( @Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action )
-    {
-        super( turtle );
+    public TurtleActionEvent(@Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action) {
+        super(turtle);
 
-        Objects.requireNonNull( action, "action cannot be null" );
+        Objects.requireNonNull(action, "action cannot be null");
         this.action = action;
     }
 
-    public TurtleAction getAction()
-    {
-        return action;
+    public TurtleAction getAction() {
+        return this.action;
     }
 
     /**
@@ -45,11 +42,9 @@ public class TurtleActionEvent extends TurtleEvent
      * @see TurtleCommandResult#failure()
      * @deprecated Use {@link #setCanceled(boolean, String)} instead.
      */
-    @Override
     @Deprecated
-    public void setCanceled( boolean cancel )
-    {
-        setCanceled( cancel, null );
+    public void setCanceled(boolean cancel) {
+        this.setCanceled(cancel, null);
     }
 
     /**
@@ -57,13 +52,12 @@ public class TurtleActionEvent extends TurtleEvent
      *
      * If {@code cancel} is {@code true}, this action will not be carried out.
      *
-     * @param cancel         The new canceled value.
+     * @param cancel The new canceled value.
      * @param failureMessage The message to return to the user explaining the failure.
      * @see TurtleCommandResult#failure(String)
      */
-    public void setCanceled( boolean cancel, @Nullable String failureMessage )
-    {
-        super.setCanceled( cancel );
+    public void setCanceled(boolean cancel, @Nullable String failureMessage) {
+        this.cancelled = true;
         this.failureMessage = cancel ? failureMessage : null;
     }
 
@@ -75,8 +69,11 @@ public class TurtleActionEvent extends TurtleEvent
      * @see #setCanceled(boolean, String)
      */
     @Nullable
-    public String getFailureMessage()
-    {
-        return failureMessage;
+    public String getFailureMessage() {
+        return this.failureMessage;
+    }
+
+    public boolean isCancelled() {
+        return this.cancelled;
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleAttackEvent.java

@@ -1,45 +1,38 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.turtle.FakePlayer;
 import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
-import dan200.computercraft.api.turtle.TurtleVerb;
-import net.minecraft.entity.Entity;
-import net.minecraft.util.EnumFacing;
-import net.minecraftforge.common.util.FakePlayer;
-import net.minecraftforge.event.entity.player.AttackEntityEvent;
 
-import javax.annotation.Nonnull;
-import java.util.Objects;
+import net.minecraft.entity.Entity;
 
 /**
  * Fired when a turtle attempts to attack an entity.
  *
- * This must be fired by {@link ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, EnumFacing)},
- * as the base {@code turtle.attack()} command does not fire it.
- *
- * Note that such commands should also fire {@link AttackEntityEvent}, so you do not need to listen to both.
- *
  * @see TurtleAction#ATTACK
  */
-public class TurtleAttackEvent extends TurtlePlayerEvent
-{
+public class TurtleAttackEvent extends TurtlePlayerEvent {
     private final Entity target;
     private final ITurtleUpgrade upgrade;
     private final TurtleSide side;
 
-    public TurtleAttackEvent( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull Entity target, @Nonnull ITurtleUpgrade upgrade, @Nonnull TurtleSide side )
-    {
-        super( turtle, TurtleAction.ATTACK, player );
-        Objects.requireNonNull( target, "target cannot be null" );
-        Objects.requireNonNull( upgrade, "upgrade cannot be null" );
-        Objects.requireNonNull( side, "side cannot be null" );
+    public TurtleAttackEvent(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull Entity target, @Nonnull ITurtleUpgrade upgrade,
+                             @Nonnull TurtleSide side) {
+        super(turtle, TurtleAction.ATTACK, player);
+        Objects.requireNonNull(target, "target cannot be null");
+        Objects.requireNonNull(upgrade, "upgrade cannot be null");
+        Objects.requireNonNull(side, "side cannot be null");
         this.target = target;
         this.upgrade = upgrade;
         this.side = side;
@@ -51,9 +44,8 @@ public class TurtleAttackEvent extends TurtlePlayerEvent
      * @return The entity being attacked.
      */
     @Nonnull
-    public Entity getTarget()
-    {
-        return target;
+    public Entity getTarget() {
+        return this.target;
     }
 
     /**
@@ -62,9 +54,8 @@ public class TurtleAttackEvent extends TurtlePlayerEvent
      * @return The upgrade responsible for attacking.
      */
     @Nonnull
-    public ITurtleUpgrade getUpgrade()
-    {
-        return upgrade;
+    public ITurtleUpgrade getUpgrade() {
+        return this.upgrade;
     }
 
     /**
@@ -73,8 +64,7 @@ public class TurtleAttackEvent extends TurtlePlayerEvent
      * @return The upgrade's side.
      */
     @Nonnull
-    public TurtleSide getSide()
-    {
-        return side;
+    public TurtleSide getSide() {
+        return this.side;
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleBlockEvent.java

@@ -1,52 +1,46 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.lua.ILuaContext;
-import dan200.computercraft.api.peripheral.IComputerAccess;
+import java.util.Map;
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.lua.MethodResult;
+import dan200.computercraft.api.turtle.FakePlayer;
 import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
-import dan200.computercraft.api.turtle.TurtleVerb;
-import net.minecraft.block.state.IBlockState;
+
+import net.minecraft.block.BlockState;
 import net.minecraft.item.ItemStack;
-import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
-import net.minecraftforge.common.util.FakePlayer;
-import net.minecraftforge.event.world.BlockEvent;
-
-import javax.annotation.Nonnull;
-import java.util.Map;
-import java.util.Objects;
 
 /**
  * A general event for when a turtle interacts with a block or region.
  *
- * You should generally listen to one of the sub-events instead, cancelling them where
- * appropriate.
+ * You should generally listen to one of the sub-events instead, cancelling them where appropriate.
  *
- * Note that you are not guaranteed to receive this event, if it has been cancelled by other
- * mechanisms, such as block protection systems.
+ * Note that you are not guaranteed to receive this event, if it has been cancelled by other mechanisms, such as block protection systems.
  *
- * Be aware that some events (such as {@link TurtleInventoryEvent}) do not necessarily interact
- * with a block, simply objects within that block space.
+ * Be aware that some events (such as {@link TurtleInventoryEvent}) do not necessarily interact with a block, simply objects within that block space.
  */
-public abstract class TurtleBlockEvent extends TurtlePlayerEvent
-{
+public abstract class TurtleBlockEvent extends TurtlePlayerEvent {
     private final World world;
     private final BlockPos pos;
 
-    protected TurtleBlockEvent( @Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos )
-    {
-        super( turtle, action, player );
+    protected TurtleBlockEvent(@Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player, @Nonnull World world,
+                               @Nonnull BlockPos pos) {
+        super(turtle, action, player);
 
-        Objects.requireNonNull( world, "world cannot be null" );
-        Objects.requireNonNull( pos, "pos cannot be null" );
+        Objects.requireNonNull(world, "world cannot be null");
+        Objects.requireNonNull(pos, "pos cannot be null");
         this.world = world;
         this.pos = pos;
     }
@@ -56,45 +50,36 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
      *
      * @return The world the turtle is interacting in.
      */
-    public World getWorld()
-    {
-        return world;
+    public World getWorld() {
+        return this.world;
     }
 
     /**
-     * Get the position the turtle is interacting with. Note that this is different
-     * to {@link ITurtleAccess#getPosition()}.
+     * Get the position the turtle is interacting with. Note that this is different to {@link ITurtleAccess#getPosition()}.
      *
      * @return The position the turtle is interacting with.
      */
-    public BlockPos getPos()
-    {
-        return pos;
+    public BlockPos getPos() {
+        return this.pos;
     }
 
     /**
      * Fired when a turtle attempts to dig a block.
      *
-     * This must be fired by {@link ITurtleUpgrade#useTool(ITurtleAccess, TurtleSide, TurtleVerb, EnumFacing)},
-     * as the base {@code turtle.dig()} command does not fire it.
-     *
-     * Note that such commands should also fire {@link BlockEvent.BreakEvent}, so you do not need to listen to both.
-     *
      * @see TurtleAction#DIG
      */
-    public static class Dig extends TurtleBlockEvent
-    {
-        private final IBlockState block;
+    public static class Dig extends TurtleBlockEvent {
+        private final BlockState block;
         private final ITurtleUpgrade upgrade;
         private final TurtleSide side;
 
-        public Dig( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull IBlockState block, @Nonnull ITurtleUpgrade upgrade, @Nonnull TurtleSide side )
-        {
-            super( turtle, TurtleAction.DIG, player, world, pos );
+        public Dig(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull BlockState block,
+                   @Nonnull ITurtleUpgrade upgrade, @Nonnull TurtleSide side) {
+            super(turtle, TurtleAction.DIG, player, world, pos);
 
-            Objects.requireNonNull( block, "block cannot be null" );
-            Objects.requireNonNull( upgrade, "upgrade cannot be null" );
-            Objects.requireNonNull( side, "side cannot be null" );
+            Objects.requireNonNull(block, "block cannot be null");
+            Objects.requireNonNull(upgrade, "upgrade cannot be null");
+            Objects.requireNonNull(side, "side cannot be null");
             this.block = block;
             this.upgrade = upgrade;
             this.side = side;
@@ -106,20 +91,18 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
          * @return The block which is going to be broken.
          */
         @Nonnull
-        public IBlockState getBlock()
-        {
-            return block;
+        public BlockState getBlock() {
+            return this.block;
         }
 
         /**
-         * Get the upgrade doing the digging
+         * Get the upgrade doing the digging.
          *
          * @return The upgrade doing the digging.
          */
         @Nonnull
-        public ITurtleUpgrade getUpgrade()
-        {
-            return upgrade;
+        public ITurtleUpgrade getUpgrade() {
+            return this.upgrade;
         }
 
         /**
@@ -128,9 +111,8 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
          * @return The upgrade's side.
          */
         @Nonnull
-        public TurtleSide getSide()
-        {
-            return side;
+        public TurtleSide getSide() {
+            return this.side;
         }
     }
 
@@ -139,11 +121,9 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
      *
      * @see TurtleAction#MOVE
      */
-    public static class Move extends TurtleBlockEvent
-    {
-        public Move( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos )
-        {
-            super( turtle, TurtleAction.MOVE, player, world, pos );
+    public static class Move extends TurtleBlockEvent {
+        public Move(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos) {
+            super(turtle, TurtleAction.MOVE, player, world, pos);
         }
     }
 
@@ -152,15 +132,13 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
      *
      * @see TurtleAction#PLACE
      */
-    public static class Place extends TurtleBlockEvent
-    {
+    public static class Place extends TurtleBlockEvent {
         private final ItemStack stack;
 
-        public Place( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull ItemStack stack )
-        {
-            super( turtle, TurtleAction.PLACE, player, world, pos );
+        public Place(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull ItemStack stack) {
+            super(turtle, TurtleAction.PLACE, player, world, pos);
 
-            Objects.requireNonNull( stack, "stack cannot be null" );
+            Objects.requireNonNull(stack, "stack cannot be null");
             this.stack = stack;
         }
 
@@ -170,9 +148,8 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
          * @return The item stack to be placed.
          */
         @Nonnull
-        public ItemStack getStack()
-        {
-            return stack;
+        public ItemStack getStack() {
+            return this.stack;
         }
     }
 
@@ -183,17 +160,16 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
      *
      * @see TurtleAction#INSPECT
      */
-    public static class Inspect extends TurtleBlockEvent
-    {
-        private final IBlockState state;
+    public static class Inspect extends TurtleBlockEvent {
+        private final BlockState state;
         private final Map<String, Object> data;
 
-        public Inspect( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull IBlockState state, @Nonnull Map<String, Object> data )
-        {
-            super( turtle, TurtleAction.INSPECT, player, world, pos );
+        public Inspect(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nonnull BlockState state,
+                       @Nonnull Map<String, Object> data) {
+            super(turtle, TurtleAction.INSPECT, player, world, pos);
 
-            Objects.requireNonNull( state, "state cannot be null" );
-            Objects.requireNonNull( data, "data cannot be null" );
+            Objects.requireNonNull(state, "state cannot be null");
+            Objects.requireNonNull(data, "data cannot be null");
             this.data = data;
             this.state = state;
         }
@@ -204,9 +180,8 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
          * @return The inspected block state.
          */
         @Nonnull
-        public IBlockState getState()
-        {
-            return state;
+        public BlockState getState() {
+            return this.state;
         }
 
         /**
@@ -215,21 +190,18 @@ public abstract class TurtleBlockEvent extends TurtlePlayerEvent
          * @return This block's inspection data.
          */
         @Nonnull
-        public Map<String, Object> getData()
-        {
-            return data;
+        public Map<String, Object> getData() {
+            return this.data;
         }
 
         /**
          * Add new information to the inspection result. Note this will override fields with the same name.
          *
-         * @param newData The data to add. Note all values should be convertible to Lua (see
-         *                {@link dan200.computercraft.api.peripheral.IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])}).
+         * @param newData The data to add. Note all values should be convertible to Lua (see {@link MethodResult#of(Object)}).
          */
-        public void addData( @Nonnull Map<String, ?> newData )
-        {
-            Objects.requireNonNull( newData, "newData cannot be null" );
-            data.putAll( newData );
+        public void addData(@Nonnull Map<String, ?> newData) {
+            Objects.requireNonNull(newData, "newData cannot be null");
+            this.data.putAll(newData);
         }
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleEvent.java

@@ -1,43 +1,49 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import net.minecraftforge.eventbus.api.Event;
-
-import javax.annotation.Nonnull;
 import java.util.Objects;
 
+import javax.annotation.Nonnull;
+
+import com.google.common.eventbus.EventBus;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+
 /**
- * A base class for all events concerning a turtle. This will only ever constructed and fired on the server side,
- * so sever specific methods on {@link ITurtleAccess} are safe to use.
+ * A base class for all events concerning a turtle. This will only ever constructed and fired on the server side, so sever specific methods on {@link
+ * ITurtleAccess} are safe to use.
  *
  * You should generally not need to subscribe to this event, preferring one of the more specific classes.
  *
  * @see TurtleActionEvent
  */
-public abstract class TurtleEvent extends Event
-{
+public abstract class TurtleEvent {
+    public static final EventBus EVENT_BUS = new EventBus();
+
     private final ITurtleAccess turtle;
 
-    protected TurtleEvent( @Nonnull ITurtleAccess turtle )
-    {
-        Objects.requireNonNull( turtle, "turtle cannot be null" );
+    protected TurtleEvent(@Nonnull ITurtleAccess turtle) {
+        Objects.requireNonNull(turtle, "turtle cannot be null");
         this.turtle = turtle;
     }
 
+    public static boolean post(TurtleActionEvent event) {
+        EVENT_BUS.post(event);
+        return event.isCancelled();
+    }
+
     /**
      * Get the turtle which is performing this action.
      *
      * @return The access for this turtle.
      */
     @Nonnull
-    public ITurtleAccess getTurtle()
-    {
-        return turtle;
+    public ITurtleAccess getTurtle() {
+        return this.turtle;
     }
+
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleInspectItemEvent.java

@@ -1,41 +1,47 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.lua.ILuaContext;
-import dan200.computercraft.api.peripheral.IComputerAccess;
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import net.minecraft.item.ItemStack;
-
-import javax.annotation.Nonnull;
 import java.util.Map;
 import java.util.Objects;
 
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.lua.MethodResult;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+
+import net.minecraft.item.ItemStack;
+
 /**
  * Fired when a turtle gathers data on an item in its inventory.
  *
- * You may prevent items being inspected, or add additional information to the result. Be aware that this is fired on
- * the computer thread, and so any operations on it must be thread safe.
+ * You may prevent items being inspected, or add additional information to the result. Be aware that this may be fired on the computer thread, and so any
+ * operations on it must be thread safe.
  *
  * @see TurtleAction#INSPECT_ITEM
  */
-public class TurtleInspectItemEvent extends TurtleActionEvent
-{
+public class TurtleInspectItemEvent extends TurtleActionEvent {
     private final ItemStack stack;
     private final Map<String, Object> data;
+    private final boolean mainThread;
 
-    public TurtleInspectItemEvent( @Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack, @Nonnull Map<String, Object> data )
-    {
-        super( turtle, TurtleAction.INSPECT_ITEM );
+    @Deprecated
+    public TurtleInspectItemEvent(@Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack, @Nonnull Map<String, Object> data) {
+        this(turtle, stack, data, false);
+    }
 
-        Objects.requireNonNull( stack, "stack cannot be null" );
-        Objects.requireNonNull( data, "data cannot be null" );
+    public TurtleInspectItemEvent(@Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack, @Nonnull Map<String, Object> data, boolean mainThread) {
+        super(turtle, TurtleAction.INSPECT_ITEM);
+
+        Objects.requireNonNull(stack, "stack cannot be null");
+        Objects.requireNonNull(data, "data cannot be null");
         this.stack = stack;
         this.data = data;
+        this.mainThread = mainThread;
     }
 
     /**
@@ -44,9 +50,8 @@ public class TurtleInspectItemEvent extends TurtleActionEvent
      * @return The item stack which is being inspected. This should <b>not</b> be modified.
      */
     @Nonnull
-    public ItemStack getStack()
-    {
-        return stack;
+    public ItemStack getStack() {
+        return this.stack;
     }
 
     /**
@@ -55,20 +60,26 @@ public class TurtleInspectItemEvent extends TurtleActionEvent
      * @return This items's inspection data.
      */
     @Nonnull
-    public Map<String, Object> getData()
-    {
-        return data;
+    public Map<String, Object> getData() {
+        return this.data;
+    }
+
+    /**
+     * If this event is being fired on the server thread. When true, information which relies on server state may be exposed.
+     *
+     * @return If this is run on the main thread.
+     */
+    public boolean onMainThread() {
+        return this.mainThread;
     }
 
     /**
      * Add new information to the inspection result. Note this will override fields with the same name.
      *
-     * @param newData The data to add. Note all values should be convertible to Lua (see
-     *                {@link dan200.computercraft.api.peripheral.IPeripheral#callMethod(IComputerAccess, ILuaContext, int, Object[])}).
+     * @param newData The data to add. Note all values should be convertible to Lua (see {@link MethodResult#of(Object)}).
      */
-    public void addData( @Nonnull Map<String, ?> newData )
-    {
-        Objects.requireNonNull( newData, "newData cannot be null" );
-        data.putAll( newData );
+    public void addData(@Nonnull Map<String, ?> newData) {
+        Objects.requireNonNull(newData, "newData cannot be null");
+        this.data.putAll(newData);
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleInventoryEvent.java

@@ -1,44 +1,44 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import net.minecraft.item.ItemStack;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.World;
-import net.minecraftforge.common.util.FakePlayer;
-import net.minecraftforge.items.IItemHandler;
+import java.util.Objects;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Objects;
+
+import dan200.computercraft.api.turtle.FakePlayer;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+
+import net.minecraft.inventory.Inventory;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.World;
 
 /**
  * Fired when a turtle attempts to interact with an inventory.
  */
-public abstract class TurtleInventoryEvent extends TurtleBlockEvent
-{
-    private final IItemHandler handler;
+public abstract class TurtleInventoryEvent extends TurtleBlockEvent {
+    private final Inventory handler;
 
-    protected TurtleInventoryEvent( @Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nullable IItemHandler handler )
-    {
-        super( turtle, action, player, world, pos );
+    protected TurtleInventoryEvent(@Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player, @Nonnull World world,
+                                   @Nonnull BlockPos pos, @Nullable Inventory handler) {
+        super(turtle, action, player, world, pos);
         this.handler = handler;
     }
 
     /**
-     * Get the inventory being interacted with
+     * Get the inventory being interacted with.
      *
      * @return The inventory being interacted with, {@code null} if the item will be dropped to/sucked from the world.
      */
     @Nullable
-    public IItemHandler getItemHandler()
-    {
-        return handler;
+    public Inventory getItemHandler() {
+        return this.handler;
     }
 
     /**
@@ -46,11 +46,9 @@ public abstract class TurtleInventoryEvent extends TurtleBlockEvent
      *
      * @see TurtleAction#SUCK
      */
-    public static class Suck extends TurtleInventoryEvent
-    {
-        public Suck( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nullable IItemHandler handler )
-        {
-            super( turtle, TurtleAction.SUCK, player, world, pos, handler );
+    public static class Suck extends TurtleInventoryEvent {
+        public Suck(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nullable Inventory handler) {
+            super(turtle, TurtleAction.SUCK, player, world, pos, handler);
         }
     }
 
@@ -59,15 +57,14 @@ public abstract class TurtleInventoryEvent extends TurtleBlockEvent
      *
      * @see TurtleAction#DROP
      */
-    public static class Drop extends TurtleInventoryEvent
-    {
+    public static class Drop extends TurtleInventoryEvent {
         private final ItemStack stack;
 
-        public Drop( @Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nullable IItemHandler handler, @Nonnull ItemStack stack )
-        {
-            super( turtle, TurtleAction.DROP, player, world, pos, handler );
+        public Drop(@Nonnull ITurtleAccess turtle, @Nonnull FakePlayer player, @Nonnull World world, @Nonnull BlockPos pos, @Nullable Inventory handler,
+                    @Nonnull ItemStack stack) {
+            super(turtle, TurtleAction.DROP, player, world, pos, handler);
 
-            Objects.requireNonNull( stack, "stack cannot be null" );
+            Objects.requireNonNull(stack, "stack cannot be null");
             this.stack = stack;
         }
 
@@ -77,9 +74,8 @@ public abstract class TurtleInventoryEvent extends TurtleBlockEvent
          * @return The item stack which will be dropped. This should <b>not</b> be modified.
          */
         @Nonnull
-        public ItemStack getStack()
-        {
-            return stack;
+        public ItemStack getStack() {
+            return this.stack;
         }
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtlePlayerEvent.java

@@ -1,31 +1,30 @@
 /*
  * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import net.minecraftforge.common.util.FakePlayer;
+import java.util.Objects;
 
 import javax.annotation.Nonnull;
-import java.util.Objects;
+
+import dan200.computercraft.api.turtle.FakePlayer;
+import dan200.computercraft.api.turtle.ITurtleAccess;
 
 /**
  * An action done by a turtle which is normally done by a player.
  *
  * {@link #getPlayer()} may be used to modify the player's attributes or perform permission checks.
  */
-public abstract class TurtlePlayerEvent extends TurtleActionEvent
-{
+public abstract class TurtlePlayerEvent extends TurtleActionEvent {
     private final FakePlayer player;
 
-    protected TurtlePlayerEvent( @Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player )
-    {
-        super( turtle, action );
+    protected TurtlePlayerEvent(@Nonnull ITurtleAccess turtle, @Nonnull TurtleAction action, @Nonnull FakePlayer player) {
+        super(turtle, action);
 
-        Objects.requireNonNull( player, "player cannot be null" );
+        Objects.requireNonNull(player, "player cannot be null");
         this.player = player;
     }
 
@@ -37,8 +36,7 @@ public abstract class TurtlePlayerEvent extends TurtleActionEvent
      * @return A {@link FakePlayer} representing this turtle.
      */
     @Nonnull
-    public FakePlayer getPlayer()
-    {
-        return player;
+    public FakePlayer getPlayer() {
+        return this.player;
     }
 }

src/main/java/dan200/computercraft/api/turtle/event/TurtleRefuelEvent.java

@@ -1,34 +1,34 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
 
 package dan200.computercraft.api.turtle.event;
 
-import dan200.computercraft.api.turtle.ITurtleAccess;
-import net.minecraft.item.ItemStack;
+import java.util.Objects;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Objects;
+
+import dan200.computercraft.api.turtle.ITurtleAccess;
+
+import net.minecraft.item.ItemStack;
 
 /**
  * Fired when a turtle attempts to refuel from an item.
  *
- * One may use {@link #setCanceled(boolean, String)} to prevent refueling from this specific item. Additionally, you
- * may use {@link #setHandler(Handler)} to register a custom fuel provider.
+ * One may use {@link #setCanceled(boolean, String)} to prevent refueling from this specific item. Additionally, you may use {@link #setHandler(Handler)} to
+ * register a custom fuel provider.
  */
-public class TurtleRefuelEvent extends TurtleActionEvent
-{
+public class TurtleRefuelEvent extends TurtleActionEvent {
     private final ItemStack stack;
     private Handler handler;
 
-    public TurtleRefuelEvent( @Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack )
-    {
-        super( turtle, TurtleAction.REFUEL );
+    public TurtleRefuelEvent(@Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack) {
+        super(turtle, TurtleAction.REFUEL);
 
-        Objects.requireNonNull( turtle, "turtle cannot be null" );
+        Objects.requireNonNull(turtle, "turtle cannot be null");
         this.stack = stack;
     }
 
@@ -39,9 +39,8 @@ public class TurtleRefuelEvent extends TurtleActionEvent
      *
      * @return The stack to refuel from.
      */
-    public ItemStack getStack()
-    {
-        return stack;
+    public ItemStack getStack() {
+        return this.stack;
     }
 
     /**
@@ -51,22 +50,19 @@ public class TurtleRefuelEvent extends TurtleActionEvent
      * @see #setHandler(Handler)
      */
     @Nullable
-    public Handler getHandler()
-    {
-        return handler;
+    public Handler getHandler() {
+        return this.handler;
     }
 
     /**
      * Set the refuel handler for this stack.
      *
-     * You should call this if you can actually refuel from this item, and ideally only if there are no existing
-     * handlers.
+     * You should call this if you can actually refuel from this item, and ideally only if there are no existing handlers.
      *
      * @param handler The new refuel handler.
      * @see #getHandler()
      */
-    public void setHandler( @Nullable Handler handler )
-    {
+    public void setHandler(@Nullable Handler handler) {
         this.handler = handler;
     }
 
@@ -74,18 +70,16 @@ public class TurtleRefuelEvent extends TurtleActionEvent
      * Handles refuelling a turtle from a specific item.
      */
     @FunctionalInterface
-    public interface Handler
-    {
+    public interface Handler {
         /**
          * Refuel a turtle using an item.
          *
          * @param turtle The turtle to refuel.
-         * @param stack  The stack to refuel with.
-         * @param slot   The slot the stack resides within. This may be used to modify the inventory afterwards.
-         * @param limit  The maximum number of refuel operations to perform. This will often correspond to the number of
-         *               items to consume.
+         * @param stack The stack to refuel with.
+         * @param slot The slot the stack resides within. This may be used to modify the inventory afterwards.
+         * @param limit The maximum number of refuel operations to perform. This will often correspond to the number of items to consume.
          * @return The amount of fuel gained.
          */
-        int refuel( @Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack, int slot, int limit );
+        int refuel(@Nonnull ITurtleAccess turtle, @Nonnull ItemStack stack, int slot, int limit);
     }
 }

src/main/java/dan200/computercraft/client/ClientRegistry.java

@@ -1,44 +1,43 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client;
 
+import java.util.HashSet;
+import java.util.function.Consumer;
+
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.client.render.TurtleModelLoader;
+import dan200.computercraft.shared.ComputerCraftRegistry;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.media.items.ItemDisk;
+import dan200.computercraft.shared.media.items.ItemTreasureDisk;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.IUnbakedModel;
-import net.minecraft.client.renderer.model.ModelResourceLocation;
-import net.minecraft.client.renderer.model.ModelRotation;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.resources.IResourceManager;
-import net.minecraft.util.ResourceLocation;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.ColorHandlerEvent;
-import net.minecraftforge.client.event.ModelBakeEvent;
-import net.minecraftforge.client.event.ModelRegistryEvent;
-import net.minecraftforge.client.event.TextureStitchEvent;
-import net.minecraftforge.client.model.ModelLoader;
-import net.minecraftforge.client.model.ModelLoaderRegistry;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
 
-import java.util.HashSet;
-import java.util.Map;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.ModelLoader;
+import net.minecraft.client.render.model.ModelRotation;
+import net.minecraft.client.render.model.UnbakedModel;
+import net.minecraft.client.texture.SpriteAtlasTexture;
+import net.minecraft.client.util.ModelIdentifier;
+import net.minecraft.resource.ResourceManager;
+import net.minecraft.util.Identifier;
+
+import net.fabricmc.fabric.api.client.rendering.v1.ColorProviderRegistry;
+import net.fabricmc.fabric.api.event.client.ClientSpriteRegistryCallback;
 
 /**
  * Registers textures and models for items.
  */
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class ClientRegistry
-{
+@SuppressWarnings ({
+    "MethodCallSideOnly",
+    "LocalVariableDeclarationSideOnly"
+})
+public final class ClientRegistry {
     private static final String[] EXTRA_MODELS = new String[] {
         "turtle_modem_normal_off_left",
         "turtle_modem_normal_on_left",
@@ -57,112 +56,68 @@ public final class ClientRegistry
 
         "turtle_colour",
         "turtle_elf_overlay",
-    };
+        };
 
     private static final String[] EXTRA_TEXTURES = new String[] {
-        // TODO: Gather these automatically from the model. I'm unable to get this working with Forge's current
-        //  model loading code.
+        // TODO: Gather these automatically from the model. Sadly the model loader isn't available
+        //  when stitching textures.
         "block/turtle_colour",
         "block/turtle_elf_overlay",
         "block/turtle_crafty_face",
         "block/turtle_speaker_face",
-    };
+        };
 
     private ClientRegistry() {}
 
-    @SubscribeEvent
-    public static void registerModels( ModelRegistryEvent event )
-    {
-        ModelLoaderRegistry.registerLoader( TurtleModelLoader.INSTANCE );
-    }
-
-    @SubscribeEvent
-    public static void onTextureStitchEvent( TextureStitchEvent.Pre event )
-    {
-        IResourceManager manager = Minecraft.getInstance().getResourceManager();
-        for( String extra : EXTRA_TEXTURES )
-        {
-            event.getMap().registerSprite( manager, new ResourceLocation( ComputerCraft.MOD_ID, extra ) );
+    public static void onTextureStitchEvent(SpriteAtlasTexture atlasTexture, ClientSpriteRegistryCallback.Registry registry) {
+        for (String extra : EXTRA_TEXTURES) {
+            registry.register(new Identifier(ComputerCraft.MOD_ID, extra));
         }
     }
 
-    @SubscribeEvent
-    public static void onModelBakeEvent( ModelBakeEvent event )
-    {
-        // Load all extra models
-        ModelLoader loader = event.getModelLoader();
-        Map<ModelResourceLocation, IBakedModel> registry = event.getModelRegistry();
+    @SuppressWarnings ("NewExpressionSideOnly")
+    public static void onModelBakeEvent(ResourceManager manager, Consumer<ModelIdentifier> out) {
+        for (String model : EXTRA_MODELS) {
+            out.accept(new ModelIdentifier(new Identifier(ComputerCraft.MOD_ID, model), "inventory"));
+        }
+    }
 
-        for( String model : EXTRA_MODELS )
-        {
-            IBakedModel bakedModel = bake( loader, loader.getUnbakedModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/" + model ) ) );
+    public static void onItemColours() {
+        ColorProviderRegistry.ITEM.register((stack, layer) -> {
+            return layer == 1 ? ((ItemDisk) stack.getItem()).getColour(stack) : 0xFFFFFF;
+        }, ComputerCraftRegistry.ModItems.DISK);
 
-            if( bakedModel != null )
+        ColorProviderRegistry.ITEM.register((stack, layer) -> layer == 1 ? ItemTreasureDisk.getColour(stack) : 0xFFFFFF,
+                                            ComputerCraftRegistry.ModItems.TREASURE_DISK);
+
+        ColorProviderRegistry.ITEM.register((stack, layer) -> {
+            switch (layer) {
+            case 0:
+            default:
+                return 0xFFFFFF;
+            case 1: // Frame colour
+                return IColouredItem.getColourBasic(stack);
+            case 2: // Light colour
             {
-                registry.put(
-                    new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, model ), "inventory" ),
-                    bakedModel
-                );
+                int light = ItemPocketComputer.getLightState(stack);
+                return light == -1 ? Colour.BLACK.getHex() : light;
             }
-        }
-
-        // And load the custom turtle models in too.
-        registry.put(
-            new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, "turtle_normal" ), "inventory" ),
-            bake( loader, TurtleModelLoader.INSTANCE.loadModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/turtle_normal" ) ) )
-        );
-
-        registry.put(
-            new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, "turtle_advanced" ), "inventory" ),
-            bake( loader, TurtleModelLoader.INSTANCE.loadModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/turtle_advanced" ) ) )
-        );
-    }
-
-    @SubscribeEvent
-    public static void onItemColours( ColorHandlerEvent.Item event )
-    {
-        if( ComputerCraft.Items.disk == null || ComputerCraft.Blocks.turtleNormal == null )
-        {
-            ComputerCraft.log.warn( "Block/item registration has failed. Skipping registration of item colours." );
-            return;
-        }
-
-        event.getItemColors().register(
-            ( stack, layer ) -> layer == 1 ? ((ItemDisk) stack.getItem()).getColour( stack ) : 0xFFFFFF,
-            ComputerCraft.Items.disk
-        );
-
-        event.getItemColors().register( ( stack, layer ) -> {
-            switch( layer )
-            {
-                case 0:
-                default:
-                    return 0xFFFFFF;
-                case 1: // Frame colour
-                    return IColouredItem.getColourBasic( stack );
-                case 2: // Light colour
-                {
-                    int light = ItemPocketComputer.getLightState( stack );
-                    return light == -1 ? Colour.Black.getHex() : light;
-                }
             }
-        }, ComputerCraft.Items.pocketComputerNormal, ComputerCraft.Items.pocketComputerAdvanced );
+        }, ComputerCraftRegistry.ModItems.POCKET_COMPUTER_NORMAL, ComputerCraftRegistry.ModItems.POCKET_COMPUTER_ADVANCED);
 
