Merge branch 'mc-1.20.x' into mc-1.21.x

Ahhhh, I hate graphics code.

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -6,7 +6,8 @@ body:
   id: mc-version
   attributes:
     label: Minecraft Version
-    description: What version of Minecraft are you using?
+    description: |
+        What version of Minecraft are you using? If your version is not listed, please try to reproduce on one of the supported versions.
     options:
       - 1.20.1
       - 1.21.x
@@ -26,8 +27,5 @@ body:
     label: Details
     description: |
       Description of the bug. Please include the following:
-      - Logs: These will be located in the `logs/` directory of your Minecraft
-        instance. Please upload them as a gist or directly into this editor.
-      - Detailed reproduction steps: sometimes I can spot a bug pretty easily,
-        but often it's much more obscure. The more information I have to help
-        reproduce it, the quicker it'll get fixed.
+      - Logs: These will be located in the `logs/` directory of your Minecraft instance. This is always useful, even if it doesn't include errors, so please upload this!
+      - Detailed reproduction steps: sometimes I can spot a bug pretty easily, but often it's much more obscure. The more information I have to help reproduce it, the quicker it'll get fixed.

.github/workflows/main-ci.yml

@@ -30,8 +30,16 @@ jobs:
     - name: ⚒️ Build
       run: ./gradlew assemble || ./gradlew assemble
 
+    - name: Cache pre-commit
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pre-commit
+        key: pre-commit-3|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
+
     - name: 💡 Lint
-      uses: pre-commit/action@v3.0.0
+      run: |
+        pipx install pre-commit
+        pre-commit run --show-diff-on-failure --color=always
 
     - name: 🧪 Run tests
       run: ./gradlew test validateMixinNames checkChangelog
@@ -42,11 +50,6 @@ jobs:
     - name: 🧪 Run integration tests
       run: ./gradlew runGametest
 
-    - name: 🧪 Run client tests
-      run: ./gradlew runGametestClient # Not checkClient, as no point running rendering tests.
-      # These are a little flaky on GH actions: its useful to run them, but don't break the build.
-      continue-on-error: true
-
     - name: 🧪 Parse test reports
       run: ./tools/parse-reports.py
       if: ${{ failure() }}
@@ -63,9 +66,6 @@ jobs:
         name: CC-Tweaked
         path: ./jars
 
-    - name: 📤 Upload coverage
-      uses: codecov/codecov-action@v4
-
   build-core:
     strategy:
       fail-fast: false

.pre-commit-config.yaml

@@ -27,7 +27,7 @@ repos:
     exclude: "^(.*\\.(bat)|LICENSE)$"
 
 - repo: https://github.com/fsfe/reuse-tool
-  rev: v2.1.0
+  rev: v4.0.3
   hooks:
   - id: reuse
 

.reuse/dep5

@@ -1,100 +0,0 @@
-Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
-Source: https://github.com/cc-tweaked/cc-tweaked
-Upstream-Name: CC: Tweaked
-Upstream-Contact: Jonathan Coates <git@squiddev.cc>
-
-Files:
-  projects/common/src/main/resources/assets/computercraft/sounds.json
-  projects/common/src/main/resources/assets/computercraft/sounds/empty.ogg
-  projects/common/src/testMod/resources/data/cctest/computercraft/turtle_upgrade/*
-  projects/common/src/testMod/resources/data/cctest/structures/*
-  projects/*/src/generated/*
-  projects/web/src/htmlTransform/export/index.json
-  projects/web/src/htmlTransform/export/items/minecraft/*
-Comment: Generated/data files are CC0.
-Copyright: The CC: Tweaked Developers
-License: CC0-1.0
-
-Files:
-  doc/images/*
-  package.json
-  package-lock.json
-  projects/common/src/client/resources/computercraft-client.mixins.json
-  projects/common/src/main/resources/assets/minecraft/shaders/core/computercraft/monitor_tbo.json
-  projects/common/src/main/resources/computercraft.mixins.json
-  projects/common/src/testMod/resources/computercraft-gametest.mixins.json
-  projects/common/src/testMod/resources/data/computercraft/loot_tables/treasure_disk.json
-  projects/common/src/testMod/resources/pack.mcmeta
-  projects/core/src/main/resources/data/computercraft/lua/rom/modules/command/.ignoreme
-  projects/core/src/main/resources/data/computercraft/lua/rom/modules/main/.ignoreme
-  projects/core/src/main/resources/data/computercraft/lua/rom/modules/turtle/.ignoreme
-  projects/core/src/main/resources/data/computercraft/lua/rom/motd.txt
-  projects/fabric-api/src/main/modJson/fabric.mod.json
-  projects/fabric/src/client/resources/computercraft-client.fabric.mixins.json
-  projects/fabric/src/main/resources/computercraft.fabric.mixins.json
-  projects/fabric/src/main/resources/fabric.mod.json
-  projects/fabric/src/testMod/resources/computercraft-gametest.fabric.mixins.json
-  projects/fabric/src/testMod/resources/fabric.mod.json
-  projects/forge/src/client/resources/computercraft-client.forge.mixins.json
-  projects/forge/src/main/resources/computercraft.forge.mixins.json
-  projects/web/src/frontend/mount/.settings
-  projects/web/src/frontend/mount/example.nfp
-  projects/web/src/frontend/mount/example.nft
-  projects/web/src/frontend/mount/expr_template.lua
-  projects/web/tsconfig.json
-Comment: Several assets where it's inconvenient to create a .license file.
-Copyright: The CC: Tweaked Developers
-License: MPL-2.0
-
-Files:
-  doc/logo.png
-  doc/logo-darkmode.png
-  projects/common/src/main/resources/assets/computercraft/models/*
-  projects/common/src/main/resources/assets/computercraft/textures/*
-  projects/common/src/main/resources/pack.mcmeta
-  projects/common/src/main/resources/pack.png
-  projects/core/src/main/resources/assets/computercraft/textures/gui/term_font.png
-  projects/core/src/main/resources/data/computercraft/lua/rom/autorun/.ignoreme
-  projects/core/src/main/resources/data/computercraft/lua/rom/help/*
-  projects/core/src/main/resources/data/computercraft/lua/rom/programs/fun/advanced/levels/*
-  projects/web/src/htmlTransform/export/items/computercraft/*
-Comment: Bulk-license original assets as CCPL.
-Copyright: 2011 Daniel Ratcliffe
-License: LicenseRef-CCPL
-
-Files:
-  projects/common/src/main/resources/assets/computercraft/lang/cs_cz.json
-  projects/common/src/main/resources/assets/computercraft/lang/ko_kr.json
-  projects/common/src/main/resources/assets/computercraft/lang/pl_pl.json
-  projects/common/src/main/resources/assets/computercraft/lang/pt_br.json
-  projects/common/src/main/resources/assets/computercraft/lang/ru_ru.json
-  projects/common/src/main/resources/assets/computercraft/lang/uk_ua.json
-  projects/common/src/main/resources/assets/computercraft/lang/zh_cn.json
-Comment: Community-contributed license files
-Copyright: 2017 The CC: Tweaked Developers
-License: LicenseRef-CCPL
-
-Files:
-  projects/common/src/main/resources/assets/computercraft/lang/*
-Comment: Community-contributed license files
-Copyright: 2017 The CC: Tweaked Developers
-License: MPL-2.0
-
-Files:
-  .github/*
-Comment:
-  GitHub build scripts are CC0. While we could add a header to each file,
-  it's unclear if it will break actions or issue templates in some way.
-Copyright: Jonathan Coates <git@squiddev.cc>
-License: CC0-1.0
-
-Files:
-  gradle/wrapper/*
-  gradlew
-  gradlew.bat
-Copyright: Gradle Inc
-License: Apache-2.0
-
-Files: projects/core/src/test/resources/test-rom/data/json-parsing/*
-Copyright: 2016 Nicolas Seriot
-License: MIT

CONTRIBUTING.md

@@ -22,16 +22,16 @@ If you have a bug, suggestion, or other feedback, the best thing to do is [file
 use the issue templates - they provide a useful hint on what information to provide.
 
 ## Translations
-Translations are managed through [Weblate], an online interface for managing language strings. This is synced
-automatically with GitHub, so please don't submit PRs adding/changing translations!
+Translations are managed through [CrowdIn], an online interface for managing language strings. Translations may either
+be contributed there, or directly via a pull request.
 
 ## Setting up a development environment
 In order to develop CC: Tweaked, you'll need to download the source code and then run it.
 
  - Make sure you've got the following software installed:
-   - Java Development Kit (JDK). This can be downloaded from [Adoptium].
+   - Java Development Kit 21 (JDK). This can be downloaded from [Adoptium].
    - [Git](https://git-scm.com/).
-   - [NodeJS][node].
+   - [NodeJS 20 or later][node].
 
  - Download CC: Tweaked's source code:
    ```
@@ -101,10 +101,10 @@ about how you can build on that until you've covered everything!
 [community]: README.md#community "Get in touch with the community."
 [Adoptium]: https://adoptium.net/temurin/releases?version=17 "Download OpenJDK 17"
 [illuaminate]: https://github.com/SquidDev/illuaminate/ "Illuaminate on GitHub"
-[weblate]: https://i18n.tweaked.cc/projects/cc-tweaked/minecraft/ "CC: Tweaked weblate instance"
 [docs]: https://tweaked.cc/ "CC: Tweaked documentation"
 [ldoc]: http://stevedonovan.github.io/ldoc/ "ldoc, a Lua documentation generator."
 [mc-test]: https://www.youtube.com/watch?v=vXaWOJTCYNg
 [busted]: https://github.com/Olivine-Labs/busted "busted: Elegant Lua unit testing."
 [node]: https://nodejs.org/en/ "Node.js"
 [architecture]: projects/ARCHITECTURE.md
+[Crowdin]: https://crowdin.com/project/cc-tweaked/

README.md

@@ -11,14 +11,13 @@ SPDX-License-Identifier: MPL-2.0
 </picture>
 
 [![Current build status](https://github.com/cc-tweaked/CC-Tweaked/workflows/Build/badge.svg)](https://github.com/cc-tweaked/CC-Tweaked/actions "Current build status")
-[![Download CC: Tweaked on CurseForge](https://img.shields.io/static/v1?label=Download&message=CC:%20Tweaked&color=E04E14&logoColor=E04E14&logo=CurseForge)][CurseForge]
 [![Download CC: Tweaked on Modrinth](https://img.shields.io/static/v1?label=Download&color=00AF5C&logoColor=00AF5C&logo=Modrinth&message=CC:%20Tweaked)][Modrinth]
 
 CC: Tweaked is a mod for Minecraft which adds programmable computers, turtles and more to the game. A fork of the
 much-beloved [ComputerCraft], it continues its legacy with improved performance and stability, along with a wealth of
 new features.
 
-CC: Tweaked can be installed from [CurseForge] or [Modrinth]. It runs on both [Minecraft Forge] and [Fabric].
+CC: Tweaked can be installed from [Modrinth]. It runs on both [Minecraft Forge] and [Fabric].
 
 ## Contributing
 Any contribution is welcome, be that using the mod, reporting bugs or contributing code. If you want to get started
@@ -26,8 +25,9 @@ developing the mod, [check out the instructions here](CONTRIBUTING.md#developing
 
 ## Community
 If you need help getting started with CC: Tweaked, want to show off your latest project, or just want to chat about
-ComputerCraft, do check out our [forum] and [GitHub discussions page][GitHub discussions]! There's also a fairly
-populated, albeit quiet [IRC channel][irc], if that's more your cup of tea.
+ComputerCraft, do check out our [GitHub discussions page][GitHub discussions]! There's also a fairly populated,
+albeit quiet IRC channel on [EsperNet], if that's more your cup of tea. You can join `#computercraft` through your
+desktop client, or online using [KiwiIRC].
 