         // Setup turtle colours
-        event.getItemColors().register(
-            ( stack, tintIndex ) -> tintIndex == 0 ? ((IColouredItem) stack.getItem()).getColour( stack ) : 0xFFFFFF,
-            ComputerCraft.Blocks.turtleNormal, ComputerCraft.Blocks.turtleAdvanced
-        );
+        ColorProviderRegistry.ITEM.register((stack, tintIndex) -> tintIndex == 0 ? ((IColouredItem) stack.getItem()).getColour(stack) : 0xFFFFFF,
+                                            ComputerCraftRegistry.ModBlocks.TURTLE_NORMAL,
+                                            ComputerCraftRegistry.ModBlocks.TURTLE_ADVANCED);
     }
 
-    private static IBakedModel bake( ModelLoader loader, IUnbakedModel model )
-    {
-        model.getTextures( loader::getUnbakedModel, new HashSet<>() );
-
-        return model.bake(
-            loader::getUnbakedModel,
-            ModelLoader.defaultTextureGetter(),
-            ModelRotation.X0_Y0, false, DefaultVertexFormats.BLOCK
-        );
+    private static BakedModel bake(ModelLoader loader, UnbakedModel model, Identifier identifier) {
+        model.getTextureDependencies(loader::getOrLoadModel, new HashSet<>());
+        return model.bake(loader,
+                          spriteIdentifier -> MinecraftClient.getInstance()
+                                                             .getSpriteAtlas(spriteIdentifier.getAtlasId())
+                                                             .apply(spriteIdentifier.getTextureId()),
+                          ModelRotation.X0_Y0,
+                          identifier);
     }
 }

src/main/java/dan200/computercraft/client/ClientTableFormatter.java

@@ -1,89 +1,91 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client;
 
+import javax.annotation.Nullable;
+
+import dan200.computercraft.mixin.ChatHudAccess;
 import dan200.computercraft.shared.command.text.ChatHelpers;
 import dan200.computercraft.shared.command.text.TableBuilder;
 import dan200.computercraft.shared.command.text.TableFormatter;
 import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.gui.FontRenderer;
-import net.minecraft.client.gui.GuiNewChat;
-import net.minecraft.client.gui.GuiUtilRenderComponents;
-import net.minecraft.util.math.MathHelper;
-import net.minecraft.util.text.ITextComponent;
-import net.minecraft.util.text.TextFormatting;
 import org.apache.commons.lang3.StringUtils;
 
-import javax.annotation.Nullable;
-import java.util.List;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.font.TextRenderer;
+import net.minecraft.client.gui.hud.ChatHud;
+import net.minecraft.text.Text;
+import net.minecraft.util.Formatting;
+import net.minecraft.util.math.MathHelper;
 
-public class ClientTableFormatter implements TableFormatter
-{
+@SuppressWarnings ({
+    "MethodCallSideOnly",
+    "LocalVariableDeclarationSideOnly"
+})
+public class ClientTableFormatter implements TableFormatter {
     public static final ClientTableFormatter INSTANCE = new ClientTableFormatter();
 
     private static Int2IntOpenHashMap lastHeights = new Int2IntOpenHashMap();
 
-    private static FontRenderer renderer()
-    {
-        return Minecraft.getInstance().fontRenderer;
-    }
-
     @Override
     @Nullable
-    public ITextComponent getPadding( ITextComponent component, int width )
-    {
-        int extraWidth = width - getWidth( component );
-        if( extraWidth <= 0 ) return null;
+    public Text getPadding(Text component, int width) {
+        int extraWidth = width - this.getWidth(component);
+        if (extraWidth <= 0) {
+            return null;
+        }
 
-        FontRenderer renderer = renderer();
+        TextRenderer renderer = renderer();
 
-        float spaceWidth = renderer.getStringWidth( " " );
-        int spaces = MathHelper.floor( extraWidth / spaceWidth );
+        float spaceWidth = renderer.getWidth(" ");
+        int spaces = MathHelper.floor(extraWidth / spaceWidth);
         int extra = extraWidth - (int) (spaces * spaceWidth);
 
-        return ChatHelpers.coloured( StringUtils.repeat( ' ', spaces ) + StringUtils.repeat( (char) 712, extra ), TextFormatting.GRAY );
+        return ChatHelpers.coloured(StringUtils.repeat(' ', spaces) + StringUtils.repeat((char) 712, extra), Formatting.GRAY);
+    }
+
+    private static TextRenderer renderer() {
+        return MinecraftClient.getInstance().textRenderer;
     }
 
     @Override
-    public int getColumnPadding()
-    {
+    public int getColumnPadding() {
         return 3;
     }
 
     @Override
-    public int getWidth( ITextComponent component )
-    {
-        return renderer().getStringWidth( component.getFormattedText() );
+    public int getWidth(Text component) {
+        return renderer().getWidth(component);
     }
 
     @Override
-    public void writeLine( int id, ITextComponent component )
-    {
-        Minecraft mc = Minecraft.getInstance();
-        GuiNewChat chat = mc.ingameGUI.getChatGUI();
+    public void writeLine(int id, Text component) {
+        MinecraftClient mc = MinecraftClient.getInstance();
+        ChatHud chat = mc.inGameHud.getChatHud();
 
-        // Trim the text if it goes over the allowed length
-        int maxWidth = MathHelper.floor( chat.getChatWidth() / chat.getScale() );
-        List<ITextComponent> list = GuiUtilRenderComponents.splitText( component, maxWidth, mc.fontRenderer, false, false );
-        if( !list.isEmpty() ) chat.printChatMessageWithOptionalDeletion( list.get( 0 ), id );
+        // TODO: Trim the text if it goes over the allowed length
+        // int maxWidth = MathHelper.floor( chat.getChatWidth() / chat.getScale() );
+        // List<ITextProperties> list = RenderComponentsUtil.func_238505_a_( component, maxWidth, mc.fontRenderer );
+        // if( !list.isEmpty() ) chat.printChatMessageWithOptionalDeletion( list.get( 0 ), id );
+        ((ChatHudAccess)chat).callAddMessage(component, id);
     }
 
     @Override
-    public int display( TableBuilder table )
-    {
-        GuiNewChat chat = Minecraft.getInstance().ingameGUI.getChatGUI();
+    public int display(TableBuilder table) {
+        ChatHud chat = MinecraftClient.getInstance().inGameHud.getChatHud();
 
-        int lastHeight = lastHeights.get( table.getId() );
+        int lastHeight = lastHeights.get(table.getId());
 
-        int height = TableFormatter.super.display( table );
-        lastHeights.put( table.getId(), height );
+        int height = TableFormatter.super.display(table);
+        lastHeights.put(table.getId(), height);
 
-        for( int i = height; i < lastHeight; i++ ) chat.deleteChatLine( i + table.getId() );
+        for (int i = height; i < lastHeight; i++) {
+            ((ChatHudAccess)chat).callRemoveMessage(i + table.getId());
+        }
         return height;
     }
 }

src/main/java/dan200/computercraft/client/FrameInfo.java

@@ -1,46 +1,45 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client;
 
-import dan200.computercraft.ComputerCraft;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.common.gameevent.TickEvent;
+import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
 
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class FrameInfo
-{
+public final class FrameInfo {
     private static int tick;
     private static long renderFrame;
 
-    private FrameInfo()
-    {
+    static {
+
     }
 
-    public static boolean getGlobalCursorBlink()
-    {
+    private FrameInfo() {
+    }
+
+    public static void init() {
+        ClientTickEvents.START_CLIENT_TICK.register(m -> {
+            tick++;
+        });
+    }
+
+    public static boolean getGlobalCursorBlink() {
         return (tick / 8) % 2 == 0;
     }
 
-    public static long getRenderFrame()
-    {
+    public static long getRenderFrame() {
         return renderFrame;
     }
 
-    @SubscribeEvent
-    public static void onTick( TickEvent.ClientTickEvent event )
-    {
-        if( event.phase == TickEvent.Phase.START ) tick++;
+    // TODO Call this in a callback
+    public static void onTick() {
+        tick++;
     }
 
-    @SubscribeEvent
-    public static void onRenderTick( TickEvent.RenderTickEvent event )
-    {
-        if( event.phase == TickEvent.Phase.START ) renderFrame++;
+    // TODO Call this in a callback
+    public static void onRenderFrame() {
+        renderFrame++;
     }
 }

src/main/java/dan200/computercraft/client/gui/FixedWidthFontRenderer.java

@@ -1,200 +1,384 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.mojang.blaze3d.systems.RenderSystem;
+import dan200.computercraft.client.FrameInfo;
+import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
+import dan200.computercraft.shared.util.Colour;
 import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.texture.TextureManager;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.ResourceLocation;
 import org.lwjgl.opengl.GL11;
 
-import java.util.Arrays;
-
-public final class FixedWidthFontRenderer
-{
-    private static final ResourceLocation FONT = new ResourceLocation( "computercraft", "textures/gui/term_font.png" );
-    public static final ResourceLocation BACKGROUND = new ResourceLocation( "computercraft", "textures/gui/term_background.png" );
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.RenderLayer;
+import net.minecraft.client.render.RenderPhase;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.VertexFormat;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.client.util.math.AffineTransformation;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.math.Matrix4f;
 
+public final class FixedWidthFontRenderer {
     public static final int FONT_HEIGHT = 9;
     public static final int FONT_WIDTH = 6;
+    public static final float WIDTH = 256.0f;
+    public static final float BACKGROUND_START = (WIDTH - 6.0f) / WIDTH;
+    public static final float BACKGROUND_END = (WIDTH - 4.0f) / WIDTH;
+    private static final Matrix4f IDENTITY = AffineTransformation.identity()
+                                                                 .getMatrix();
+    private static final Identifier FONT = new Identifier("computercraft", "textures/gui/term_font.png");
+    public static final RenderLayer TYPE = Type.MAIN;
 
-    private static FixedWidthFontRenderer instance;
 
-    public static FixedWidthFontRenderer instance()
-    {
-        if( instance != null ) return instance;
-        return instance = new FixedWidthFontRenderer();
+    private FixedWidthFontRenderer() {
     }
 
-    private final TextureManager m_textureManager;
+    public static void drawString(float x, float y, @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nullable TextBuffer backgroundColour,
+                                  @Nonnull Palette palette, boolean greyscale, float leftMarginSize, float rightMarginSize) {
+        bindFont();
 
-    private FixedWidthFontRenderer()
-    {
-        m_textureManager = Minecraft.getInstance().getTextureManager();
+        VertexConsumerProvider.Immediate renderer = MinecraftClient.getInstance()
+                                                                   .getBufferBuilders()
+                                                                   .getEntityVertexConsumers();
+        drawString(IDENTITY,
+                   ((VertexConsumerProvider) renderer).getBuffer(TYPE),
+                   x,
+                   y,
+                   text,
+                   textColour,
+                   backgroundColour,
+                   palette,
+                   greyscale,
+                   leftMarginSize,
+                   rightMarginSize);
+        renderer.draw();
     }
 
-    private static void greyscaleify( double[] rgb )
-    {
-        Arrays.fill( rgb, (rgb[0] + rgb[1] + rgb[2]) / 3.0f );
+    private static void bindFont() {
+        MinecraftClient.getInstance()
+                       .getTextureManager()
+                       .bindTexture(FONT);
+        RenderSystem.texParameter(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_CLAMP);
     }
 
-    private void drawChar( BufferBuilder renderer, double x, double y, int index, int color, Palette p, boolean greyscale )
-    {
+    public static void drawString(@Nonnull Matrix4f transform, @Nonnull VertexConsumer renderer, float x, float y, @Nonnull TextBuffer text,
+                                  @Nonnull TextBuffer textColour, @Nullable TextBuffer backgroundColour, @Nonnull Palette palette, boolean greyscale,
+                                  float leftMarginSize, float rightMarginSize) {
+        if (backgroundColour != null) {
+            drawBackground(transform, renderer, x, y, backgroundColour, palette, greyscale, leftMarginSize, rightMarginSize, FONT_HEIGHT);
+        }
+
+        for (int i = 0; i < text.length(); i++) {
+            double[] colour = palette.getColour(getColour(textColour.charAt(i), Colour.BLACK));
+            float r, g, b;
+            if (greyscale) {
+                r = g = b = toGreyscale(colour);
+            } else {
+                r = (float) colour[0];
+                g = (float) colour[1];
+                b = (float) colour[2];
+            }
+
+            // Draw char
+            int index = text.charAt(i);
+            if (index > 255) {
+                index = '?';
+            }
+            drawChar(transform, renderer, x + i * FONT_WIDTH, y, index, r, g, b);
+        }
+
+    }
+
+    private static void drawBackground(@Nonnull Matrix4f transform, @Nonnull VertexConsumer renderer, float x, float y,
+                                       @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette, boolean greyscale, float leftMarginSize,
+                                       float rightMarginSize, float height) {
+        if (leftMarginSize > 0) {
+            drawQuad(transform, renderer, x - leftMarginSize, y, leftMarginSize, height, palette, greyscale, backgroundColour.charAt(0));
+        }
+
+        if (rightMarginSize > 0) {
+            drawQuad(transform,
+                     renderer,
+                     x + backgroundColour.length() * FONT_WIDTH,
+                     y,
+                     rightMarginSize,
+                     height,
+                     palette,
+                     greyscale,
+                     backgroundColour.charAt(backgroundColour.length() - 1));
+        }
+
+        // Batch together runs of identical background cells.
+        int blockStart = 0;
+        char blockColour = '\0';
+        for (int i = 0; i < backgroundColour.length(); i++) {
+            char colourIndex = backgroundColour.charAt(i);
+            if (colourIndex == blockColour) {
+                continue;
+            }
+
+            if (blockColour != '\0') {
+                drawQuad(transform, renderer, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, greyscale, blockColour);
+            }
+
+            blockColour = colourIndex;
+            blockStart = i;
+        }
+
+        if (blockColour != '\0') {
+            drawQuad(transform,
+                     renderer,
+                     x + blockStart * FONT_WIDTH,
+                     y,
+                     FONT_WIDTH * (backgroundColour.length() - blockStart),
+                     height,
+                     palette,
+                     greyscale,
+                     blockColour);
+        }
+    }
+
+    public static int getColour(char c, Colour def) {
+        return 15 - Terminal.getColour(c, def);
+    }
+
+    public static float toGreyscale(double[] rgb) {
+        return (float) ((rgb[0] + rgb[1] + rgb[2]) / 3);
+    }
+
+    private static void drawChar(Matrix4f transform, VertexConsumer buffer, float x, float y, int index, float r, float g, float b) {
+        // Short circuit to avoid the common case - the texture should be blank here after all.
+        if (index == '\0' || index == ' ') {
+            return;
+        }
+
         int column = index % 16;
         int row = index / 16;
 
-        double[] colour = p.getColour( 15 - color );
-        if( greyscale )
-        {
-            greyscaleify( colour );
-        }
-        float r = (float) colour[0];
-        float g = (float) colour[1];
-        float b = (float) colour[2];
-
         int xStart = 1 + column * (FONT_WIDTH + 2);
         int yStart = 1 + row * (FONT_HEIGHT + 2);
 
-        renderer.pos( x, y, 0.0 ).tex( xStart / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).tex( xStart / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + FONT_WIDTH, y, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + FONT_WIDTH, y, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).tex( xStart / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + FONT_WIDTH, y + FONT_HEIGHT, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
+        buffer.vertex(transform, x, y, 0f)
+              .color(r, g, b, 1.0f)
+              .texture(xStart / WIDTH, yStart / WIDTH)
+              .next();
+        buffer.vertex(transform, x, y + FONT_HEIGHT, 0f)
+              .color(r, g, b, 1.0f)
+              .texture(xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH)
+              .next();
+        buffer.vertex(transform, x + FONT_WIDTH, y, 0f)
+              .color(r, g, b, 1.0f)
+              .texture((xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH)
+              .next();
+        buffer.vertex(transform, x + FONT_WIDTH, y, 0f)
+              .color(r, g, b, 1.0f)
+              .texture((xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH)
+              .next();
+        buffer.vertex(transform, x, y + FONT_HEIGHT, 0f)
+              .color(r, g, b, 1.0f)
+              .texture(xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH)
+              .next();
+        buffer.vertex(transform, x + FONT_WIDTH, y + FONT_HEIGHT, 0f)
+              .color(r, g, b, 1.0f)
+              .texture((xStart + FONT_WIDTH) / WIDTH, (yStart + FONT_HEIGHT) / WIDTH)
+              .next();
     }
 
-    private void drawQuad( BufferBuilder renderer, double x, double y, int color, double width, Palette p, boolean greyscale )
-    {
-        double[] colour = p.getColour( 15 - color );
-        if( greyscale )
-        {
-            greyscaleify( colour );
+    private static void drawQuad(Matrix4f transform, VertexConsumer buffer, float x, float y, float width, float height, Palette palette,
+                                 boolean greyscale, char colourIndex) {
+        double[] colour = palette.getColour(getColour(colourIndex, Colour.BLACK));
+        float r, g, b;
+        if (greyscale) {
+            r = g = b = toGreyscale(colour);
+        } else {
+            r = (float) colour[0];
+            g = (float) colour[1];
+            b = (float) colour[2];
         }
-        float r = (float) colour[0];
-        float g = (float) colour[1];
-        float b = (float) colour[2];
 
-        renderer.pos( x, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + width, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + width, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-        renderer.pos( x + width, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
+        drawQuad(transform, buffer, x, y, width, height, r, g, b);
     }
 
-    private boolean isGreyScale( int colour )
-    {
-        return colour == 0 || colour == 15 || colour == 7 || colour == 8;
+    private static void drawQuad(Matrix4f transform, VertexConsumer buffer, float x, float y, float width, float height, float r, float g, float b) {
+        buffer.vertex(transform, x, y, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_START, BACKGROUND_START)
+              .next();
+        buffer.vertex(transform, x, y + height, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_START, BACKGROUND_END)
+              .next();
+        buffer.vertex(transform, x + width, y, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_END, BACKGROUND_START)
+              .next();
+        buffer.vertex(transform, x + width, y, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_END, BACKGROUND_START)
+              .next();
+        buffer.vertex(transform, x, y + height, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_START, BACKGROUND_END)
+              .next();
+        buffer.vertex(transform, x + width, y + height, 0)
+              .color(r, g, b, 1.0f)
+              .texture(BACKGROUND_END, BACKGROUND_END)
+              .next();
     }
 
-    public void drawStringBackgroundPart( int x, int y, TextBuffer backgroundColour, double leftMarginSize, double rightMarginSize, boolean greyScale, Palette p )
-    {
-        // Draw the quads
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder renderer = tessellator.getBuffer();
-        renderer.begin( GL11.GL_TRIANGLES, DefaultVertexFormats.POSITION_COLOR );
-        if( leftMarginSize > 0.0 )
-        {
-            int colour1 = "0123456789abcdef".indexOf( backgroundColour.charAt( 0 ) );
-            if( colour1 < 0 || (greyScale && !isGreyScale( colour1 )) )
-            {
-                colour1 = 15;
-            }
-            drawQuad( renderer, x - leftMarginSize, y, colour1, leftMarginSize, p, greyScale );
+    public static void drawTerminalWithoutCursor(@Nonnull Matrix4f transform, @Nonnull VertexConsumer buffer, float x, float y,
+                                                 @Nonnull Terminal terminal, boolean greyscale, float topMarginSize, float bottomMarginSize,
+                                                 float leftMarginSize, float rightMarginSize) {
+        Palette palette = terminal.getPalette();
+        int height = terminal.getHeight();
+
+        // Top and bottom margins
+        drawBackground(transform,
+                       buffer,
+                       x,
+                       y - topMarginSize,
+                       terminal.getBackgroundColourLine(0),
+                       palette,
+                       greyscale,
+                       leftMarginSize,
+                       rightMarginSize,
+                       topMarginSize);
+
+        drawBackground(transform,
+                       buffer,
+                       x,
+                       y + height * FONT_HEIGHT,
+                       terminal.getBackgroundColourLine(height - 1),
+                       palette,
+                       greyscale,
+                       leftMarginSize,
+                       rightMarginSize,
+                       bottomMarginSize);
+
+        // The main text
+        for (int i = 0; i < height; i++) {
+            drawString(transform,
+                       buffer,
+                       x,
+                       y + FixedWidthFontRenderer.FONT_HEIGHT * i,
+                       terminal.getLine(i),
+                       terminal.getTextColourLine(i),
+                       terminal.getBackgroundColourLine(i),
+                       palette,
+                       greyscale,
+                       leftMarginSize,
+                       rightMarginSize);
         }
-        if( rightMarginSize > 0.0 )
-        {
-            int colour2 = "0123456789abcdef".indexOf( backgroundColour.charAt( backgroundColour.length() - 1 ) );
-            if( colour2 < 0 || (greyScale && !isGreyScale( colour2 )) )
-            {
-                colour2 = 15;
-            }
-            drawQuad( renderer, x + backgroundColour.length() * FONT_WIDTH, y, colour2, rightMarginSize, p, greyScale );
-        }
-        for( int i = 0; i < backgroundColour.length(); i++ )
-        {
-            int colour = "0123456789abcdef".indexOf( backgroundColour.charAt( i ) );
-            if( colour < 0 || (greyScale && !isGreyScale( colour )) )
-            {
-                colour = 15;
-            }
-            drawQuad( renderer, x + i * FONT_WIDTH, y, colour, FONT_WIDTH, p, greyScale );
-        }
-        GlStateManager.disableTexture2D();
-        tessellator.draw();
-        GlStateManager.enableTexture2D();
     }
 
-    public void drawStringTextPart( int x, int y, TextBuffer s, TextBuffer textColour, boolean greyScale, Palette p )
-    {
-        // Draw the quads
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder renderer = tessellator.getBuffer();
-        renderer.begin( GL11.GL_TRIANGLES, DefaultVertexFormats.POSITION_TEX_COLOR );
-        for( int i = 0; i < s.length(); i++ )
-        {
-            // Switch colour
-            int colour = "0123456789abcdef".indexOf( textColour.charAt( i ) );
-            if( colour < 0 || (greyScale && !isGreyScale( colour )) )
-            {
-                colour = 0;
+    public static void drawCursor(@Nonnull Matrix4f transform, @Nonnull VertexConsumer buffer, float x, float y, @Nonnull Terminal terminal,
+                                  boolean greyscale) {
+        Palette palette = terminal.getPalette();
+        int width = terminal.getWidth();
+        int height = terminal.getHeight();
+
+        int cursorX = terminal.getCursorX();
+        int cursorY = terminal.getCursorY();
+        if (terminal.getCursorBlink() && cursorX >= 0 && cursorX < width && cursorY >= 0 && cursorY < height && FrameInfo.getGlobalCursorBlink()) {
+            double[] colour = palette.getColour(15 - terminal.getTextColour());
+            float r, g, b;
+            if (greyscale) {
+                r = g = b = toGreyscale(colour);
+            } else {
+                r = (float) colour[0];
+                g = (float) colour[1];
+                b = (float) colour[2];
             }
 
-            // Draw char
-            int index = s.charAt( i );
-            if( index < 0 || index > 255 )
-            {
-                index = '?';
-            }
-            drawChar( renderer, x + i * FONT_WIDTH, y, index, colour, p, greyScale );
-        }
-        tessellator.draw();
-    }
-
-    public void drawString( TextBuffer s, int x, int y, TextBuffer textColour, TextBuffer backgroundColour, double leftMarginSize, double rightMarginSize, boolean greyScale, Palette p )
-    {
-        // Draw background
-        if( backgroundColour != null )
-        {
-            // Bind the background texture
-            m_textureManager.bindTexture( BACKGROUND );
-
-            // Draw the quads
-            drawStringBackgroundPart( x, y, backgroundColour, leftMarginSize, rightMarginSize, greyScale, p );
-        }
-
-        // Draw text
-        if( s != null && textColour != null )
-        {
-            // Bind the font texture
-            bindFont();
-
-            // Draw the quads
-            drawStringTextPart( x, y, s, textColour, greyScale, p );
+            drawChar(transform, buffer, x + cursorX * FONT_WIDTH, y + cursorY * FONT_HEIGHT, '_', r, g, b);
         }
     }
 
-    public int getStringWidth( String s )
-    {
-        if( s == null )
-        {
-            return 0;
-        }
-        return s.length() * FONT_WIDTH;
+    public static void drawTerminal(@Nonnull Matrix4f transform, @Nonnull VertexConsumer buffer, float x, float y, @Nonnull Terminal terminal,
+                                    boolean greyscale, float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize) {
+        drawTerminalWithoutCursor(transform, buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize);
+        drawCursor(transform, buffer, x, y, terminal, greyscale);
     }
 
-    public void bindFont()
-    {
-        m_textureManager.bindTexture( FONT );
-        GlStateManager.texParameteri( GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_CLAMP );
+    public static void drawTerminal(@Nonnull Matrix4f transform, float x, float y, @Nonnull Terminal terminal, boolean greyscale, float topMarginSize,
+                                    float bottomMarginSize, float leftMarginSize, float rightMarginSize) {
+        bindFont();
+
+        VertexConsumerProvider.Immediate renderer = MinecraftClient.getInstance()
+                                                                   .getBufferBuilders()
+                                                                   .getEntityVertexConsumers();
+        VertexConsumer buffer = renderer.getBuffer(TYPE);
+        drawTerminal(transform, buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize);
+        renderer.draw(TYPE);
+    }
+
+    public static void drawTerminal(float x, float y, @Nonnull Terminal terminal, boolean greyscale, float topMarginSize, float bottomMarginSize,
+                                    float leftMarginSize, float rightMarginSize) {
+        drawTerminal(IDENTITY, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize);
+    }
+
+    public static void drawEmptyTerminal(float x, float y, float width, float height) {
+        drawEmptyTerminal(IDENTITY, x, y, width, height);
+    }
+
+    public static void drawEmptyTerminal(@Nonnull Matrix4f transform, float x, float y, float width, float height) {
+        bindFont();
+
+        VertexConsumerProvider.Immediate renderer = MinecraftClient.getInstance()
+                                                                   .getBufferBuilders()
+                                                                   .getEntityVertexConsumers();
+        drawEmptyTerminal(transform, renderer, x, y, width, height);
+        renderer.draw();
+    }
+
+    public static void drawEmptyTerminal(@Nonnull Matrix4f transform, @Nonnull VertexConsumerProvider renderer, float x, float y, float width,
+                                         float height) {
+        Colour colour = Colour.BLACK;
+        drawQuad(transform, renderer.getBuffer(TYPE), x, y, width, height, colour.getR(), colour.getG(), colour.getB());
+    }
+
+    public static void drawBlocker(@Nonnull Matrix4f transform, @Nonnull VertexConsumerProvider renderer, float x, float y, float width, float height) {
+        Colour colour = Colour.BLACK;
+        drawQuad(transform, renderer.getBuffer(Type.BLOCKER), x, y, width, height, colour.getR(), colour.getG(), colour.getB());
+    }
+
+    private static final class Type extends RenderPhase {
+        private static final int GL_MODE = GL11.GL_TRIANGLES;
+
+        private static final VertexFormat FORMAT = VertexFormats.POSITION_COLOR_TEXTURE;
+
+        static final RenderLayer MAIN = RenderLayer.of("terminal_font", FORMAT, GL_MODE, 1024, false, false, // useDelegate, needsSorting
+                                                       RenderLayer.MultiPhaseParameters.builder()
+                                                                                       .texture(new RenderPhase.Texture(FONT,
+                                                                                                                        false,
+                                                                                                                        false)) // blur, minimap
+                                                                                       .alpha(ONE_TENTH_ALPHA)
+                                                                                       .lightmap(DISABLE_LIGHTMAP)
+                                                                                       .writeMaskState(COLOR_MASK)
+                                                                                       .build(false));
+
+        static final RenderLayer BLOCKER = RenderLayer.of("terminal_blocker", FORMAT, GL_MODE, 256, false, false, // useDelegate, needsSorting
+                                                          RenderLayer.MultiPhaseParameters.builder()
+                                                                                          .texture(new RenderPhase.Texture(FONT,
+                                                                                                                           false,
+                                                                                                                           false)) // blur, minimap
+                                                                                          .alpha(ONE_TENTH_ALPHA)
+                                                                                          .writeMaskState(DEPTH_MASK)
+                                                                                          .lightmap(DISABLE_LIGHTMAP)
+                                                                                          .build(false));
+
+        private Type(String name, Runnable setup, Runnable destroy) {
+            super(name, setup, destroy);
+        }
     }
 }

src/main/java/dan200/computercraft/client/gui/GuiComputer.java

@@ -1,154 +1,134 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import static dan200.computercraft.client.render.ComputerBorderRenderer.BORDER;
+import static dan200.computercraft.client.render.ComputerBorderRenderer.MARGIN;
+
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.gui.widgets.WidgetWrapper;
-import dan200.computercraft.shared.computer.blocks.TileComputer;
+import dan200.computercraft.client.render.ComputerBorderRenderer;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.inventory.ContainerComputer;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.inventory.Container;
-import net.minecraft.util.ResourceLocation;
+import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
+import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
+import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
+import org.lwjgl.glfw.GLFW;
 
-public class GuiComputer extends GuiContainer
-{
-    public static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_normal.png" );
-    public static final ResourceLocation BACKGROUND_ADVANCED = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_advanced.png" );
-    public static final ResourceLocation BACKGROUND_COMMAND = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_command.png" );
-    public static final ResourceLocation BACKGROUND_COLOUR = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_colour.png" );
+import net.minecraft.client.gui.screen.ingame.HandledScreen;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.Text;
 
-    private final ComputerFamily m_family;
-    private final ClientComputer m_computer;
-    private final int m_termWidth;
-    private final int m_termHeight;
+public final class GuiComputer<T extends ContainerComputerBase> extends HandledScreen<T> {
+    private final ComputerFamily family;
+    private final ClientComputer computer;
+    private final int termWidth;
+    private final int termHeight;
 
     private WidgetTerminal terminal;
     private WidgetWrapper terminalWrapper;
 
-    public GuiComputer( Container container, ComputerFamily family, ClientComputer computer, int termWidth, int termHeight )
-    {
-        super( container );
-        m_family = family;
-        m_computer = computer;
-        m_termWidth = termWidth;
-        m_termHeight = termHeight;
-        terminal = null;
+    private GuiComputer(T container, PlayerInventory player, Text title, int termWidth, int termHeight) {
+        super(container, player, title);
+        this.family = container.getFamily();
+        this.computer = (ClientComputer) container.getComputer();
+        this.termWidth = termWidth;
+        this.termHeight = termHeight;
+        this.terminal = null;
     }
 
-    public GuiComputer( TileComputer computer )
-    {
-        this(
-            new ContainerComputer( computer ),
-            computer.getFamily(),
-            computer.createClientComputer(),
-            ComputerCraft.terminalWidth_computer,
-            ComputerCraft.terminalHeight_computer
-        );
+    public static GuiComputer<ContainerComputer> create(ContainerComputer container, PlayerInventory inventory, Text component) {
+        return new GuiComputer<>(container, inventory, component, ComputerCraft.terminalWidth_computer, ComputerCraft.terminalHeight_computer);
+    }
+
+    public static GuiComputer<ContainerPocketComputer> createPocket(ContainerPocketComputer container, PlayerInventory inventory, Text component) {
+        return new GuiComputer<>(container, inventory, component, ComputerCraft.terminalWidth_pocketComputer, ComputerCraft.terminalHeight_pocketComputer);
+    }
+
+    public static GuiComputer<ContainerViewComputer> createView(ContainerViewComputer container, PlayerInventory inventory, Text component) {
+        return new GuiComputer<>(container, inventory, component, container.getWidth(), container.getHeight());
+    }
+
+
+    @Override
+    protected void init() {
+        this.client.keyboard.setRepeatEvents(true);
+
+        int termPxWidth = this.termWidth * FixedWidthFontRenderer.FONT_WIDTH;
+        int termPxHeight = this.termHeight * FixedWidthFontRenderer.FONT_HEIGHT;
+
+        this.backgroundWidth = termPxWidth + MARGIN * 2 + BORDER * 2;
+        this.backgroundHeight = termPxHeight + MARGIN * 2 + BORDER * 2;
+
+        super.init();
+
+        this.terminal = new WidgetTerminal(this.client, () -> this.computer, this.termWidth, this.termHeight, MARGIN, MARGIN, MARGIN, MARGIN);
+        this.terminalWrapper = new WidgetWrapper(this.terminal, MARGIN + BORDER + this.x, MARGIN + BORDER + this.y, termPxWidth, termPxHeight);
+
+        this.children.add(this.terminalWrapper);
+        this.setFocused(this.terminalWrapper);
     }
 
     @Override
-    protected void initGui()
-    {
-        mc.keyboardListener.enableRepeatEvents( true );
-
-        int termPxWidth = m_termWidth * FixedWidthFontRenderer.FONT_WIDTH;
-        int termPxHeight = m_termHeight * FixedWidthFontRenderer.FONT_HEIGHT;
-
-        xSize = termPxWidth + 4 + 24;
-        ySize = termPxHeight + 4 + 24;
-
-        super.initGui();
-
-        terminal = new WidgetTerminal( mc, () -> m_computer, m_termWidth, m_termHeight, 2, 2, 2, 2 );
-        terminalWrapper = new WidgetWrapper( terminal, 2 + 12 + guiLeft, 2 + 12 + guiTop, termPxWidth, termPxHeight );
-
-        children.add( terminalWrapper );
-        setFocused( terminalWrapper );
+    public void render(@Nonnull MatrixStack stack, int mouseX, int mouseY, float partialTicks) {
+        super.render(stack, mouseX, mouseY, partialTicks);
+        this.drawMouseoverTooltip(stack, mouseX, mouseY);
     }
 