 We also host fairly comprehensive documentation at [tweaked.cc](https://tweaked.cc/ "The CC: Tweaked website").
 
@@ -81,10 +81,9 @@ We bundle the API sources with the jar, so documentation should be easily viewab
 the generated documentation [can be browsed online](https://tweaked.cc/javadoc/).
 
 [computercraft]: https://github.com/dan200/ComputerCraft "ComputerCraft on GitHub"
-[curseforge]: https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked from CurseForge"
 [modrinth]: https://modrinth.com/mod/gu7yAYhd "Download CC: Tweaked from Modrinth"
 [Minecraft Forge]: https://files.minecraftforge.net/ "Download Minecraft Forge."
 [Fabric]: https://fabricmc.net/use/installer/ "Download Fabric."
-[forum]: https://forums.computercraft.cc/
 [GitHub Discussions]: https://github.com/cc-tweaked/CC-Tweaked/discussions
-[IRC]: https://webchat.esper.net/?channels=computercraft "#computercraft on EsperNet"
+[EsperNet]: https://www.esper.net/
+[KiwiIRC]: https://kiwiirc.com/nextclient/#irc://irc.esper.net:+6697/#computercraft "#computercraft on EsperNet"

REUSE.toml

@@ -0,0 +1,111 @@
+# SPDX-FileCopyrightText: 2017 The CC: Tweaked Developers
+#
+# SPDX-License-Identifier: MPL-2.0
+
+version = 1
+SPDX-PackageName = "CC: Tweaked"
+SPDX-PackageSupplier = "Jonathan Coates <git@squiddev.cc>"
+SPDX-PackageDownloadLocation = "https://github.com/cc-tweaked/cc-tweaked"
+
+[[annotations]]
+# Generated/data files are CC0.
+SPDX-FileCopyrightText = "The CC: Tweaked Developers"
+SPDX-License-Identifier = "CC0-1.0"
+path = [
+    "gradle/gradle-daemon-jvm.properties",
+    "projects/common/src/main/resources/assets/computercraft/sounds.json",
+    "projects/common/src/main/resources/assets/computercraft/sounds/empty.ogg",
+    "projects/common/src/testMod/resources/data/cctest/computercraft/turtle_upgrade/**",
+    "projects/common/src/testMod/resources/data/cctest/structures/**",
+    "projects/**/src/generated/**",
+    "projects/web/src/htmlTransform/export/index.json",
+    "projects/web/src/htmlTransform/export/items/minecraft/**",
+]
+
+[[annotations]]
+# Several assets where it's inconvenient to create a .license file.
+SPDX-FileCopyrightText = "The CC: Tweaked Developers"
+SPDX-License-Identifier = "MPL-2.0"
+path = [
+    "doc/images/**",
+    "package.json",
+    "package-lock.json",
+    "projects/common/src/client/resources/computercraft-client.mixins.json",
+    "projects/common/src/main/resources/assets/minecraft/shaders/core/computercraft/monitor_tbo.json",
+    "projects/common/src/main/resources/computercraft.mixins.json",
+    "projects/common/src/testMod/resources/computercraft-gametest.mixins.json",
+    "projects/common/src/testMod/resources/data/computercraft/loot_tables/treasure_disk.json",
+    "projects/common/src/testMod/resources/pack.mcmeta",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/modules/command/.ignoreme",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/modules/main/.ignoreme",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/modules/turtle/.ignoreme",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/motd.txt",
+    "projects/fabric-api/src/main/modJson/fabric.mod.json",
+    "projects/fabric/src/client/resources/computercraft-client.fabric.mixins.json",
+    "projects/fabric/src/main/resources/computercraft.fabric.mixins.json",
+    "projects/fabric/src/main/resources/fabric.mod.json",
+    "projects/fabric/src/testMod/resources/computercraft-gametest.fabric.mixins.json",
+    "projects/fabric/src/testMod/resources/fabric.mod.json",
+    "projects/forge/src/client/resources/computercraft-client.forge.mixins.json",
+    "projects/forge/src/main/resources/computercraft.forge.mixins.json",
+    "projects/web/src/frontend/mount/.settings",
+    "projects/web/src/frontend/mount/example.nfp",
+    "projects/web/src/frontend/mount/example.nft",
+    "projects/web/src/frontend/mount/expr_template.lua",
+    "projects/web/tsconfig.json",
+]
+
+[[annotations]]
+# Bulk-license original assets as CCPL.
+SPDX-FileCopyrightText = "2011 Daniel Ratcliffe"
+SPDX-License-Identifier = "LicenseRef-CCPL"
+path = [
+    "doc/logo.png",
+    "doc/logo-darkmode.png",
+    "projects/common/src/main/resources/assets/computercraft/models/**",
+    "projects/common/src/main/resources/assets/computercraft/textures/**",
+    "projects/common/src/main/resources/pack.mcmeta",
+    "projects/common/src/main/resources/pack.png",
+    "projects/core/src/main/resources/assets/computercraft/textures/gui/term_font.png",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/autorun/.ignoreme",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/help/**",
+    "projects/core/src/main/resources/data/computercraft/lua/rom/programs/fun/advanced/levels/**",
+    "projects/web/src/htmlTransform/export/items/computercraft/**",
+]
+
+[[annotations]]
+# Community-contributed license files
+SPDX-FileCopyrightText = "2017 The CC: Tweaked Developers"
+SPDX-License-Identifier = "LicenseRef-CCPL"
+path = [
+    "projects/common/src/main/resources/assets/computercraft/lang/cs_cz.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/ko_kr.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/pl_pl.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/pt_br.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/ru_ru.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/uk_ua.json",
+    "projects/common/src/main/resources/assets/computercraft/lang/zh_cn.json",
+]
+
+[[annotations]]
+# Community-contributed license files
+SPDX-FileCopyrightText = "2017 The CC: Tweaked Developers"
+SPDX-License-Identifier = "MPL-2.0"
+path = "projects/common/src/main/resources/assets/computercraft/lang/**"
+
+[[annotations]]
+# GitHub build scripts are CC0. While we could add a header to each file,
+# it's unclear if it will break actions or issue templates in some way.
+SPDX-FileCopyrightText = "Jonathan Coates <git@squiddev.cc>"
+SPDX-License-Identifier = "CC0-1.0"
+path = ".github/**"
+
+[[annotations]]
+path = ["gradle/wrapper/**"]
+SPDX-FileCopyrightText = "Gradle Inc"
+SPDX-License-Identifier = "Apache-2.0"
+
+[[annotations]]
+path = "projects/core/src/test/resources/test-rom/data/json-parsing/**"
+SPDX-FileCopyrightText = "2016 Nicolas Seriot"
+SPDX-License-Identifier = "MIT"

buildSrc/build.gradle.kts

@@ -45,7 +45,6 @@ dependencies {
     implementation(libs.kotlin.plugin)
     implementation(libs.spotless)
 
-    implementation(libs.curseForgeGradle)
     implementation(libs.fabric.loom)
     implementation(libs.ideaExt)
     implementation(libs.minotaur)

buildSrc/src/main/kotlin/cc-tweaked.java-convention.gradle.kts

@@ -47,6 +47,7 @@ repositories {
         filter {
             includeGroup("cc.tweaked")
             // Things we mirror
+            includeGroup("com.simibubi.create")
             includeGroup("commoble.morered")
             includeGroup("dev.architectury")
             includeGroup("dev.emi")

buildSrc/src/main/kotlin/cc-tweaked.mod-publishing.gradle.kts

@@ -2,11 +2,9 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
-import net.darkhax.curseforgegradle.TaskPublishCurseForge
 import cc.tweaked.gradle.setProvider
 
 plugins {
-    id("net.darkhax.curseforgegradle")
     id("com.modrinth.minotaur")
     id("cc-tweaked.publishing")
 }
@@ -25,23 +23,6 @@ val isUnstable = project.properties["isUnstable"] == "true"
 val modVersion: String by extra
 val mcVersion: String by extra
 
-val publishCurseForge by tasks.registering(TaskPublishCurseForge::class) {
-    group = PublishingPlugin.PUBLISH_TASK_GROUP
-    description = "Upload artifacts to CurseForge"
-
-    apiToken = findProperty("curseForgeApiKey") ?: ""
-    enabled = apiToken != ""
-
-    val mainFile = upload("282001", modPublishing.output)
-    mainFile.changelog =
-        "Release notes can be found on the [GitHub repository](https://github.com/cc-tweaked/CC-Tweaked/releases/tag/v$mcVersion-$modVersion)."
-    mainFile.changelogType = "markdown"
-    mainFile.releaseType = if (isUnstable) "alpha" else "release"
-    mainFile.gameVersions.add(mcVersion)
-}
-
-tasks.publish { dependsOn(publishCurseForge) }
-
 modrinth {
     token.set(findProperty("modrinthApiKey") as String? ?: "")
     projectId.set("gu7yAYhd")

buildSrc/src/main/kotlin/cc/tweaked/gradle/CCTweakedExtension.kt

@@ -22,7 +22,6 @@ import org.gradle.api.tasks.SourceSet
 import org.gradle.api.tasks.bundling.Jar
 import org.gradle.api.tasks.compile.JavaCompile
 import org.gradle.api.tasks.javadoc.Javadoc
-import org.gradle.configurationcache.extensions.capitalized
 import org.gradle.language.base.plugins.LifecycleBasePlugin
 import org.gradle.language.jvm.tasks.ProcessResources
 import org.gradle.process.JavaForkOptions
@@ -181,7 +180,7 @@ abstract class CCTweakedExtension(
 
     fun <T> jacoco(task: NamedDomainObjectProvider<T>) where T : Task, T : JavaForkOptions {
         val classDump = project.layout.buildDirectory.dir("jacocoClassDump/${task.name}")
-        val reportTaskName = "jacoco${task.name.capitalized()}Report"
+        val reportTaskName = "jacoco${task.name.capitalise()}Report"
 
         val jacoco = project.extensions.getByType(JacocoPluginExtension::class.java)
         task.configure {
@@ -270,7 +269,7 @@ abstract class CCTweakedExtension(
     companion object {
         private val COMMIT_COUNTS = Pattern.compile("""^\s*[0-9]+\s+(.*)$""")
         private val IGNORED_USERS = setOf(
-            "GitHub", "Daniel Ratcliffe", "Weblate",
+            "GitHub", "Daniel Ratcliffe", "NotSquidDev", "Weblate",
         )
 
         private fun <T> gitProvider(project: Project, default: T, supplier: () -> T): Provider<T> {

buildSrc/src/main/kotlin/cc/tweaked/gradle/Extensions.kt

@@ -159,7 +159,7 @@ fun getNextVersion(version: String): String {
     val lastIndex = mainVersion.lastIndexOf('.')
     if (lastIndex < 0) throw IllegalArgumentException("Cannot parse version format \"$version\"")
     val lastVersion = try {
-        version.substring(lastIndex + 1).toInt()
+        mainVersion.substring(lastIndex + 1).toInt()
     } catch (e: NumberFormatException) {
         throw IllegalArgumentException("Cannot parse version format \"$version\"", e)
     }
@@ -171,3 +171,15 @@ fun getNextVersion(version: String): String {
     if (dashIndex >= 0) out.append(version, dashIndex, version.length)
     return out.toString()
 }
+
+/**
+ * Capitalise the first letter of the string.
+ *
+ * This is a replacement for the now deprecated [String.capitalize].
+ */
+fun String.capitalise(): String {
+    if (isEmpty()) return this
+    val first = this[0]
+    val firstTitle = first.titlecaseChar()
+    return if (first == firstTitle) this else firstTitle + substring(1)
+}

buildSrc/src/main/kotlin/cc/tweaked/gradle/MinecraftExec.kt

@@ -18,6 +18,7 @@ import java.nio.file.Files
 import java.util.concurrent.TimeUnit
 import java.util.function.Supplier
 import javax.inject.Inject
+import kotlin.collections.set
 import kotlin.random.Random
 
 /**
@@ -108,6 +109,23 @@ abstract class ClientJavaExec : JavaExec() {
         }
     }
 
+    /**
+     * Configure Iris to use Complementary Shaders.
+     */
+    fun withComplementaryShaders() {
+        val cct = project.extensions.getByType(CCTweakedExtension::class.java)
+
+        withFileFrom(workingDir.resolve("shaderpacks/ComplementaryShaders_v4.6.zip")) {
+            cct.downloadFile("Complementary Shaders", "https://edge.forgecdn.net/files/3951/170/ComplementaryShaders_v4.6.zip")
+        }
+        withFileContents(workingDir.resolve("config/iris.properties")) {
+            """
+            enableShaders=true
+            shaderPack=ComplementaryShaders_v4.6.zip
+            """.trimIndent()
+        }
+    }
+
     @TaskAction
     override fun exec() {
         Files.createDirectories(workingDir.toPath())

config/checkstyle/checkstyle.xml

@@ -21,6 +21,15 @@ SPDX-License-Identifier: MPL-2.0
         <property name="file" value="${config_loc}/suppressions.xml" />
     </module>
 
+    <!--
+        Checkstyle doesn't support @snippet (https://github.com/checkstyle/checkstyle/issues/11455),
+        so suppress warnings nearby
+    -->
+    <module name="SuppressWithNearbyTextFilter">
+        <property name="nearbyTextPattern" value="@snippet" />
+        <property name="lineRange" value="20" />
+    </module>
+
     <module name="BeforeExecutionExclusionFileFilter">
         <property name="fileNamePattern" value="render_old"/>
     </module>

crowdin.yml

@@ -0,0 +1,28 @@
+# SPDX-FileCopyrightText: 2017 The CC: Tweaked Developers
+#
+# SPDX-License-Identifier: MPL-2.0
+
+files:
+  - source: projects/common/src/generated/resources/assets/computercraft/lang/en_us.json
+    translation: /projects/common/src/main/resources/assets/computercraft/lang/%locale_with_underscore%.json
+    languages_mapping:
+      locale_with_underscore:
+        cs: cs_cz    # Czech
+        da: da_dk    # Danish
+        de: de_de    # German
+        es-ES: es_es # Spanish
+        fr: fr_fr    # French
+        it: it_it    # Italian
+        ja: ja_jp    # Japanese
+        ko: ko_kr    # Korean
+        nb: nb_no    # Norwegian Bokmal
+        nl: nl_nl    # Dutch
+        pl: pl_pl    # Polish
+        pt-BR: pt_br # Portuguese, Brazilian
+        ru: ru_ru    # Russian
+        sv-SE: sv_se # Sweedish
+        tok: tok     # Toki Pona
+        tr: tr_tr    # Turkish
+        uk: uk_ua    # Ukraine
+        vi: vi_vn    # Vietnamese
+        zh-CN: zh_cn # Chinese Simplified

doc/events/redstone.md

@@ -8,7 +8,7 @@ SPDX-FileCopyrightText: 2021 The CC: Tweaked Developers
 SPDX-License-Identifier: MPL-2.0
 -->
 
-The [`event!redstone`] event is fired whenever any redstone inputs on the computer change.
+The [`event!redstone`] event is fired whenever any redstone inputs on the computer or [relay][`redstone_relay`] change.
 