     @Override
-    public void onGuiClosed()
-    {
-        super.onGuiClosed();
-        children.remove( terminal );
-        terminal = null;
-        mc.keyboardListener.enableRepeatEvents( false );
+    protected void drawForeground(@Nonnull MatrixStack transform, int mouseX, int mouseY) {
+        // Skip rendering labels.
     }
 
     @Override
-    public void tick()
-    {
-        super.tick();
-        terminal.update();
-    }
-
-    @Override
-    public void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
-    {
-        // Work out where to draw
-        int startX = terminalWrapper.getX() - 2;
-        int startY = terminalWrapper.getY() - 2;
-        int endX = startX + terminalWrapper.getWidth() + 4;
-        int endY = startY + terminalWrapper.getHeight() + 4;
-
+    public void drawBackground(@Nonnull MatrixStack stack, float partialTicks, int mouseX, int mouseY) {
         // Draw terminal
-        terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
+        this.terminal.draw(this.terminalWrapper.getX(), this.terminalWrapper.getY());
 
         // Draw a border around the terminal
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        switch( m_family )
-        {
-            case Normal:
-            default:
-                mc.getTextureManager().bindTexture( BACKGROUND_NORMAL );
-                break;
-            case Advanced:
-                mc.getTextureManager().bindTexture( BACKGROUND_ADVANCED );
-                break;
-            case Command:
-                mc.getTextureManager().bindTexture( BACKGROUND_COMMAND );
-                break;
+        RenderSystem.color4f(1, 1, 1, 1);
+        this.client.getTextureManager()
+                   .bindTexture(ComputerBorderRenderer.getTexture(this.family));
+        ComputerBorderRenderer.render(this.terminalWrapper.getX() - MARGIN, this.terminalWrapper.getY() - MARGIN,
+                                      this.getZOffset(), this.terminalWrapper.getWidth() + MARGIN * 2, this.terminalWrapper.getHeight() + MARGIN * 2);
+    }
+
+    @Override
+    public boolean mouseDragged(double x, double y, int button, double deltaX, double deltaY) {
+        return (this.getFocused() != null && this.getFocused().mouseDragged(x, y, button, deltaX, deltaY)) || super.mouseDragged(x, y, button, deltaX, deltaY);
+    }
+
+    @Override
+    public boolean keyPressed(int key, int scancode, int modifiers) {
+        // Forward the tab key to the terminal, rather than moving between controls.
+        if (key == GLFW.GLFW_KEY_TAB && this.getFocused() != null && this.getFocused() == this.terminalWrapper) {
+            return this.getFocused().keyPressed(key, scancode, modifiers);
         }
 
-        drawTexturedModalRect( startX - 12, startY - 12, 12, 28, 12, 12 );
-        drawTexturedModalRect( startX - 12, endY, 12, 40, 12, 12 );
-        drawTexturedModalRect( endX, startY - 12, 24, 28, 12, 12 );
-        drawTexturedModalRect( endX, endY, 24, 40, 12, 12 );
-
-        drawTexturedModalRect( startX, startY - 12, 0, 0, endX - startX, 12 );
-        drawTexturedModalRect( startX, endY, 0, 12, endX - startX, 12 );
-
-        drawTexturedModalRect( startX - 12, startY, 0, 28, 12, endY - startY );
-        drawTexturedModalRect( endX, startY, 36, 28, 12, endY - startY );
+        return super.keyPressed(key, scancode, modifiers);
     }
 
     @Override
-    public void render( int mouseX, int mouseY, float partialTicks )
-    {
-        drawDefaultBackground();
-        super.render( mouseX, mouseY, partialTicks );
-        renderHoveredToolTip( mouseX, mouseY );
+    public void removed() {
+        super.removed();
+        this.children.remove(this.terminal);
+        this.terminal = null;
+        this.client.keyboard.setRepeatEvents(false);
     }
 
     @Override
-    public boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
-    {
-        return (getFocused() != null && getFocused().mouseDragged( x, y, button, deltaX, deltaY ))
-            || super.mouseDragged( x, y, button, deltaX, deltaY );
-    }
-
-    @Override
-    public boolean mouseReleased( double x, double y, int button )
-    {
-        return (getFocused() != null && getFocused().mouseReleased( x, y, button ))
-            || super.mouseReleased( x, y, button );
+    public void tick() {
+        super.tick();
+        this.terminal.update();
     }
 }

src/main/java/dan200/computercraft/client/gui/GuiDiskDrive.java

@@ -1,50 +1,41 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.resources.I18n;
-import net.minecraft.util.ResourceLocation;
 
-public class GuiDiskDrive extends GuiContainer
-{
-    private static final ResourceLocation BACKGROUND = new ResourceLocation( "computercraft", "textures/gui/disk_drive.png" );
+import net.minecraft.client.gui.screen.ingame.HandledScreen;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.Text;
+import net.minecraft.util.Identifier;
 
-    private final ContainerDiskDrive m_container;
+public class GuiDiskDrive extends HandledScreen<ContainerDiskDrive> {
+    private static final Identifier BACKGROUND = new Identifier("computercraft", "textures/gui/disk_drive.png");
 
-    public GuiDiskDrive( ContainerDiskDrive container )
-    {
-        super( container );
-        m_container = container;
+    public GuiDiskDrive(ContainerDiskDrive container, PlayerInventory player, Text title) {
+        super(container, player, title);
     }
 
     @Override
-    protected void drawGuiContainerForegroundLayer( int mouseX, int mouseY )
-    {
-        String title = m_container.getDiskDrive().getDisplayName().getString();
-        fontRenderer.drawString( title, (xSize - fontRenderer.getStringWidth( title )) / 2.0f, 6, 0x404040 );
-        fontRenderer.drawString( I18n.format( "container.inventory" ), 8, ySize - 96 + 2, 0x404040 );
+    public void render(@Nonnull MatrixStack transform, int mouseX, int mouseY, float partialTicks) {
+        this.renderBackground(transform);
+        super.render(transform, mouseX, mouseY, partialTicks);
+        this.drawMouseoverTooltip(transform, mouseX, mouseY);
     }
 
     @Override
-    protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
-    {
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
-        mc.getTextureManager().bindTexture( BACKGROUND );
-        drawTexturedModalRect( guiLeft, guiTop, 0, 0, xSize, ySize );
-    }
-
-    @Override
-    public void render( int mouseX, int mouseY, float partialTicks )
-    {
-        drawDefaultBackground();
-        super.render( mouseX, mouseY, partialTicks );
-        renderHoveredToolTip( mouseX, mouseY );
+    protected void drawBackground(@Nonnull MatrixStack transform, float partialTicks, int mouseX, int mouseY) {
+        RenderSystem.color4f(1.0F, 1.0F, 1.0F, 1.0F);
+        this.client.getTextureManager()
+                   .bindTexture(BACKGROUND);
+        this.drawTexture(transform, this.x, this.y, 0, 0, this.backgroundWidth, this.backgroundHeight);
     }
 }

src/main/java/dan200/computercraft/client/gui/GuiPocketComputer.java

@@ -1,34 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.client.gui;
-
-import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.shared.computer.core.ComputerFamily;
-import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
-import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
-import net.minecraft.item.Item;
-import net.minecraft.item.ItemStack;
-
-public class GuiPocketComputer extends GuiComputer
-{
-    public GuiPocketComputer( ContainerPocketComputer container )
-    {
-        super(
-            container,
-            getFamily( container.getStack() ),
-            ItemPocketComputer.createClientComputer( container.getStack() ),
-            ComputerCraft.terminalWidth_pocketComputer,
-            ComputerCraft.terminalHeight_pocketComputer
-        );
-    }
-
-    private static ComputerFamily getFamily( ItemStack stack )
-    {
-        Item item = stack.getItem();
-        return item instanceof ItemPocketComputer ? ((ItemPocketComputer) item).getFamily() : ComputerFamily.Normal;
-    }
-}

src/main/java/dan200/computercraft/client/gui/GuiPrinter.java

@@ -1,52 +1,53 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.resources.I18n;
-import net.minecraft.util.ResourceLocation;
 
-public class GuiPrinter extends GuiContainer
-{
-    private static final ResourceLocation BACKGROUND = new ResourceLocation( "computercraft", "textures/gui/printer.png" );
+import net.minecraft.client.gui.screen.ingame.HandledScreen;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.Text;
+import net.minecraft.util.Identifier;
 
-    private final ContainerPrinter container;
+public class GuiPrinter extends HandledScreen<ContainerPrinter> {
+    private static final Identifier BACKGROUND = new Identifier("computercraft", "textures/gui/printer.png");
 
-    public GuiPrinter( ContainerPrinter container )
-    {
-        super( container );
-        this.container = container;
+    public GuiPrinter(ContainerPrinter container, PlayerInventory player, Text title) {
+        super(container, player, title);
     }
 
-    @Override
+    /*@Override
     protected void drawGuiContainerForegroundLayer( int mouseX, int mouseY )
     {
-        String title = container.getPrinter().getDisplayName().getString();
-        fontRenderer.drawString( title, (xSize - fontRenderer.getStringWidth( title )) / 2.0f, 6, 0x404040 );
-        fontRenderer.drawString( I18n.format( "container.inventory" ), 8, ySize - 96 + 2, 0x404040 );
+        String title = getTitle().getFormattedText();
+        font.drawString( title, (xSize - font.getStringWidth( title )) / 2.0f, 6, 0x404040 );
+        font.drawString( I18n.format( "container.inventory" ), 8, ySize - 96 + 2, 0x404040 );
+    }*/
+
+    @Override
+    public void render(@Nonnull MatrixStack stack, int mouseX, int mouseY, float partialTicks) {
+        this.renderBackground(stack);
+        super.render(stack, mouseX, mouseY, partialTicks);
+        this.drawMouseoverTooltip(stack, mouseX, mouseY);
     }
 
     @Override
-    protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
-    {
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
-        mc.getTextureManager().bindTexture( BACKGROUND );
-        drawTexturedModalRect( guiLeft, guiTop, 0, 0, xSize, ySize );
+    protected void drawBackground(@Nonnull MatrixStack transform, float partialTicks, int mouseX, int mouseY) {
+        RenderSystem.color4f(1.0F, 1.0F, 1.0F, 1.0F);
+        this.client.getTextureManager()
+                   .bindTexture(BACKGROUND);
+        this.drawTexture(transform, this.x, this.y, 0, 0, this.backgroundWidth, this.backgroundHeight);
 
-        if( container.isPrinting() ) drawTexturedModalRect( guiLeft + 34, guiTop + 21, 176, 0, 25, 45 );
-    }
-
-    @Override
-    public void render( int mouseX, int mouseY, float partialTicks )
-    {
-        drawDefaultBackground();
-        super.render( mouseX, mouseY, partialTicks );
-        renderHoveredToolTip( mouseX, mouseY );
+        if (this.getScreenHandler().isPrinting()) {
+            this.drawTexture(transform, this.x + 34, this.y + 21, 176, 0, 25, 45);
+        }
     }
 }

src/main/java/dan200/computercraft/client/gui/GuiPrintout.java

@@ -1,82 +1,81 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import static dan200.computercraft.client.render.PrintoutRenderer.X_TEXT_MARGIN;
+import static dan200.computercraft.client.render.PrintoutRenderer.Y_SIZE;
+import static dan200.computercraft.client.render.PrintoutRenderer.Y_TEXT_MARGIN;
+import static dan200.computercraft.client.render.PrintoutRenderer.drawBorder;
+import static dan200.computercraft.client.render.PrintoutRenderer.drawText;
+
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.common.ContainerHeldItem;
 import dan200.computercraft.shared.media.items.ItemPrintout;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.client.renderer.GlStateManager;
 import org.lwjgl.glfw.GLFW;
 
-import static dan200.computercraft.client.render.PrintoutRenderer.*;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.screen.ingame.HandledScreen;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.Text;
+import net.minecraft.util.math.Matrix4f;
 
-public class GuiPrintout extends GuiContainer
-{
+public class GuiPrintout extends HandledScreen<ContainerHeldItem> {
     private final boolean m_book;
     private final int m_pages;
     private final TextBuffer[] m_text;
     private final TextBuffer[] m_colours;
     private int m_page;
 
-    public GuiPrintout( ContainerHeldItem container )
-    {
-        super( container );
+    public GuiPrintout(ContainerHeldItem container, PlayerInventory player, Text title) {
+        super(container, player, title);
 
-        ySize = Y_SIZE;
+        this.backgroundHeight = Y_SIZE;
 
-        String[] text = ItemPrintout.getText( container.getStack() );
-        m_text = new TextBuffer[text.length];
-        for( int i = 0; i < m_text.length; i++ ) m_text[i] = new TextBuffer( text[i] );
+        String[] text = ItemPrintout.getText(container.getStack());
+        this.m_text = new TextBuffer[text.length];
+        for (int i = 0; i < this.m_text.length; i++) {
+            this.m_text[i] = new TextBuffer(text[i]);
+        }
 
-        String[] colours = ItemPrintout.getColours( container.getStack() );
-        m_colours = new TextBuffer[colours.length];
-        for( int i = 0; i < m_colours.length; i++ ) m_colours[i] = new TextBuffer( colours[i] );
+        String[] colours = ItemPrintout.getColours(container.getStack());
+        this.m_colours = new TextBuffer[colours.length];
+        for (int i = 0; i < this.m_colours.length; i++) {
+            this.m_colours[i] = new TextBuffer(colours[i]);
+        }
 
-        m_page = 0;
-        m_pages = Math.max( m_text.length / ItemPrintout.LINES_PER_PAGE, 1 );
-        m_book = ((ItemPrintout) container.getStack().getItem()).getType() == ItemPrintout.Type.BOOK;
+        this.m_page = 0;
+        this.m_pages = Math.max(this.m_text.length / ItemPrintout.LINES_PER_PAGE, 1);
+        this.m_book = ((ItemPrintout) container.getStack()
+                                               .getItem()).getType() == ItemPrintout.Type.BOOK;
     }
 
     @Override
-    public boolean keyPressed( int key, int scancode, int modifiers )
-    {
-        if( super.keyPressed( key, scancode, modifiers ) ) return true;
-
-        if( key == GLFW.GLFW_KEY_RIGHT )
-        {
-            if( m_page < m_pages - 1 ) m_page++;
+    public boolean mouseScrolled(double x, double y, double delta) {
+        if (super.mouseScrolled(x, y, delta)) {
             return true;
         }
-
-        if( key == GLFW.GLFW_KEY_LEFT )
-        {
-            if( m_page > 0 ) m_page--;
-            return true;
-        }
-
-        return false;
-    }
-
-    @Override
-    public boolean mouseScrolled( double delta )
-    {
-        if( super.mouseScrolled( delta ) ) return true;
-        if( delta < 0 )
-        {
+        if (delta < 0) {
             // Scroll up goes to the next page
-            if( m_page < m_pages - 1 ) m_page++;
+            if (this.m_page < this.m_pages - 1) {
+                this.m_page++;
+            }
             return true;
         }
 
-        if( delta > 0 )
-        {
+        if (delta > 0) {
             // Scroll down goes to the previous page
-            if( m_page > 0 ) m_page--;
+            if (this.m_page > 0) {
+                this.m_page--;
+            }
             return true;
         }
 
@@ -84,25 +83,56 @@ public class GuiPrintout extends GuiContainer
     }
 
     @Override
-    public void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
-    {
-        // Draw the printout
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableDepthTest();
+    public void render(@Nonnull MatrixStack stack, int mouseX, int mouseY, float partialTicks) {
+        // We must take the background further back in order to not overlap with our printed pages.
+        this.setZOffset(this.getZOffset() - 1);
+        this.renderBackground(stack);
+        this.setZOffset(this.getZOffset() + 1);
 
-        drawBorder( guiLeft, guiTop, zLevel, m_page, m_pages, m_book );
-        drawText( guiLeft + X_TEXT_MARGIN, guiTop + Y_TEXT_MARGIN, ItemPrintout.LINES_PER_PAGE * m_page, m_text, m_colours );
+        super.render(stack, mouseX, mouseY, partialTicks);
     }
 
     @Override
-    public void render( int mouseX, int mouseY, float partialTicks )
-    {
-        // We must take the background further back in order to not overlap with our printed pages.
-        zLevel--;
-        drawDefaultBackground();
-        zLevel++;
+    protected void drawForeground(@Nonnull MatrixStack transform, int mouseX, int mouseY) {
+        // Skip rendering labels.
+    }
 
-        super.render( mouseX, mouseY, partialTicks );
-        renderHoveredToolTip( mouseX, mouseY );
+    @Override
+    protected void drawBackground(@Nonnull MatrixStack transform, float partialTicks, int mouseX, int mouseY) {
+        // Draw the printout
+        RenderSystem.color4f(1.0f, 1.0f, 1.0f, 1.0f);
+        RenderSystem.enableDepthTest();
+
+        VertexConsumerProvider.Immediate renderer = MinecraftClient.getInstance()
+                                                                   .getBufferBuilders()
+                                                                   .getEntityVertexConsumers();
+        Matrix4f matrix = transform.peek()
+                                   .getModel();
+        drawBorder(matrix, renderer, this.x, this.y, this.getZOffset(), this.m_page, this.m_pages, this.m_book);
+        drawText(matrix, renderer, this.x + X_TEXT_MARGIN, this.y + Y_TEXT_MARGIN, ItemPrintout.LINES_PER_PAGE * this.m_page, this.m_text, this.m_colours);
+        renderer.draw();
+    }
+
+    @Override
+    public boolean keyPressed(int key, int scancode, int modifiers) {
+        if (super.keyPressed(key, scancode, modifiers)) {
+            return true;
+        }
+
+        if (key == GLFW.GLFW_KEY_RIGHT) {
+            if (this.m_page < this.m_pages - 1) {
+                this.m_page++;
+            }
+            return true;
+        }
+
+        if (key == GLFW.GLFW_KEY_LEFT) {
+            if (this.m_page > 0) {
+                this.m_page--;
+            }
+            return true;
+        }
+
+        return false;
     }
 }

src/main/java/dan200/computercraft/client/gui/GuiTurtle.java

@@ -1,117 +1,126 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui;
 
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.gui.widgets.WidgetWrapper;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
-import dan200.computercraft.shared.turtle.blocks.TileTurtle;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.util.ResourceLocation;
+import org.lwjgl.glfw.GLFW;
 
-public class GuiTurtle extends GuiContainer
-{
-    private static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation( "computercraft", "textures/gui/turtle_normal.png" );
-    private static final ResourceLocation BACKGROUND_ADVANCED = new ResourceLocation( "computercraft", "textures/gui/turtle_advanced.png" );
-
-    private ContainerTurtle m_container;
+import net.minecraft.client.gui.screen.ingame.HandledScreen;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.Text;
+import net.minecraft.util.Identifier;
 
+public class GuiTurtle extends HandledScreen<ContainerTurtle> {
+    private static final Identifier BACKGROUND_NORMAL = new Identifier("computercraft", "textures/gui/turtle_normal.png");
+    private static final Identifier BACKGROUND_ADVANCED = new Identifier("computercraft", "textures/gui/turtle_advanced.png");
     private final ComputerFamily m_family;
     private final ClientComputer m_computer;
-
+    private ContainerTurtle m_container;
     private WidgetTerminal terminal;
     private WidgetWrapper terminalWrapper;
 
-    public GuiTurtle( TileTurtle turtle, ContainerTurtle container )
-    {
-        super( container );
+    public GuiTurtle(ContainerTurtle container, PlayerInventory player, Text title) {
+        super(container, player, title);
 
-        m_container = container;
-        m_family = turtle.getFamily();
-        m_computer = turtle.getClientComputer();
+        this.m_container = container;
+        this.m_family = container.getFamily();
+        this.m_computer = (ClientComputer) container.getComputer();
 
-        xSize = 254;
-        ySize = 217;
+        this.backgroundWidth = 254;
+        this.backgroundHeight = 217;
     }
 
     @Override
-    protected void initGui()
-    {
-        super.initGui();
-        mc.keyboardListener.enableRepeatEvents( true );
+    protected void init() {
+        super.init();
+        this.client.keyboard.setRepeatEvents(true);
 
         int termPxWidth = ComputerCraft.terminalWidth_turtle * FixedWidthFontRenderer.FONT_WIDTH;
         int termPxHeight = ComputerCraft.terminalHeight_turtle * FixedWidthFontRenderer.FONT_HEIGHT;
 
-        terminal = new WidgetTerminal(
-            mc, () -> m_computer,
-            ComputerCraft.terminalWidth_turtle,
-            ComputerCraft.terminalHeight_turtle,
-            2, 2, 2, 2
-        );
-        terminalWrapper = new WidgetWrapper( terminal, 2 + 8 + guiLeft, 2 + 8 + guiTop, termPxWidth, termPxHeight );
+        this.terminal = new WidgetTerminal(this.client, () -> this.m_computer, ComputerCraft.terminalWidth_turtle, ComputerCraft.terminalHeight_turtle, 2, 2, 2, 2);
+        this.terminalWrapper = new WidgetWrapper(this.terminal, 2 + 8 + this.x, 2 + 8 + this.y, termPxWidth, termPxHeight);
 
-        children.add( terminalWrapper );
-        setFocused( terminalWrapper );
+        this.children.add(this.terminalWrapper);
+        this.setFocused(this.terminalWrapper);
     }
 
     @Override
-    public void onGuiClosed()
-    {
-        children.remove( terminal );
-        terminal = null;
-        mc.keyboardListener.enableRepeatEvents( false );
+    public void render(@Nonnull MatrixStack stack, int mouseX, int mouseY, float partialTicks) {
+        this.renderBackground(stack);
+        super.render(stack, mouseX, mouseY, partialTicks);
+        this.drawMouseoverTooltip(stack, mouseX, mouseY);
     }
 
     @Override
-    public void tick()
-    {
-        super.tick();
-        terminal.update();
+    protected void drawForeground(@Nonnull MatrixStack transform, int mouseX, int mouseY) {
+        // Skip rendering labels.
     }
 
-    private void drawSelectionSlot( boolean advanced )
-    {
+    @Override
+    protected void drawBackground(@Nonnull MatrixStack transform, float partialTicks, int mouseX, int mouseY) {
+        // Draw term
+        Identifier texture = this.m_family == ComputerFamily.ADVANCED ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL;
+        this.terminal.draw(this.terminalWrapper.getX(), this.terminalWrapper.getY());
+
+        // Draw border/inventory
+        RenderSystem.color4f(1.0F, 1.0F, 1.0F, 1.0F);
+        this.client.getTextureManager()
+                   .bindTexture(texture);
+        this.drawTexture(transform, this.x, this.y, 0, 0, this.backgroundWidth, this.backgroundHeight);
+
         // Draw selection slot
-        int slot = m_container.getSelectedSlot();
-        if( slot >= 0 )
-        {
-            GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+        int slot = this.m_container.getSelectedSlot();
+        if (slot >= 0) {
             int slotX = slot % 4;
             int slotY = slot / 4;
-            mc.getTextureManager().bindTexture( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
-            drawTexturedModalRect( guiLeft + m_container.m_turtleInvStartX - 2 + slotX * 18, guiTop + m_container.m_playerInvStartY - 2 + slotY * 18, 0, 217, 24, 24 );
+            this.drawTexture(transform, this.x + ContainerTurtle.TURTLE_START_X - 2 + slotX * 18, this.y + ContainerTurtle.PLAYER_START_Y - 2 + slotY * 18,
+                             0,
+                             217,
+                             24,
+                             24);
         }
     }
 
     @Override
-    protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
-    {
-        // Draw term
-        boolean advanced = m_family == ComputerFamily.Advanced;
-        terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
-
-        // Draw border/inventory
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
-        mc.getTextureManager().bindTexture( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
-        drawTexturedModalRect( guiLeft, guiTop, 0, 0, xSize, ySize );
-
-        drawSelectionSlot( advanced );
+    public boolean mouseDragged(double x, double y, int button, double deltaX, double deltaY) {
+        return (this.getFocused() != null && this.getFocused().mouseDragged(x, y, button, deltaX, deltaY)) || super.mouseDragged(x, y, button, deltaX, deltaY);
     }
 
     @Override
-    public void render( int mouseX, int mouseY, float partialTicks )
-    {
-        drawDefaultBackground();
-        super.render( mouseX, mouseY, partialTicks );
-        renderHoveredToolTip( mouseX, mouseY );
+    public boolean keyPressed(int key, int scancode, int modifiers) {
+        // Forward the tab key to the terminal, rather than moving between controls.
+        if (key == GLFW.GLFW_KEY_TAB && this.getFocused() != null && this.getFocused() == this.terminalWrapper) {
+            return this.getFocused().keyPressed(key, scancode, modifiers);
+        }
+
+        return super.keyPressed(key, scancode, modifiers);
+    }
+
+    @Override
+    public void removed() {
+        super.removed();
+        this.children.remove(this.terminal);
+        this.terminal = null;
+        this.client.keyboard.setRepeatEvents(false);
+    }
+
+    @Override
+    public void tick() {
+        super.tick();
+        this.terminal.update();
     }
 }

src/main/java/dan200/computercraft/client/gui/widgets/WidgetTerminal.java

@@ -1,61 +1,49 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui.widgets;
 
-import dan200.computercraft.client.FrameInfo;
-import dan200.computercraft.client.gui.FixedWidthFontRenderer;
-import dan200.computercraft.core.terminal.Terminal;
-import dan200.computercraft.core.terminal.TextBuffer;
-import dan200.computercraft.shared.computer.core.ClientComputer;
-import dan200.computercraft.shared.computer.core.IComputer;
-import dan200.computercraft.shared.util.Colour;
-import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.gui.IGuiEventListener;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.SharedConstants;
-import org.lwjgl.glfw.GLFW;
-import org.lwjgl.opengl.GL11;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
 
 import java.util.BitSet;
 import java.util.function.Supplier;
 
-import static dan200.computercraft.client.gui.FixedWidthFontRenderer.BACKGROUND;
+import dan200.computercraft.client.gui.FixedWidthFontRenderer;
+import dan200.computercraft.core.terminal.Terminal;
+import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.shared.computer.core.IComputer;
+import org.lwjgl.glfw.GLFW;
 
-public class WidgetTerminal implements IGuiEventListener
-{
+import net.minecraft.SharedConstants;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.Element;
+
+public class WidgetTerminal implements Element {
     private static final float TERMINATE_TIME = 0.5f;
 
-    private final Minecraft client;
-
+    private final MinecraftClient client;
     private final Supplier<ClientComputer> computer;
     private final int termWidth;
     private final int termHeight;
-
-    private float terminateTimer = -1;
-    private float rebootTimer = -1;
-    private float shutdownTimer = -1;
-
-    private int lastMouseButton = -1;
-    private int lastMouseX = -1;
-    private int lastMouseY = -1;
-
     private final int leftMargin;
     private final int rightMargin;
     private final int topMargin;
     private final int bottomMargin;
+    private final BitSet keysDown = new BitSet(256);
+    private boolean focused;
+    private float terminateTimer = -1;
+    private float rebootTimer = -1;
+    private float shutdownTimer = -1;
+    private int lastMouseButton = -1;
+    private int lastMouseX = -1;
+    private int lastMouseY = -1;
 
-    private final BitSet keysDown = new BitSet( 256 );
-
-    public WidgetTerminal( Minecraft client, Supplier<ClientComputer> computer, int termWidth, int termHeight, int leftMargin, int rightMargin, int topMargin, int bottomMargin )
-    {
+    public WidgetTerminal(MinecraftClient client, Supplier<ClientComputer> computer, int termWidth, int termHeight, int leftMargin, int rightMargin,
+                          int topMargin, int bottomMargin) {
         this.client = client;
         this.computer = computer;
         this.termWidth = termWidth;
@@ -67,351 +55,287 @@ public class WidgetTerminal implements IGuiEventListener
     }
 
     @Override
-    public boolean charTyped( char ch, int modifiers )
-    {
-        if( ch >= 32 && ch <= 126 || ch >= 160 && ch <= 255 ) // printable chars in byte range
+    public boolean mouseClicked(double mouseX, double mouseY, int button) {
+        ClientComputer computer = this.computer.get();
+        if (computer == null || !computer.isColour() || button < 0 || button > 2) {
+            return false;
+        }
+
+        Terminal term = computer.getTerminal();
+        if (term != null) {
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
+            charX = Math.min(Math.max(charX, 0), term.getWidth() - 1);
+            charY = Math.min(Math.max(charY, 0), term.getHeight() - 1);
+
+            computer.mouseClick(button + 1, charX + 1, charY + 1);
+
+            this.lastMouseButton = button;
+            this.lastMouseX = charX;
+            this.lastMouseY = charY;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean mouseReleased(double mouseX, double mouseY, int button) {
+        ClientComputer computer = this.computer.get();
+        if (computer == null || !computer.isColour() || button < 0 || button > 2) {
+            return false;
+        }
+
+        Terminal term = computer.getTerminal();
+        if (term != null) {
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
+            charX = Math.min(Math.max(charX, 0), term.getWidth() - 1);
+            charY = Math.min(Math.max(charY, 0), term.getHeight() - 1);
+
+            if (this.lastMouseButton == button) {
+                computer.mouseUp(this.lastMouseButton + 1, charX + 1, charY + 1);
+                this.lastMouseButton = -1;
+            }
+
+            this.lastMouseX = charX;
+            this.lastMouseY = charY;
+        }
+
+        return false;
+    }
+
+    @Override
+    public boolean mouseDragged(double mouseX, double mouseY, int button, double v2, double v3) {
+        ClientComputer computer = this.computer.get();
+        if (computer == null || !computer.isColour() || button < 0 || button > 2) {
+            return false;
+        }
+
+        Terminal term = computer.getTerminal();
+        if (term != null) {
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
+            charX = Math.min(Math.max(charX, 0), term.getWidth() - 1);
+            charY = Math.min(Math.max(charY, 0), term.getHeight() - 1);
+
+            if (button == this.lastMouseButton && (charX != this.lastMouseX || charY != this.lastMouseY)) {
+                computer.mouseDrag(button + 1, charX + 1, charY + 1);
+                this.lastMouseX = charX;
+                this.lastMouseY = charY;
+            }
+        }
+
+        return false;
+    }
+
+    @Override
+    public boolean mouseScrolled(double mouseX, double mouseY, double delta) {
+        ClientComputer computer = this.computer.get();
+        if (computer == null || !computer.isColour() || delta == 0) {
+            return false;
+        }
+
+        Terminal term = computer.getTerminal();
+        if (term != null) {
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
+            charX = Math.min(Math.max(charX, 0), term.getWidth() - 1);
+            charY = Math.min(Math.max(charY, 0), term.getHeight() - 1);
+
+            computer.mouseScroll(delta < 0 ? 1 : -1, charX + 1, charY + 1);
+
+            this.lastMouseX = charX;
+            this.lastMouseY = charY;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean keyPressed(int key, int scancode, int modifiers) {
+        if (key == GLFW.GLFW_KEY_ESCAPE) {
+            return false;
+        }
+        if ((modifiers & GLFW.GLFW_MOD_CONTROL) != 0) {
+            switch (key) {
+            case GLFW.GLFW_KEY_T:
+                if (this.terminateTimer < 0) {
+                    this.terminateTimer = 0;
+                }
+                return true;
+            case GLFW.GLFW_KEY_S:
+                if (this.shutdownTimer < 0) {
+                    this.shutdownTimer = 0;
+                }
+                return true;
+            case GLFW.GLFW_KEY_R:
+                if (this.rebootTimer < 0) {
+                    this.rebootTimer = 0;
+                }
+                return true;
+
+            case GLFW.GLFW_KEY_V:
+                // Ctrl+V for paste
+                String clipboard = this.client.keyboard.getClipboard();
+                if (clipboard != null) {
+                    // Clip to the first occurrence of \r or \n
+                    int newLineIndex1 = clipboard.indexOf("\r");
+                    int newLineIndex2 = clipboard.indexOf("\n");
+                    if (newLineIndex1 >= 0 && newLineIndex2 >= 0) {
+                        clipboard = clipboard.substring(0, Math.min(newLineIndex1, newLineIndex2));
+                    } else if (newLineIndex1 >= 0) {
+                        clipboard = clipboard.substring(0, newLineIndex1);
+                    } else if (newLineIndex2 >= 0) {
+                        clipboard = clipboard.substring(0, newLineIndex2);
+                    }
+
+                    // Filter the string
+                    clipboard = SharedConstants.stripInvalidChars(clipboard);
+                    if (!clipboard.isEmpty()) {
+                        // Clip to 512 characters and queue the event
+                        if (clipboard.length() > 512) {
+                            clipboard = clipboard.substring(0, 512);
+                        }
+                        this.queueEvent("paste", clipboard);
+                    }
+
+                    return true;
+                }
+            }
+        }
+
+        if (key >= 0 && this.terminateTimer < 0 && this.rebootTimer < 0 && this.shutdownTimer < 0) {
+            // Queue the "key" event and add to the down set
+            boolean repeat = this.keysDown.get(key);
+            this.keysDown.set(key);
+            IComputer computer = this.computer.get();
+            if (computer != null) {
+                computer.keyDown(key, repeat);
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean keyReleased(int key, int scancode, int modifiers) {
+        // Queue the "key_up" event and remove from the down set
+        if (key >= 0 && this.keysDown.get(key)) {
+            this.keysDown.set(key, false);
+            IComputer computer = this.computer.get();
+            if (computer != null) {
+                computer.keyUp(key);
+            }
+        }
+
+        switch (key) {
+        case GLFW.GLFW_KEY_T:
+            this.terminateTimer = -1;
+            break;
+        case GLFW.GLFW_KEY_R:
+            this.rebootTimer = -1;
+            break;
+        case GLFW.GLFW_KEY_S:
+            this.shutdownTimer = -1;
+            break;
+        case GLFW.GLFW_KEY_LEFT_CONTROL:
+        case GLFW.GLFW_KEY_RIGHT_CONTROL:
+            this.terminateTimer = this.rebootTimer = this.shutdownTimer = -1;
+            break;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean charTyped(char ch, int modifiers) {
+        if (ch >= 32 && ch <= 126 || ch >= 160 && ch <= 255) // printable chars in byte range
         {
             // Queue the "char" event
-            queueEvent( "char", Character.toString( ch ) );
+            this.queueEvent("char", Character.toString(ch));
         }
 