 ## Return values
 1. [`string`]: The event name.
@@ -21,3 +21,7 @@ while true do
   print("A redstone input has changed!")
 end
 ```
+
+## See also
+ - [The `redstone` API on computers][`module!redstone`]
+ - [The `redstone_relay` peripheral][`redstone_relay`]

doc/guides/speaker_audio.md

@@ -191,7 +191,7 @@ end
 
 > [Confused?][!NOTE]
 > Don't worry if you don't understand this example. It's quite advanced, and does use some ideas that this guide doesn't
-> cover. That said, don't be afraid to ask on [GitHub Discussions] or [IRC] either!
+> cover. That said, don't be afraid to ask [the community for help][community].
 
 It's worth noting that the examples of audio processing we've mentioned here are about manipulating the _amplitude_ of
 the wave. If you wanted to modify the _frequency_ (for instance, shifting the pitch), things get rather more complex.
@@ -205,5 +205,4 @@ This is, I'm afraid, left as an exercise to the reader.
 [PCM]: https://en.wikipedia.org/wiki/Pulse-code_modulation "Pulse-code Modulation - Wikipedia"
 [Ring Buffer]: https://en.wikipedia.org/wiki/Circular_buffer "Circular buffer - Wikipedia"
 [Sine Wave]: https://en.wikipedia.org/wiki/Sine_wave "Sine wave - Wikipedia"
-[GitHub Discussions]: https://github.com/cc-tweaked/CC-Tweaked/discussions
-[IRC]: https://webchat.esper.net/?channels=computercraft "#computercraft on EsperNet"
+[Community]: /#community

doc/index.md

@@ -16,7 +16,7 @@ CC: Tweaked is a mod for Minecraft which adds programmable computers, turtles an
 much-beloved [ComputerCraft], it continues its legacy with improved performance and stability, along with a wealth of
 new features.
 
-CC: Tweaked can be installed from [CurseForge] or [Modrinth]. It runs on both [Minecraft Forge] and [Fabric].
+CC: Tweaked can be installed from [Modrinth]. It runs on both [Minecraft Forge] and [Fabric].
 
 ## Features
 Controlled using the [Lua programming language][lua], CC: Tweaked's computers provides all the tools you need to start
@@ -50,7 +50,11 @@ little daunting getting started. Thankfully, there's several fantastic tutorials
 Once you're a little more familiar with the mod, the sidebar and links below provide more detailed documentation on the
 various APIs and peripherals provided by the mod.
 
-If you get stuck, do [ask a question on GitHub][GitHub Discussions] or pop in to the ComputerCraft's [IRC channel][IRC].
+<h2 id="community">Community</h2>
+If you need help getting started with CC: Tweaked, want to show off your latest project, or just want to chat about
+ComputerCraft, do check out our [GitHub discussions page][GitHub discussions]! There's also a fairly populated,
+albeit quiet IRC channel on [EsperNet], if that's more your cup of tea. You can join `#computercraft` through your
+desktop client, or online using [KiwiIRC].
 
 ## Get Involved
 CC: Tweaked lives on [GitHub]. If you've got any ideas, feedback or bugs please do [create an issue][bug].
@@ -58,11 +62,11 @@ CC: Tweaked lives on [GitHub]. If you've got any ideas, feedback or bugs please
 [github]: https://github.com/cc-tweaked/CC-Tweaked/ "CC: Tweaked on GitHub"
 [bug]: https://github.com/cc-tweaked/CC-Tweaked/issues/new/choose
 [computercraft]: https://github.com/dan200/ComputerCraft "ComputerCraft on GitHub"
-[curseforge]: https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked from CurseForge"
 [modrinth]: https://modrinth.com/mod/gu7yAYhd "Download CC: Tweaked from Modrinth"
 [forge]: https://files.minecraftforge.net/ "Download Minecraft Forge."
 [Minecraft Forge]: https://files.minecraftforge.net/ "Download Minecraft Forge."
 [Fabric]: https://fabricmc.net/use/installer/ "Download Fabric."
 [lua]: https://www.lua.org/ "Lua's main website"
 [GitHub Discussions]: https://github.com/cc-tweaked/CC-Tweaked/discussions
-[IRC]: https://webchat.esper.net/?channels=computercraft "#computercraft on EsperNet"
+[EsperNet]: https://www.esper.net/
+[KiwiIRC]: https://kiwiirc.com/nextclient/#irc://irc.esper.net:+6697/#computercraft "#computercraft on EsperNet"

doc/mod-page.md

@@ -50,7 +50,11 @@ little daunting getting started. Thankfully, there's several fantastic tutorials
 Once you're a little more familiar with the mod, the [wiki](https://tweaked.cc/) provides more detailed documentation on the
 various APIs and peripherals provided by the mod.
 
-If you get stuck, do [ask a question on GitHub][GitHub Discussions] or pop in to the ComputerCraft's [IRC channel][IRC].
+## Community
+If you need help getting started with CC: Tweaked, want to show off your latest project, or just want to chat about
+ComputerCraft, do check out our [GitHub discussions page][GitHub discussions]! There's also a fairly populated,
+albeit quiet IRC channel on [EsperNet], if that's more your cup of tea. You can join `#computercraft` through your
+desktop client, or online using [KiwiIRC].
 
 ## Get Involved
 CC: Tweaked lives on [GitHub]. If you've got any ideas, feedback or bugs please do [create an issue][bug].
@@ -60,4 +64,5 @@ CC: Tweaked lives on [GitHub]. If you've got any ideas, feedback or bugs please
 [computercraft]: https://github.com/dan200/ComputerCraft "ComputerCraft on GitHub"
 [lua]: https://www.lua.org/ "Lua's main website"
 [GitHub Discussions]: https://github.com/cc-tweaked/CC-Tweaked/discussions
-[IRC]: http://webchat.esper.net/?channels=computercraft "#computercraft on EsperNet"
+[EsperNet]: https://www.esper.net/
+[KiwiIRC]: https://kiwiirc.com/nextclient/#irc://irc.esper.net:+6697/#computercraft "#computercraft on EsperNet"

doc/reference/feature_compat.md

@@ -81,7 +81,7 @@ compatibility for these newer versions.
 | `string.dump` strip argument                                                          | ✔          |                           |
 | `string.pack`/`string.unpack`/`string.packsize`                                       | ✔          |                           |
 | `table.move`                                                                          | ✔          |                           |
-| `math.atan2` -> `math.atan`                                                           | ❌         |                           |
+| `math.atan2` -> `math.atan`                                                           | 🔶         | `math.atan` supports its two argument form. |
 | Removed `math.frexp`, `math.ldexp`, `math.pow`, `math.cosh`, `math.sinh`, `math.tanh` | ❌         |                           |
 | `math.maxinteger`/`math.mininteger`                                                   | ❌         |                           |
 | `math.tointeger`                                                                      | ❌         |                           |

gradle.properties

@@ -12,7 +12,7 @@ neogradle.subsystems.conventions.runs.enabled=false
 
 # Mod properties
 isUnstable=true
-modVersion=1.111.1
+modVersion=1.114.2
 
 # Minecraft properties: We want to configure this here so we can read it in settings.gradle
-mcVersion=1.21
+mcVersion=1.21.1

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1,2 @@
+#This file is generated by updateDaemonJvm
+toolchainVersion=21

gradle/libs.versions.toml

@@ -7,14 +7,14 @@
 # Minecraft
 # MC version is specified in gradle.properties, as we need that in settings.gradle.
 # Remember to update corresponding versions in fabric.mod.json/neoforge.mods.toml
-fabric-api = "0.100.3+1.21"
+fabric-api = "0.102.1+1.21.1"
 fabric-loader = "0.15.11"
-neoForge = "21.0.42-beta"
+neoForge = "21.1.9"
 neoForgeSpi = "8.0.1"
 mixin = "0.8.5"
-parchment = "2024.06.16"
-parchmentMc = "1.20.6"
-yarn = "1.21+build.1"
+parchment = "2024.07.28"
+parchmentMc = "1.21"
+yarn = "1.21.1+build.1"
 
 # Core dependencies (these versions are tied to the version Minecraft uses)
 fastutil = "8.5.12"
@@ -26,7 +26,7 @@ slf4j = "2.0.9"
 asm = "9.6"
 autoService = "1.1.1"
 checkerFramework = "3.42.0"
-cobalt = { strictly = "0.9.3" }
+cobalt = { strictly = "0.9.5" }
 commonsCli = "1.6.0"
 jetbrainsAnnotations = "24.1.0"
 jsr305 = "3.0.2"
@@ -38,15 +38,17 @@ nightConfig = "3.6.7"
 # Minecraft mods
 emi = "1.1.7+1.21"
 fabricPermissions = "0.3.1"
-iris = "1.6.14+1.20.4"
-jei = "19.0.0.1"
+iris-fabric = "1.8.0-beta.3+1.21-fabric"
+iris-forge = "1.8.0-beta.3+1.21-neoforge"
+jei = "19.8.2.99"
 modmenu = "11.0.0-rc.4"
 moreRed = "4.0.0.4"
-oculus = "1.2.5"
 rei = "16.0.729"
-rubidium = "0.6.1"
-sodium = "mc1.20-0.4.10"
+sodium-fabric = "mc1.21-0.6.0-beta.1-fabric"
+sodium-forge = "mc1.21-0.6.0-beta.1-neoforge"
 mixinExtra = "0.3.5"
+create-forge = "0.5.1.f-33"
+create-fabric = "0.5.1-f-build.1467+mc1.20.1"
 
 # Testing
 hamcrest = "2.2"
@@ -55,20 +57,20 @@ junit = "5.10.1"
 jmh = "1.37"
 
 # Build tools
-cctJavadoc = "1.8.2"
-checkstyle = "10.14.1"
-curseForgeGradle = "1.1.18"
+cctJavadoc = "1.8.3"
+checkstyle = "10.20.1"
 errorProne-core = "2.27.0"
 errorProne-plugin = "3.1.0"
 fabric-loom = "1.7.1"
 githubRelease = "2.5.2"
 gradleVersions = "0.50.0"
 ideaExt = "1.1.7"
-illuaminate = "0.1.0-73-g43ee16c"
+illuaminate = "0.1.0-74-gf1551d5"
 lwjgl = "3.3.3"
 minotaur = "2.8.7"
-neoGradle = "7.0.152"
+neoGradle = "7.0.170"
 nullAway = "0.10.25"
+shadow = "8.3.1"
 spotless = "6.23.3"
 taskTree = "2.1.1"
 teavm = "0.11.0-SQUID.1"
@@ -92,20 +94,24 @@ jzlib = { module = "com.jcraft:jzlib", version.ref = "jzlib" }
 kotlin-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlin-coroutines" }
 kotlin-platform = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "kotlin" }
 kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib", version.ref = "kotlin" }
+netty-codec = { module = "io.netty:netty-codec", version.ref = "netty" }
 netty-http = { module = "io.netty:netty-codec-http", version.ref = "netty" }
-netty-socks = { module = "io.netty:netty-codec-socks", version.ref = "netty" }
 netty-proxy = { module = "io.netty:netty-handler-proxy", version.ref = "netty" }
+netty-socks = { module = "io.netty:netty-codec-socks", version.ref = "netty" }
 nightConfig-core = { module = "com.electronwill.night-config:core", version.ref = "nightConfig" }
 nightConfig-toml = { module = "com.electronwill.night-config:toml", version.ref = "nightConfig" }
 slf4j = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
 
 # Minecraft mods
-fabric-api = { module = "net.fabricmc.fabric-api:fabric-api", version.ref = "fabric-api" }
-fabric-loader = { module = "net.fabricmc:fabric-loader", version.ref = "fabric-loader" }
-fabric-junit = { module = "net.fabricmc:fabric-loader-junit", version.ref = "fabric-loader" }
-fabricPermissions = { module = "me.lucko:fabric-permissions-api", version.ref = "fabricPermissions" }
+create-fabric = { module = "com.simibubi.create:create-fabric-1.20.1", version.ref = "create-fabric" }
+create-forge = { module = "com.simibubi.create:create-1.20.1", version.ref = "create-forge" }
 emi = { module = "dev.emi:emi-xplat-mojmap", version.ref = "emi" }
-iris = { module = "maven.modrinth:iris", version.ref = "iris" }
+fabric-api = { module = "net.fabricmc.fabric-api:fabric-api", version.ref = "fabric-api" }
+fabric-junit = { module = "net.fabricmc:fabric-loader-junit", version.ref = "fabric-loader" }
+fabric-loader = { module = "net.fabricmc:fabric-loader", version.ref = "fabric-loader" }
+fabricPermissions = { module = "me.lucko:fabric-permissions-api", version.ref = "fabricPermissions" }
+iris-fabric = { module = "maven.modrinth:iris", version.ref = "iris-fabric" }
+iris-forge = { module = "maven.modrinth:iris", version.ref = "iris-forge" }
 jei-api = { module = "mezz.jei:jei-1.21-common-api", version.ref = "jei" }
 jei-fabric = { module = "mezz.jei:jei-1.21-fabric", version.ref = "jei" }
 jei-forge = { module = "mezz.jei:jei-1.21-neoforge", version.ref = "jei" }
@@ -113,12 +119,11 @@ mixin = { module = "org.spongepowered:mixin", version.ref = "mixin" }
 mixinExtra = { module = "io.github.llamalad7:mixinextras-common", version.ref = "mixinExtra" }
 modmenu = { module = "com.terraformersmc:modmenu", version.ref = "modmenu" }
 moreRed = { module = "commoble.morered:morered-1.20.1", version.ref = "moreRed" }
-oculus = { module = "maven.modrinth:oculus", version.ref = "oculus" }
 rei-api = { module = "me.shedaniel:RoughlyEnoughItems-api", version.ref = "rei" }
 rei-builtin = { module = "me.shedaniel:RoughlyEnoughItems-default-plugin", version.ref = "rei" }
 rei-fabric = { module = "me.shedaniel:RoughlyEnoughItems-fabric", version.ref = "rei" }
-rubidium = { module = "maven.modrinth:rubidium", version.ref = "rubidium" }
-sodium = { module = "maven.modrinth:sodium", version.ref = "sodium" }
+sodium-fabric = { module = "maven.modrinth:sodium", version.ref = "sodium.fabric" }
+sodium-forge = { module = "maven.modrinth:sodium", version.ref = "sodium.forge" }
 
 # Testing
 hamcrest = { module = "org.hamcrest:hamcrest", version.ref = "hamcrest" }