         return true;
     }
 
     @Override
-    public boolean keyPressed( int key, int scancode, int modifiers )
-    {
-        if( key == GLFW.GLFW_KEY_ESCAPE ) return false;
-        if( (modifiers & GLFW.GLFW_MOD_CONTROL) != 0 )
-        {
-            switch( key )
-            {
-                case GLFW.GLFW_KEY_T:
-                    if( terminateTimer < 0 ) terminateTimer = 0;
-                    return true;
-                case GLFW.GLFW_KEY_S:
-                    if( shutdownTimer < 0 ) shutdownTimer = 0;
-                    return true;
-                case GLFW.GLFW_KEY_R:
-                    if( rebootTimer < 0 ) rebootTimer = 0;
-                    return true;
-
-                case GLFW.GLFW_KEY_V:
-                    // Ctrl+V for paste
-                    String clipboard = client.keyboardListener.getClipboardString();
-                    if( clipboard != null )
-                    {
-                        // Clip to the first occurrence of \r or \n
-                        int newLineIndex1 = clipboard.indexOf( "\r" );
-                        int newLineIndex2 = clipboard.indexOf( "\n" );
-                        if( newLineIndex1 >= 0 && newLineIndex2 >= 0 )
-                        {
-                            clipboard = clipboard.substring( 0, Math.min( newLineIndex1, newLineIndex2 ) );
-                        }
-                        else if( newLineIndex1 >= 0 )
-                        {
-                            clipboard = clipboard.substring( 0, newLineIndex1 );
-                        }
-                        else if( newLineIndex2 >= 0 )
-                        {
-                            clipboard = clipboard.substring( 0, newLineIndex2 );
-                        }
-
-                        // Filter the string
-                        clipboard = SharedConstants.filterAllowedCharacters( clipboard );
-                        if( !clipboard.isEmpty() )
-                        {
-                            // Clip to 512 characters and queue the event
-                            if( clipboard.length() > 512 ) clipboard = clipboard.substring( 0, 512 );
-                            queueEvent( "paste", clipboard );
-                        }
-
-                        return true;
-                    }
-            }
-        }
-
-        if( key >= 0 && terminateTimer < 0 && rebootTimer < 0 && shutdownTimer < 0 )
-        {
-            // Queue the "key" event and add to the down set
-            boolean repeat = keysDown.get( key );
-            keysDown.set( key );
-            IComputer computer = this.computer.get();
-            if( computer != null ) computer.keyDown( key, repeat );
-        }
-
-        return true;
-    }
-
-    @Override
-    public boolean keyReleased( int key, int scancode, int modifiers )
-    {
-        // Queue the "key_up" event and remove from the down set
-        if( key >= 0 && keysDown.get( key ) )
-        {
-            keysDown.set( key, false );
-            IComputer computer = this.computer.get();
-            if( computer != null ) computer.keyUp( key );
-        }
-
-        switch( key )
-        {
-            case GLFW.GLFW_KEY_T:
-                terminateTimer = -1;
-                break;
-            case GLFW.GLFW_KEY_R:
-                rebootTimer = -1;
-                break;
-            case GLFW.GLFW_KEY_S:
-                shutdownTimer = -1;
-                break;
-            case GLFW.GLFW_KEY_LEFT_CONTROL:
-            case GLFW.GLFW_KEY_RIGHT_CONTROL:
-                terminateTimer = rebootTimer = shutdownTimer = -1;
-                break;
-        }
-
-        return true;
-    }
-
-    @Override
-    public boolean mouseClicked( double mouseX, double mouseY, int button )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
-
-        Terminal term = computer.getTerminal();
-        if( term != null )
-        {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
-
-            computer.mouseClick( button + 1, charX + 1, charY + 1 );
-
-            lastMouseButton = button;
-            lastMouseX = charX;
-            lastMouseY = charY;
-        }
-
-        return true;
-    }
-
-    @Override
-    public boolean mouseReleased( double mouseX, double mouseY, int button )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
-
-        Terminal term = computer.getTerminal();
-        if( term != null )
-        {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
-
-            if( lastMouseButton == button )
-            {
-                computer.mouseUp( lastMouseButton + 1, charX + 1, charY + 1 );
-                lastMouseButton = -1;
-            }
-
-            lastMouseX = charX;
-            lastMouseY = charY;
-        }
-
-        return false;
-    }
-
-    @Override
-    public boolean mouseDragged( double mouseX, double mouseY, int button, double v2, double v3 )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
-
-        Terminal term = computer.getTerminal();
-        if( term != null )
-        {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
-
-            computer.mouseDrag( button + 1, charX + 1, charY + 1 );
-
-            lastMouseX = charX;
-            lastMouseY = charY;
-            lastMouseButton = button;
-        }
-
-        return false;
-    }
-
-    @Override
-    public boolean mouseScrolled( double delta )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer == null || !computer.isColour() ) return false;
-
-        if( lastMouseX >= 0 && lastMouseY >= 0 && delta != 0 )
-        {
-            queueEvent( "mouse_scroll", delta < 0 ? 1 : -1, lastMouseX + 1, lastMouseY + 1 );
-        }
-
-        return true;
-    }
-
-    public void update()
-    {
-        if( terminateTimer >= 0 && terminateTimer < TERMINATE_TIME && (terminateTimer += 0.05f) > TERMINATE_TIME )
-        {
-            queueEvent( "terminate" );
-        }
-
-        if( shutdownTimer >= 0 && shutdownTimer < TERMINATE_TIME && (shutdownTimer += 0.05f) > TERMINATE_TIME )
-        {
-            ClientComputer computer = this.computer.get();
-            if( computer != null ) computer.shutdown();
-        }
-
-        if( rebootTimer >= 0 && rebootTimer < TERMINATE_TIME && (rebootTimer += 0.05f) > TERMINATE_TIME )
-        {
-            ClientComputer computer = this.computer.get();
-            if( computer != null ) computer.reboot();
-        }
-    }
-
-    @Override
-    public void focusChanged( boolean focused )
-    {
-        if( !focused )
-        {
+    public boolean changeFocus(boolean reversed) {
+        if (this.focused) {
             // When blurring, we should make all keys go up
-            for( int key = 0; key < keysDown.size(); key++ )
-            {
-                if( keysDown.get( key ) ) queueEvent( "key_up", key );
+            for (int key = 0; key < this.keysDown.size(); key++) {
+                if (this.keysDown.get(key)) {
+                    this.queueEvent("key_up", key);
+                }
             }
-            keysDown.clear();
+            this.keysDown.clear();
 
             // When blurring, we should make the last mouse button go up
-            if( lastMouseButton > 0 )
-            {
+            if (this.lastMouseButton > 0) {
                 IComputer computer = this.computer.get();
-                if( computer != null ) computer.mouseUp( lastMouseButton + 1, lastMouseX + 1, lastMouseY + 1 );
-                lastMouseButton = -1;
+                if (computer != null) {
+                    computer.mouseUp(this.lastMouseButton + 1, this.lastMouseX + 1, this.lastMouseY + 1);
+                }
+                this.lastMouseButton = -1;
             }
 
-            shutdownTimer = terminateTimer = rebootTimer = -1;
+            this.shutdownTimer = this.terminateTimer = this.rebootTimer = -1;
+        }
+        this.focused = !this.focused;
+        return true;
+    }
+
+    @Override
+    public boolean isMouseOver(double x, double y) {
+        return true;
+    }
+
+    private void queueEvent(String event, Object... args) {
+        ClientComputer computer = this.computer.get();
+        if (computer != null) {
+            computer.queueEvent(event, args);
         }
     }
 
-    public void draw( int originX, int originY )
-    {
-        synchronized( computer )
-        {
+    public void update() {
+        if (this.terminateTimer >= 0 && this.terminateTimer < TERMINATE_TIME && (this.terminateTimer += 0.05f) > TERMINATE_TIME) {
+            this.queueEvent("terminate");
+        }
+
+        if (this.shutdownTimer >= 0 && this.shutdownTimer < TERMINATE_TIME && (this.shutdownTimer += 0.05f) > TERMINATE_TIME) {
+            ClientComputer computer = this.computer.get();
+            if (computer != null) {
+                computer.shutdown();
+            }
+        }
+
+        if (this.rebootTimer >= 0 && this.rebootTimer < TERMINATE_TIME && (this.rebootTimer += 0.05f) > TERMINATE_TIME) {
+            ClientComputer computer = this.computer.get();
+            if (computer != null) {
+                computer.reboot();
+            }
+        }
+    }
+
+    private void queueEvent(String event) {
+        ClientComputer computer = this.computer.get();
+        if (computer != null) {
+            computer.queueEvent(event);
+        }
+    }
+
+    public void draw(int originX, int originY) {
+        synchronized (this.computer) {
             // Draw the screen contents
             ClientComputer computer = this.computer.get();
             Terminal terminal = computer != null ? computer.getTerminal() : null;
-            if( terminal != null )
-            {
-                // Draw the terminal
-                boolean greyscale = !computer.isColour();
-                Palette palette = terminal.getPalette();
-
-                // Get the data from the terminal first
-                // Unfortunately we have to keep the lock for the whole of drawing, so the text doesn't change under us.
-                FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
-                boolean tblink = terminal.getCursorBlink() && FrameInfo.getGlobalCursorBlink();
-                int tw = terminal.getWidth();
-                int th = terminal.getHeight();
-                int tx = terminal.getCursorX();
-                int ty = terminal.getCursorY();
-
-                // Draw margins
-                TextBuffer emptyLine = new TextBuffer( ' ', tw );
-                if( topMargin > 0 )
-                {
-                    fontRenderer.drawString( emptyLine, originX, originY - topMargin,
-                        terminal.getTextColourLine( 0 ), terminal.getBackgroundColourLine( 0 ),
-                        leftMargin, rightMargin, greyscale, palette );
-                }
-
-                if( bottomMargin > 0 )
-                {
-                    fontRenderer.drawString( emptyLine, originX, originY + bottomMargin + (th - 1) * FixedWidthFontRenderer.FONT_HEIGHT,
-                        terminal.getTextColourLine( th - 1 ), terminal.getBackgroundColourLine( th - 1 ),
-                        leftMargin, rightMargin, greyscale, palette );
-                }
-
-                // Draw lines
-                int y = originY;
-                for( int line = 0; line < th; line++ )
-                {
-                    TextBuffer text = terminal.getLine( line );
-                    TextBuffer colour = terminal.getTextColourLine( line );
-                    TextBuffer backgroundColour = terminal.getBackgroundColourLine( line );
-                    fontRenderer.drawString( text, originX, y, colour, backgroundColour, leftMargin, rightMargin, greyscale, palette );
-                    y += FixedWidthFontRenderer.FONT_HEIGHT;
-                }
-
-                if( tblink && tx >= 0 && ty >= 0 && tx < tw && ty < th )
-                {
-                    TextBuffer cursor = new TextBuffer( '_', 1 );
-                    TextBuffer cursorColour = new TextBuffer( "0123456789abcdef".charAt( terminal.getTextColour() ), 1 );
-
-                    fontRenderer.drawString(
-                        cursor,
-                        originX + FixedWidthFontRenderer.FONT_WIDTH * tx,
-                        originY + FixedWidthFontRenderer.FONT_HEIGHT * ty,
-                        cursorColour, null,
-                        0, 0,
-                        greyscale,
-                        palette
-                    );
-                }
-            }
-            else
-            {
-                // Draw a black background
-                Colour black = Colour.Black;
-                GlStateManager.color4f( black.getR(), black.getG(), black.getB(), 1.0f );
-                try
-                {
-                    int x = originX - leftMargin;
-                    int y = originY - rightMargin;
-                    int width = termWidth * FixedWidthFontRenderer.FONT_WIDTH + leftMargin + rightMargin;
-                    int height = termHeight * FixedWidthFontRenderer.FONT_HEIGHT + topMargin + bottomMargin;
-
-                    client.getTextureManager().bindTexture( BACKGROUND );
-
-                    Tessellator tesslector = Tessellator.getInstance();
-                    BufferBuilder buffer = tesslector.getBuffer();
-                    buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX );
-                    buffer.pos( x, y + height, 0 ).tex( 0 / 256.0, height / 256.0 ).endVertex();
-                    buffer.pos( x + width, y + height, 0 ).tex( width / 256.0, height / 256.0 ).endVertex();
-                    buffer.pos( x + width, y, 0 ).tex( width / 256.0, 0 / 256.0 ).endVertex();
-                    buffer.pos( x, y, 0 ).tex( 0 / 256.0, 0 / 256.0 ).endVertex();
-                    tesslector.draw();
-                }
-                finally
-                {
-                    GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-                }
+            if (terminal != null) {
+                FixedWidthFontRenderer.drawTerminal(originX, originY, terminal, !computer.isColour(), this.topMargin, this.bottomMargin, this.leftMargin,
+                                                    this.rightMargin);
+            } else {
+                FixedWidthFontRenderer.drawEmptyTerminal(originX - this.leftMargin,
+                                                         originY - this.rightMargin, this.termWidth * FONT_WIDTH + this.leftMargin + this.rightMargin,
+                                                         this.termHeight * FONT_HEIGHT + this.topMargin + this.bottomMargin);
             }
         }
     }
-
-    private void queueEvent( String event )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer != null ) computer.queueEvent( event );
-    }
-
-    private void queueEvent( String event, Object... args )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer != null ) computer.queueEvent( event, args );
-    }
 }

src/main/java/dan200/computercraft/client/gui/widgets/WidgetWrapper.java

@@ -1,23 +1,21 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.gui.widgets;
 
-import net.minecraft.client.gui.IGuiEventListener;
+import net.minecraft.client.gui.Element;
 
-public class WidgetWrapper implements IGuiEventListener
-{
-    private final IGuiEventListener listener;
+public class WidgetWrapper implements Element {
+    private final Element listener;
     private final int x;
     private final int y;
     private final int width;
     private final int height;
 
-    public WidgetWrapper( IGuiEventListener listener, int x, int y, int width, int height )
-    {
+    public WidgetWrapper(Element listener, int x, int y, int width, int height) {
         this.listener = listener;
         this.x = x;
         this.y = y;
@@ -26,79 +24,68 @@ public class WidgetWrapper implements IGuiEventListener
     }
 
     @Override
-    public void focusChanged( boolean b )
-    {
-        listener.focusChanged( b );
-    }
-
-    @Override
-    public boolean canFocus()
-    {
-        return listener.canFocus();
-    }
-
-    @Override
-    public boolean mouseClicked( double x, double y, int button )
-    {
+    public boolean mouseClicked(double x, double y, int button) {
         double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseClicked( dx, dy, button );
+        return dx >= 0 && dx < this.width && dy >= 0 && dy < this.height && this.listener.mouseClicked(dx, dy, button);
     }
 
     @Override
-    public boolean mouseReleased( double x, double y, int button )
-    {
+    public boolean mouseReleased(double x, double y, int button) {
         double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseReleased( dx, dy, button );
+        return dx >= 0 && dx < this.width && dy >= 0 && dy < this.height && this.listener.mouseReleased(dx, dy, button);
     }
 
     @Override
-    public boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
-    {
+    public boolean mouseDragged(double x, double y, int button, double deltaX, double deltaY) {
         double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseDragged( dx, dy, button, deltaX, deltaY );
+        return dx >= 0 && dx < this.width && dy >= 0 && dy < this.height && this.listener.mouseDragged(dx, dy, button, deltaX, deltaY);
     }
 
     @Override
-    public boolean mouseScrolled( double delta )
-    {
-        return listener.mouseScrolled( delta );
+    public boolean mouseScrolled(double x, double y, double delta) {
+        double dx = x - this.x, dy = y - this.y;
+        return dx >= 0 && dx < this.width && dy >= 0 && dy < this.height && this.listener.mouseScrolled(dx, dy, delta);
     }
 
     @Override
-    public boolean keyPressed( int key, int scancode, int modifiers )
-    {
-        return listener.keyPressed( key, scancode, modifiers );
+    public boolean keyPressed(int key, int scancode, int modifiers) {
+        return this.listener.keyPressed(key, scancode, modifiers);
     }
 
     @Override
-    public boolean keyReleased( int key, int scancode, int modifiers )
-    {
-        return listener.keyReleased( key, scancode, modifiers );
+    public boolean keyReleased(int key, int scancode, int modifiers) {
+        return this.listener.keyReleased(key, scancode, modifiers);
     }
 
     @Override
-    public boolean charTyped( char character, int modifiers )
-    {
-        return listener.charTyped( character, modifiers );
+    public boolean charTyped(char character, int modifiers) {
+        return this.listener.charTyped(character, modifiers);
     }
 
-    public int getX()
-    {
-        return x;
+    @Override
+    public boolean changeFocus(boolean b) {
+        return this.listener.changeFocus(b);
     }
 
-    public int getY()
-    {
-        return y;
+    @Override
+    public boolean isMouseOver(double x, double y) {
+        double dx = x - this.x, dy = y - this.y;
+        return dx >= 0 && dx < this.width && dy >= 0 && dy < this.height;
     }
 
-    public int getWidth()
-    {
-        return width;
+    public int getX() {
+        return this.x;
     }
 
-    public int getHeight()
-    {
-        return height;
+    public int getY() {
+        return this.y;
+    }
+
+    public int getWidth() {
+        return this.width;
+    }
+
+    public int getHeight() {
+        return this.height;
     }
 }

src/main/java/dan200/computercraft/client/proxy/ComputerCraftProxyClient.java

@@ -1,96 +1,141 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.proxy;
 
+import java.util.function.Supplier;
+
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.client.gui.*;
-import dan200.computercraft.client.render.TileEntityCableRenderer;
+import dan200.computercraft.client.ClientRegistry;
+import dan200.computercraft.client.FrameInfo;
+import dan200.computercraft.client.gui.GuiComputer;
+import dan200.computercraft.client.gui.GuiDiskDrive;
+import dan200.computercraft.client.gui.GuiPrinter;
+import dan200.computercraft.client.gui.GuiPrintout;
+import dan200.computercraft.client.gui.GuiTurtle;
 import dan200.computercraft.client.render.TileEntityMonitorRenderer;
 import dan200.computercraft.client.render.TileEntityTurtleRenderer;
-import dan200.computercraft.shared.computer.blocks.TileComputer;
-import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.client.render.TurtleModelLoader;
+import dan200.computercraft.client.render.TurtlePlayerRenderer;
+import dan200.computercraft.shared.ComputerCraftRegistry;
+import dan200.computercraft.shared.common.ContainerHeldItem;
+import dan200.computercraft.shared.common.IColouredItem;
+import dan200.computercraft.shared.computer.inventory.ContainerComputer;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
-import dan200.computercraft.shared.network.container.*;
-import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
+import dan200.computercraft.shared.network.container.ViewComputerContainerData;
+import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
 import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
-import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
-import dan200.computercraft.shared.turtle.blocks.TileTurtle;
+import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
+import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
+import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.gui.inventory.GuiContainer;
-import net.minecraft.entity.player.EntityPlayer;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.event.world.WorldEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.ExtensionPoint;
-import net.minecraftforge.fml.ModLoadingContext;
-import net.minecraftforge.fml.client.registry.ClientRegistry;
-import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
 
-import java.util.function.BiFunction;
+import net.minecraft.client.item.ModelPredicateProvider;
+import net.minecraft.client.render.RenderLayer;
+import net.minecraft.item.Item;
+import net.minecraft.screen.PlayerScreenHandler;
+import net.minecraft.util.Identifier;
 
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT, bus = Mod.EventBusSubscriber.Bus.MOD )
-public final class ComputerCraftProxyClient
-{
-    @SubscribeEvent
-    public static void setupClient( FMLClientSetupEvent event )
-    {
+import net.fabricmc.api.ClientModInitializer;
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+import net.fabricmc.fabric.api.blockrenderlayer.v1.BlockRenderLayerMap;
+import net.fabricmc.fabric.api.client.model.ModelLoadingRegistry;
+import net.fabricmc.fabric.api.client.rendereregistry.v1.BlockEntityRendererRegistry;
+import net.fabricmc.fabric.api.client.rendereregistry.v1.EntityRendererRegistry;
+import net.fabricmc.fabric.api.client.screenhandler.v1.ScreenRegistry;
+import net.fabricmc.fabric.api.event.client.ClientSpriteRegistryCallback;
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerWorldEvents;
+import net.fabricmc.fabric.mixin.object.builder.ModelPredicateProviderRegistrySpecificAccessor;
+
+@Environment (EnvType.CLIENT)
+public final class ComputerCraftProxyClient implements ClientModInitializer {
+
+    public static void initEvents() {
+
+    }
+
+    @Override
+    public void onInitializeClient() {
+        FrameInfo.init();
         registerContainers();
 
+        // While turtles themselves are not transparent, their upgrades may be.
+        BlockRenderLayerMap.INSTANCE.putBlock(ComputerCraftRegistry.ModBlocks.TURTLE_NORMAL, RenderLayer.getTranslucent());
+        BlockRenderLayerMap.INSTANCE.putBlock(ComputerCraftRegistry.ModBlocks.TURTLE_ADVANCED, RenderLayer.getTranslucent());
+
+        // Monitors' textures have transparent fronts and so count as cutouts.
+        BlockRenderLayerMap.INSTANCE.putBlock(ComputerCraftRegistry.ModBlocks.MONITOR_NORMAL, RenderLayer.getCutout());
+        BlockRenderLayerMap.INSTANCE.putBlock(ComputerCraftRegistry.ModBlocks.MONITOR_ADVANCED, RenderLayer.getCutout());
+
         // Setup TESRs
-        ClientRegistry.bindTileEntitySpecialRenderer( TileMonitor.class, new TileEntityMonitorRenderer() );
-        ClientRegistry.bindTileEntitySpecialRenderer( TileCable.class, new TileEntityCableRenderer() );
-        ClientRegistry.bindTileEntitySpecialRenderer( TileTurtle.class, new TileEntityTurtleRenderer() );
+        BlockEntityRendererRegistry.INSTANCE.register(ComputerCraftRegistry.ModTiles.MONITOR_NORMAL, TileEntityMonitorRenderer::new);
+        BlockEntityRendererRegistry.INSTANCE.register(ComputerCraftRegistry.ModTiles.MONITOR_ADVANCED, TileEntityMonitorRenderer::new);
+        BlockEntityRendererRegistry.INSTANCE.register(ComputerCraftRegistry.ModTiles.TURTLE_NORMAL, TileEntityTurtleRenderer::new);
+        BlockEntityRendererRegistry.INSTANCE.register(ComputerCraftRegistry.ModTiles.TURTLE_ADVANCED, TileEntityTurtleRenderer::new);
+        // TODO: ClientRegistry.bindTileEntityRenderer( TileCable.FACTORY, x -> new TileEntityCableRenderer() );
+
+        ClientSpriteRegistryCallback.event(PlayerScreenHandler.BLOCK_ATLAS_TEXTURE)
+                                    .register(ClientRegistry::onTextureStitchEvent);
+        ModelLoadingRegistry.INSTANCE.registerAppender(ClientRegistry::onModelBakeEvent);
+        ModelLoadingRegistry.INSTANCE.registerResourceProvider(loader -> (name, context) -> TurtleModelLoader.INSTANCE.accepts(name) ?
+                                                                                            TurtleModelLoader.INSTANCE.loadModel(
+            name) : null);
+
+        EntityRendererRegistry.INSTANCE.register(ComputerCraftRegistry.ModEntities.TURTLE_PLAYER, TurtlePlayerRenderer::new);
+
+        registerItemProperty("state",
+                             (stack, world, player) -> ItemPocketComputer.getState(stack)
+                                                                         .ordinal(),
+                             () -> ComputerCraftRegistry.ModItems.POCKET_COMPUTER_NORMAL,
+                             () -> ComputerCraftRegistry.ModItems.POCKET_COMPUTER_ADVANCED);
+        registerItemProperty("state",
+                             (stack, world, player) -> IColouredItem.getColourBasic(stack) != -1 ? 1 : 0,
+                             () -> ComputerCraftRegistry.ModItems.POCKET_COMPUTER_NORMAL,
+                             () -> ComputerCraftRegistry.ModItems.POCKET_COMPUTER_ADVANCED);
+        ClientRegistry.onItemColours();
+
+        // TODO Verify this does things properly
+        ServerWorldEvents.UNLOAD.register(((minecraftServer, serverWorld) -> {
+            ClientMonitor.destroyAll();
+        }));
     }
 
-    private static void registerContainers()
-    {
-        ContainerType.registerGui( TileEntityContainerType::computer, ( packet, player ) ->
-            new GuiComputer( (TileComputer) packet.getTileEntity( player ) ) );
-        ContainerType.registerGui( TileEntityContainerType::diskDrive, GuiDiskDrive::new );
-        ContainerType.registerGui( TileEntityContainerType::printer, GuiPrinter::new );
-        ContainerType.registerGui( TileEntityContainerType::turtle, ( packet, player ) -> {
-            TileTurtle turtle = (TileTurtle) packet.getTileEntity( player );
-            return new GuiTurtle( turtle, new ContainerTurtle( player.inventory, turtle.getAccess(), turtle.getClientComputer() ) );
-        } );
 
-        ContainerType.registerGui( PocketComputerContainerType::new, GuiPocketComputer::new );
-        ContainerType.registerGui( PrintoutContainerType::new, GuiPrintout::new );
-        ContainerType.registerGui( ViewComputerContainerType::new, ( packet, player ) -> {
-            ClientComputer computer = ComputerCraft.clientComputerRegistry.get( packet.instanceId );
-            if( computer == null )
-            {
-                ComputerCraft.clientComputerRegistry.add( packet.instanceId, computer = new ClientComputer( packet.instanceId ) );
-            }
+    // My IDE doesn't think so, but we do actually need these generics.
+    private static void registerContainers() {
+        ScreenRegistry.<ContainerComputer, GuiComputer<ContainerComputer>>register(ComputerCraftRegistry.ModContainers.COMPUTER, GuiComputer::create);
+        ScreenRegistry.<ContainerPocketComputer, GuiComputer<ContainerPocketComputer>>register(ComputerCraftRegistry.ModContainers.POCKET_COMPUTER,
+                                GuiComputer::createPocket);
+        ScreenRegistry.<ContainerTurtle, GuiTurtle>register(ComputerCraftRegistry.ModContainers.TURTLE, GuiTurtle::new);
 
-            ContainerViewComputer container = new ContainerViewComputer( computer );
-            return new GuiComputer( container, packet.family, computer, packet.width, packet.height );
-        } );
+        ScreenRegistry.<ContainerPrinter, GuiPrinter>register(ComputerCraftRegistry.ModContainers.PRINTER, GuiPrinter::new);
+        ScreenRegistry.<ContainerDiskDrive, GuiDiskDrive>register(ComputerCraftRegistry.ModContainers.DISK_DRIVE, GuiDiskDrive::new);
+        ScreenRegistry.<ContainerHeldItem, GuiPrintout>register(ComputerCraftRegistry.ModContainers.PRINTOUT, GuiPrintout::new);
 
-        ModLoadingContext.get().registerExtensionPoint( ExtensionPoint.GUIFACTORY, () -> packet -> {
-            ContainerType<?> type = ContainerType.factories.get( packet.getId() ).get();
-            if( packet.getAdditionalData() != null ) type.fromBytes( packet.getAdditionalData() );
-            @SuppressWarnings( "unchecked" )
-            BiFunction<ContainerType<?>, EntityPlayer, GuiContainer> factory = (BiFunction<ContainerType<?>, EntityPlayer, GuiContainer>) ContainerType.guiFactories.get( packet.getId() );
-            return factory.apply( type, Minecraft.getInstance().player );
-        } );
+        ScreenRegistry.<ContainerViewComputer, GuiComputer<ContainerViewComputer>>register(ComputerCraftRegistry.ModContainers.VIEW_COMPUTER,
+                                                                        GuiComputer::createView);
     }
 
-    @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-    public static final class ForgeHandlers
-    {
-        @SubscribeEvent
-        public static void onWorldUnload( WorldEvent.Unload event )
-        {
-            if( event.getWorld().isRemote() )
-            {
-                ClientMonitor.destroyAll();
-            }
+    @SafeVarargs
+    private static void registerItemProperty(String name, ModelPredicateProvider getter, Supplier<? extends Item>... items) {
+        Identifier id = new Identifier(ComputerCraft.MOD_ID, name);
+        for (Supplier<? extends Item> item : items) {
+            ModelPredicateProviderRegistrySpecificAccessor.callRegister(item.get(), id, getter);
         }
     }
+
+    //    @Mod.EventBusSubscriber (modid = ComputerCraft.MOD_ID, value = Dist.CLIENT)
+    //    public static final class ForgeHandlers {
+    //        @SubscribeEvent
+    //        public static void onWorldUnload(WorldEvent.Unload event) {
+    //            if (event.getWorld()
+    //                     .isClient()) {
+    //                ClientMonitor.destroyAll();
+    //            }
+    //        }
+    //    }
 }

src/main/java/dan200/computercraft/client/render/CableHighlightRenderer.java

@@ -1,88 +1,71 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.ComputerCraftRegistry;
 import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
 import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
 import dan200.computercraft.shared.util.WorldUtil;
-import net.minecraft.block.state.IBlockState;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.WorldRenderer;
-import net.minecraft.entity.player.EntityPlayer;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.util.math.shapes.VoxelShape;
-import net.minecraft.world.World;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.DrawBlockHighlightEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
-import org.lwjgl.opengl.GL11;
 
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class CableHighlightRenderer
-{
-    private CableHighlightRenderer()
-    {
+import net.minecraft.block.BlockState;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.Camera;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.Entity;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Matrix4f;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.util.shape.VoxelShape;
+import net.minecraft.world.World;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+@Environment (EnvType.CLIENT)
+public final class CableHighlightRenderer {
+    private CableHighlightRenderer() {
     }
 
     /**
      * Draw an outline for a specific part of a cable "Multipart".
-     *
-     * @param event The event to observe
-     * @see WorldRenderer#drawSelectionBox(EntityPlayer, RayTraceResult, int, float)
      */
-    @SubscribeEvent
-    public static void drawHighlight( DrawBlockHighlightEvent event )
-    {
-        if( event.getTarget().type != RayTraceResult.Type.BLOCK ) return;
-
-        BlockPos pos = event.getTarget().getBlockPos();
-        World world = event.getPlayer().getEntityWorld();
-
-        IBlockState state = world.getBlockState( pos );
+    public static boolean drawHighlight(MatrixStack stack, VertexConsumer consumer, Entity entity, double d, double e, double f, BlockPos pos,
+                                        BlockState state) {
+        World world = entity.getEntityWorld();
+        Camera info = MinecraftClient.getInstance().gameRenderer.getCamera();
 
         // We only care about instances with both cable and modem.
-        if( state.getBlock() != ComputerCraft.Blocks.cable || state.get( BlockCable.MODEM ).getFacing() == null || !state.get( BlockCable.CABLE ) )
-        {
-            return;
+        if (state.getBlock() != ComputerCraftRegistry.ModBlocks.CABLE || state.get(BlockCable.MODEM)
+                                                                              .getFacing() == null || !state.get(BlockCable.CABLE)) {
+            return false;
         }
 
-        event.setCanceled( true );
+        VoxelShape shape = WorldUtil.isVecInside(CableShapes.getModemShape(state),
+                                                 new Vec3d(d, e, f).subtract(pos.getX(),
+                                                                             pos.getY(),
+                                                                             pos.getZ())) ? CableShapes.getModemShape(state) : CableShapes.getCableShape(
+            state);
 
-        EntityPlayer player = event.getPlayer();
-        Minecraft mc = Minecraft.getInstance();
-        float partialTicks = event.getPartialTicks();
+        Vec3d cameraPos = info.getPos();
+        double xOffset = pos.getX() - cameraPos.getX();
+        double yOffset = pos.getY() - cameraPos.getY();
+        double zOffset = pos.getZ() - cameraPos.getZ();
+        Matrix4f matrix4f = stack.peek()
+                                 .getModel();
+        shape.forEachEdge((x1, y1, z1, x2, y2, z2) -> {
+            consumer.vertex(matrix4f, (float) (x1 + xOffset), (float) (y1 + yOffset), (float) (z1 + zOffset))
+                    .color(0, 0, 0, 0.4f)
+                    .next();
+            consumer.vertex(matrix4f, (float) (x2 + xOffset), (float) (y2 + yOffset), (float) (z2 + zOffset))
+                    .color(0, 0, 0, 0.4f)
+                    .next();
+        });
 