@@ -140,7 +145,6 @@ lwjgl-glfw = { module = "org.lwjgl:lwjgl-glfw" }
 # Build tools
 cctJavadoc = { module = "cc.tweaked:cct-javadoc", version.ref = "cctJavadoc" }
 checkstyle = { module = "com.puppycrawl.tools:checkstyle", version.ref = "checkstyle" }
-curseForgeGradle = { module = "net.darkhax.curseforgegradle:CurseForgeGradle", version.ref = "curseForgeGradle" }
 errorProne-annotations = { module = "com.google.errorprone:error_prone_annotations", version.ref = "errorProne-core" }
 errorProne-api = { module = "com.google.errorprone:error_prone_check_api", version.ref = "errorProne-core" }
 errorProne-core = { module = "com.google.errorprone:error_prone_core", version.ref = "errorProne-core" }
@@ -169,6 +173,7 @@ yarn = { module = "net.fabricmc:yarn", version.ref = "yarn" }
 githubRelease = { id = "com.github.breadmoirai.github-release", version.ref = "githubRelease" }
 gradleVersions = { id = "com.github.ben-manes.versions", version.ref = "gradleVersions" }
 kotlin = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+shadow = { id = "com.gradleup.shadow", version.ref = "shadow" }
 taskTree = { id = "com.dorongold.task-tree", version.ref = "taskTree" }
 versionCatalogUpdate = { id = "nl.littlerobots.version-catalog-update", version.ref = "versionCatalogUpdate" }
 
@@ -177,10 +182,10 @@ annotations = ["jsr305", "checkerFramework", "jetbrainsAnnotations"]
 kotlin = ["kotlin-stdlib", "kotlin-coroutines"]
 
 # Minecraft
-externalMods-common = ["jei-api", "nightConfig-core", "nightConfig-toml"]
-externalMods-forge-compile = ["moreRed", "oculus", "jei-api"]
+externalMods-common = ["iris-forge", "jei-api", "nightConfig-core", "nightConfig-toml"]
+externalMods-forge-compile = ["moreRed", "iris-forge", "jei-api"]
 externalMods-forge-runtime = ["jei-forge"]
-externalMods-fabric-compile = ["fabricPermissions", "iris", "jei-api", "rei-api", "rei-builtin"]
+externalMods-fabric-compile = ["fabricPermissions", "iris-fabric", "jei-api", "rei-api", "rei-builtin"]
 externalMods-fabric-runtime = ["jei-fabric", "modmenu"]
 
 # Testing

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.2-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

gradlew

@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -84,7 +86,8 @@ done
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
 # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum

gradlew.bat

@@ -13,6 +13,8 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################

package.json

@@ -13,10 +13,10 @@
   },
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^15.2.1",
-    "@rollup/plugin-typescript": "^11.0.0",
+    "@rollup/plugin-typescript": "^12.0.0",
     "@rollup/plugin-url": "^8.0.1",
     "@swc/core": "^1.3.92",
-    "@types/node": "^20.8.3",
+    "@types/node": "^22.0.0",
     "lightningcss": "^1.22.0",
     "preact-render-to-string": "^6.2.1",
     "rehype": "^13.0.0",

projects/common-api/build.gradle.kts

@@ -8,6 +8,8 @@ plugins {
     id("cc-tweaked.vanilla")
 }
 
+val mcVersion: String by extra
+
 java {
     withJavadocJar()
 }
@@ -17,8 +19,36 @@ dependencies {
 }
 
 tasks.javadoc {
+    title = "CC: Tweaked $version Minecraft $mcVersion"
     include("dan200/computercraft/api/**/*.java")
 
+    options {
+        (this as StandardJavadocDocletOptions)
+
+        groups = mapOf(
+            "Common" to listOf(
+                "dan200.computercraft.api",
+                "dan200.computercraft.api.lua",
+                "dan200.computercraft.api.peripheral",
+            ),
+            "Upgrades" to listOf(
+                "dan200.computercraft.api.client.turtle",
+                "dan200.computercraft.api.pocket",
+                "dan200.computercraft.api.turtle",
+                "dan200.computercraft.api.upgrades",
+            ),
+        )
+
+        addBooleanOption("-allow-script-in-comments", true)
+        bottom(
+            """
+            <script src="https://cdn.jsdelivr.net/npm/prismjs@v1.29.0/components/prism-core.min.js"></script>
+            <script src="https://cdn.jsdelivr.net/npm/prismjs@v1.29.0/plugins/autoloader/prism-autoloader.min.js"></script>
+            <link href=" https://cdn.jsdelivr.net/npm/prismjs@1.29.0/themes/prism.min.css " rel="stylesheet">
+            """.trimIndent(),
+        )
+    }
+
     // Include the core-api in our javadoc export. This is wrong, but it means we can export a single javadoc dump.
     source(project(":core-api").sourceSets.main.map { it.allJava })
 

projects/common-api/src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -4,9 +4,11 @@
 
 package dan200.computercraft.api;
 
+import dan200.computercraft.api.component.ComputerComponent;
 import dan200.computercraft.api.filesystem.Mount;
 import dan200.computercraft.api.filesystem.WritableMount;
 import dan200.computercraft.api.lua.GenericSource;
+import dan200.computercraft.api.lua.IComputerSystem;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaAPIFactory;
 import dan200.computercraft.api.media.IMedia;
@@ -165,7 +167,20 @@ public final class ComputerCraftAPI {
      * Register a custom {@link ILuaAPI}, which may be added onto all computers without requiring a peripheral.
      * <p>
      * Before implementing this interface, consider alternative methods of providing methods. It is generally preferred
-     * to use peripherals to provide functionality to users.
+     * to use peripherals to provide functionality to users. If an API is <em>required</em>, you may want to consider
+     * using {@link ILuaAPI#getModuleName()} to expose this library as a module instead of as a global.
+     * <p>
+     * This may be used with {@link IComputerSystem#getComponent(ComputerComponent)} to only attach APIs to specific
+     * computers. For example, one can add an additional API just to turtles with the following code:
+     *
+     * {@snippet lang="java":
+     * ComputerCraftAPI.registerAPIFactory(computer -> {
+     *   // Read the turtle component.
+     *   var turtle = computer.getComponent(ComputerComponents.TURTLE);
+     *   // If present then add our API.
+     *   return turtle == null ? null : new MyCustomTurtleApi(turtle);
+     * });
+     * }
      *
      * @param factory The factory for your API subclass.
      * @see ILuaAPIFactory

projects/common-api/src/main/java/dan200/computercraft/api/component/AdminComputer.java

@@ -0,0 +1,24 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.component;
+
+import net.minecraft.commands.CommandSourceStack;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * A computer which has permission to perform administrative/op commands, such as the command computer.
+ */
+@ApiStatus.NonExtendable
+public interface AdminComputer {
+    /**
+     * The permission level that this computer can operate at.
+     *
+     * @return The permission level for this computer.
+     * @see CommandSourceStack#hasPermission(int)
+     */
+    default int permissionLevel() {
+        return 2;
+    }
+}

projects/common-api/src/main/java/dan200/computercraft/api/component/ComputerComponent.java

@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.component;
+
+import dan200.computercraft.api.lua.IComputerSystem;
+import dan200.computercraft.api.lua.ILuaAPIFactory;
+
+/**
+ * A component attached to a computer.
+ * <p>
+ * Components provide a mechanism to attach additional data to a computer, that can then be queried with
+ * {@link IComputerSystem#getComponent(ComputerComponent)}.
+ * <p>
+ * This is largely designed for {@linkplain ILuaAPIFactory custom APIs}, allowing APIs to read additional properties
+ * of the computer, such as its position.
+ *
+ * @param <T> The type of this component.
+ * @see ComputerComponents The built-in components.
+ */
+@SuppressWarnings("UnusedTypeParameter")
+public final class ComputerComponent<T> {
+    private final String id;
+
+    private ComputerComponent(String id) {
+        this.id = id;
+    }
+
+    /**
+     * Create a new computer component.
+     * <p>
+     * Mods typically will not need to create their own components.
+     *
+     * @param namespace The namespace of this component. This should be the mod id.
+     * @param id        The unique id of this component.
+     * @param <T>       The component
+     * @return The newly created component.
+     */
+    public static <T> ComputerComponent<T> create(String namespace, String id) {
+        return new ComputerComponent<>(namespace + ":" + id);
+    }
+
+    @Override
+    public String toString() {
+        return "ComputerComponent(" + id + ")";
+    }
+}

projects/common-api/src/main/java/dan200/computercraft/api/component/ComputerComponents.java

@@ -0,0 +1,29 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.component;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.pocket.IPocketAccess;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+
+/**
+ * The {@link ComputerComponent}s provided by ComputerCraft.
+ */
+public class ComputerComponents {
+    /**
+     * The {@link ITurtleAccess} associated with a turtle.
+     */
+    public static final ComputerComponent<ITurtleAccess> TURTLE = ComputerComponent.create(ComputerCraftAPI.MOD_ID, "turtle");
+
+    /**
+     * The {@link IPocketAccess} associated with a pocket computer.
+     */
+    public static final ComputerComponent<IPocketAccess> POCKET = ComputerComponent.create(ComputerCraftAPI.MOD_ID, "pocket");
+
+    /**
+     * This component is only present on "command computers", and other computers with admin capabilities.
+     */
+    public static final ComputerComponent<AdminComputer> ADMIN_COMPUTER = ComputerComponent.create(ComputerCraftAPI.MOD_ID, "admin_computer");
+}

projects/common-api/src/main/java/dan200/computercraft/api/detail/BasicItemDetailProvider.java

@@ -13,7 +13,7 @@ import java.util.Map;
 import java.util.Objects;
 
 /**
- * An item detail provider for {@link ItemStack}'s whose {@link Item} has a specific type.
+ * An item detail provider for {@link ItemStack}s whose {@link Item} has a specific type.
  *
  * @param <T> The type the stack's item must have.
  */
@@ -22,7 +22,7 @@ public abstract class BasicItemDetailProvider<T> implements DetailProvider<ItemS
     private final @Nullable String namespace;
 
     /**
-     * Create a new item detail provider. Meta will be inserted into a new sub-map named as per {@code namespace}.
+     * Create a new item detail provider. Details will be inserted into a new sub-map named as per {@code namespace}.
      *
      * @param itemType  The type the stack's item must have.
      * @param namespace The namespace to use for this provider.
@@ -34,7 +34,7 @@ public abstract class BasicItemDetailProvider<T> implements DetailProvider<ItemS
     }
 
     /**
-     * Create a new item detail provider. Meta will be inserted directly into the results.
+     * Create a new item detail provider. Details will be inserted directly into the results.
      *
      * @param itemType The type the stack's item must have.
      */
@@ -53,21 +53,18 @@ public abstract class BasicItemDetailProvider<T> implements DetailProvider<ItemS
      * @param stack The item stack to provide details for.
      * @param item  The item to provide details for.
      */
-    public abstract void provideDetails(
-        Map<? super String, Object> data, ItemStack stack, T item
-    );
+    public abstract void provideDetails(Map<? super String, Object> data, ItemStack stack, T item);
 
     @Override
-    public void provideDetails(Map<? super String, Object> data, ItemStack stack) {
+    public final void provideDetails(Map<? super String, Object> data, ItemStack stack) {
         var item = stack.getItem();
         if (!itemType.isInstance(item)) return;
 
-        // If `namespace` is specified, insert into a new data map instead of the existing one.
-        Map<? super String, Object> child = namespace == null ? data : new HashMap<>();
-
-        provideDetails(child, stack, itemType.cast(item));
-
-        if (namespace != null) {
+        if (namespace == null) {
+            provideDetails(data, stack, itemType.cast(item));
+        } else {
+            Map<? super String, Object> child = new HashMap<>();
+            provideDetails(child, stack, itemType.cast(item));
             data.put(namespace, child);
         }
     }

projects/common-api/src/main/java/dan200/computercraft/api/detail/ComponentDetailProvider.java

@@ -0,0 +1,72 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.detail;
+
+import net.minecraft.core.component.DataComponentHolder;
+import net.minecraft.core.component.DataComponentType;
+import net.minecraft.world.item.ItemStack;
+