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
-        GlStateManager.lineWidth( Math.max( 2.5F, mc.mainWindow.getFramebufferWidth() / 1920.0F * 2.5F ) );
-        GlStateManager.disableTexture2D();
-        GlStateManager.depthMask( false );
-        GlStateManager.matrixMode( GL11.GL_PROJECTION );
-        GlStateManager.pushMatrix();
-        GlStateManager.scalef( 1.0F, 1.0F, 0.999F );
-
-        double x = player.lastTickPosX + (player.posX - player.lastTickPosX) * partialTicks;
-        double y = player.lastTickPosY + (player.posY - player.lastTickPosY) * partialTicks;
-        double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * partialTicks;
-
-        VoxelShape shape = WorldUtil.isVecInside( CableShapes.getModemShape( state ), event.getTarget().hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-            ? CableShapes.getModemShape( state )
-            : CableShapes.getCableShape( state );
-
-        WorldRenderer.drawShape( shape, pos.getX() - x, pos.getY() - y, pos.getZ() - z, 0.0F, 0.0F, 0.0F, 0.4F );
-
-        GlStateManager.popMatrix();
-        GlStateManager.matrixMode( GL11.GL_MODELVIEW );
-        GlStateManager.depthMask( true );
-        GlStateManager.enableTexture2D();
-        GlStateManager.disableBlend();
+        return true;
     }
 }

src/main/java/dan200/computercraft/client/render/ComputerBorderRenderer.java

@@ -0,0 +1,167 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.client.render;
+
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.systems.RenderSystem;
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.computer.core.ComputerFamily;
+import org.lwjgl.opengl.GL11;
+
+import net.minecraft.client.render.BufferBuilder;
+import net.minecraft.client.render.Tessellator;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.math.Matrix4f;
+
+public class ComputerBorderRenderer {
+    public static final Identifier BACKGROUND_NORMAL = new Identifier(ComputerCraft.MOD_ID, "textures/gui/corners_normal.png");
+    public static final Identifier BACKGROUND_ADVANCED = new Identifier(ComputerCraft.MOD_ID, "textures/gui/corners_advanced.png");
+    public static final Identifier BACKGROUND_COMMAND = new Identifier(ComputerCraft.MOD_ID, "textures/gui/corners_command.png");
+    public static final Identifier BACKGROUND_COLOUR = new Identifier(ComputerCraft.MOD_ID, "textures/gui/corners_colour.png");
+    /**
+     * The margin between the terminal and its border.
+     */
+    public static final int MARGIN = 2;
+    /**
+     * The width of the terminal border.
+     */
+    public static final int BORDER = 12;
+    private static final Matrix4f IDENTITY = new Matrix4f();
+    private static final int CORNER_TOP_Y = 28;
+    private static final int CORNER_BOTTOM_Y = CORNER_TOP_Y + BORDER;
+    private static final int CORNER_LEFT_X = BORDER;
+    private static final int CORNER_RIGHT_X = CORNER_LEFT_X + BORDER;
+    private static final int BORDER_RIGHT_X = 36;
+    private static final int GAP = 4;
+    private static final float TEX_SCALE = 1 / 256.0f;
+
+    static {
+        IDENTITY.loadIdentity();
+    }
+
+    private final Matrix4f transform;
+    private final VertexConsumer builder;
+    private final int z;
+    private final float r, g, b;
+
+    public ComputerBorderRenderer(Matrix4f transform, VertexConsumer builder, int z, float r, float g, float b) {
+        this.transform = transform;
+        this.builder = builder;
+        this.z = z;
+        this.r = r;
+        this.g = g;
+        this.b = b;
+    }
+
+
+    @Nonnull
+    public static Identifier getTexture(@Nonnull ComputerFamily family) {
+        switch (family) {
+        case NORMAL:
+        default:
+            return BACKGROUND_NORMAL;
+        case ADVANCED:
+            return BACKGROUND_ADVANCED;
+        case COMMAND:
+            return BACKGROUND_COMMAND;
+        }
+    }
+
+    public static void render(int x, int y, int z, int width, int height) {
+        Tessellator tessellator = Tessellator.getInstance();
+        BufferBuilder buffer = tessellator.getBuffer();
+        buffer.begin(GL11.GL_QUADS, VertexFormats.POSITION_COLOR_TEXTURE);
+
+        render(IDENTITY, buffer, x, y, z, width, height);
+
+        RenderSystem.enableAlphaTest();
+        tessellator.draw();
+    }
+
+    public static void render(Matrix4f transform, VertexConsumer buffer, int x, int y, int z, int width, int height) {
+        render(transform, buffer, x, y, z, width, height, 1, 1, 1);
+    }
+
+    public static void render(Matrix4f transform, VertexConsumer buffer, int x, int y, int z, int width, int height, float r, float g, float b) {
+        render(transform, buffer, x, y, z, width, height, 0, r, g, b);
+    }
+
+    public static void render(Matrix4f transform, VertexConsumer buffer, int x, int y, int z, int width, int height, int borderHeight, float r, float g,
+                              float b) {
+        new ComputerBorderRenderer(transform, buffer, z, r, g, b).doRender(x, y, width, height, borderHeight);
+    }
+
+    public void doRender(int x, int y, int width, int height, int bottomHeight) {
+        int endX = x + width;
+        int endY = y + height;
+
+        // Vertical bars
+        this.renderLine(x - BORDER, y, 0, CORNER_TOP_Y, BORDER, endY - y);
+        this.renderLine(endX, y, BORDER_RIGHT_X, CORNER_TOP_Y, BORDER, endY - y);
+
+        // Top bar
+        this.renderLine(x, y - BORDER, 0, 0, endX - x, BORDER);
+        this.renderCorner(x - BORDER, y - BORDER, CORNER_LEFT_X, CORNER_TOP_Y);
+        this.renderCorner(endX, y - BORDER, CORNER_RIGHT_X, CORNER_TOP_Y);
+
+        // Bottom bar. We allow for drawing a stretched version, which allows for additional elements (such as the
+        // pocket computer's lights).
+        if (bottomHeight <= 0) {
+            this.renderLine(x, endY, 0, BORDER, endX - x, BORDER);
+            this.renderCorner(x - BORDER, endY, CORNER_LEFT_X, CORNER_BOTTOM_Y);
+            this.renderCorner(endX, endY, CORNER_RIGHT_X, CORNER_BOTTOM_Y);
+        } else {
+            // Bottom left, middle, right. We do this in three portions: the top inner corners, an extended region for
+            // lights, and then the bottom outer corners.
+            this.renderTexture(x - BORDER, endY, CORNER_LEFT_X, CORNER_BOTTOM_Y, BORDER, BORDER / 2);
+            this.renderTexture(x, endY, 0, BORDER, width, BORDER / 2, BORDER, BORDER / 2);
+            this.renderTexture(endX, endY, CORNER_RIGHT_X, CORNER_BOTTOM_Y, BORDER, BORDER / 2);
+
+            this.renderTexture(x - BORDER, endY + BORDER / 2, CORNER_LEFT_X, CORNER_BOTTOM_Y + GAP, BORDER, bottomHeight, BORDER, GAP);
+            this.renderTexture(x, endY + BORDER / 2, 0, BORDER + GAP, width, bottomHeight, BORDER, GAP);
+            this.renderTexture(endX, endY + BORDER / 2, CORNER_RIGHT_X, CORNER_BOTTOM_Y + GAP, BORDER, bottomHeight, BORDER, GAP);
+
+            this.renderTexture(x - BORDER, endY + bottomHeight + BORDER / 2, CORNER_LEFT_X, CORNER_BOTTOM_Y + BORDER / 2, BORDER, BORDER / 2);
+            this.renderTexture(x, endY + bottomHeight + BORDER / 2, 0, BORDER + BORDER / 2, width, BORDER / 2);
+            this.renderTexture(endX, endY + bottomHeight + BORDER / 2, CORNER_RIGHT_X, CORNER_BOTTOM_Y + BORDER / 2, BORDER, BORDER / 2);
+        }
+    }
+
+    private void renderLine(int x, int y, int u, int v, int width, int height) {
+        this.renderTexture(x, y, u, v, width, height, BORDER, BORDER);
+    }
+
+    private void renderCorner(int x, int y, int u, int v) {
+        this.renderTexture(x, y, u, v, BORDER, BORDER, BORDER, BORDER);
+    }
+
+    private void renderTexture(int x, int y, int u, int v, int width, int height) {
+        this.renderTexture(x, y, u, v, width, height, width, height);
+    }
+
+    private void renderTexture(int x, int y, int u, int v, int width, int height, int textureWidth, int textureHeight) {
+        this.builder.vertex(this.transform, x, y + height, this.z)
+                    .color(this.r, this.g, this.b, 1.0f)
+                    .texture(u * TEX_SCALE, (v + textureHeight) * TEX_SCALE)
+                    .next();
+        this.builder.vertex(this.transform, x + width, y + height, this.z)
+                    .color(this.r, this.g, this.b, 1.0f)
+                    .texture((u + textureWidth) * TEX_SCALE, (v + textureHeight) * TEX_SCALE)
+                    .next();
+        this.builder.vertex(this.transform, x + width, y, this.z)
+                    .color(this.r, this.g, this.b, 1.0f)
+                    .texture((u + textureWidth) * TEX_SCALE, v * TEX_SCALE)
+                    .next();
+        this.builder.vertex(this.transform, x, y, this.z)
+                    .color(this.r, this.g, this.b, 1.0f)
+                    .texture(u * TEX_SCALE, v * TEX_SCALE)
+                    .next();
+    }
+}

src/main/java/dan200/computercraft/client/render/ItemMapLikeRenderer.java

@@ -1,118 +1,142 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.FirstPersonRenderer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.entity.player.EntityPlayer;
+import dan200.computercraft.mixin.HeldItemRendererAccess;
+
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.item.HeldItemRenderer;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
-import net.minecraft.util.EnumHand;
-import net.minecraft.util.EnumHandSide;
+import net.minecraft.util.Arm;
+import net.minecraft.util.Hand;
 import net.minecraft.util.math.MathHelper;
 
-public abstract class ItemMapLikeRenderer
-{
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+@Environment (EnvType.CLIENT)
+public abstract class ItemMapLikeRenderer {
+    public void renderItemFirstPerson(MatrixStack transform, VertexConsumerProvider render, int lightTexture, Hand hand, float pitch, float equipProgress
+        , float swingProgress, ItemStack stack) {
+        PlayerEntity player = MinecraftClient.getInstance().player;
+
+        transform.push();
+        if (hand == Hand.MAIN_HAND && player.getOffHandStack()
+                                            .isEmpty()) {
+            this.renderItemFirstPersonCenter(transform, render, lightTexture, pitch, equipProgress, swingProgress, stack);
+        } else {
+            this.renderItemFirstPersonSide(transform,
+                                           render,
+                                           lightTexture,
+                                      hand == Hand.MAIN_HAND ? player.getMainArm() : player.getMainArm()
+                                                                                           .getOpposite(),
+                                           equipProgress,
+                                           swingProgress,
+                                           stack);
+        }
+        transform.pop();
+    }
+
     /**
-     * The main rendering method for the item
+     * Render an item in the middle of the screen.
      *
+     * @param transform The matrix transformation stack
+     * @param render The buffer to render to
+     * @param combinedLight The current light level
+     * @param pitch The pitch of the player
+     * @param equipProgress The equip progress of this item
+     * @param swingProgress The swing progress of this item
      * @param stack The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPerson(ItemStack)
      */
-    protected abstract void renderItem( ItemStack stack );
+    private void renderItemFirstPersonCenter(MatrixStack transform, VertexConsumerProvider render, int combinedLight, float pitch, float equipProgress,
+                                             float swingProgress, ItemStack stack) {
+        MinecraftClient minecraft = MinecraftClient.getInstance();
+        HeldItemRenderer renderer = minecraft.getHeldItemRenderer();
 
-    protected void renderItemFirstPerson( EnumHand hand, float pitch, float equipProgress, float swingProgress, ItemStack stack )
-    {
-        EntityPlayer player = Minecraft.getInstance().player;
+        // Setup the appropriate transformations. This is just copied from the
+        // corresponding method in ItemRenderer.
+        float swingRt = MathHelper.sqrt(swingProgress);
+        float tX = -0.2f * MathHelper.sin(swingProgress * (float) Math.PI);
+        float tZ = -0.4f * MathHelper.sin(swingRt * (float) Math.PI);
+        transform.translate(0, -tX / 2, tZ);
 
-        GlStateManager.pushMatrix();
-        if( hand == EnumHand.MAIN_HAND && player.getHeldItemOffhand().isEmpty() )
-        {
-            renderItemFirstPersonCenter( pitch, equipProgress, swingProgress, stack );
+        HeldItemRendererAccess access = (HeldItemRendererAccess) renderer;
+        float pitchAngle = access.callGetMapAngle(pitch);
+        transform.translate(0, 0.04F + equipProgress * -1.2f + pitchAngle * -0.5f, -0.72f);
+        transform.multiply(Vector3f.POSITIVE_X.getDegreesQuaternion(pitchAngle * -85.0f));
+        if (!minecraft.player.isInvisible()) {
+            transform.push();
+            transform.multiply(Vector3f.POSITIVE_Y.getDegreesQuaternion(90.0F));
+            access.callRenderArm(transform, render, combinedLight, Arm.RIGHT);
+            access.callRenderArm(transform, render, combinedLight, Arm.LEFT);
+            transform.pop();
         }
-        else
-        {
-            renderItemFirstPersonSide(
-                hand == EnumHand.MAIN_HAND ? player.getPrimaryHand() : player.getPrimaryHand().opposite(),
-                equipProgress, swingProgress, stack
-            );
-        }
-        GlStateManager.popMatrix();
+
+        float rX = MathHelper.sin(swingRt * (float) Math.PI);
+        transform.multiply(Vector3f.POSITIVE_X.getDegreesQuaternion(rX * 20.0F));
+        transform.scale(2.0F, 2.0F, 2.0F);
+
+        this.renderItem(transform, render, stack);
     }
 
     /**
      * Renders the item to one side of the player.
      *
-     * @param side          The side to render on
+     * @param transform The matrix transformation stack
+     * @param render The buffer to render to
+     * @param combinedLight The current light level
+     * @param side The side to render on
      * @param equipProgress The equip progress of this item
      * @param swingProgress The swing progress of this item
-     * @param stack         The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPersonSide(float, EnumHandSide, float, ItemStack)
+     * @param stack The stack to render
      */
-    private void renderItemFirstPersonSide( EnumHandSide side, float equipProgress, float swingProgress, ItemStack stack )
-    {
-        Minecraft minecraft = Minecraft.getInstance();
-        float offset = side == EnumHandSide.RIGHT ? 1f : -1f;
-        GlStateManager.translatef( offset * 0.125f, -0.125f, 0f );
+    private void renderItemFirstPersonSide(MatrixStack transform, VertexConsumerProvider render, int combinedLight, Arm side, float equipProgress,
+                                           float swingProgress, ItemStack stack) {
+        MinecraftClient minecraft = MinecraftClient.getInstance();
+        float offset = side == Arm.RIGHT ? 1f : -1f;
+        transform.translate(offset * 0.125f, -0.125f, 0f);
 
         // If the player is not invisible then render a single arm
-        if( !minecraft.player.isInvisible() )
-        {
-            GlStateManager.pushMatrix();
-            GlStateManager.rotatef( offset * 10f, 0f, 0f, 1f );
-            minecraft.getFirstPersonRenderer().renderArmFirstPerson( equipProgress, swingProgress, side );
-            GlStateManager.popMatrix();
+        if (!minecraft.player.isInvisible()) {
+            transform.push();
+            transform.multiply(Vector3f.POSITIVE_Z.getDegreesQuaternion(offset * 10f));
+            ((HeldItemRendererAccess)minecraft.getHeldItemRenderer())
+                     .callRenderArmHoldingItem(transform, render, combinedLight, equipProgress, swingProgress, side);
+            transform.pop();
         }
 
         // Setup the appropriate transformations. This is just copied from the
         // corresponding method in ItemRenderer.
-        GlStateManager.pushMatrix();
-        GlStateManager.translatef( offset * 0.51f, -0.08f + equipProgress * -1.2f, -0.75f );
-        float f1 = MathHelper.sqrt( swingProgress );
-        float f2 = MathHelper.sin( f1 * (float) Math.PI );
+        transform.push();
+        transform.translate(offset * 0.51f, -0.08f + equipProgress * -1.2f, -0.75f);
+        float f1 = MathHelper.sqrt(swingProgress);
+        float f2 = MathHelper.sin(f1 * (float) Math.PI);
         float f3 = -0.5f * f2;
-        float f4 = 0.4f * MathHelper.sin( f1 * ((float) Math.PI * 2f) );
-        float f5 = -0.3f * MathHelper.sin( swingProgress * (float) Math.PI );
-        GlStateManager.translatef( offset * f3, f4 - 0.3f * f2, f5 );
-        GlStateManager.rotatef( f2 * -45f, 1f, 0f, 0f );
-        GlStateManager.rotatef( offset * f2 * -30f, 0f, 1f, 0f );
+        float f4 = 0.4f * MathHelper.sin(f1 * ((float) Math.PI * 2f));
+        float f5 = -0.3f * MathHelper.sin(swingProgress * (float) Math.PI);
+        transform.translate(offset * f3, f4 - 0.3f * f2, f5);
+        transform.multiply(Vector3f.POSITIVE_X.getDegreesQuaternion(f2 * -45f));
+        transform.multiply(Vector3f.POSITIVE_Y.getDegreesQuaternion(offset * f2 * -30f));
 
-        renderItem( stack );
+        this.renderItem(transform, render, stack);
 
-        GlStateManager.popMatrix();
+        transform.pop();
     }
 
     /**
-     * Render an item in the middle of the screen
+     * The main rendering method for the item.
      *
-     * @param pitch         The pitch of the player
-     * @param equipProgress The equip progress of this item
-     * @param swingProgress The swing progress of this item
-     * @param stack         The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPerson(float, float, float)
+     * @param transform The matrix transformation stack
+     * @param render The buffer to render to
+     * @param stack The stack to render
      */
-    private void renderItemFirstPersonCenter( float pitch, float equipProgress, float swingProgress, ItemStack stack )
-    {
-        FirstPersonRenderer renderer = Minecraft.getInstance().getFirstPersonRenderer();
-
-        // Setup the appropriate transformations. This is just copied from the
-        // corresponding method in ItemRenderer.
-        float swingRt = MathHelper.sqrt( swingProgress );
-        float tX = -0.2f * MathHelper.sin( swingProgress * (float) Math.PI );
-        float tZ = -0.4f * MathHelper.sin( swingRt * (float) Math.PI );
-        GlStateManager.translatef( 0f, -tX / 2f, tZ );
-        float pitchAngle = renderer.getMapAngleFromPitch( pitch );
-        GlStateManager.translatef( 0f, 0.04f + equipProgress * -1.2f + pitchAngle * -0.5f, -0.72f );
-        GlStateManager.rotatef( pitchAngle * -85f, 1f, 0f, 0f );
-        renderer.renderArms();
-        float rX = MathHelper.sin( swingRt * (float) Math.PI );
-        GlStateManager.rotatef( rX * 20f, 1f, 0f, 0f );
-        GlStateManager.scalef( 2f, 2f, 2f );
-
-        renderItem( stack );
-    }
+    protected abstract void renderItem(MatrixStack transform, VertexConsumerProvider render, ItemStack stack);
 }

src/main/java/dan200/computercraft/client/render/ItemPocketRenderer.java

@@ -1,76 +1,56 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
+import static dan200.computercraft.client.render.ComputerBorderRenderer.BORDER;
+import static dan200.computercraft.client.render.ComputerBorderRenderer.MARGIN;
+
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.client.FrameInfo;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
-import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
-import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.item.ItemStack;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.RenderSpecificHandEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
 import org.lwjgl.opengl.GL11;
 
-import static dan200.computercraft.client.gui.FixedWidthFontRenderer.*;
-import static dan200.computercraft.client.gui.GuiComputer.*;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.BufferBuilder;
+import net.minecraft.client.render.Tessellator;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.math.Matrix4f;
 
 /**
- * Emulates map rendering for pocket computers
+ * Emulates map rendering for pocket computers.
  */
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class ItemPocketRenderer extends ItemMapLikeRenderer
-{
-    private static final int MARGIN = 2;
-    private static final int FRAME = 12;
+public final class ItemPocketRenderer extends ItemMapLikeRenderer {
+    public static final ItemPocketRenderer INSTANCE = new ItemPocketRenderer();
     private static final int LIGHT_HEIGHT = 8;
 
-    private static final ItemPocketRenderer INSTANCE = new ItemPocketRenderer();
-
-    private ItemPocketRenderer()
-    {
-    }
-
-    @SubscribeEvent
-    public static void renderItem( RenderSpecificHandEvent event )
-    {
-        ItemStack stack = event.getItemStack();
-        if( !(stack.getItem() instanceof ItemPocketComputer) ) return;
-
-        event.setCanceled( true );
-        INSTANCE.renderItemFirstPerson( event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack() );
+    private ItemPocketRenderer() {
     }
 
     @Override
-    protected void renderItem( ItemStack stack )
-    {
-        ClientComputer computer = ItemPocketComputer.createClientComputer( stack );
+    protected void renderItem(MatrixStack transform, VertexConsumerProvider render, ItemStack stack) {
+        ClientComputer computer = ItemPocketComputer.createClientComputer(stack);
         Terminal terminal = computer == null ? null : computer.getTerminal();
 
         int termWidth, termHeight;
-        if( terminal == null )
-        {
+        if (terminal == null) {
             termWidth = ComputerCraft.terminalWidth_pocketComputer;
             termHeight = ComputerCraft.terminalHeight_pocketComputer;
-        }
-        else
-        {
+        } else {
             termWidth = terminal.getWidth();
             termHeight = terminal.getHeight();
         }
@@ -80,61 +60,44 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
 
         // Setup various transformations. Note that these are partially adapted from the corresponding method
         // in ItemRenderer
-        GlStateManager.pushMatrix();
+        transform.push();
+        transform.multiply(Vector3f.POSITIVE_Y.getDegreesQuaternion(180f));
+        transform.multiply(Vector3f.POSITIVE_Z.getDegreesQuaternion(180f));
+        transform.scale(0.5f, 0.5f, 0.5f);
 
-        GlStateManager.disableLighting();
-        GlStateManager.disableDepthTest();
-
-        GlStateManager.rotatef( 180f, 0f, 1f, 0f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.5f, 0.5f, 0.5f );
-
-        double scale = 0.75 / Math.max( width + FRAME * 2, height + FRAME * 2 + LIGHT_HEIGHT );
-        GlStateManager.scaled( scale, scale, 0 );
-        GlStateManager.translated( -0.5 * width, -0.5 * height, 0 );
+        float scale = 0.75f / Math.max(width + BORDER * 2, height + BORDER * 2 + LIGHT_HEIGHT);
+        transform.scale(scale, scale, 0);
+        transform.translate(-0.5 * width, -0.5 * height, 0);
 
         // Render the main frame
         ItemPocketComputer item = (ItemPocketComputer) stack.getItem();
         ComputerFamily family = item.getFamily();
-        int frameColour = item.getColour( stack );
-        renderFrame( family, frameColour, width, height );
+        int frameColour = item.getColour(stack);
+
+        Matrix4f matrix = transform.peek()
+                                   .getModel();
+        renderFrame(matrix, family, frameColour, width, height);
 
         // Render the light
-        int lightColour = ItemPocketComputer.getLightState( stack );
-        if( lightColour == -1 ) lightColour = Colour.Black.getHex();
-        renderLight( lightColour, width, height );
-
-        if( computer != null && terminal != null )
-        {
-            // If we've a computer and terminal then attempt to render it.
-            renderTerminal( terminal, !computer.isColour(), width, height );
+        int lightColour = ItemPocketComputer.getLightState(stack);
+        if (lightColour == -1) {
+            lightColour = Colour.BLACK.getHex();
         }
-        else
-        {
-            // Otherwise render a plain background
-            Minecraft.getInstance().getTextureManager().bindTexture( BACKGROUND );
+        renderLight(matrix, lightColour, width, height);
 
-            Tessellator tessellator = Tessellator.getInstance();
-            BufferBuilder buffer = tessellator.getBuffer();
-
-            Colour black = Colour.Black;
-            buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION );
-            renderTexture( buffer, 0, 0, 0, 0, width, height, black.getR(), black.getG(), black.getB() );
-            tessellator.draw();
+        if (computer != null && terminal != null) {
+            FixedWidthFontRenderer.drawTerminal(matrix, MARGIN, MARGIN, terminal, !computer.isColour(), MARGIN, MARGIN, MARGIN, MARGIN);
+        } else {
+            FixedWidthFontRenderer.drawEmptyTerminal(matrix, 0, 0, width, height);
         }
 
-        GlStateManager.enableDepthTest();
-        GlStateManager.enableLighting();
-        GlStateManager.popMatrix();
+        transform.pop();
     }
 
-    private static void renderFrame( ComputerFamily family, int colour, int width, int height )
-    {
-
-        Minecraft.getInstance().getTextureManager().bindTexture( colour != -1
-            ? BACKGROUND_COLOUR
-            : family == ComputerFamily.Normal ? BACKGROUND_NORMAL : BACKGROUND_ADVANCED
-        );
+    private static void renderFrame(Matrix4f transform, ComputerFamily family, int colour, int width, int height) {
+        MinecraftClient.getInstance()
+                       .getTextureManager()
+                       .bindTexture(colour != -1 ? ComputerBorderRenderer.BACKGROUND_COLOUR : ComputerBorderRenderer.getTexture(family));
 
         float r = ((colour >>> 16) & 0xFF) / 255.0f;
         float g = ((colour >>> 8) & 0xFF) / 255.0f;
@@ -142,38 +105,16 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
 
         Tessellator tessellator = Tessellator.getInstance();
         BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX_COLOR );
+        buffer.begin(GL11.GL_QUADS, VertexFormats.POSITION_COLOR_TEXTURE);
 
-        // Top left, middle, right
-        renderTexture( buffer, -FRAME, -FRAME, 12, 28, FRAME, FRAME, r, g, b );
-        renderTexture( buffer, 0, -FRAME, 0, 0, width, FRAME, r, g, b );
-        renderTexture( buffer, width, -FRAME, 24, 28, FRAME, FRAME, r, g, b );
-
-        // Left and bright border
-        renderTexture( buffer, -FRAME, 0, 0, 28, FRAME, height, r, g, b );
-        renderTexture( buffer, width, 0, 36, 28, FRAME, height, r, g, b );
-
-        // Bottom left, middle, right. We do this in three portions: the top inner corners, an extended region for
-        // lights, and then the bottom outer corners.
-        renderTexture( buffer, -FRAME, height, 12, 40, FRAME, FRAME / 2, r, g, b );
-        renderTexture( buffer, 0, height, 0, 12, width, FRAME / 2, r, g, b );
-        renderTexture( buffer, width, height, 24, 40, FRAME, FRAME / 2, r, g, b );
-
-        renderTexture( buffer, -FRAME, height + FRAME / 2, 12, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
-        renderTexture( buffer, 0, height + FRAME / 2, 0, 16, width, LIGHT_HEIGHT, FRAME, 4, r, g, b );
-        renderTexture( buffer, width, height + FRAME / 2, 24, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
-
-        renderTexture( buffer, -FRAME, height + LIGHT_HEIGHT + FRAME / 2, 12, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
-        renderTexture( buffer, 0, height + LIGHT_HEIGHT + FRAME / 2, 0, 12 + FRAME / 2, width, FRAME / 2, r, g, b );
-        renderTexture( buffer, width, height + LIGHT_HEIGHT + FRAME / 2, 24, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
+        ComputerBorderRenderer.render(transform, buffer, 0, 0, 0, width, height, LIGHT_HEIGHT, r, g, b);
 
         tessellator.draw();
     }
 
-    private static void renderLight( int colour, int width, int height )
-    {
-        GlStateManager.enableBlend();
-        GlStateManager.disableTexture2D();
+    private static void renderLight(Matrix4f transform, int colour, int width, int height) {
+        RenderSystem.enableBlend();
+        RenderSystem.disableTexture();
 
         float r = ((colour >>> 16) & 0xFF) / 255.0f;
         float g = ((colour >>> 8) & 0xFF) / 255.0f;
@@ -181,74 +122,21 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
 
         Tessellator tessellator = Tessellator.getInstance();
         BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_COLOR );
-        buffer.pos( width - LIGHT_HEIGHT * 2, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width - LIGHT_HEIGHT * 2, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+        buffer.begin(GL11.GL_QUADS, VertexFormats.POSITION_COLOR);
+        buffer.vertex(transform, width - LIGHT_HEIGHT * 2, height + LIGHT_HEIGHT + BORDER / 2.0f, 0)
+              .color(r, g, b, 1.0f)
+              .next();
+        buffer.vertex(transform, width, height + LIGHT_HEIGHT + BORDER / 2.0f, 0)
+              .color(r, g, b, 1.0f)
+              .next();
+        buffer.vertex(transform, width, height + BORDER / 2.0f, 0)
+              .color(r, g, b, 1.0f)
+              .next();
+        buffer.vertex(transform, width - LIGHT_HEIGHT * 2, height + BORDER / 2.0f, 0)
+              .color(r, g, b, 1.0f)
+              .next();
 
         tessellator.draw();
-        GlStateManager.enableTexture2D();
-    }
-
-    private static void renderTerminal( Terminal terminal, boolean greyscale, int width, int height )
-    {
-        synchronized( terminal )
-        {
-            int termWidth = terminal.getWidth();
-            int termHeight = terminal.getHeight();
-
-            FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
-            Palette palette = terminal.getPalette();
-
-            // Render top/bottom borders
-            TextBuffer emptyLine = new TextBuffer( ' ', termWidth );
-            fontRenderer.drawString(
-                emptyLine, MARGIN, 0,
-                terminal.getTextColourLine( 0 ), terminal.getBackgroundColourLine( 0 ), MARGIN, MARGIN, greyscale, palette
-            );
-            fontRenderer.drawString(
-                emptyLine, MARGIN, 2 * MARGIN + (termHeight - 1) * FixedWidthFontRenderer.FONT_HEIGHT,
-                terminal.getTextColourLine( termHeight - 1 ), terminal.getBackgroundColourLine( termHeight - 1 ), MARGIN, MARGIN, greyscale, palette
-            );
-
-            // Render the actual text
-            for( int line = 0; line < termWidth; line++ )
-            {
-                TextBuffer text = terminal.getLine( line );
-                TextBuffer colour = terminal.getTextColourLine( line );
-                TextBuffer backgroundColour = terminal.getBackgroundColourLine( line );
-                fontRenderer.drawString(
-                    text, MARGIN, MARGIN + line * FONT_HEIGHT,
-                    colour, backgroundColour, MARGIN, MARGIN, greyscale, palette
-                );
-            }
-
-            // And render the cursor;
-            int tx = terminal.getCursorX(), ty = terminal.getCursorY();
-            if( terminal.getCursorBlink() && FrameInfo.getGlobalCursorBlink() &&
-                tx >= 0 && ty >= 0 && tx < termWidth && ty < termHeight )
-            {
-                TextBuffer cursorColour = new TextBuffer( "0123456789abcdef".charAt( terminal.getTextColour() ), 1 );
-                fontRenderer.drawString(
-                    new TextBuffer( '_', 1 ), MARGIN + FONT_WIDTH * tx, MARGIN + FONT_HEIGHT * ty,
-                    cursorColour, null, 0, 0, greyscale, palette
-                );
-            }
-        }
-    }
-
-    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, float r, float g, float b )
-    {
-        renderTexture( builder, x, y, textureX, textureY, width, height, width, height, r, g, b );
-    }
-
-    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, int textureWidth, int textureHeight, float r, float g, float b )
-    {
-        float scale = 1 / 255.0f;
-        builder.pos( x, y + height, 0 ).tex( textureX * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x + width, y + height, 0 ).tex( (textureX + textureWidth) * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x + width, y, 0 ).tex( (textureX + textureWidth) * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x, y, 0 ).tex( textureX * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
+        RenderSystem.enableTexture();
     }
 }

src/main/java/dan200/computercraft/client/render/ItemPrintoutRenderer.java

@@ -1,116 +1,94 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.shared.media.items.ItemPrintout;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.item.ItemStack;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.RenderItemInFrameEvent;
-import net.minecraftforge.client.event.RenderSpecificHandEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
-
 import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
 import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
-import static dan200.computercraft.client.render.PrintoutRenderer.*;
+import static dan200.computercraft.client.render.PrintoutRenderer.COVER_SIZE;
+import static dan200.computercraft.client.render.PrintoutRenderer.X_TEXT_MARGIN;
+import static dan200.computercraft.client.render.PrintoutRenderer.Y_TEXT_MARGIN;
+import static dan200.computercraft.client.render.PrintoutRenderer.drawBorder;
+import static dan200.computercraft.client.render.PrintoutRenderer.drawText;
+import static dan200.computercraft.client.render.PrintoutRenderer.offsetAt;
 import static dan200.computercraft.shared.media.items.ItemPrintout.LINES_PER_PAGE;
 import static dan200.computercraft.shared.media.items.ItemPrintout.LINE_MAX_LENGTH;
 
+import dan200.computercraft.shared.media.items.ItemPrintout;
+
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.math.Matrix4f;
+
 /**
- * Emulates map and item-frame rendering for printouts
+ * Emulates map and item-frame rendering for printouts.
  */
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class ItemPrintoutRenderer extends ItemMapLikeRenderer
-{
-    private static final ItemPrintoutRenderer INSTANCE = new ItemPrintoutRenderer();
+public final class ItemPrintoutRenderer extends ItemMapLikeRenderer {
+    public static final ItemPrintoutRenderer INSTANCE = new ItemPrintoutRenderer();
 
-    private ItemPrintoutRenderer()
-    {
-    }
-
-    @SubscribeEvent
-    public static void onRenderInHand( RenderSpecificHandEvent event )
-    {
-        ItemStack stack = event.getItemStack();
-        if( !(stack.getItem() instanceof ItemPrintout) ) return;
-
-        event.setCanceled( true );
-        INSTANCE.renderItemFirstPerson( event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack() );
+    private ItemPrintoutRenderer() {
     }
 
     @Override
-    protected void renderItem( ItemStack stack )
-    {
-        // Setup various transformations. Note that these are partially adapated from the corresponding method
-        // in FirstPersonRenderer.renderFirstPersonMap
-        GlStateManager.disableLighting();
+    protected void renderItem(MatrixStack transform, VertexConsumerProvider render, ItemStack stack) {
+        transform.multiply(Vector3f.POSITIVE_X.getDegreesQuaternion(180f));
+        transform.scale(0.42f, 0.42f, -0.42f);
+        transform.translate(-0.5f, -0.48f, 0.0f);
 
-        GlStateManager.rotatef( 180f, 0f, 1f, 0f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.42f, 0.42f, -0.42f );
-        GlStateManager.translatef( -0.5f, -0.48f, 0.0f );
-
-        drawPrintout( stack );
-
-        GlStateManager.enableLighting();
+        drawPrintout(transform, render, stack);
     }
 
-    @SubscribeEvent
-    public static void onRenderInFrame( RenderItemInFrameEvent event )
-    {
-        ItemStack stack = event.getItem();
-        if( !(stack.getItem() instanceof ItemPrintout) ) return;
-
-        event.setCanceled( true );
-
-        GlStateManager.disableLighting();
-
-        // Move a little bit forward to ensure we're not clipping with the frame
-        GlStateManager.translatef( 0.0f, 0.0f, -0.001f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.95f, 0.95f, -0.95f );
-        GlStateManager.translatef( -0.5f, -0.5f, 0.0f );
-
-        drawPrintout( stack );
-
-        GlStateManager.enableLighting();
-        GlStateManager.disableBlend();
-    }
-
-    private static void drawPrintout( ItemStack stack )
-    {
-        int pages = ItemPrintout.getPageCount( stack );
+    private static void drawPrintout(MatrixStack transform, VertexConsumerProvider render, ItemStack stack) {
+        int pages = ItemPrintout.getPageCount(stack);
         boolean book = ((ItemPrintout) stack.getItem()).getType() == ItemPrintout.Type.BOOK;
 
         double width = LINE_MAX_LENGTH * FONT_WIDTH + X_TEXT_MARGIN * 2;
         double height = LINES_PER_PAGE * FONT_HEIGHT + Y_TEXT_MARGIN * 2;
 
         // Non-books will be left aligned
-        if( !book ) width += offsetAt( pages );
+        if (!book) {
+            width += offsetAt(pages);
+        }
 
         double visualWidth = width, visualHeight = height;
 
         // Meanwhile books will be centred
-        if( book )
-        {
-            visualWidth += 2 * COVER_SIZE + 2 * offsetAt( pages );
+        if (book) {
+            visualWidth += 2 * COVER_SIZE + 2 * offsetAt(pages);
             visualHeight += 2 * COVER_SIZE;
         }
 
-        double max = Math.max( visualHeight, visualWidth );
+        double max = Math.max(visualHeight, visualWidth);
 
         // Scale the printout to fit correctly.
-        double scale = 1.0 / max;
-        GlStateManager.scaled( scale, scale, scale );
-        GlStateManager.translated( (max - width) / 2.0, (max - height) / 2.0, 0.0 );
+        float scale = (float) (1.0 / max);
+        transform.scale(scale, scale, scale);
+        transform.translate((max - width) / 2.0, (max - height) / 2.0, 0.0);
 
-        drawBorder( 0, 0, -0.01, 0, pages, book );
-        drawText( X_TEXT_MARGIN, Y_TEXT_MARGIN, 0, ItemPrintout.getText( stack ), ItemPrintout.getColours( stack ) );
+        Matrix4f matrix = transform.peek()
+                                   .getModel();
+        drawBorder(matrix, render, 0, 0, -0.01f, 0, pages, book);
+        drawText(matrix, render, X_TEXT_MARGIN, Y_TEXT_MARGIN, 0, ItemPrintout.getText(stack), ItemPrintout.getColours(stack));
+    }
+
+    public boolean renderInFrame(MatrixStack matrixStack, VertexConsumerProvider consumerProvider, ItemStack stack) {
+        if (!(stack.getItem() instanceof ItemPrintout)) {
+            return false;
+        }
+
+        // Move a little bit forward to ensure we're not clipping with the frame
+        matrixStack.translate(0.0f, 0.0f, -0.001f);
+        matrixStack.multiply(Vector3f.POSITIVE_Z.getDegreesQuaternion(180f));
+        matrixStack.scale(0.95f, 0.95f, -0.95f);
+        matrixStack.translate(-0.5f, -0.5f, 0.0f);
+
+        drawPrintout(matrixStack, consumerProvider, stack);
+
+        return true;
     }
 }

src/main/java/dan200/computercraft/client/render/ModelTransformer.java

@@ -6,265 +6,93 @@
 
 package dan200.computercraft.client.render;
 
-import net.minecraft.client.renderer.model.BakedQuad;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.vertex.VertexFormat;
-import net.minecraft.util.EnumFacing;
-import net.minecraftforge.client.model.pipeline.IVertexConsumer;
-import net.minecraftforge.client.model.pipeline.LightUtil;
-import net.minecraftforge.client.model.pipeline.VertexTransformer;
-import net.minecraftforge.common.model.TRSRTransformation;
-
-import javax.annotation.Nonnull;
-import javax.vecmath.Matrix4f;
-import javax.vecmath.Point3f;
-import javax.vecmath.Vector3f;
 import java.util.List;
 
+import dan200.computercraft.mixin.BakedQuadAccess;
+
+import net.minecraft.client.render.VertexFormat;
+import net.minecraft.client.render.VertexFormatElement;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.client.render.model.BakedQuad;
+import net.minecraft.util.math.Matrix4f;
+import net.minecraft.util.math.Quaternion;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
 /**
- * Transforms vertices of a model, remaining aware of winding order, and rearranging
- * vertices if needed.
+ * Transforms vertices of a model, remaining aware of winding order, and rearranging vertices if needed.
  */
-public final class ModelTransformer
-{
+@Environment (EnvType.CLIENT)
+public final class ModelTransformer {
     private static final Matrix4f identity;
 
-    static
-    {
+    static {
         identity = new Matrix4f();
-        identity.setIdentity();
+        identity.loadIdentity();
     }
 
-    private ModelTransformer()
-    {
+    private ModelTransformer() {
     }
 
-    public static void transformQuadsTo( List<BakedQuad> output, List<BakedQuad> input, Matrix4f transform )
-    {
-        if( transform == null || transform.equals( identity ) )
-        {
-            output.addAll( input );
-        }
-        else
-        {
-            Matrix4f normalMatrix = new Matrix4f( transform );
-            normalMatrix.invert();
-            normalMatrix.transpose();
+    public static void transformQuadsTo(List<BakedQuad> output, List<BakedQuad> input, Matrix4f transform) {
+        transformQuadsTo(VertexFormats.POSITION_COLOR_TEXTURE_LIGHT_NORMAL, output, input, transform);
+    }
 
-            for( BakedQuad quad : input ) output.add( doTransformQuad( quad, transform, normalMatrix ) );
+    public static void transformQuadsTo(VertexFormat format, List<BakedQuad> output, List<BakedQuad> input, Matrix4f transform) {
+        if (transform == null || transform.equals(identity)) {
+            output.addAll(input);
+        } else {
+            for (BakedQuad quad : input) {
+                output.add(doTransformQuad(format, quad, transform));
+            }
         }
     }
 
-    public static BakedQuad transformQuad( BakedQuad input, Matrix4f transform )
-    {
-        if( transform == null || transform.equals( identity ) ) return input;
-
-        Matrix4f normalMatrix = new Matrix4f( transform );
-        normalMatrix.invert();
-        normalMatrix.transpose();
-        return doTransformQuad( input, transform, normalMatrix );
-    }
-
-    private static BakedQuad doTransformQuad( BakedQuad input, Matrix4f positionMatrix, Matrix4f normalMatrix )
-    {
-
-        BakedQuadBuilder builder = new BakedQuadBuilder( input.getFormat() );
-        NormalAwareTransformer transformer = new NormalAwareTransformer( builder, positionMatrix, normalMatrix );
-        input.pipe( transformer );
-
-        if( transformer.areNormalsInverted() )
+    private static BakedQuad doTransformQuad(VertexFormat format, BakedQuad quad, Matrix4f transform) {
+        int[] vertexData = quad.getVertexData()
+                               .clone();
+        int offset = 0;
+        BakedQuad copy = new BakedQuad(vertexData, -1, quad.getFace(), ((BakedQuadAccess)quad).getSprite(), true);
+        for (int i = 0; i < format.getElements()
+                                  .size(); ++i) // For each vertex element
         {
-            builder.swap( 1, 3 );
-            transformer.areNormalsInverted();
-        }
-
-        return builder.build();
-    }
-
-    /**
-     * A vertex transformer that tracks whether the normals have been inverted and so the vertices
-     * should be reordered so backface culling works as expected.
-     */
-    private static class NormalAwareTransformer extends VertexTransformer
-    {
-        private final Matrix4f positionMatrix;
-        private final Matrix4f normalMatrix;
-
-        private int vertexIndex = 0, elementIndex = 0;
-        private final Point3f[] before = new Point3f[4];
-        private final Point3f[] after = new Point3f[4];
-
-        public NormalAwareTransformer( IVertexConsumer parent, Matrix4f positionMatrix, Matrix4f normalMatrix )
-        {
-            super( parent );
-            this.positionMatrix = positionMatrix;
-            this.normalMatrix = normalMatrix;
-        }
-
-        @Override
-        public void setQuadOrientation( @Nonnull EnumFacing orientation )
-        {
-            super.setQuadOrientation( orientation == null ? orientation : TRSRTransformation.rotate( positionMatrix, orientation ) );
-        }
-
-        @Override
-        public void put( int element, @Nonnull float... data )
-        {
-            switch( getVertexFormat().getElement( element ).getUsage() )
+            VertexFormatElement element = format.getElements()
+                                                .get(i);
+            if (element.getType() == VertexFormatElement.Type.POSITION && element.getFormat() == VertexFormatElement.Format.FLOAT && element.getSize() == 3) // When we find a position
+            // element
             {
-                case POSITION:
+                for (int j = 0; j < 4; ++j) // For each corner of the quad
                 {
-                    Point3f vec = new Point3f( data );
-                    Point3f newVec = new Point3f();
-                    positionMatrix.transform( vec, newVec );
+                    int start = offset + j * format.getVertexSize();
+                    if ((start % 4) == 0) {
+                        start = start / 4;
 
-                    float[] newData = new float[4];
-                    newVec.get( newData );
-                    super.put( element, newData );
+                        // Extract the position
+                        Quaternion pos = new Quaternion(Float.intBitsToFloat(vertexData[start]),
+                                                        Float.intBitsToFloat(vertexData[start + 1]),
+                                                        Float.intBitsToFloat(vertexData[start + 2]),
+                                                        1);
 
+                        // Transform the position
+                        transform.multiply(pos);
 
-                    before[vertexIndex] = vec;
-                    after[vertexIndex] = newVec;
-                    break;
+                        // Insert the position
+                        vertexData[start] = Float.floatToRawIntBits(pos.getX());
+                        vertexData[start + 1] = Float.floatToRawIntBits(pos.getY());
+                        vertexData[start + 2] = Float.floatToRawIntBits(pos.getZ());
+                    }
                 }
-                case NORMAL:
-                {
-                    Vector3f vec = new Vector3f( data );
-                    normalMatrix.transform( vec );
-
-                    float[] newData = new float[4];
-                    vec.get( newData );
-                    super.put( element, newData );
-                    break;
-                }
-                default:
-                    super.put( element, data );
-                    break;
-            }
-
-            elementIndex++;
-            if( elementIndex == getVertexFormat().getElementCount() )
-            {
-                vertexIndex++;
-                elementIndex = 0;
             }
+            offset += element.getSize();
         }
-
-        public boolean areNormalsInverted()
-        {
-            Vector3f temp1 = new Vector3f(), temp2 = new Vector3f();
-            Vector3f crossBefore = new Vector3f(), crossAfter = new Vector3f();
-
-            // Determine what cross product we expect to have
-            temp1.sub( before[1], before[0] );
-            temp2.sub( before[1], before[2] );
-            crossBefore.cross( temp1, temp2 );
-            normalMatrix.transform( crossBefore );
-
-            // And determine what cross product we actually have
-            temp1.sub( after[1], after[0] );
-            temp2.sub( after[1], after[2] );
-            crossAfter.cross( temp1, temp2 );
-
-            // If the angle between expected and actual cross product is greater than
-            // pi/2 radians then we will need to reorder our quads.
-            return Math.abs( crossBefore.angle( crossAfter ) ) >= Math.PI / 2;
-        }
+        return copy;
     }
 
-    /**
-     * A vertex consumer which is capable of building {@link BakedQuad}s.
-     *
-     * Equivalent to {@link net.minecraftforge.client.model.pipeline.UnpackedBakedQuad.Builder} but more memory
-     * efficient.
-     *
-     * This also provides the ability to swap vertices through {@link #swap(int, int)} to allow reordering.
-     */
-    private static final class BakedQuadBuilder implements IVertexConsumer
-    {
-        private final VertexFormat format;
-
-        private final int[] vertexData;
-        private int vertexIndex = 0, elementIndex = 0;
-
-        private EnumFacing orientation;
-        private int quadTint;
-        private boolean diffuse;
-        private TextureAtlasSprite texture;
-
-        private BakedQuadBuilder( VertexFormat format )
-        {
-            this.format = format;
-            vertexData = new int[format.getSize()];
-        }
-
-        @Nonnull
-        @Override
-        public VertexFormat getVertexFormat()
-        {
-            return format;
-        }
-
-        @Override
-        public void setQuadTint( int tint )
-        {
-            quadTint = tint;
-        }
-
-        @Override
-        public void setQuadOrientation( @Nonnull EnumFacing orientation )
-        {
-            this.orientation = orientation;
-        }
-
-        @Override
-        public void setApplyDiffuseLighting( boolean diffuse )
-        {
-            this.diffuse = diffuse;
-        }
-
-        @Override
-        public void setTexture( @Nonnull TextureAtlasSprite texture )
-        {
-            this.texture = texture;
-        }
-
-        @Override
-        public void put( int element, @Nonnull float... data )
-        {
-            LightUtil.pack( data, vertexData, format, vertexIndex, element );
-
-            elementIndex++;
-            if( elementIndex == getVertexFormat().getElementCount() )
-            {
-                vertexIndex++;
-                elementIndex = 0;
-            }
-        }
-
-        public void swap( int a, int b )
-        {
-            int length = vertexData.length / 4;
-            for( int i = 0; i < length; i++ )
-            {
-                int temp = vertexData[a * length + i];
-                vertexData[a * length + i] = vertexData[b * length + i];
-                vertexData[b * length + i] = temp;
-            }
-        }
-
-        public BakedQuad build()
-        {
-            if( elementIndex != 0 || vertexIndex != 4 )
-            {
-                throw new IllegalStateException( "Got an unexpected number of elements/vertices" );
-            }
-            if( texture == null )
-            {
-                throw new IllegalStateException( "Texture has not been set" );
-            }
-
-            return new BakedQuad( vertexData, quadTint, orientation, texture, diffuse, format );
+    public static BakedQuad transformQuad(VertexFormat format, BakedQuad input, Matrix4f transform) {
+        if (transform == null || transform.equals(identity)) {
+            return input;
         }
+        return doTransformQuad(format, input, transform);
     }
 }

src/main/java/dan200/computercraft/client/render/MonitorHighlightRenderer.java

@@ -1,117 +1,137 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.entity.player.EntityPlayer;
-import net.minecraft.tileentity.TileEntity;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.world.World;
-import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.DrawBlockHighlightEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
-import org.lwjgl.opengl.GL11;
+import static net.minecraft.util.math.Direction.DOWN;
+import static net.minecraft.util.math.Direction.EAST;
+import static net.minecraft.util.math.Direction.NORTH;
+import static net.minecraft.util.math.Direction.SOUTH;
+import static net.minecraft.util.math.Direction.UP;
+import static net.minecraft.util.math.Direction.WEST;
 
 import java.util.EnumSet;
 
-import static net.minecraft.util.EnumFacing.*;
+import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
 
-@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class MonitorHighlightRenderer
-{
-    private static final float EXPAND = 0.002f;
+import net.minecraft.block.BlockState;
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.Entity;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Matrix4f;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
 
-    private MonitorHighlightRenderer()
-    {
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+/**
+ * Overrides monitor highlighting to only render the outline of the <em>whole</em> monitor, rather than the current block. This means you do not get an
+ * intrusive outline on top of the screen.
+ */
+@Environment (EnvType.CLIENT)
+public final class MonitorHighlightRenderer {
+    private MonitorHighlightRenderer() {
     }
 
-    @SubscribeEvent
-    public static void drawHighlight( DrawBlockHighlightEvent event )
-    {
-        if( event.getTarget().type != RayTraceResult.Type.BLOCK || event.getPlayer().isSneaking() ) return;
+    public static boolean drawHighlight(MatrixStack matrixStack, VertexConsumer vertexConsumer, Entity entity, double d, double e, double f, BlockPos pos
+        , BlockState blockState) {
+        // Preserve normal behaviour when crouching.
+        if (entity.isInSneakingPose()) {
+            return false;
+        }
 
-        World world = event.getPlayer().getEntityWorld();
-        BlockPos pos = event.getTarget().getBlockPos();
+        World world = entity.getEntityWorld();
 
-        TileEntity tile = world.getTileEntity( pos );
-        if( !(tile instanceof TileMonitor) ) return;
+        BlockEntity tile = world.getBlockEntity(pos);
+        if (!(tile instanceof TileMonitor)) {
+            return false;
+        }
 
         TileMonitor monitor = (TileMonitor) tile;
-        event.setCanceled( true );
 
         // Determine which sides are part of the external faces of the monitor, and so which need to be rendered.
-        EnumSet<EnumFacing> faces = EnumSet.allOf( EnumFacing.class );
-        EnumFacing front = monitor.getFront();
-        faces.remove( front );
-        if( monitor.getXIndex() != 0 ) faces.remove( monitor.getRight().getOpposite() );
-        if( monitor.getXIndex() != monitor.getWidth() - 1 ) faces.remove( monitor.getRight() );
-        if( monitor.getYIndex() != 0 ) faces.remove( monitor.getDown().getOpposite() );
-        if( monitor.getYIndex() != monitor.getHeight() - 1 ) faces.remove( monitor.getDown() );
+        EnumSet<Direction> faces = EnumSet.allOf(Direction.class);
+        Direction front = monitor.getFront();
+        faces.remove(front);
+        if (monitor.getXIndex() != 0) {
+            faces.remove(monitor.getRight()
+                                .getOpposite());
+        }
+        if (monitor.getXIndex() != monitor.getWidth() - 1) {
+            faces.remove(monitor.getRight());
+        }
+        if (monitor.getYIndex() != 0) {
+            faces.remove(monitor.getDown()
+                                .getOpposite());
+        }
+        if (monitor.getYIndex() != monitor.getHeight() - 1) {
+            faces.remove(monitor.getDown());
+        }
 
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate(GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO);
-        GlStateManager.lineWidth(Math.max(2.5F, (float) Minecraft.getInstance().mainWindow.getFramebufferWidth() / 1920.0F * 2.5F));
-        GlStateManager.disableTexture2D();
-        GlStateManager.depthMask( false );
-        GlStateManager.pushMatrix();
-
-        EntityPlayer player = event.getPlayer();
-        double x = player.lastTickPosX + (player.posX - player.lastTickPosX) * event.getPartialTicks();
-        double y = player.lastTickPosY + (player.posY - player.lastTickPosY) * event.getPartialTicks();
-        double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * event.getPartialTicks();
-
-        GlStateManager.translated( -x + pos.getX(), -y + pos.getY(), -z + pos.getZ() );
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_LINES, DefaultVertexFormats.POSITION_COLOR );
+        Vec3d cameraPos = MinecraftClient.getInstance().gameRenderer.getCamera()
+                                                                    .getPos();
+        matrixStack.push();
+        matrixStack.translate(pos.getX() - cameraPos.getX(), pos.getY() - cameraPos.getY(), pos.getZ() - cameraPos.getZ());
 
         // I wish I could think of a better way to do this
-        if( faces.contains( NORTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 0, UP );
-        if( faces.contains( SOUTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 1, UP );
-        if( faces.contains( NORTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 0, UP );
-        if( faces.contains( SOUTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 1, UP );
-        if( faces.contains( NORTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, EAST );
-        if( faces.contains( SOUTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 1, EAST );
-        if( faces.contains( NORTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, EAST );
-        if( faces.contains( SOUTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 1, EAST );
-        if( faces.contains( WEST ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, SOUTH );
-        if( faces.contains( EAST ) || faces.contains( DOWN ) ) line( buffer, 1, 0, 0, SOUTH );
-        if( faces.contains( WEST ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, SOUTH );
-        if( faces.contains( EAST ) || faces.contains( UP ) ) line( buffer, 1, 1, 0, SOUTH );
+        Matrix4f transform = matrixStack.peek()
+                                        .getModel();
+        if (faces.contains(NORTH) || faces.contains(WEST)) {
+            line(vertexConsumer, transform, 0, 0, 0, UP);
+        }
+        if (faces.contains(SOUTH) || faces.contains(WEST)) {
+            line(vertexConsumer, transform, 0, 0, 1, UP);
+        }
+        if (faces.contains(NORTH) || faces.contains(EAST)) {
+            line(vertexConsumer, transform, 1, 0, 0, UP);
+        }
+        if (faces.contains(SOUTH) || faces.contains(EAST)) {
+            line(vertexConsumer, transform, 1, 0, 1, UP);
+        }
+        if (faces.contains(NORTH) || faces.contains(DOWN)) {
+            line(vertexConsumer, transform, 0, 0, 0, EAST);
+        }
+        if (faces.contains(SOUTH) || faces.contains(DOWN)) {
+            line(vertexConsumer, transform, 0, 0, 1, EAST);
+        }
+        if (faces.contains(NORTH) || faces.contains(UP)) {
+            line(vertexConsumer, transform, 0, 1, 0, EAST);
+        }
+        if (faces.contains(SOUTH) || faces.contains(UP)) {
+            line(vertexConsumer, transform, 0, 1, 1, EAST);
+        }
+        if (faces.contains(WEST) || faces.contains(DOWN)) {
+            line(vertexConsumer, transform, 0, 0, 0, SOUTH);
+        }
+        if (faces.contains(EAST) || faces.contains(DOWN)) {
+            line(vertexConsumer, transform, 1, 0, 0, SOUTH);
+        }
+        if (faces.contains(WEST) || faces.contains(UP)) {
+            line(vertexConsumer, transform, 0, 1, 0, SOUTH);
+        }
+        if (faces.contains(EAST) || faces.contains(UP)) {
+            line(vertexConsumer, transform, 1, 1, 0, SOUTH);
+        }
 
-        tessellator.draw();
+        matrixStack.pop();
 
-        GlStateManager.popMatrix();
-        GlStateManager.depthMask( true );
-        GlStateManager.enableTexture2D();
-        GlStateManager.disableBlend();
+        return true;
     }
 
-    private static void line( BufferBuilder buffer, int x, int y, int z, EnumFacing direction )
-    {
-        double minX = x == 0 ? -EXPAND : 1 + EXPAND;
-        double minY = y == 0 ? -EXPAND : 1 + EXPAND;
-        double minZ = z == 0 ? -EXPAND : 1 + EXPAND;
-
-        buffer.pos( minX, minY, minZ ).color( 0, 0, 0, 0.4f ).endVertex();
-        buffer.pos(
-            minX + direction.getXOffset() * (1 + EXPAND * 2),
-            minY + direction.getYOffset() * (1 + EXPAND * 2),
-            minZ + direction.getZOffset() * (1 + EXPAND * 2)
-        ).color( 0, 0, 0, 0.4f ).endVertex();
+    private static void line(VertexConsumer buffer, Matrix4f transform, float x, float y, float z, Direction direction) {
+        buffer.vertex(transform, x, y, z)
+              .color(0, 0, 0, 0.4f)
+              .next();
+        buffer.vertex(transform, x + direction.getOffsetX(), y + direction.getOffsetY(), z + direction.getOffsetZ())
+              .color(0, 0, 0, 0.4f)
+              .next();
     }
 }

src/main/java/dan200/computercraft/client/render/MonitorTextureBufferShader.java

@@ -0,0 +1,165 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.client.render;
+
+import java.io.InputStream;
+import java.nio.FloatBuffer;
+
+import com.google.common.base.Strings;
+import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.gui.FixedWidthFontRenderer;
+import dan200.computercraft.shared.util.Palette;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL20;
+
+import net.minecraft.client.texture.TextureUtil;
+import net.minecraft.util.math.Matrix4f;
+
+class MonitorTextureBufferShader {
+    static final int TEXTURE_INDEX = GL13.GL_TEXTURE3;
+
+    private static final FloatBuffer MATRIX_BUFFER = BufferUtils.createFloatBuffer(16);
+    private static final FloatBuffer PALETTE_BUFFER = BufferUtils.createFloatBuffer(16 * 3);
+
+    private static int uniformMv;
+
+    private static int uniformFont;
+    private static int uniformWidth;
+    private static int uniformHeight;
+    private static int uniformTbo;
+    private static int uniformPalette;
+
+    private static boolean initialised;
+    private static boolean ok;
+    private static int program;
+
+    static void setupUniform(Matrix4f transform, int width, int height, Palette palette, boolean greyscale) {
+        MATRIX_BUFFER.rewind();
+        transform.writeToBuffer(MATRIX_BUFFER);
+        MATRIX_BUFFER.rewind();
+        RenderSystem.glUniformMatrix4(uniformMv, false, MATRIX_BUFFER);
+
+        RenderSystem.glUniform1i(uniformWidth, width);
+        RenderSystem.glUniform1i(uniformHeight, height);
+
+        // TODO: Cache this? Maybe??
+        PALETTE_BUFFER.rewind();
+        for (int i = 0; i < 16; i++) {
+            double[] colour = palette.getColour(i);
+            if (greyscale) {
+                float f = FixedWidthFontRenderer.toGreyscale(colour);
+                PALETTE_BUFFER.put(f)
+                              .put(f)
+                              .put(f);
+            } else {
+                PALETTE_BUFFER.put((float) colour[0])
+                              .put((float) colour[1])
+                              .put((float) colour[2]);
+            }
+        }
+        PALETTE_BUFFER.flip();
+        RenderSystem.glUniform3(uniformPalette, PALETTE_BUFFER);
+    }
+
+    static boolean use() {
+        if (initialised) {
+            if (ok) {
+                GlStateManager.useProgram(program);
+            }
+            return ok;
+        }
+
+        if (ok = load()) {
+            GL20.glUseProgram(program);
+            RenderSystem.glUniform1i(uniformFont, 0);
+            RenderSystem.glUniform1i(uniformTbo, TEXTURE_INDEX - GL13.GL_TEXTURE0);
+        }
+
+        return ok;
+    }
+
+    private static boolean load() {
+        initialised = true;
+
+        try {
+            int vertexShader = loadShader(GL20.GL_VERTEX_SHADER, "assets/computercraft/shaders/monitor.vert");
+            int fragmentShader = loadShader(GL20.GL_FRAGMENT_SHADER, "assets/computercraft/shaders/monitor.frag");
+
+            program = GlStateManager.createProgram();
+            GlStateManager.attachShader(program, vertexShader);
+            GlStateManager.attachShader(program, fragmentShader);
+            GL20.glBindAttribLocation(program, 0, "v_pos");
+
+            GlStateManager.linkProgram(program);
+            boolean ok = GlStateManager.getProgram(program, GL20.GL_LINK_STATUS) != 0;
+            String log = GlStateManager.getProgramInfoLog(program, Short.MAX_VALUE)
+                                       .trim();
+            if (!Strings.isNullOrEmpty(log)) {
+                ComputerCraft.log.warn("Problems when linking monitor shader: {}", log);
+            }
+
+            GL20.glDetachShader(program, vertexShader);
+            GL20.glDetachShader(program, fragmentShader);
+            GlStateManager.deleteShader(vertexShader);
+            GlStateManager.deleteShader(fragmentShader);
+
+            if (!ok) {
+                return false;
+            }
+
+            uniformMv = getUniformLocation(program, "u_mv");
+            uniformFont = getUniformLocation(program, "u_font");
+            uniformWidth = getUniformLocation(program, "u_width");
+            uniformHeight = getUniformLocation(program, "u_height");
+            uniformTbo = getUniformLocation(program, "u_tbo");
+            uniformPalette = getUniformLocation(program, "u_palette");
+
+            ComputerCraft.log.info("Loaded monitor shader.");
+            return true;
+        } catch (Exception e) {
+            ComputerCraft.log.error("Cannot load monitor shaders", e);
+            return false;
+        }
+    }
+
+    private static int loadShader(int kind, String path) {
+        InputStream stream = TileEntityMonitorRenderer.class.getClassLoader()
+                                                            .getResourceAsStream(path);
+        if (stream == null) {
+            throw new IllegalArgumentException("Cannot find " + path);
+        }
+        String contents = TextureUtil.readAllToString(stream);
+
+        int shader = GlStateManager.createShader(kind);
+
+        GlStateManager.shaderSource(shader, contents);
+        GlStateManager.compileShader(shader);
+
+        boolean ok = GlStateManager.getShader(shader, GL20.GL_COMPILE_STATUS) != 0;
+        String log = GlStateManager.getShaderInfoLog(shader, Short.MAX_VALUE)
+                                   .trim();
+        if (!Strings.isNullOrEmpty(log)) {
+            ComputerCraft.log.warn("Problems when loading monitor shader {}: {}", path, log);
+        }
+
+        if (!ok) {
+            throw new IllegalStateException("Cannot compile shader " + path);
+        }
+        return shader;
+    }
+
+    private static int getUniformLocation(int program, String name) {
+        int uniform = GlStateManager.getUniformLocation(program, name);
+        if (uniform == -1) {
+            throw new IllegalStateException("Cannot find uniform " + name);
+        }
+        return uniform;
+    }
+}

src/main/java/dan200/computercraft/client/render/PrintoutRenderer.java

@@ -1,180 +1,199 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.client.gui.FixedWidthFontRenderer;
-import dan200.computercraft.core.terminal.TextBuffer;
-import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.GlStateManager.DestFactor;
-import net.minecraft.client.renderer.GlStateManager.SourceFactor;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.ResourceLocation;
-import org.lwjgl.opengl.GL11;
-
 import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
 import static dan200.computercraft.shared.media.items.ItemPrintout.LINES_PER_PAGE;
 
-public final class PrintoutRenderer
-{
-    private static final ResourceLocation BG = new ResourceLocation( "computercraft", "textures/gui/printout.png" );
-    private static final double BG_SIZE = 256.0;
+import dan200.computercraft.client.gui.FixedWidthFontRenderer;
+import dan200.computercraft.core.terminal.TextBuffer;
+import dan200.computercraft.shared.util.Palette;
+import org.lwjgl.opengl.GL11;
 
+import net.minecraft.client.render.RenderLayer;
+import net.minecraft.client.render.RenderPhase;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.math.Matrix4f;
+
+public final class PrintoutRenderer {
     /**
-     * Width of a page
+     * Width of a page.
      */
     public static final int X_SIZE = 172;
-
     /**
-     * Height of a page
+     * Height of a page.
      */
     public static final int Y_SIZE = 209;
-
     /**
-     * Padding between the left and right of a page and the text
+     * Padding between the left and right of a page and the text.
      */
     public static final int X_TEXT_MARGIN = 13;
-
     /**
-     * Padding between the top and bottom of a page and the text
+     * Padding between the top and bottom of a page and the text.
      */
     public static final int Y_TEXT_MARGIN = 11;
-
     /**
-     * Width of the extra page texture
-     */
-    private static final int X_FOLD_SIZE = 12;
-
-    /**
-     * Size of the leather cover
+     * Size of the leather cover.
      */
     public static final int COVER_SIZE = 12;
-
+    private static final Identifier BG = new Identifier("computercraft", "textures/gui/printout.png");
+    private static final float BG_SIZE = 256.0f;
+    /**
+     * Width of the extra page texture.
+     */
+    private static final int X_FOLD_SIZE = 12;
     private static final int COVER_Y = Y_SIZE;
     private static final int COVER_X = X_SIZE + 4 * X_FOLD_SIZE;
 
     private PrintoutRenderer() {}
 
-    public static void drawText( int x, int y, int start, TextBuffer[] text, TextBuffer[] colours )
-    {
-        FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
-
-        for( int line = 0; line < LINES_PER_PAGE && line < text.length; line++ )
-        {
-            fontRenderer.drawString( text[start + line], x, y + line * FONT_HEIGHT, colours[start + line], null, 0, 0, false, Palette.DEFAULT );
+    public static void drawText(Matrix4f transform, VertexConsumerProvider renderer, int x, int y, int start, TextBuffer[] text, TextBuffer[] colours) {
+        VertexConsumer buffer = renderer.getBuffer(FixedWidthFontRenderer.TYPE);
+        for (int line = 0; line < LINES_PER_PAGE && line < text.length; line++) {
+            FixedWidthFontRenderer.drawString(transform,
+                                              buffer,
+                                              x,
+                                              y + line * FONT_HEIGHT,
+                                              text[start + line],
+                                              colours[start + line],
+                                              null,
+                                              Palette.DEFAULT,
+                                              false,
+                                              0,
+                                              0);
         }
     }
 