+import javax.annotation.Nullable;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * An item detail provider for a specific {@linkplain DataComponentType data component} on {@link ItemStack}s or
+ * other {@link DataComponentHolder}.
+ *
+ * @param <T> The type of the component's contents.
+ */
+public abstract class ComponentDetailProvider<T> implements DetailProvider<DataComponentHolder> {
+    private final DataComponentType<T> component;
+    private final @Nullable String namespace;
+
+    /**
+     * Create a new component detail provider. Details will be inserted into a new sub-map named as per {@code namespace}.
+     *
+     * @param component The data component to provide details for.
+     * @param namespace The namespace to use for this provider.
+     */
+    public ComponentDetailProvider(@Nullable String namespace, DataComponentType<T> component) {
+        Objects.requireNonNull(component);
+        this.component = component;
+        this.namespace = namespace;
+    }
+
+    /**
+     * Create a new component detail provider. Details will be inserted directly into the results.
+     *
+     * @param component The data component to provide details for.
+     */
+    public ComponentDetailProvider(DataComponentType<T> component) {
+        this(null, component);
+    }
+
+    /**
+     * Provide additional details for the given data component. This method is called by {@code turtle.getItemDetail()}.
+     * New properties should be added to the given {@link Map}, {@code data}.
+     * <p>
+     * This method is always called on the server thread, so it is safe to interact with the world here, but you should
+     * take care to avoid long blocking operations as this will stall the server and other computers.
+     *
+     * @param data The full details to be returned for this item stack. New properties should be added to this map.
+     * @param item The component to provide details for.
+     */
+    public abstract void provideComponentDetails(Map<? super String, Object> data, T item);
+
+    @Override
+    public final void provideDetails(Map<? super String, Object> data, DataComponentHolder holder) {
+        var value = holder.get(component);
+        if (value == null) return;
+
+        if (namespace == null) {
+            provideComponentDetails(data, value);
+        } else {
+            Map<? super String, Object> child = new HashMap<>();
+            provideComponentDetails(child, value);
+            data.put(namespace, child);
+        }
+    }
+}

projects/common-api/src/main/java/dan200/computercraft/api/detail/DetailRegistry.java

@@ -26,7 +26,7 @@ public interface DetailRegistry<T> {
      * @param provider The detail provider to register.
      * @see DetailProvider
      */
-    void addProvider(DetailProvider<T> provider);
+    void addProvider(DetailProvider<? super T> provider);
 
     /**
      * Compute basic details about an object. This is cheaper than computing all details operation, and so is suitable

projects/common-api/src/main/java/dan200/computercraft/api/lua/IComputerSystem.java

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: 2017 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.lua;
+
+import dan200.computercraft.api.component.ComputerComponent;
+import dan200.computercraft.api.peripheral.IComputerAccess;
+import net.minecraft.core.BlockPos;
+import net.minecraft.server.level.ServerLevel;
+import org.jetbrains.annotations.ApiStatus;
+
+import javax.annotation.Nullable;
+
+/**
+ * An interface passed to {@link ILuaAPIFactory} in order to provide additional information
+ * about a computer.
+ */
+@ApiStatus.NonExtendable
+public interface IComputerSystem extends IComputerAccess {
+    /**
+     * Get the level this computer is currently in.
+     * <p>
+     * This method is not guaranteed to remain the same (even for stationary computers).
+     *
+     * @return The computer's current level.
+     */
+    ServerLevel getLevel();
+
+    /**
+     * Get the position this computer is currently at.
+     * <p>
+     * This method is not guaranteed to remain the same (even for stationary computers).
+     *
+     * @return The computer's current position.
+     */
+    BlockPos getPosition();
+
+    /**
+     * Get the label for this computer.
+     *
+     * @return This computer's label, or {@code null} if it is not set.
+     */
+    @Nullable
+    String getLabel();
+
+    /**
+     * Get a component attached to this computer.
+     * <p>
+     * No component is guaranteed to be on a computer, and so this method should always be guarded with a null check.
+     * <p>
+     * This method will always return the same value for a given component, and so may be cached.
+     *
+     * @param component The component to query.
+     * @param <T>       The type of the component.
+     * @return The component, if present.
+     */
+    <T> @Nullable T getComponent(ComputerComponent<T> component);
+}

projects/common-api/src/main/java/dan200/computercraft/api/lua/ILuaAPIFactory.java

@@ -4,13 +4,15 @@
 
 package dan200.computercraft.api.lua;
 
+import dan200.computercraft.api.ComputerCraftAPI;
+
 import javax.annotation.Nullable;
 
 /**
- * Construct an {@link ILuaAPI} for a specific computer.
+ * Construct an {@link ILuaAPI} for a computer.
  *
  * @see ILuaAPI
- * @see dan200.computercraft.api.ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
+ * @see ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
  */
 @FunctionalInterface
 public interface ILuaAPIFactory {

projects/common-api/src/main/java/dan200/computercraft/api/network/wired/WiredElement.java

@@ -14,7 +14,7 @@ import dan200.computercraft.api.ComputerCraftAPI;
  * as a proxy for all network objects. Whilst the node may change networks, an element's node should remain constant
  * for its lifespan.
  * <p>
- * Elements are generally tied to a block or tile entity in world. In such as case, one should provide the
+ * Elements are generally tied to a block or block entity in world. In such as case, one should provide the
  * {@link WiredElement} capability for the appropriate sides.
  */
 public interface WiredElement extends WiredSender {

projects/common-api/src/main/java/dan200/computercraft/api/pocket/IPocketAccess.java

@@ -5,16 +5,35 @@
 package dan200.computercraft.api.pocket;
 
 import dan200.computercraft.api.upgrades.UpgradeBase;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import net.minecraft.core.component.DataComponentPatch;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.phys.Vec3;
+import org.jetbrains.annotations.ApiStatus;
 
 import javax.annotation.Nullable;
 
 /**
  * Wrapper class for pocket computers.
  */
+@ApiStatus.NonExtendable
 public interface IPocketAccess {
+    /**
+     * Get the level in which the pocket computer exists.
+     *
+     * @return The pocket computer's level.
+     */
+    ServerLevel getLevel();
+
+    /**
+     * Get the position of the pocket computer.
+     *
+     * @return The pocket computer's position.
+     */
+    Vec3 getPosition();
+
     /**
      * Gets the entity holding this item.
      * <p>
@@ -61,6 +80,26 @@ public interface IPocketAccess {
      */
     void setLight(int colour);
 
+    /**
+     * Get the currently equipped upgrade.
+     *
+     * @return The currently equipped upgrade.
+     * @see #getUpgradeData()
+     * @see #setUpgrade(UpgradeData)
+     */
+    @Nullable
+    UpgradeData<IPocketUpgrade> getUpgrade();
+
+    /**
+     * Set the upgrade for this pocket computer, also updating the item stack.
+     * <p>
+     * Note this method is not thread safe - it must be called from the server thread.
+     *
+     * @param upgrade The new upgrade to set it to, may be {@code null}.
+     * @see #getUpgrade()
+     */
+    void setUpgrade(@Nullable UpgradeData<IPocketUpgrade> upgrade);
+
     /**
      * Get the upgrade-specific NBT.
      * <p>
@@ -70,6 +109,7 @@ public interface IPocketAccess {
      * @see #setUpgradeData(DataComponentPatch)
      * @see UpgradeBase#getUpgradeItem(DataComponentPatch)
      * @see UpgradeBase#getUpgradeData(ItemStack)
+     * @see #getUpgrade()
      */
     DataComponentPatch getUpgradeData();
 

projects/common-api/src/main/java/dan200/computercraft/api/turtle/TurtleSide.java

@@ -5,7 +5,7 @@
 package dan200.computercraft.api.turtle;
 
 /**
- * An enum representing the two sides of the turtle that a turtle turtle might reside.
+ * An enum representing the two sides of the turtle that a turtle upgrade might reside.
  */
 public enum TurtleSide {
     /**

projects/common/build.gradle.kts

@@ -38,13 +38,14 @@ repositories {
 
 dependencies {
     // Pull in our other projects. See comments in MinecraftConfigurations on this nastiness.
-    implementation(project(":core"))
-    implementation(commonClasses(project(":common-api")))
-    clientImplementation(clientClasses(project(":common-api")))
+    api(project(":core"))
+    api(commonClasses(project(":common-api")))
+    clientApi(clientClasses(project(":common-api")))
 
     compileOnly(libs.mixin)
     compileOnly(libs.mixinExtra)
     compileOnly(libs.bundles.externalMods.common)
+    compileOnly(variantOf(libs.create.forge) { classifier("slim") }) { isTransitive = false }
     clientCompileOnly(variantOf(libs.emi) { classifier("api") })
 
     annotationProcessorEverywhere(libs.autoService)

projects/common/src/client/java/dan200/computercraft/client/ClientHooks.java

@@ -64,6 +64,9 @@ public final class ClientHooks {
     public static void onWorldUnload() {
         MonitorRenderState.destroyAll();
         SpeakerManager.reset();
+    }
+
+    public static void onDisconnect() {
         ClientPocketComputers.reset();
     }
 

projects/common/src/client/java/dan200/computercraft/client/ClientRegistry.java

@@ -13,6 +13,7 @@ import dan200.computercraft.api.client.turtle.RegisterTurtleUpgradeModeller;
 import dan200.computercraft.api.client.turtle.TurtleUpgradeModeller;
 import dan200.computercraft.client.gui.*;
 import dan200.computercraft.client.pocket.ClientPocketComputers;
+import dan200.computercraft.client.render.CustomLecternRenderer;
 import dan200.computercraft.client.render.RenderTypes;
 import dan200.computercraft.client.render.TurtleBlockEntityRenderer;
 import dan200.computercraft.client.render.monitor.MonitorBlockEntityRenderer;
@@ -79,6 +80,7 @@ public final class ClientRegistry {
         BlockEntityRenderers.register(ModRegistry.BlockEntities.MONITOR_ADVANCED.get(), MonitorBlockEntityRenderer::new);
         BlockEntityRenderers.register(ModRegistry.BlockEntities.TURTLE_NORMAL.get(), TurtleBlockEntityRenderer::new);
         BlockEntityRenderers.register(ModRegistry.BlockEntities.TURTLE_ADVANCED.get(), TurtleBlockEntityRenderer::new);
+        BlockEntityRenderers.register(ModRegistry.BlockEntities.LECTERN.get(), CustomLecternRenderer::new);
     }
 
     /**

projects/common/src/client/java/dan200/computercraft/client/gui/PrintoutScreen.java

@@ -6,15 +6,19 @@ package dan200.computercraft.client.gui;
 
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.ModRegistry;
-import dan200.computercraft.shared.common.HeldItemMenu;
+import dan200.computercraft.shared.media.PrintoutMenu;
 import dan200.computercraft.shared.media.items.PrintoutData;
-import dan200.computercraft.shared.media.items.PrintoutItem;
 import net.minecraft.client.gui.GuiGraphics;
 import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ContainerListener;
+import net.minecraft.world.item.ItemStack;
 import org.lwjgl.glfw.GLFW;
 
+import java.util.Objects;
+
 import static dan200.computercraft.client.render.PrintoutRenderer.*;
 import static dan200.computercraft.client.render.RenderTypes.FULL_BRIGHT_LIGHTMAP;
 
@@ -23,41 +27,65 @@ import static dan200.computercraft.client.render.RenderTypes.FULL_BRIGHT_LIGHTMA
  *
  * @see dan200.computercraft.client.render.PrintoutRenderer
  */
-public class PrintoutScreen extends AbstractContainerScreen<HeldItemMenu> {
-    private final boolean book;
-    private final int pages;
-    private final TextBuffer[] text;
-    private final TextBuffer[] colours;
-    private int page;
+public final class PrintoutScreen extends AbstractContainerScreen<PrintoutMenu> implements ContainerListener {
+    private PrintoutInfo printout = PrintoutInfo.DEFAULT;
+    private int page = 0;
 
-    public PrintoutScreen(HeldItemMenu container, Inventory player, Component title) {
+    public PrintoutScreen(PrintoutMenu container, Inventory player, Component title) {
         super(container, player, title);
-
         imageHeight = Y_SIZE;
+    }
 
-        var printout = container.getStack().getOrDefault(ModRegistry.DataComponents.PRINTOUT.get(), PrintoutData.EMPTY);
-        this.text = new TextBuffer[printout.lines().size()];
-        this.colours = new TextBuffer[printout.lines().size()];
-        for (var i = 0; i < this.text.length; i++) {
-            var line = printout.lines().get(i);
-            this.text[i] = new TextBuffer(line.text());
-            this.colours[i] = new TextBuffer(line.foreground());
-        }
-
+    private void setPrintout(ItemStack stack) {
         page = 0;
-        pages = Math.max(this.text.length / PrintoutData.LINES_PER_PAGE, 1);
-        book = ((PrintoutItem) container.getStack().getItem()).getType() == PrintoutItem.Type.BOOK;
+        printout = PrintoutInfo.of(PrintoutData.getOrEmpty(stack), stack.is(ModRegistry.Items.PRINTED_BOOK.get()));
+    }
+
+    @Override
+    protected void init() {
+        super.init();
+        menu.addSlotListener(this);
+    }
+
+    @Override
+    public void removed() {
+        menu.removeSlotListener(this);
+    }
+
+    @Override
+    public void slotChanged(AbstractContainerMenu menu, int slot, ItemStack stack) {
+        if (slot == 0) setPrintout(stack);
+    }
+
+    @Override
+    public void dataChanged(AbstractContainerMenu menu, int slot, int data) {
+        if (slot == PrintoutMenu.DATA_CURRENT_PAGE) page = data;
+    }
+
+    private void setPage(int page) {
+        this.page = page;
+
+        var gameMode = Objects.requireNonNull(Objects.requireNonNull(minecraft).gameMode);
+        gameMode.handleInventoryButtonClick(menu.containerId, PrintoutMenu.PAGE_BUTTON_OFFSET + page);
+    }
+
+    private void previousPage() {
+        if (page > 0) setPage(page - 1);
+    }
+
+    private void nextPage() {
+        if (page < printout.pages() - 1) setPage(page + 1);
     }
 
     @Override
     public boolean keyPressed(int key, int scancode, int modifiers) {
         if (key == GLFW.GLFW_KEY_RIGHT) {
-            if (page < pages - 1) page++;
+            nextPage();
             return true;
         }
 
         if (key == GLFW.GLFW_KEY_LEFT) {
-            if (page > 0) page--;
+            previousPage();
             return true;
         }
 
@@ -69,13 +97,13 @@ public class PrintoutScreen extends AbstractContainerScreen<HeldItemMenu> {
         if (super.mouseScrolled(x, y, deltaX, deltaY)) return true;
         if (deltaY < 0) {
             // Scroll up goes to the next page
-            if (page < pages - 1) page++;
+            nextPage();
             return true;
         }
 
         if (deltaY > 0) {
             // Scroll down goes to the previous page
-            if (page > 0) page--;
+            previousPage();
             return true;
         }
 
@@ -88,8 +116,8 @@ public class PrintoutScreen extends AbstractContainerScreen<HeldItemMenu> {
         graphics.pose().pushPose();
         graphics.pose().translate(0, 0, 1);
 
-        drawBorder(graphics.pose(), graphics.bufferSource(), leftPos, topPos, 0, page, pages, book, FULL_BRIGHT_LIGHTMAP);
-        drawText(graphics.pose(), graphics.bufferSource(), leftPos + X_TEXT_MARGIN, topPos + Y_TEXT_MARGIN, PrintoutData.LINES_PER_PAGE * page, FULL_BRIGHT_LIGHTMAP, text, colours);
+        drawBorder(graphics.pose(), graphics.bufferSource(), leftPos, topPos, 0, page, printout.pages(), printout.book(), FULL_BRIGHT_LIGHTMAP);
+        drawText(graphics.pose(), graphics.bufferSource(), leftPos + X_TEXT_MARGIN, topPos + Y_TEXT_MARGIN, PrintoutData.LINES_PER_PAGE * page, FULL_BRIGHT_LIGHTMAP, printout.text(), printout.colour());
 
         graphics.pose().popPose();
     }
@@ -98,4 +126,21 @@ public class PrintoutScreen extends AbstractContainerScreen<HeldItemMenu> {
     protected void renderLabels(GuiGraphics graphics, int mouseX, int mouseY) {
         // Skip rendering labels.
     }
+
+    record PrintoutInfo(int pages, boolean book, TextBuffer[] text, TextBuffer[] colour) {
+        public static final PrintoutInfo DEFAULT = of(PrintoutData.EMPTY, false);
+
+        public static PrintoutInfo of(PrintoutData printout, boolean book) {
+            var text = new TextBuffer[printout.lines().size()];
+            var colours = new TextBuffer[printout.lines().size()];
+            for (var i = 0; i < text.length; i++) {
+                var line = printout.lines().get(i);
+                text[i] = new TextBuffer(line.text());
+                colours[i] = new TextBuffer(line.foreground());
+            }
+
+            var pages = Math.max(text.length / PrintoutData.LINES_PER_PAGE, 1);
+            return new PrintoutInfo(pages, book, text, colours);
+        }
+    }
 }

projects/common/src/client/java/dan200/computercraft/client/integration/IrisShaderMod.java

@@ -8,9 +8,10 @@ import com.google.auto.service.AutoService;
 import com.mojang.blaze3d.vertex.VertexFormat;
 import dan200.computercraft.client.render.RenderTypes;
 import dan200.computercraft.client.render.text.DirectFixedWidthFontRenderer;
-import net.fabricmc.loader.api.FabricLoader;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import net.irisshaders.iris.api.v0.IrisApi;
 import net.irisshaders.iris.api.v0.IrisTextVertexSink;
+import net.minecraft.util.FastColor;
 
 import java.nio.ByteBuffer;
 import java.util.Optional;
@@ -20,7 +21,7 @@ import java.util.function.IntFunction;
 public class IrisShaderMod implements ShaderMod.Provider {
     @Override
     public Optional<ShaderMod> get() {
-        return FabricLoader.getInstance().isModLoaded("iris") ? Optional.of(new Impl()) : Optional.empty();
+        return PlatformHelper.get().isModLoaded("iris") ? Optional.of(new Impl()) : Optional.empty();
     }
 
     private static final class Impl extends ShaderMod {
@@ -54,12 +55,8 @@ public class IrisShaderMod implements ShaderMod.Provider {
             }
 
             @Override
-            public void quad(float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2) {
-                sink.quad(x1, y1, x2, y2, z, pack(rgba[0], rgba[1], rgba[2], rgba[3]), u1, v1, u2, v2, RenderTypes.FULL_BRIGHT_LIGHTMAP);
-            }
-
-            private static int pack(int r, int g, int b, int a) {
-                return (a & 255) << 24 | (b & 255) << 16 | (g & 255) << 8 | r & 255;
+            public void quad(float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2) {
+                sink.quad(x1, y1, x2, y2, z, FastColor.ABGR32.fromArgb32(colour), u1, v1, u2, v2, RenderTypes.FULL_BRIGHT_LIGHTMAP);
             }
         }
     }

projects/common/src/client/java/dan200/computercraft/client/model/LecternPrintoutModel.java

@@ -0,0 +1,117 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.client.model;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.VertexConsumer;
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.client.render.CustomLecternRenderer;
+import dan200.computercraft.shared.media.items.PrintoutItem;
+import net.minecraft.client.model.geom.ModelPart;
+import net.minecraft.client.model.geom.PartPose;
+import net.minecraft.client.model.geom.builders.CubeListBuilder;
+import net.minecraft.client.model.geom.builders.MeshDefinition;
+import net.minecraft.client.resources.model.Material;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.inventory.InventoryMenu;
+
+import java.util.List;
+
+/**
+ * A model for {@linkplain PrintoutItem printouts} placed on a lectern.
+ * <p>
+ * This provides two models, {@linkplain #renderPages(PoseStack, VertexConsumer, int, int, int) one for a variable
+ * number of pages}, and {@linkplain #renderBook(PoseStack, VertexConsumer, int, int) one for books}.
+ *
+ * @see CustomLecternRenderer
+ */
+public class LecternPrintoutModel {
+    public static final ResourceLocation TEXTURE = ResourceLocation.fromNamespaceAndPath(ComputerCraftAPI.MOD_ID, "entity/printout");
+    public static final Material MATERIAL = new Material(InventoryMenu.BLOCK_ATLAS, TEXTURE);
+
+    private static final int TEXTURE_WIDTH = 32;
+    private static final int TEXTURE_HEIGHT = 32;
+
+    private static final String PAGE_1 = "page_1";
+    private static final String PAGE_2 = "page_2";
+    private static final String PAGE_3 = "page_3";
+    private static final List<String> PAGES = List.of(PAGE_1, PAGE_2, PAGE_3);
+
+    private final ModelPart pagesRoot;
+    private final ModelPart bookRoot;
+    private final ModelPart[] pages;
+
+    public LecternPrintoutModel() {
+        pagesRoot = buildPages();
+        bookRoot = buildBook();
+        pages = PAGES.stream().map(pagesRoot::getChild).toArray(ModelPart[]::new);
+    }
+
+    private static ModelPart buildPages() {
+        var mesh = new MeshDefinition();
+        var parts = mesh.getRoot();
+        parts.addOrReplaceChild(
+            PAGE_1,
+            CubeListBuilder.create().texOffs(0, 0).addBox(-0.005f, -4.0f, -2.5f, 1f, 8.0f, 5.0f),
+            PartPose.ZERO
+        );
+
+        parts.addOrReplaceChild(
+            PAGE_2,
+            CubeListBuilder.create().texOffs(12, 0).addBox(-0.005f, -4.0f, -2.5f, 1f, 8.0f, 5.0f),
+            PartPose.offsetAndRotation(-0.125f, 0, 1.5f, (float) Math.PI * (1f / 16), 0, 0)
+        );
+        parts.addOrReplaceChild(
+            PAGE_3,
+            CubeListBuilder.create().texOffs(12, 0).addBox(-0.005f, -4.0f, -2.5f, 1f, 8.0f, 5.0f),
+            PartPose.offsetAndRotation(-0.25f, 0, -1.5f, (float) -Math.PI * (2f / 16), 0, 0)
+        );
+
+        return mesh.getRoot().bake(TEXTURE_WIDTH, TEXTURE_HEIGHT);
+    }
+
+    private static ModelPart buildBook() {
+        var mesh = new MeshDefinition();
+        var parts = mesh.getRoot();
+
+        parts.addOrReplaceChild(
+            "spine",
+            CubeListBuilder.create().texOffs(12, 15).addBox(-0.005f, -5.0f, -0.5f, 0, 10, 1.0f),
+            PartPose.ZERO
+        );
+
+        var angle = (float) Math.toRadians(5);
+        parts.addOrReplaceChild(
+            "left",
+            CubeListBuilder.create()
+                .texOffs(0, 10).addBox(0, -5.0f, -6.0f, 0, 10, 6.0f)
+                .texOffs(0, 0).addBox(0.005f, -4.0f, -5.0f, 1.0f, 8.0f, 5.0f),
+            PartPose.offsetAndRotation(-0.005f, 0, -0.5f, 0, -angle, 0)
+        );
+
+        parts.addOrReplaceChild(
+            "right",
+            CubeListBuilder.create()
+                .texOffs(14, 10).addBox(0, -5.0f, 0, 0, 10, 6.0f)
+                .texOffs(0, 0).addBox(0.005f, -4.0f, 0, 1.0f, 8.0f, 5.0f),
+            PartPose.offsetAndRotation(-0.005f, 0, 0.5f, 0, angle, 0)
+        );
+
+        return mesh.getRoot().bake(TEXTURE_WIDTH, TEXTURE_HEIGHT);
+    }
+
+    public void renderBook(PoseStack poseStack, VertexConsumer buffer, int packedLight, int packedOverlay) {
+        bookRoot.render(poseStack, buffer, packedLight, packedOverlay);
+    }
+
+    public void renderPages(PoseStack poseStack, VertexConsumer buffer, int packedLight, int packedOverlay, int pageCount) {
+        if (pageCount > pages.length) pageCount = pages.length;
+        var i = 0;
+        for (; i < pageCount; i++) pages[i].visible = true;
+        for (; i < pages.length; i++) pages[i].visible = false;
+
+        pagesRoot.render(poseStack, buffer, packedLight, packedOverlay);
+    }
+}

projects/common/src/client/java/dan200/computercraft/client/render/CustomLecternRenderer.java

@@ -0,0 +1,52 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.client.render;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.math.Axis;
+import dan200.computercraft.client.model.LecternPrintoutModel;
+import dan200.computercraft.shared.lectern.CustomLecternBlockEntity;
+import dan200.computercraft.shared.media.items.PrintoutData;
+import dan200.computercraft.shared.media.items.PrintoutItem;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.blockentity.BlockEntityRenderer;
+import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
+import net.minecraft.client.renderer.blockentity.LecternRenderer;
+import net.minecraft.world.level.block.LecternBlock;
+
+/**
+ * A block entity renderer for our {@linkplain CustomLecternBlockEntity lectern}.
+ * <p>
+ * This largely follows {@link LecternRenderer}, but with support for multiple types of item.
+ */
+public class CustomLecternRenderer implements BlockEntityRenderer<CustomLecternBlockEntity> {
+    private final LecternPrintoutModel printoutModel;
+
+    public CustomLecternRenderer(BlockEntityRendererProvider.Context context) {
+        printoutModel = new LecternPrintoutModel();
+    }
+
+    @Override
+    public void render(CustomLecternBlockEntity lectern, float partialTick, PoseStack poseStack, MultiBufferSource buffer, int packedLight, int packedOverlay) {
+        poseStack.pushPose();
+        poseStack.translate(0.5f, 1.0625f, 0.5f);
+        poseStack.mulPose(Axis.YP.rotationDegrees(-lectern.getBlockState().getValue(LecternBlock.FACING).getClockWise().toYRot()));
+        poseStack.mulPose(Axis.ZP.rotationDegrees(67.5f));