-    public static void drawText( int x, int y, int start, String[] text, String[] colours )
-    {
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableBlend();
-        GlStateManager.enableTexture2D();
-        GlStateManager.blendFuncSeparate( SourceFactor.SRC_ALPHA, DestFactor.ONE_MINUS_SRC_ALPHA, SourceFactor.ONE, DestFactor.ZERO );
-
-        FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
-
-        for( int line = 0; line < LINES_PER_PAGE && line < text.length; line++ )
-        {
-            fontRenderer.drawString( new TextBuffer( text[start + line] ), x, y + line * FONT_HEIGHT, new TextBuffer( colours[start + line] ), null, 0, 0, false, Palette.DEFAULT );
+    public static void drawText(Matrix4f transform, VertexConsumerProvider renderer, int x, int y, int start, String[] text, String[] colours) {
+        VertexConsumer buffer = renderer.getBuffer(FixedWidthFontRenderer.TYPE);
+        for (int line = 0; line < LINES_PER_PAGE && line < text.length; line++) {
+            FixedWidthFontRenderer.drawString(transform,
+                                              buffer,
+                                              x,
+                                              y + line * FONT_HEIGHT,
+                                              new TextBuffer(text[start + line]),
+                                              new TextBuffer(colours[start + line]),
+                                              null,
+                                              Palette.DEFAULT,
+                                              false,
+                                              0,
+                                              0);
         }
     }
 
-    public static void drawBorder( double x, double y, double z, int page, int pages, boolean isBook )
-    {
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableBlend();
-        GlStateManager.enableTexture2D();
-        GlStateManager.blendFuncSeparate( SourceFactor.SRC_ALPHA, DestFactor.ONE_MINUS_SRC_ALPHA, SourceFactor.ONE, DestFactor.ZERO );
-
-        Minecraft.getInstance().getTextureManager().bindTexture( BG );
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX );
-
+    public static void drawBorder(Matrix4f transform, VertexConsumerProvider renderer, float x, float y, float z, int page, int pages, boolean isBook) {
         int leftPages = page;
         int rightPages = pages - page - 1;
 
-        if( isBook )
-        {
+        VertexConsumer buffer = renderer.getBuffer(Type.TYPE);
+
+        if (isBook) {
             // Border
-            double offset = offsetAt( pages );
-            final double left = x - 4 - offset;
-            final double right = x + X_SIZE + offset - 4;
+            float offset = offsetAt(pages);
+            float left = x - 4 - offset;
+            float right = x + X_SIZE + offset - 4;
 
             // Left and right border
-            drawTexture( buffer, left - 4, y - 8, z - 0.02, COVER_X, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
-            drawTexture( buffer, right, y - 8, z - 0.02, COVER_X + COVER_SIZE, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
+            drawTexture(transform, buffer, left - 4, y - 8, z - 0.02f, COVER_X, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2);
+            drawTexture(transform, buffer, right, y - 8, z - 0.02f, COVER_X + COVER_SIZE, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2);
 
             // Draw centre panel (just stretched texture, sorry).
-            drawTexture( buffer,
-                x - offset, y, z - 0.02, X_SIZE + offset * 2, Y_SIZE,
-                COVER_X + COVER_SIZE / 2.0f, COVER_SIZE, COVER_SIZE, Y_SIZE
-            );
+            drawTexture(transform,
+                        buffer,
+                        x - offset,
+                        y,
+                        z - 0.02f,
+                        X_SIZE + offset * 2,
+                        Y_SIZE,
+                        COVER_X + COVER_SIZE / 2.0f,
+                        COVER_SIZE,
+                        COVER_SIZE,
+                        Y_SIZE);
 
-            double borderX = left;
-            while( borderX < right )
-            {
-                double thisWidth = Math.min( right - borderX, X_SIZE );
-                drawTexture( buffer, borderX, y - 8, z - 0.02, 0, COVER_Y, thisWidth, COVER_SIZE );
-                drawTexture( buffer, borderX, y + Y_SIZE - 4, z - 0.02, 0, COVER_Y + COVER_SIZE, thisWidth, COVER_SIZE );
+            float borderX = left;
+            while (borderX < right) {
+                double thisWidth = Math.min(right - borderX, X_SIZE);
+                drawTexture(transform, buffer, borderX, y - 8, z - 0.02f, 0, COVER_Y, (float) thisWidth, COVER_SIZE);
+                drawTexture(transform, buffer, borderX, y + Y_SIZE - 4, z - 0.02f, 0, COVER_Y + COVER_SIZE, (float) thisWidth, COVER_SIZE);
                 borderX += thisWidth;
             }
         }
 
         // Left half
-        drawTexture( buffer, x, y, z, X_FOLD_SIZE * 2, 0, X_SIZE / 2.0f, Y_SIZE );
-        for( int n = 0; n <= leftPages; n++ )
-        {
-            drawTexture( buffer,
-                x - offsetAt( n ), y, z - 1e-3 * n,
-                // Use the left "bold" fold for the outermost page
-                n == leftPages ? 0 : X_FOLD_SIZE, 0,
-                X_FOLD_SIZE, Y_SIZE
-            );
+        drawTexture(transform, buffer, x, y, z, X_FOLD_SIZE * 2, 0, X_SIZE / 2.0f, Y_SIZE);
+        for (int n = 0; n <= leftPages; n++) {
+            drawTexture(transform, buffer, x - offsetAt(n), y, z - 1e-3f * n,
+                        // Use the left "bold" fold for the outermost page
+                        n == leftPages ? 0 : X_FOLD_SIZE, 0, X_FOLD_SIZE, Y_SIZE);
         }
 
         // Right half
-        drawTexture( buffer, x + X_SIZE / 2.0f, y, z, X_FOLD_SIZE * 2 + X_SIZE / 2.0f, 0, X_SIZE / 2.0f, Y_SIZE );
-        for( int n = 0; n <= rightPages; n++ )
-        {
-            drawTexture( buffer,
-                x + (X_SIZE - X_FOLD_SIZE) + offsetAt( n ), y, z - 1e-3 * n,
-                // Two folds, then the main page. Use the right "bold" fold for the outermost page.
-                X_FOLD_SIZE * 2 + X_SIZE + (n == rightPages ? X_FOLD_SIZE : 0), 0,
-                X_FOLD_SIZE, Y_SIZE
-            );
+        drawTexture(transform, buffer, x + X_SIZE / 2.0f, y, z, X_FOLD_SIZE * 2 + X_SIZE / 2.0f, 0, X_SIZE / 2.0f, Y_SIZE);
+        for (int n = 0; n <= rightPages; n++) {
+            drawTexture(transform, buffer, x + (X_SIZE - X_FOLD_SIZE) + offsetAt(n), y, z - 1e-3f * n,
+                        // Two folds, then the main page. Use the right "bold" fold for the outermost page.
+                        X_FOLD_SIZE * 2 + X_SIZE + (n == rightPages ? X_FOLD_SIZE : 0), 0, X_FOLD_SIZE, Y_SIZE);
         }
-
-        tessellator.draw();
     }
 
-    private static void drawTexture( BufferBuilder buffer, double x, double y, double z, double u, double v, double width, double height )
-    {
-        buffer.pos( x, y + height, z ).tex( u / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y + height, z ).tex( (u + width) / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y, z ).tex( (u + width) / BG_SIZE, v / BG_SIZE ).endVertex();
-        buffer.pos( x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
+    public static float offsetAt(int page) {
+        return (float) (32 * (1 - Math.pow(1.2, -page)));
     }
 
-    private static void drawTexture( BufferBuilder buffer, double x, double y, double z, double width, double height, double u, double v, double tWidth, double tHeight )
-    {
-        buffer.pos( x, y + height, z ).tex( u / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y + height, z ).tex( (u + tWidth) / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y, z ).tex( (u + tWidth) / BG_SIZE, v / BG_SIZE ).endVertex();
-        buffer.pos( x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
+    private static void drawTexture(Matrix4f matrix, VertexConsumer buffer, float x, float y, float z, float u, float v, float width, float height) {
+        buffer.vertex(matrix, x, y + height, z)
+              .texture(u / BG_SIZE, (v + height) / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x + width, y + height, z)
+              .texture((u + width) / BG_SIZE, (v + height) / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x + width, y, z)
+              .texture((u + width) / BG_SIZE, v / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x, y, z)
+              .texture(u / BG_SIZE, v / BG_SIZE)
+              .next();
     }
 
-    public static double offsetAt( int page )
-    {
-        return 32 * (1 - Math.pow( 1.2, -page ));
+    private static void drawTexture(Matrix4f matrix, VertexConsumer buffer, float x, float y, float z, float width, float height, float u, float v,
+                                    float tWidth, float tHeight) {
+        buffer.vertex(matrix, x, y + height, z)
+              .texture(u / BG_SIZE, (v + tHeight) / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x + width, y + height, z)
+              .texture((u + tWidth) / BG_SIZE, (v + tHeight) / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x + width, y, z)
+              .texture((u + tWidth) / BG_SIZE, v / BG_SIZE)
+              .next();
+        buffer.vertex(matrix, x, y, z)
+              .texture(u / BG_SIZE, v / BG_SIZE)
+              .next();
+    }
+
+    private static final class Type extends RenderPhase {
+        static final RenderLayer TYPE = RenderLayer.of("printout_background",
+                                                       VertexFormats.POSITION_TEXTURE,
+                                                       GL11.GL_QUADS,
+                                                       1024,
+                                                       false,
+                                                       false,
+                                                       // useDelegate, needsSorting
+                                                       RenderLayer.MultiPhaseParameters.builder()
+                                                                                       .texture(new RenderPhase.Texture(BG, false, false)) // blur, minimap
+                                                                                       .alpha(ONE_TENTH_ALPHA)
+                                                                                       .lightmap(DISABLE_LIGHTMAP)
+                                                                                       .build(false));
+
+        private Type(String name, Runnable setup, Runnable destroy) {
+            super(name, setup, destroy);
+        }
     }
 }

src/main/java/dan200/computercraft/client/render/TileEntityCableRenderer.java

@@ -1,125 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.client.render;
-
-import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
-import dan200.computercraft.shared.peripheral.modem.wired.CableModemVariant;
-import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
-import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
-import dan200.computercraft.shared.util.WorldUtil;
-import net.minecraft.block.Block;
-import net.minecraft.block.state.IBlockState;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.WorldRenderer;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.BlockRenderLayer;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.world.World;
-import net.minecraftforge.client.ForgeHooksClient;
-import net.minecraftforge.client.MinecraftForgeClient;
-import net.minecraftforge.client.model.data.EmptyModelData;
-import org.lwjgl.opengl.GL11;
-
-import javax.annotation.Nonnull;
-import java.util.Random;
-
-/**
- * Render breaking animation only over part of a {@link TileCable}.
- */
-public class TileEntityCableRenderer extends TileEntityRenderer<TileCable>
-{
-    private static final Random random = new Random();
-
-    @Override
-    public void render( @Nonnull TileCable te, double x, double y, double z, float partialTicks, int destroyStage )
-    {
-        if( destroyStage < 0 ) return;
-
-        BlockPos pos = te.getPos();
-
-        Minecraft mc = Minecraft.getInstance();
-
-        RayTraceResult hit = mc.objectMouseOver;
-        if( hit == null || !hit.getBlockPos().equals( pos ) ) return;
-
-        if( MinecraftForgeClient.getRenderPass() != 0 ) return;
-
-        World world = te.getWorld();
-        IBlockState state = world.getBlockState( pos );
-        Block block = state.getBlock();
-        if( block != ComputerCraft.Blocks.cable ) return;
-
-        state = WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-            ? block.getDefaultState().with( BlockCable.MODEM, state.get( BlockCable.MODEM ) )
-            : state.with( BlockCable.MODEM, CableModemVariant.None );
-
-        IBakedModel model = mc.getBlockRendererDispatcher().getModelForState( state );
-
-        preRenderDamagedBlocks();
-
-        BufferBuilder buffer = Tessellator.getInstance().getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.BLOCK );
-        buffer.setTranslation( x - pos.getX(), y - pos.getY(), z - pos.getZ() );
-        buffer.noColor();
-
-        ForgeHooksClient.setRenderLayer( block.getRenderLayer() );
-
-        // See BlockRendererDispatcher#renderBlockDamage
-        TextureAtlasSprite breakingTexture = mc.getTextureMap().getSprite( DESTROY_STAGES[destroyStage] );
-        mc.getBlockRendererDispatcher().getBlockModelRenderer().renderModel(
-            world,
-            ForgeHooksClient.getDamageModel( model, breakingTexture, state, world, pos ),
-            state, pos, buffer, true, random, state.getPositionRandom( pos ), EmptyModelData.INSTANCE
-        );
-
-        ForgeHooksClient.setRenderLayer( BlockRenderLayer.SOLID );
-
-        buffer.setTranslation( 0, 0, 0 );
-        Tessellator.getInstance().draw();
-
-        postRenderDamagedBlocks();
-    }
-
-    /**
-     * @see WorldRenderer#preRenderDamagedBlocks()
-     */
-    private void preRenderDamagedBlocks()
-    {
-        GlStateManager.disableLighting();
-
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.DST_COLOR, GlStateManager.DestFactor.SRC_COLOR, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
-        GlStateManager.enableBlend();
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 0.5F );
-        GlStateManager.polygonOffset( -3.0F, -3.0F );
-        GlStateManager.enablePolygonOffset();
-        GlStateManager.alphaFunc( 516, 0.1F );
-        GlStateManager.enableAlphaTest();
-        GlStateManager.pushMatrix();
-    }
-
-    /**
-     * @see WorldRenderer#postRenderDamagedBlocks()
-     */
-    private void postRenderDamagedBlocks()
-    {
-        GlStateManager.disableAlphaTest();
-        GlStateManager.polygonOffset( 0.0F, 0.0F );
-        GlStateManager.disablePolygonOffset();
-        GlStateManager.disablePolygonOffset();
-        GlStateManager.depthMask( true );
-        GlStateManager.popMatrix();
-    }
-}

src/main/java/dan200/computercraft/client/render/TileEntityMonitorRenderer.java

@@ -1,48 +1,72 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.getColour;
+
+import java.nio.ByteBuffer;
+
+import javax.annotation.Nonnull;
+
+import com.mojang.blaze3d.platform.GlStateManager;
 import dan200.computercraft.client.FrameInfo;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
+import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
 import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
 import dan200.computercraft.shared.util.Colour;
 import dan200.computercraft.shared.util.DirectionUtil;
-import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.OpenGlHelper;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.math.BlockPos;
 import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL31;
 
-public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
-{
-    @Override
-    public void render( TileMonitor tileEntity, double posX, double posY, double posZ, float f, int i )
-    {
-        if( tileEntity != null )
-        {
-            renderMonitorAt( tileEntity, posX, posY, posZ, f, i );
-        }
+import net.minecraft.client.gl.VertexBuffer;
+import net.minecraft.client.render.BufferBuilder;
+import net.minecraft.client.render.Tessellator;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.VertexFormats;
+import net.minecraft.client.render.block.entity.BlockEntityRenderDispatcher;
+import net.minecraft.client.render.block.entity.BlockEntityRenderer;
+import net.minecraft.client.util.GlAllocationUtils;
+import net.minecraft.client.util.math.AffineTransformation;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Matrix4f;
+
+public class TileEntityMonitorRenderer extends BlockEntityRenderer<TileMonitor> {
+    /**
+     * {@link TileMonitor#RENDER_MARGIN}, but a tiny bit of additional padding to ensure that there is no space between the monitor frame and contents.
+     */
+    private static final float MARGIN = (float) (TileMonitor.RENDER_MARGIN * 1.1);
+    private static final Matrix4f IDENTITY = AffineTransformation.identity()
+                                                                 .getMatrix();
+    private static ByteBuffer tboContents;
+
+    public TileEntityMonitorRenderer(BlockEntityRenderDispatcher rendererDispatcher) {
+        super(rendererDispatcher);
     }
 
-    private static void renderMonitorAt( TileMonitor monitor, double posX, double posY, double posZ, float f, int i )
-    {
+    @Override
+    public void render(@Nonnull TileMonitor monitor, float partialTicks, @Nonnull MatrixStack transform, @Nonnull VertexConsumerProvider renderer,
+                       int lightmapCoord, int overlayLight) {
         // Render from the origin monitor
         ClientMonitor originTerminal = monitor.getClientMonitor();
 
-        if( originTerminal == null ) return;
+        if (originTerminal == null) {
+            return;
+        }
         TileMonitor origin = originTerminal.getOrigin();
         BlockPos monitorPos = monitor.getPos();
 
@@ -50,8 +74,7 @@ public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
         // multiple times in a single frame to ensure compatibility with shaders which may run a
         // pass multiple times.
         long renderFrame = FrameInfo.getRenderFrame();
-        if( originTerminal.lastRenderFrame == renderFrame && !monitorPos.equals( originTerminal.lastRenderPos ) )
-        {
+        if (originTerminal.lastRenderFrame == renderFrame && !monitorPos.equals(originTerminal.lastRenderPos)) {
             return;
         }
 
@@ -59,234 +82,170 @@ public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
         originTerminal.lastRenderPos = monitorPos;
 
         BlockPos originPos = origin.getPos();
-        posX += originPos.getX() - monitorPos.getX();
-        posY += originPos.getY() - monitorPos.getY();
-        posZ += originPos.getZ() - monitorPos.getZ();
 
         // Determine orientation
-        EnumFacing dir = origin.getDirection();
-        EnumFacing front = origin.getFront();
-        float yaw = dir.getHorizontalAngle();
-        float pitch = DirectionUtil.toPitchAngle( front );
+        Direction dir = origin.getDirection();
+        Direction front = origin.getFront();
+        float yaw = dir.asRotation();
+        float pitch = DirectionUtil.toPitchAngle(front);
 
-        GlStateManager.pushMatrix();
-        try
-        {
-            // Setup initial transform
-            GlStateManager.translated( posX + 0.5, posY + 0.5, posZ + 0.5 );
-            GlStateManager.rotatef( -yaw, 0.0f, 1.0f, 0.0f );
-            GlStateManager.rotatef( pitch, 1.0f, 0.0f, 0.0f );
-            GlStateManager.translated(
-                -0.5 + TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN,
-                origin.getHeight() - 0.5 - (TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN) + 0,
-                0.5
-            );
-            double xSize = origin.getWidth() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
-            double ySize = origin.getHeight() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
+        // Setup initial transform
+        transform.push();
+        transform.translate(originPos.getX() - monitorPos.getX() + 0.5,
+                            originPos.getY() - monitorPos.getY() + 0.5,
+                            originPos.getZ() - monitorPos.getZ() + 0.5);
 
-            // Get renderers
-            Minecraft mc = Minecraft.getInstance();
-            Tessellator tessellator = Tessellator.getInstance();
-            BufferBuilder renderer = tessellator.getBuffer();
+        transform.multiply(Vector3f.NEGATIVE_Y.getDegreesQuaternion(yaw));
+        transform.multiply(Vector3f.POSITIVE_X.getDegreesQuaternion(pitch));
+        transform.translate(-0.5 + TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN,
+                            origin.getHeight() - 0.5 - (TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN) + 0,
+                            0.5);
+        double xSize = origin.getWidth() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
+        double ySize = origin.getHeight() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
 
-            // Get terminal
-            boolean redraw = originTerminal.pollTerminalChanged();
+        // Draw the contents
+        Terminal terminal = originTerminal.getTerminal();
+        if (terminal != null) {
+            // Draw a terminal
+            int width = terminal.getWidth(), height = terminal.getHeight();
+            int pixelWidth = width * FONT_WIDTH, pixelHeight = height * FONT_HEIGHT;
+            double xScale = xSize / pixelWidth;
+            double yScale = ySize / pixelHeight;
+            transform.push();
+            transform.scale((float) xScale, (float) -yScale, 1.0f);
 
-            // Draw the contents
-            GlStateManager.depthMask( false );
-            OpenGlHelper.glMultiTexCoord2f( OpenGlHelper.GL_TEXTURE1, 0xFFFF, 0xFFFF );
-            GlStateManager.disableLighting();
-            mc.gameRenderer.disableLightmap();
-            try
-            {
-                Terminal terminal = originTerminal.getTerminal();
-                if( terminal != null )
-                {
-                    Palette palette = terminal.getPalette();
+            Matrix4f matrix = transform.peek()
+                                       .getModel();
 
-                    // Allocate display lists
-                    if( originTerminal.renderDisplayLists == null )
-                    {
-                        originTerminal.createLists();
-                        redraw = true;
-                    }
+            // Sneaky hack here: we get a buffer now in order to flush existing ones and set up the appropriate
+            // render state. I've no clue how well this'll work in future versions of Minecraft, but it does the trick
+            // for now.
+            VertexConsumer buffer = renderer.getBuffer(FixedWidthFontRenderer.TYPE);
+            FixedWidthFontRenderer.TYPE.startDrawing();
 
-                    // Draw a terminal
-                    boolean greyscale = !originTerminal.isColour();
-                    int width = terminal.getWidth();
-                    int height = terminal.getHeight();
-                    int cursorX = terminal.getCursorX();
-                    int cursorY = terminal.getCursorY();
-                    FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
+            renderTerminal(matrix, originTerminal, (float) (MARGIN / xScale), (float) (MARGIN / yScale));
 
-                    GlStateManager.pushMatrix();
-                    try
-                    {
-                        double xScale = xSize / (width * FixedWidthFontRenderer.FONT_WIDTH);
-                        double yScale = ySize / (height * FixedWidthFontRenderer.FONT_HEIGHT);
-                        GlStateManager.scaled( xScale, -yScale, 1.0 );
+            // We don't draw the cursor with the VBO, as it's dynamic and so we'll end up refreshing far more than is
+            // reasonable.
+            FixedWidthFontRenderer.drawCursor(matrix, buffer, 0, 0, terminal, !originTerminal.isColour());
 
-                        // Draw background
-                        mc.getTextureManager().bindTexture( FixedWidthFontRenderer.BACKGROUND );
-                        if( redraw )
-                        {
-                            // Build background display list
-                            GlStateManager.newList( originTerminal.renderDisplayLists[0], GL11.GL_COMPILE );
-                            try
-                            {
-                                double marginXSize = TileMonitor.RENDER_MARGIN / xScale;
-                                double marginYSize = TileMonitor.RENDER_MARGIN / yScale;
-                                double marginSquash = marginYSize / FixedWidthFontRenderer.FONT_HEIGHT;
-
-                                // Top and bottom margins
-                                GlStateManager.pushMatrix();
-                                try
-                                {
-                                    GlStateManager.scaled( 1.0, marginSquash, 1.0 );
-                                    GlStateManager.translated( 0.0, -marginYSize / marginSquash, 0.0 );
-                                    fontRenderer.drawStringBackgroundPart( 0, 0, terminal.getBackgroundColourLine( 0 ), marginXSize, marginXSize, greyscale, palette );
-                                    GlStateManager.translated( 0.0, (marginYSize + height * FixedWidthFontRenderer.FONT_HEIGHT) / marginSquash, 0.0 );
-                                    fontRenderer.drawStringBackgroundPart( 0, 0, terminal.getBackgroundColourLine( height - 1 ), marginXSize, marginXSize, greyscale, palette );
-                                }
-                                finally
-                                {
-                                    GlStateManager.popMatrix();
-                                }
-
-                                // Backgrounds
-                                for( int y = 0; y < height; y++ )
-                                {
-                                    fontRenderer.drawStringBackgroundPart(
-                                        0, FixedWidthFontRenderer.FONT_HEIGHT * y,
-                                        terminal.getBackgroundColourLine( y ),
-                                        marginXSize, marginXSize,
-                                        greyscale,
-                                        palette
-                                    );
-                                }
-                            }
-                            finally
-                            {
-                                GlStateManager.endList();
-                            }
-                        }
-                        GlStateManager.callList( originTerminal.renderDisplayLists[0] );
-                        GlStateManager.resetColor();
-
-                        // Draw text
-                        fontRenderer.bindFont();
-                        if( redraw )
-                        {
-                            // Build text display list
-                            GlStateManager.newList( originTerminal.renderDisplayLists[1], GL11.GL_COMPILE );
-                            try
-                            {
-                                // Lines
-                                for( int y = 0; y < height; y++ )
-                                {
-                                    fontRenderer.drawStringTextPart(
-                                        0, FixedWidthFontRenderer.FONT_HEIGHT * y,
-                                        terminal.getLine( y ),
-                                        terminal.getTextColourLine( y ),
-                                        greyscale,
-                                        palette
-                                    );
-                                }
-                            }
-                            finally
-                            {
-                                GlStateManager.endList();
-                            }
-                        }
-                        GlStateManager.callList( originTerminal.renderDisplayLists[1] );
-                        GlStateManager.resetColor();
-
-                        // Draw cursor
-                        fontRenderer.bindFont();
-                        if( redraw )
-                        {
-                            // Build cursor display list
-                            GlStateManager.newList( originTerminal.renderDisplayLists[2], GL11.GL_COMPILE );
-                            try
-                            {
-                                // Cursor
-                                if( terminal.getCursorBlink() && cursorX >= 0 && cursorX < width && cursorY >= 0 && cursorY < height )
-                                {
-                                    TextBuffer cursor = new TextBuffer( "_" );
-                                    TextBuffer cursorColour = new TextBuffer( "0123456789abcdef".charAt( terminal.getTextColour() ), 1 );
-                                    fontRenderer.drawString(
-                                        cursor,
-                                        FixedWidthFontRenderer.FONT_WIDTH * cursorX,
-                                        FixedWidthFontRenderer.FONT_HEIGHT * cursorY,
-                                        cursorColour, null,
-                                        0, 0,
-                                        greyscale,
-                                        palette
-                                    );
-                                }
-                            }
-                            finally
-                            {
-                                GlStateManager.endList();
-                            }
-                        }
-                        if( FrameInfo.getGlobalCursorBlink() )
-                        {
-                            GlStateManager.callList( originTerminal.renderDisplayLists[2] );
-                            GlStateManager.resetColor();
-                        }
-                    }
-                    finally
-                    {
-                        GlStateManager.popMatrix();
-                    }
-                }
-                else
-                {
-                    // Draw a big black quad
-                    mc.getTextureManager().bindTexture( FixedWidthFontRenderer.BACKGROUND );
-                    final Colour colour = Colour.Black;
-
-                    final float r = colour.getR();
-                    final float g = colour.getG();
-                    final float b = colour.getB();
-
-                    renderer.begin( GL11.GL_TRIANGLE_STRIP, DefaultVertexFormats.POSITION_TEX_COLOR );
-                    renderer.pos( -TileMonitor.RENDER_MARGIN, TileMonitor.RENDER_MARGIN, 0.0D ).tex( 0.0, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-                    renderer.pos( -TileMonitor.RENDER_MARGIN, -ySize - TileMonitor.RENDER_MARGIN, 0.0 ).tex( 0.0, 1.0 ).color( r, g, b, 1.0f ).endVertex();
-                    renderer.pos( xSize + TileMonitor.RENDER_MARGIN, TileMonitor.RENDER_MARGIN, 0.0D ).tex( 1.0, 0.0 ).color( r, g, b, 1.0f ).endVertex();
-                    renderer.pos( xSize + TileMonitor.RENDER_MARGIN, -ySize - TileMonitor.RENDER_MARGIN, 0.0 ).tex( 1.0, 1.0 ).color( r, g, b, 1.0f ).endVertex();
-                    tessellator.draw();
-                }
-            }
-            finally
-            {
-                GlStateManager.depthMask( true );
-                mc.gameRenderer.enableLightmap();
-                GlStateManager.enableLighting();
-            }
-
-            // Draw the depth blocker
-            GlStateManager.colorMask( false, false, false, false );
-            try
-            {
-                mc.getTextureManager().bindTexture( FixedWidthFontRenderer.BACKGROUND );
-                renderer.begin( GL11.GL_TRIANGLE_STRIP, DefaultVertexFormats.POSITION );
-                renderer.pos( -TileMonitor.RENDER_MARGIN, TileMonitor.RENDER_MARGIN, 0.0 ).endVertex();
-                renderer.pos( -TileMonitor.RENDER_MARGIN, -ySize - TileMonitor.RENDER_MARGIN, 0.0 ).endVertex();
-                renderer.pos( xSize + TileMonitor.RENDER_MARGIN, TileMonitor.RENDER_MARGIN, 0.0 ).endVertex();
-                renderer.pos( xSize + TileMonitor.RENDER_MARGIN, -ySize - TileMonitor.RENDER_MARGIN, 0.0 ).endVertex();
-                tessellator.draw();
-            }
-            finally
-            {
-                GlStateManager.colorMask( true, true, true, true );
-            }
+            transform.pop();
+        } else {
+            FixedWidthFontRenderer.drawEmptyTerminal(transform.peek()
+                                                              .getModel(),
+                                                     renderer,
+                                                     -MARGIN,
+                                                     MARGIN,
+                                                     (float) (xSize + 2 * MARGIN),
+                                                     (float) -(ySize + MARGIN * 2));
+        }
+
+        FixedWidthFontRenderer.drawBlocker(transform.peek()
+                                                    .getModel(),
+                                           renderer,
+                                           (float) -TileMonitor.RENDER_MARGIN,
+                                           (float) TileMonitor.RENDER_MARGIN,
+                                           (float) (xSize + 2 * TileMonitor.RENDER_MARGIN),
+                                           (float) -(ySize + TileMonitor.RENDER_MARGIN * 2));
+
+        transform.pop();
+    }
+
+    private static void renderTerminal(Matrix4f matrix, ClientMonitor monitor, float xMargin, float yMargin) {
+        Terminal terminal = monitor.getTerminal();
+
+        MonitorRenderer renderType = MonitorRenderer.current();
+        boolean redraw = monitor.pollTerminalChanged();
+        if (monitor.createBuffer(renderType)) {
+            redraw = true;
+        }
+
+        switch (renderType) {
+        case TBO: {
+            if (!MonitorTextureBufferShader.use()) {
+                return;
+            }
+
+            int width = terminal.getWidth(), height = terminal.getHeight();
+            int pixelWidth = width * FONT_WIDTH, pixelHeight = height * FONT_HEIGHT;
+
+            if (redraw) {
+                int size = width * height * 3;
+                if (tboContents == null || tboContents.capacity() < size) {
+                    tboContents = GlAllocationUtils.allocateByteBuffer(size);
+                }
+
+                ByteBuffer monitorBuffer = tboContents;
+                monitorBuffer.clear();
+                for (int y = 0; y < height; y++) {
+                    TextBuffer text = terminal.getLine(y), textColour = terminal.getTextColourLine(y), background = terminal.getBackgroundColourLine(y);
+                    for (int x = 0; x < width; x++) {
+                        monitorBuffer.put((byte) (text.charAt(x) & 0xFF));
+                        monitorBuffer.put((byte) getColour(textColour.charAt(x), Colour.WHITE));
+                        monitorBuffer.put((byte) getColour(background.charAt(x), Colour.BLACK));
+                    }
+                }
+                monitorBuffer.flip();
+
+                GlStateManager.bindBuffers(GL31.GL_TEXTURE_BUFFER, monitor.tboBuffer);
+                GlStateManager.bufferData(GL31.GL_TEXTURE_BUFFER, monitorBuffer, GL20.GL_STATIC_DRAW);
+                GlStateManager.bindBuffers(GL31.GL_TEXTURE_BUFFER, 0);
+            }
+
+            // Nobody knows what they're doing!
+            GlStateManager.activeTexture(MonitorTextureBufferShader.TEXTURE_INDEX);
+            GL11.glBindTexture(GL31.GL_TEXTURE_BUFFER, monitor.tboTexture);
+            GlStateManager.activeTexture(GL13.GL_TEXTURE0);
+
+            MonitorTextureBufferShader.setupUniform(matrix, width, height, terminal.getPalette(), !monitor.isColour());
+
+            Tessellator tessellator = Tessellator.getInstance();
+            BufferBuilder buffer = tessellator.getBuffer();
+            buffer.begin(GL11.GL_TRIANGLE_STRIP, VertexFormats.POSITION);
+            buffer.vertex(-xMargin, -yMargin, 0)
+                  .next();
+            buffer.vertex(-xMargin, pixelHeight + yMargin, 0)
+                  .next();
+            buffer.vertex(pixelWidth + xMargin, -yMargin, 0)
+                  .next();
+            buffer.vertex(pixelWidth + xMargin, pixelHeight + yMargin, 0)
+                  .next();
+            tessellator.draw();
+
+            GlStateManager.useProgram(0);
+            break;
+        }
+
+        case VBO: {
+            VertexBuffer vbo = monitor.buffer;
+            if (redraw) {
+                Tessellator tessellator = Tessellator.getInstance();
+                BufferBuilder builder = tessellator.getBuffer();
+                builder.begin(FixedWidthFontRenderer.TYPE.getDrawMode(), FixedWidthFontRenderer.TYPE.getVertexFormat());
+                FixedWidthFontRenderer.drawTerminalWithoutCursor(IDENTITY,
+                                                                 builder,
+                                                                 0,
+                                                                 0,
+                                                                 terminal,
+                                                                 !monitor.isColour(),
+                                                                 yMargin,
+                                                                 yMargin,
+                                                                 xMargin,
+                                                                 xMargin);
+
+                builder.end();
+                vbo.upload(builder);
+            }
+
+            vbo.bind();
+            FixedWidthFontRenderer.TYPE.getVertexFormat()
+                                       .startDrawing(0L);
+            vbo.draw(matrix, FixedWidthFontRenderer.TYPE.getDrawMode());
+            VertexBuffer.unbind();
+            FixedWidthFontRenderer.TYPE.getVertexFormat()
+                                       .endDrawing();
+            break;
         }
-        finally
-        {
-            GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-            GlStateManager.popMatrix();
         }
     }
 }

src/main/java/dan200/computercraft/client/render/TileEntityTurtleRenderer.java

@@ -1,11 +1,17 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
+import java.util.List;
+import java.util.Random;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -13,222 +19,198 @@ import dan200.computercraft.shared.turtle.blocks.TileTurtle;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.Holiday;
 import dan200.computercraft.shared.util.HolidayUtil;
-import net.minecraft.block.state.IBlockState;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GameRenderer;
-import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.model.BakedQuad;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.ModelManager;
-import net.minecraft.client.renderer.model.ModelResourceLocation;
-import net.minecraft.client.renderer.texture.TextureMap;
-import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.client.renderer.vertex.VertexFormat;
-import net.minecraft.util.EnumFacing;
-import net.minecraft.util.ResourceLocation;
+
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.font.TextRenderer;
+import net.minecraft.client.render.TexturedRenderLayers;
+import net.minecraft.client.render.VertexConsumer;
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.block.entity.BlockEntityRenderDispatcher;
+import net.minecraft.client.render.block.entity.BlockEntityRenderer;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.BakedModelManager;
+import net.minecraft.client.render.model.BakedQuad;
+import net.minecraft.client.util.ModelIdentifier;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.hit.BlockHitResult;
+import net.minecraft.util.hit.HitResult;
+import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Matrix4f;
 import net.minecraft.util.math.Vec3d;
-import net.minecraftforge.client.ForgeHooksClient;
-import net.minecraftforge.client.model.data.EmptyModelData;
-import net.minecraftforge.client.model.pipeline.LightUtil;
-import org.apache.commons.lang3.tuple.Pair;
-import org.lwjgl.opengl.GL11;
 
-import javax.vecmath.Matrix4f;
-import java.util.List;
-import java.util.Random;
+public class TileEntityTurtleRenderer extends BlockEntityRenderer<TileTurtle> {
+    private static final ModelIdentifier NORMAL_TURTLE_MODEL = new ModelIdentifier("computercraft:turtle_normal", "inventory");
+    private static final ModelIdentifier ADVANCED_TURTLE_MODEL = new ModelIdentifier("computercraft:turtle_advanced", "inventory");
+    private static final ModelIdentifier COLOUR_TURTLE_MODEL = new ModelIdentifier("computercraft:turtle_colour", "inventory");
+    private static final ModelIdentifier ELF_OVERLAY_MODEL = new ModelIdentifier("computercraft:turtle_elf_overlay", "inventory");
 
-public class TileEntityTurtleRenderer extends TileEntityRenderer<TileTurtle>
-{
-    private static final ModelResourceLocation NORMAL_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_normal", "inventory" );
-    private static final ModelResourceLocation ADVANCED_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_advanced", "inventory" );
-    private static final ModelResourceLocation COLOUR_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_colour", "inventory" );
-    private static final ModelResourceLocation ELF_OVERLAY_MODEL = new ModelResourceLocation( "computercraft:turtle_elf_overlay", "inventory" );
+    private final Random random = new Random(0);
 
-    @Override
-    public void render( TileTurtle tileEntity, double posX, double posY, double posZ, float partialTicks, int breaking )
-    {
-        if( tileEntity != null ) renderTurtleAt( tileEntity, posX, posY, posZ, partialTicks );
+    public TileEntityTurtleRenderer(BlockEntityRenderDispatcher renderDispatcher) {
+        super(renderDispatcher);
     }
 
-    public static ModelResourceLocation getTurtleModel( ComputerFamily family, boolean coloured )
-    {
-        switch( family )
-        {
-            case Normal:
-            default:
-                return coloured ? COLOUR_TURTLE_MODEL : NORMAL_TURTLE_MODEL;
-            case Advanced:
-                return coloured ? COLOUR_TURTLE_MODEL : ADVANCED_TURTLE_MODEL;
+    public static ModelIdentifier getTurtleModel(ComputerFamily family, boolean coloured) {
+        switch (family) {
+        case NORMAL:
+        default:
+            return coloured ? COLOUR_TURTLE_MODEL : NORMAL_TURTLE_MODEL;
+        case ADVANCED:
+            return coloured ? COLOUR_TURTLE_MODEL : ADVANCED_TURTLE_MODEL;
         }
     }
 
-    public static ModelResourceLocation getTurtleOverlayModel( ResourceLocation overlay, boolean christmas )
-    {
-        if( overlay != null )
-        {
-            return new ModelResourceLocation( overlay, "inventory" );
+    public static ModelIdentifier getTurtleOverlayModel(Identifier overlay, boolean christmas) {
+        if (overlay != null) {
+            return new ModelIdentifier(overlay, "inventory");
         }
-        else if( christmas )
-        {
+        if (christmas) {
             return ELF_OVERLAY_MODEL;
         }
-        else
-        {
-            return null;
+        return null;
+    }
+
+    private static void renderQuads(@Nonnull MatrixStack transform, @Nonnull VertexConsumer buffer, int lightmapCoord, int overlayLight,
+                                    List<BakedQuad> quads, int[] tints) {
+        MatrixStack.Entry matrix = transform.peek();
+
+        for (BakedQuad bakedquad : quads) {
+            int tint = -1;
+            if (tints != null && bakedquad.hasColor()) {
+                int idx = bakedquad.getColorIndex();
+                if (idx >= 0 && idx < tints.length) {
+                    tint = tints[bakedquad.getColorIndex()];
+                }
+            }
+
+            float f = (float) (tint >> 16 & 255) / 255.0F;
+            float f1 = (float) (tint >> 8 & 255) / 255.0F;
+            float f2 = (float) (tint & 255) / 255.0F;
+            buffer.quad(matrix,
+                        bakedquad,
+                        new float[] {
+                            1.0F,
+                            1.0F,
+                            1.0F,
+                            1.0F
+                        },
+                        f,
+                        f1,
+                        f2,
+                        new int[] {
+                            lightmapCoord,
+                            lightmapCoord,
+                            lightmapCoord,
+                            lightmapCoord
+                        },
+                        overlayLight,
+                        true);
         }
     }
 
-    private void renderTurtleAt( TileTurtle turtle, double posX, double posY, double posZ, float partialTicks )
-    {
+    @Override
+    public void render(@Nonnull TileTurtle turtle, float partialTicks, @Nonnull MatrixStack transform, @Nonnull VertexConsumerProvider renderer,
+                       int lightmapCoord, int overlayLight) {
         // Render the label
-        String label = turtle.createProxy().getLabel();
-        if( label != null && rendererDispatcher.cameraHitResult != null && turtle.getPos().equals( rendererDispatcher.cameraHitResult.getBlockPos() ) )
-        {
-            setLightmapDisabled( true );
-            GameRenderer.drawNameplate(
-                getFontRenderer(), label,
-                (float) posX + 0.5F, (float) posY + 1.2F, (float) posZ + 0.5F, 0,
-                rendererDispatcher.entityYaw, rendererDispatcher.entityPitch, false, false
-            );
-            setLightmapDisabled( false );
+        String label = turtle.createProxy()
+                             .getLabel();
+        HitResult hit = this.dispatcher.crosshairTarget;
+        if (label != null && hit.getType() == HitResult.Type.BLOCK && turtle.getPos()
+                                                                            .equals(((BlockHitResult) hit).getBlockPos())) {
+            MinecraftClient mc = MinecraftClient.getInstance();
+            TextRenderer font = mc.textRenderer;
+
+            transform.push();
+            transform.translate(0.5, 1.2, 0.5);
+            transform.multiply(mc.getEntityRenderDispatcher()
+                                 .getRotation());
+            transform.scale(-0.025f, -0.025f, 0.025f);
+
+            Matrix4f matrix = transform.peek()
+                                       .getModel();
+            int opacity = (int) (mc.options.getTextBackgroundOpacity(0.25f) * 255) << 24;
+            float width = -font.getWidth(label) / 2.0f;
+            font.draw(label, width, (float) 0, 0x20ffffff, false, matrix, renderer, true, opacity, lightmapCoord);
+            font.draw(label, width, (float) 0, 0xffffffff, false, matrix, renderer, false, 0, lightmapCoord);
+
+            transform.pop();
         }
 
-        GlStateManager.pushMatrix();
-        try
-        {
-            IBlockState state = turtle.getBlockState();
-            // Setup the transform
-            Vec3d offset = turtle.getRenderOffset( partialTicks );
-            float yaw = turtle.getRenderYaw( partialTicks );
-            GlStateManager.translated( posX + offset.x, posY + offset.y, posZ + offset.z );
-            // Render the turtle
-            GlStateManager.translatef( 0.5f, 0.5f, 0.5f );
-            GlStateManager.rotatef( 180.0f - yaw, 0.0f, 1.0f, 0.0f );
-            if( label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" )) )
-            {
-                // Flip the model and swap the cull face as winding order will have changed.
-                GlStateManager.scalef( 1.0f, -1.0f, 1.0f );
-                GlStateManager.cullFace( GlStateManager.CullFace.FRONT );
-            }
-            GlStateManager.translatef( -0.5f, -0.5f, -0.5f );
-            // Render the turtle
-            int colour = turtle.getColour();
-            ComputerFamily family = turtle.getFamily();
-            ResourceLocation overlay = turtle.getOverlay();
+        transform.push();
 
-            renderModel( state, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
+        // Setup the transform.
+        Vec3d offset = turtle.getRenderOffset(partialTicks);
+        float yaw = turtle.getRenderYaw(partialTicks);
+        transform.translate(offset.x, offset.y, offset.z);
 
-            // Render the overlay
-            ModelResourceLocation overlayModel = getTurtleOverlayModel(
-                overlay,
-                HolidayUtil.getCurrentHoliday() == Holiday.Christmas
-            );
-            if( overlayModel != null )
-            {
-                GlStateManager.disableCull();
-                GlStateManager.enableBlend();
-                GlStateManager.blendFunc( GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA );
-                try
-                {
-                    renderModel( state, overlayModel, null );
-                }
-                finally
-                {
-                    GlStateManager.disableBlend();
-                    GlStateManager.enableCull();
-                }
-            }
-
-            // Render the upgrades
-            renderUpgrade( state, turtle, TurtleSide.Left, partialTicks );
-            renderUpgrade( state, turtle, TurtleSide.Right, partialTicks );
+        transform.translate(0.5f, 0.5f, 0.5f);
+        transform.multiply(Vector3f.POSITIVE_Y.getDegreesQuaternion(180.0f - yaw));
+        if (label != null && (label.equals("Dinnerbone") || label.equals("Grumm"))) {
+            // Flip the model
+            transform.scale(1.0f, -1.0f, 1.0f);
         }
-        finally
-        {
-            GlStateManager.popMatrix();
-            GlStateManager.cullFace( GlStateManager.CullFace.BACK );
+        transform.translate(-0.5f, -0.5f, -0.5f);
+
+        // Render the turtle
+        int colour = turtle.getColour();
+        ComputerFamily family = turtle.getFamily();
+        Identifier overlay = turtle.getOverlay();
+
+        VertexConsumer buffer = renderer.getBuffer(TexturedRenderLayers.getEntityTranslucentCull());
+        renderModel(transform, buffer, lightmapCoord, overlayLight, getTurtleModel(family, colour != -1), colour == -1 ? null : new int[] {colour});
+
+        // Render the overlay
+        ModelIdentifier overlayModel = getTurtleOverlayModel(overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS);
+        if (overlayModel != null) {
+            renderModel(transform, buffer, lightmapCoord, overlayLight, overlayModel, null);
         }
+
+        // Render the upgrades
+        renderUpgrade(transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks);
+        renderUpgrade(transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks);
+
+        transform.pop();
     }
 
-    private void renderUpgrade( IBlockState state, TileTurtle turtle, TurtleSide side, float f )
-    {
-        ITurtleUpgrade upgrade = turtle.getUpgrade( side );
-        if( upgrade != null )
-        {
-            GlStateManager.pushMatrix();
-            try
-            {
-                float toolAngle = turtle.getToolRenderAngle( side, f );
-                GlStateManager.translatef( 0.0f, 0.5f, 0.5f );
-                GlStateManager.rotatef( -toolAngle, 1.0f, 0.0f, 0.0f );
-                GlStateManager.translatef( 0.0f, -0.5f, -0.5f );
-
-                Pair<IBakedModel, Matrix4f> pair = upgrade.getModel( turtle.getAccess(), side );
-                if( pair != null )
-                {
-                    if( pair.getRight() != null )
-                    {
-                        ForgeHooksClient.multiplyCurrentGlMatrix( pair.getRight() );
-                    }
-                    if( pair.getLeft() != null )
-                    {
-                        renderModel( state, pair.getLeft(), null );
-                    }
-                }
-            }
-            finally
-            {
-                GlStateManager.popMatrix();
-            }
+    public static void renderUpgrade(@Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, TileTurtle turtle,
+                               TurtleSide side, float f) {
+        ITurtleUpgrade upgrade = turtle.getUpgrade(side);
+        if (upgrade == null) {
+            return;
         }
+        transform.push();
+
+        float toolAngle = turtle.getToolRenderAngle(side, f);
+        transform.translate(0.0f, 0.5f, 0.5f);
+        transform.multiply(Vector3f.NEGATIVE_X.getDegreesQuaternion(toolAngle));
+        transform.translate(0.0f, -0.5f, -0.5f);
+
+        TransformedModel model = upgrade.getModel(turtle.getAccess(), side);
+        model.push(transform);
+        TileEntityTurtleRenderer.renderModel(transform, renderer, lightmapCoord, overlayLight, model.getModel(), null);
+        transform.pop();
+
+        transform.pop();
     }
 
-    private void renderModel( IBlockState state, ModelResourceLocation modelLocation, int[] tints )
-    {
-        Minecraft mc = Minecraft.getInstance();
-        ModelManager modelManager = mc.getItemRenderer().getItemModelMesher().getModelManager();
-        renderModel( state, modelManager.getModel( modelLocation ), tints );
+    public static void renderModel(@Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight,
+                             ModelIdentifier modelLocation, int[] tints) {
+        BakedModelManager modelManager = MinecraftClient.getInstance()
+                                                        .getItemRenderer()
+                                                        .getModels()
+                                                        .getModelManager();
+        renderModel(transform, renderer, lightmapCoord, overlayLight, modelManager.getModel(modelLocation), tints);
     }
 
-    private void renderModel( IBlockState state, IBakedModel model, int[] tints )
-    {
-        Random random = new Random( 0 );
-        Tessellator tessellator = Tessellator.getInstance();
-        rendererDispatcher.textureManager.bindTexture( TextureMap.LOCATION_BLOCKS_TEXTURE );
-        renderQuads( tessellator, model.getQuads( state, null, random, EmptyModelData.INSTANCE ), tints );
-        for( EnumFacing facing : DirectionUtil.FACINGS )
-        {
-            renderQuads( tessellator, model.getQuads( state, facing, random, EmptyModelData.INSTANCE ), tints );
+    public static void renderModel(@Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, BakedModel model,
+                             int[] tints) {
+        Random random = new Random();
+        random.setSeed(0);
+        renderQuads(transform, renderer, lightmapCoord, overlayLight, model.getQuads(null, null, random), tints);
+        for (Direction facing : DirectionUtil.FACINGS) {
+            renderQuads(transform, renderer, lightmapCoord, overlayLight, model.getQuads(null, facing, random), tints);
         }
     }
-
-    private static void renderQuads( Tessellator tessellator, List<BakedQuad> quads, int[] tints )
-    {
-        BufferBuilder buffer = tessellator.getBuffer();
-        VertexFormat format = DefaultVertexFormats.ITEM;
-        buffer.begin( GL11.GL_QUADS, format );
-        for( BakedQuad quad : quads )
-        {
-            VertexFormat quadFormat = quad.getFormat();
-            if( quadFormat != format )
-            {
-                tessellator.draw();
-                format = quadFormat;
-                buffer.begin( GL11.GL_QUADS, format );
-            }
-
-            int colour = 0xFFFFFFFF;
-            if( quad.hasTintIndex() && tints != null )
-            {
-                int index = quad.getTintIndex();
-                if( index >= 0 && index < tints.length ) colour = tints[index] | 0xFF000000;
-            }
-
-            LightUtil.renderQuadColor( buffer, quad, colour );
-        }
-        tessellator.draw();
-    }
 }

src/main/java/dan200/computercraft/client/render/TurtleModelLoader.java

@@ -6,96 +6,89 @@
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.ComputerCraft;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.IUnbakedModel;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.vertex.VertexFormat;
-import net.minecraft.resources.IResourceManager;
-import net.minecraft.util.ResourceLocation;
-import net.minecraftforge.client.model.ICustomModelLoader;
-import net.minecraftforge.common.model.IModelState;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-public final class TurtleModelLoader implements ICustomModelLoader
-{
-    private static final ResourceLocation NORMAL_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_normal" );
-    private static final ResourceLocation ADVANCED_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_advanced" );
-    private static final ResourceLocation COLOUR_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_colour" );
+import javax.annotation.Nonnull;
 
+import com.mojang.datafixers.util.Pair;
+import dan200.computercraft.ComputerCraft;
+
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.ModelBakeSettings;
+import net.minecraft.client.render.model.ModelLoader;
+import net.minecraft.client.render.model.UnbakedModel;
+import net.minecraft.client.texture.Sprite;
+import net.minecraft.client.util.SpriteIdentifier;
+import net.minecraft.util.Identifier;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+@Environment (EnvType.CLIENT)
+public final class TurtleModelLoader {
     public static final TurtleModelLoader INSTANCE = new TurtleModelLoader();
+    private static final Identifier NORMAL_TURTLE_MODEL = new Identifier(ComputerCraft.MOD_ID, "block/turtle_normal");
+    private static final Identifier ADVANCED_TURTLE_MODEL = new Identifier(ComputerCraft.MOD_ID, "block/turtle_advanced");
+    private static final Identifier COLOUR_TURTLE_MODEL = new Identifier(ComputerCraft.MOD_ID, "block/turtle_colour");
 
-    private TurtleModelLoader()
-    {
+    private TurtleModelLoader() {
     }
 
-    @Override
-    public void onResourceManagerReload( @Nonnull IResourceManager manager )
-    {
-    }
-
-    @Override
-    public boolean accepts( @Nonnull ResourceLocation name )
-    {
-        return name.getNamespace().equals( ComputerCraft.MOD_ID )
-            && (name.getPath().equals( "item/turtle_normal" ) || name.getPath().equals( "item/turtle_advanced" ));
+    public boolean accepts(@Nonnull Identifier name) {
+        return name.getNamespace()
+                   .equals(ComputerCraft.MOD_ID) && (name.getPath()
+                                                         .equals("item/turtle_normal") || name.getPath()
+                                                                                              .equals("item/turtle_advanced"));
     }
 
     @Nonnull
-    @Override
-    public IUnbakedModel loadModel( @Nonnull ResourceLocation name )
-    {
-        if( name.getNamespace().equals( ComputerCraft.MOD_ID ) )
-        {
-            switch( name.getPath() )
-            {
-                case "item/turtle_normal":
-                    return new TurtleModel( NORMAL_TURTLE_MODEL );
-                case "item/turtle_advanced":
-                    return new TurtleModel( ADVANCED_TURTLE_MODEL );
+    public UnbakedModel loadModel(@Nonnull Identifier name) {
+        if (name.getNamespace()
+                .equals(ComputerCraft.MOD_ID)) {
+            switch (name.getPath()) {
+            case "item/turtle_normal":
+                return new TurtleModel(NORMAL_TURTLE_MODEL);
+            case "item/turtle_advanced":
+                return new TurtleModel(ADVANCED_TURTLE_MODEL);
             }
         }
 
-        throw new IllegalStateException( "Loader does not accept " + name );
+        throw new IllegalStateException("Loader does not accept " + name);
     }
 
-    private static final class TurtleModel implements IUnbakedModel
-    {
-        private final ResourceLocation family;
+    private static final class TurtleModel implements UnbakedModel {
+        private final Identifier family;
 
-        private TurtleModel( ResourceLocation family ) {this.family = family;}
+        private TurtleModel(Identifier family) {this.family = family;}
 
-        @Nonnull
         @Override
-        public Collection<ResourceLocation> getDependencies()
-        {
-            return Arrays.asList( family, COLOUR_TURTLE_MODEL );
+        public Collection<SpriteIdentifier> getTextureDependencies(Function<Identifier, UnbakedModel> modelGetter,
+                                                                   Set<Pair<String, String>> missingTextureErrors) {
+            return this.getModelDependencies()
+                       .stream()
+                       .flatMap(x -> modelGetter.apply(x)
+                                                .getTextureDependencies(modelGetter, missingTextureErrors)
+                                                .stream())
+                       .collect(Collectors.toSet());
         }
 
         @Nonnull
         @Override
-        public Collection<ResourceLocation> getTextures( @Nonnull Function<ResourceLocation, IUnbakedModel> modelGetter, @Nonnull Set<String> missingTextureErrors )
-        {
-            return getDependencies().stream()
-                .flatMap( x -> modelGetter.apply( x ).getTextures( modelGetter, missingTextureErrors ).stream() )
-                .collect( Collectors.toSet() );
+        public Collection<Identifier> getModelDependencies() {
+            return Arrays.asList(this.family, COLOUR_TURTLE_MODEL);
         }
 
-        @Nullable
         @Override
-        public IBakedModel bake( @Nonnull Function<ResourceLocation, IUnbakedModel> modelGetter, @Nonnull Function<ResourceLocation, TextureAtlasSprite> spriteGetter, @Nonnull IModelState state, boolean uvlock, @Nonnull VertexFormat format )
-        {
-            return new TurtleSmartItemModel(
-                modelGetter.apply( family ).bake( modelGetter, spriteGetter, state, uvlock, format ),
-                modelGetter.apply( COLOUR_TURTLE_MODEL ).bake( modelGetter, spriteGetter, state, uvlock, format )
-            );
+        public BakedModel bake(@Nonnull ModelLoader loader, @Nonnull Function<SpriteIdentifier, Sprite> spriteGetter, @Nonnull ModelBakeSettings state,
+                               Identifier modelId) {
+            return new TurtleSmartItemModel(loader.getOrLoadModel(this.family)
+                                                  .bake(loader, spriteGetter, state, modelId),
+                                            loader.getOrLoadModel(COLOUR_TURTLE_MODEL)
+                                                  .bake(loader, spriteGetter, state, modelId));
         }
     }
 }

src/main/java/dan200/computercraft/client/render/TurtleMultiModel.java

@@ -1,141 +1,129 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
 
 package dan200.computercraft.client.render;
 
-import net.minecraft.block.state.IBlockState;
-import net.minecraft.client.renderer.model.BakedQuad;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.ItemOverrideList;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.util.EnumFacing;
-import net.minecraftforge.client.model.data.EmptyModelData;
-import net.minecraftforge.client.model.data.IModelData;
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
 
 import javax.annotation.Nonnull;
-import javax.vecmath.Matrix4f;
-import java.util.*;
 
-public class TurtleMultiModel implements IBakedModel
-{
-    private final IBakedModel m_baseModel;
-    private final IBakedModel m_overlayModel;
-    private final Matrix4f m_generalTransform;
-    private final IBakedModel m_leftUpgradeModel;
-    private final Matrix4f m_leftUpgradeTransform;
-    private final IBakedModel m_rightUpgradeModel;
-    private final Matrix4f m_rightUpgradeTransform;
+import dan200.computercraft.api.client.TransformedModel;
+
+import net.minecraft.block.BlockState;
+import net.minecraft.client.render.model.BakedModel;
+import net.minecraft.client.render.model.BakedQuad;
+import net.minecraft.client.render.model.json.ModelOverrideList;
+import net.minecraft.client.texture.Sprite;
+import net.minecraft.client.util.math.AffineTransformation;
+import net.minecraft.util.math.Direction;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+@Environment (EnvType.CLIENT)
+public class TurtleMultiModel implements BakedModel {
+    private final BakedModel m_baseModel;
+    private final BakedModel m_overlayModel;
+    private final AffineTransformation m_generalTransform;
+    private final TransformedModel m_leftUpgradeModel;
+    private final TransformedModel m_rightUpgradeModel;
     private List<BakedQuad> m_generalQuads = null;
-    private Map<EnumFacing, List<BakedQuad>> m_faceQuads = new EnumMap<>( EnumFacing.class );
+    private Map<Direction, List<BakedQuad>> m_faceQuads = new EnumMap<>(Direction.class);
 
-    public TurtleMultiModel( IBakedModel baseModel, IBakedModel overlayModel, Matrix4f generalTransform, IBakedModel leftUpgradeModel, Matrix4f leftUpgradeTransform, IBakedModel rightUpgradeModel, Matrix4f rightUpgradeTransform )
-    {
+    public TurtleMultiModel(BakedModel baseModel, BakedModel overlayModel, AffineTransformation generalTransform, TransformedModel leftUpgradeModel,
+                            TransformedModel rightUpgradeModel) {
         // Get the models
-        m_baseModel = baseModel;
-        m_overlayModel = overlayModel;
-        m_leftUpgradeModel = leftUpgradeModel;
-        m_leftUpgradeTransform = leftUpgradeTransform;
-        m_rightUpgradeModel = rightUpgradeModel;
-        m_rightUpgradeTransform = rightUpgradeTransform;
-        m_generalTransform = generalTransform;
+        this.m_baseModel = baseModel;
+        this.m_overlayModel = overlayModel;
+        this.m_leftUpgradeModel = leftUpgradeModel;
+        this.m_rightUpgradeModel = rightUpgradeModel;
+        this.m_generalTransform = generalTransform;
     }
 
     @Nonnull
     @Override
-    @Deprecated
-    public List<BakedQuad> getQuads( IBlockState state, EnumFacing side, @Nonnull Random rand )
-    {
-        return getQuads( state, side, rand, EmptyModelData.INSTANCE );
-    }
-
-    @Nonnull
-    @Override
-    public List<BakedQuad> getQuads( IBlockState state, EnumFacing side, @Nonnull Random rand, @Nonnull IModelData data )
-    {
-        if( side != null )
-        {
-            if( !m_faceQuads.containsKey( side ) ) m_faceQuads.put( side, buildQuads( state, side, rand ) );
-            return m_faceQuads.get( side );
-        }
-        else
-        {
-            if( m_generalQuads == null ) m_generalQuads = buildQuads( state, side, rand );
-            return m_generalQuads;
+    public List<BakedQuad> getQuads(BlockState state, Direction side, @Nonnull Random rand) {
+        if (side != null) {
+            if (!this.m_faceQuads.containsKey(side)) {
+                this.m_faceQuads.put(side, this.buildQuads(state, side, rand));
+            }
+            return this.m_faceQuads.get(side);
+        } else {
+            if (this.m_generalQuads == null) {
+                this.m_generalQuads = this.buildQuads(state, side, rand);
+            }
+            return this.m_generalQuads;
         }
     }
 
-    private List<BakedQuad> buildQuads( IBlockState state, EnumFacing side, Random rand )
-    {
+    private List<BakedQuad> buildQuads(BlockState state, Direction side, Random rand) {
         ArrayList<BakedQuad> quads = new ArrayList<>();
-        ModelTransformer.transformQuadsTo( quads, m_baseModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
-        if( m_overlayModel != null )
-        {
-            ModelTransformer.transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
+
+
+        ModelTransformer.transformQuadsTo(quads, this.m_baseModel.getQuads(state, side, rand), this.m_generalTransform.getMatrix());
+        if (this.m_overlayModel != null) {
+            ModelTransformer.transformQuadsTo(quads, this.m_overlayModel.getQuads(state, side, rand), this.m_generalTransform.getMatrix());
         }
-        if( m_leftUpgradeModel != null )
-        {
-            Matrix4f upgradeTransform = m_generalTransform;
-            if( m_leftUpgradeTransform != null )
-            {
-                upgradeTransform = new Matrix4f( m_generalTransform );
-                upgradeTransform.mul( m_leftUpgradeTransform );
-            }
-            ModelTransformer.transformQuadsTo( quads, m_leftUpgradeModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
+        if (this.m_leftUpgradeModel != null) {
+            AffineTransformation upgradeTransform = this.m_generalTransform.multiply(this.m_leftUpgradeModel.getMatrix());
+            ModelTransformer.transformQuadsTo(quads, this.m_leftUpgradeModel.getModel()
+                                                                            .getQuads(state, side, rand),
+                                              upgradeTransform.getMatrix());
         }
-        if( m_rightUpgradeModel != null )
-        {
-            Matrix4f upgradeTransform = m_generalTransform;
-            if( m_rightUpgradeTransform != null )
-            {
-                upgradeTransform = new Matrix4f( m_generalTransform );
-                upgradeTransform.mul( m_rightUpgradeTransform );
-            }
-            ModelTransformer.transformQuadsTo( quads, m_rightUpgradeModel.getQuads( state, side, rand , EmptyModelData.INSTANCE), upgradeTransform );
+        if (this.m_rightUpgradeModel != null) {
+            AffineTransformation upgradeTransform = this.m_generalTransform.multiply(this.m_rightUpgradeModel.getMatrix());
+            ModelTransformer.transformQuadsTo(quads, this.m_rightUpgradeModel.getModel()
+                                                                             .getQuads(state, side, rand),
+                                              upgradeTransform.getMatrix());
         }
         quads.trimToSize();
         return quads;
     }
 
     @Override
-    public boolean isAmbientOcclusion()
-    {
-        return m_baseModel.isAmbientOcclusion();
+    public boolean useAmbientOcclusion() {
+        return this.m_baseModel.useAmbientOcclusion();
     }
 
     @Override
-    public boolean isGui3d()
-    {
-        return m_baseModel.isGui3d();
+    public boolean hasDepth() {
+        return this.m_baseModel.hasDepth();
     }
 
     @Override
-    public boolean isBuiltInRenderer()
-    {
-        return m_baseModel.isBuiltInRenderer();
+    public boolean isSideLit() {
+        return this.m_baseModel.isSideLit();
     }
 
-    @Nonnull
     @Override
-    public TextureAtlasSprite getParticleTexture()
-    {
-        return m_baseModel.getParticleTexture();
+    public boolean isBuiltin() {
+        return this.m_baseModel.isBuiltin();
     }
 
     @Nonnull
     @Override
     @Deprecated
-    public net.minecraft.client.renderer.model.ItemCameraTransforms getItemCameraTransforms()
-    {
-        return m_baseModel.getItemCameraTransforms();
+    public Sprite getSprite() {
+        return this.m_baseModel.getSprite();
     }
 
     @Nonnull
     @Override
-    public ItemOverrideList getOverrides()
-    {
-        return ItemOverrideList.EMPTY;
+    @Deprecated
+    public net.minecraft.client.render.model.json.ModelTransformation getTransformation() {
+        return this.m_baseModel.getTransformation();
+    }
+
+    @Nonnull
+    @Override
+    public ModelOverrideList getOverrides() {
+        return ModelOverrideList.EMPTY;
     }
 }

src/main/java/dan200/computercraft/client/render/TurtlePlayerRenderer.java

@@ -0,0 +1,40 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.client.render;
+
+import javax.annotation.Nonnull;
+
+import dan200.computercraft.shared.turtle.core.TurtlePlayer;
+
+import net.minecraft.client.render.VertexConsumerProvider;
+import net.minecraft.client.render.entity.EntityRenderDispatcher;
+import net.minecraft.client.render.entity.EntityRenderer;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.util.Identifier;
+
+import net.fabricmc.fabric.api.client.rendereregistry.v1.EntityRendererRegistry;
+
+public class TurtlePlayerRenderer extends EntityRenderer<TurtlePlayer> {
+    public TurtlePlayerRenderer(EntityRenderDispatcher renderManager) {
+        super(renderManager);
+    }
+
+    public TurtlePlayerRenderer(EntityRenderDispatcher entityRenderDispatcher, EntityRendererRegistry.Context context) {
+        super(entityRenderDispatcher);
+    }
+
+    @Override
+    public void render(@Nonnull TurtlePlayer entityIn, float entityYaw, float partialTicks, @Nonnull MatrixStack transform,
+                       @Nonnull VertexConsumerProvider buffer, int packedLightIn) {
+    }
+
+    @Nonnull
+    @Override
+    public Identifier getTexture(@Nonnull TurtlePlayer entity) {
+        return ComputerBorderRenderer.BACKGROUND_NORMAL;
+    }
+}