+        poseStack.translate(0, -0.125f, 0);
+
+        var item = lectern.getItem();
+        if (item.getItem() instanceof PrintoutItem printout) {
+            var vertexConsumer = LecternPrintoutModel.MATERIAL.buffer(buffer, RenderType::entitySolid);
+            if (printout.getType() == PrintoutItem.Type.BOOK) {
+                printoutModel.renderBook(poseStack, vertexConsumer, packedLight, packedOverlay);
+            } else {
+                printoutModel.renderPages(poseStack, vertexConsumer, packedLight, packedOverlay, PrintoutData.getOrEmpty(item).pages());
+            }
+        }
+
+        poseStack.popPose();
+    }
+}

projects/common/src/client/java/dan200/computercraft/client/render/PocketItemRenderer.java

@@ -14,6 +14,7 @@ import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.config.Config;
 import dan200.computercraft.shared.pocket.items.PocketComputerItem;
 import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.util.FastColor;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.component.DyedItemColor;
 import org.joml.Matrix4f;
@@ -93,16 +94,11 @@ public final class PocketItemRenderer extends ItemMapLikeRenderer {
     }
 
     private static void renderLight(PoseStack transform, MultiBufferSource render, int colour, int width, int height) {
-        var r = (byte) ((colour >>> 16) & 0xFF);
-        var g = (byte) ((colour >>> 8) & 0xFF);
-        var b = (byte) (colour & 0xFF);
-        var c = new byte[]{ r, g, b, (byte) 255 };
-
         var buffer = render.getBuffer(RenderTypes.TERMINAL);
         FixedWidthFontRenderer.drawQuad(
             FixedWidthFontRenderer.toVertexConsumer(transform, buffer),
             width - LIGHT_HEIGHT * 2, height + BORDER / 2.0f, 0.001f, LIGHT_HEIGHT * 2, LIGHT_HEIGHT,
-            c, RenderTypes.FULL_BRIGHT_LIGHTMAP
+            FastColor.ARGB32.opaque(colour), RenderTypes.FULL_BRIGHT_LIGHTMAP
         );
     }
 }

projects/common/src/client/java/dan200/computercraft/client/render/TurtleBlockEntityRenderer.java

@@ -23,6 +23,7 @@ import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.util.CommonColors;
+import net.minecraft.util.FastColor;
 import net.minecraft.world.phys.BlockHitResult;
 import net.minecraft.world.phys.HitResult;
 
@@ -89,7 +90,7 @@ public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBloc
             renderModel(transform, buffers, lightmapCoord, overlayLight, model, null);
         } else {
             // Otherwise render it using the colour item.
-            renderModel(transform, buffers, lightmapCoord, overlayLight, COLOUR_TURTLE_MODEL, new int[]{ colour });
+            renderModel(transform, buffers, lightmapCoord, overlayLight, COLOUR_TURTLE_MODEL, new int[]{ FastColor.ARGB32.opaque(colour) });
         }
 
         // Render the overlay

projects/common/src/client/java/dan200/computercraft/client/render/monitor/MonitorBlockEntityRenderer.java

@@ -178,7 +178,7 @@ public class MonitorBlockEntityRenderer implements BlockEntityRenderer<MonitorBl
                     var size = DirectFixedWidthFontRenderer.getVertexCount(terminal);
 
                     // In an ideal world we could upload these both into one buffer. However, we can't render VBOs with
-                    // and starting and ending offset, and so need to use two buffers instead.
+                    // a starting and ending offset, and so need to use two buffers instead.
 
                     renderToBuffer(backgroundBuffer, size, sink ->
                         DirectFixedWidthFontRenderer.drawTerminalBackground(sink, 0, 0, terminal, yMargin, yMargin, xMargin, xMargin));
@@ -216,10 +216,10 @@ public class MonitorBlockEntityRenderer implements BlockEntityRenderer<MonitorBl
                 foregroundBuffer.bind();
                 foregroundBuffer.drawWithShader(
                     modelView, RenderSystem.getProjectionMatrix(), RenderTypes.getTerminalShader(),
-                    // As mentioned in the above comment, render the extra cursor quad if it is visible this frame. Each
-                    // // quad has an index count of 6.
-                    FixedWidthFontRenderer.isCursorVisible(terminal) && FrameInfo.getGlobalCursorBlink()
-                        ? foregroundBuffer.getIndexCount() + 6 : foregroundBuffer.getIndexCount()
+                    // Skip the cursor quad if it is not visible this frame.
+                    FixedWidthFontRenderer.isCursorVisible(terminal) && !FrameInfo.getGlobalCursorBlink()
+                        ? foregroundBuffer.getIndexCount() - RenderTypes.TERMINAL.mode().indexCount(4)
+                        : foregroundBuffer.getIndexCount()
                 );
 
                 // Clear state

projects/common/src/client/java/dan200/computercraft/client/render/text/DirectFixedWidthFontRenderer.java

@@ -12,9 +12,11 @@ import dan200.computercraft.core.terminal.Palette;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.core.util.Colour;
+import net.minecraft.util.FastColor;
 import org.lwjgl.system.MemoryUtil;
 
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 
 import static dan200.computercraft.client.render.text.FixedWidthFontRenderer.*;
 import static org.lwjgl.system.MemoryUtil.*;
@@ -37,10 +39,12 @@ import static org.lwjgl.system.MemoryUtil.*;
  * {@link FixedWidthFontRenderer}.
  */
 public final class DirectFixedWidthFontRenderer {
+    private static final boolean IS_LITTLE_ENDIAN = ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN;
+
     private DirectFixedWidthFontRenderer() {
     }
 
-    private static void drawChar(QuadEmitter emitter, float x, float y, int index, byte[] colour) {
+    private static void drawChar(QuadEmitter emitter, float x, float y, int index, int colour) {
         // Short circuit to avoid the common case - the texture should be blank here after all.
         if (index == '\0' || index == ' ') return;
 
@@ -157,8 +161,8 @@ public final class DirectFixedWidthFontRenderer {
         return (terminal.getHeight() + 2) * (terminal.getWidth() + 2) * 2;
     }
 
-    private static void quad(QuadEmitter buffer, float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2) {
-        buffer.quad(x1, y1, x2, y2, z, rgba, u1, v1, u2, v2);
+    private static void quad(QuadEmitter buffer, float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2) {
+        buffer.quad(x1, y1, x2, y2, z, colour, u1, v1, u2, v2);
     }
 
     public interface QuadEmitter {
@@ -166,7 +170,7 @@ public final class DirectFixedWidthFontRenderer {
 
         ByteBuffer buffer();
 
-        void quad(float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2);
+        void quad(float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2);
     }
 
     public record ByteBufferEmitter(ByteBuffer buffer) implements QuadEmitter {
@@ -176,12 +180,12 @@ public final class DirectFixedWidthFontRenderer {
         }
 
         @Override
-        public void quad(float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2) {
-            DirectFixedWidthFontRenderer.quad(buffer, x1, y1, x2, y2, z, rgba, u1, v1, u2, v2);
+        public void quad(float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2) {
+            DirectFixedWidthFontRenderer.quad(buffer, x1, y1, x2, y2, z, colour, u1, v1, u2, v2);
         }
     }
 
-    static void quad(ByteBuffer buffer, float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2) {
+    static void quad(ByteBuffer buffer, float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2) {
         // Emit a single quad to our buffer. This uses Unsafe (well, LWJGL's MemoryUtil) to directly blit bytes to the
         // underlying buffer. This allows us to have a single bounds check up-front, rather than one for every write.
         // This provides significant performance gains, at the cost of well, using Unsafe.
@@ -195,16 +199,15 @@ public final class DirectFixedWidthFontRenderer {
         if (position < 0 || 112 > buffer.limit() - position) throw new IndexOutOfBoundsException();
         // Require the pointer to be aligned to a 32-bit boundary.
         if ((addr & 3) != 0) throw new IllegalStateException("Memory is not aligned");
-        // Also assert the length of the array. This appears to help elide bounds checks on the array in some circumstances.
-        if (rgba.length != 4) throw new IllegalStateException();
+
+        // Pack colour so it is equivalent to rgba:BBBB. This matches the logic in BufferBuilder.
+        var colourAbgr = FastColor.ABGR32.fromArgb32(colour);
+        var nativeColour = IS_LITTLE_ENDIAN ? colourAbgr : Integer.reverseBytes(colourAbgr);
 
         memPutFloat(addr + 0, x1);
         memPutFloat(addr + 4, y1);
         memPutFloat(addr + 8, z);
-        memPutByte(addr + 12, rgba[0]);
-        memPutByte(addr + 13, rgba[1]);
-        memPutByte(addr + 14, rgba[2]);
-        memPutByte(addr + 15, (byte) 255);
+        memPutInt(addr + 12, nativeColour);
         memPutFloat(addr + 16, u1);
         memPutFloat(addr + 20, v1);
         memPutShort(addr + 24, (short) 0xF0);
@@ -213,10 +216,7 @@ public final class DirectFixedWidthFontRenderer {
         memPutFloat(addr + 28, x1);
         memPutFloat(addr + 32, y2);
         memPutFloat(addr + 36, z);
-        memPutByte(addr + 40, rgba[0]);
-        memPutByte(addr + 41, rgba[1]);
-        memPutByte(addr + 42, rgba[2]);
-        memPutByte(addr + 43, (byte) 255);
+        memPutInt(addr + 40, nativeColour);
         memPutFloat(addr + 44, u1);
         memPutFloat(addr + 48, v2);
         memPutShort(addr + 52, (short) 0xF0);
@@ -225,10 +225,7 @@ public final class DirectFixedWidthFontRenderer {
         memPutFloat(addr + 56, x2);
         memPutFloat(addr + 60, y2);
         memPutFloat(addr + 64, z);
-        memPutByte(addr + 68, rgba[0]);
-        memPutByte(addr + 69, rgba[1]);
-        memPutByte(addr + 70, rgba[2]);
-        memPutByte(addr + 71, (byte) 255);
+        memPutInt(addr + 68, nativeColour);
         memPutFloat(addr + 72, u2);
         memPutFloat(addr + 76, v2);
         memPutShort(addr + 80, (short) 0xF0);
@@ -237,10 +234,7 @@ public final class DirectFixedWidthFontRenderer {
         memPutFloat(addr + 84, x2);
         memPutFloat(addr + 88, y1);
         memPutFloat(addr + 92, z);
-        memPutByte(addr + 96, rgba[0]);
-        memPutByte(addr + 97, rgba[1]);
-        memPutByte(addr + 98, rgba[2]);
-        memPutByte(addr + 99, (byte) 255);
+        memPutInt(addr + 96, nativeColour);
         memPutFloat(addr + 100, u2);
         memPutFloat(addr + 104, v1);
         memPutShort(addr + 108, (short) 0xF0);

projects/common/src/client/java/dan200/computercraft/client/render/text/FixedWidthFontRenderer.java

@@ -12,6 +12,7 @@ import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.core.util.Colour;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.util.FastColor;
 import org.joml.Matrix4f;
 import org.joml.Vector3f;
 
@@ -41,7 +42,7 @@ public final class FixedWidthFontRenderer {
     static final float BACKGROUND_START = (WIDTH - 6.0f) / WIDTH;
     static final float BACKGROUND_END = (WIDTH - 4.0f) / WIDTH;
 
-    private static final byte[] BLACK = new byte[]{ byteColour(Colour.BLACK.getR()), byteColour(Colour.BLACK.getR()), byteColour(Colour.BLACK.getR()), (byte) 255 };
+    private static final int BLACK = FastColor.ARGB32.color(255, byteColour(Colour.BLACK.getR()), byteColour(Colour.BLACK.getR()), byteColour(Colour.BLACK.getR()));
     private static final float Z_OFFSET = 1e-3f;
 
     private FixedWidthFontRenderer() {
@@ -59,7 +60,7 @@ public final class FixedWidthFontRenderer {
         return 15 - Terminal.getColour(c, def);
     }
 
-    private static void drawChar(QuadEmitter emitter, float x, float y, int index, byte[] colour, int light) {
+    private static void drawChar(QuadEmitter emitter, float x, float y, int index, int colour, int light) {
         // Short circuit to avoid the common case - the texture should be blank here after all.
         if (index == '\0' || index == ' ') return;
 
@@ -75,7 +76,7 @@ public final class FixedWidthFontRenderer {
         );
     }
 
-    public static void drawQuad(QuadEmitter emitter, float x, float y, float z, float width, float height, byte[] colour, int light) {
+    public static void drawQuad(QuadEmitter emitter, float x, float y, float z, float width, float height, int colour, int light) {
         quad(emitter, x, y, x + width, y + height, z, colour, BACKGROUND_START, BACKGROUND_START, BACKGROUND_END, BACKGROUND_END, light);
     }
 
@@ -216,10 +217,10 @@ public final class FixedWidthFontRenderer {
         return new QuadEmitter(transform.last().pose(), consumer);
     }
 
-    private static void quad(QuadEmitter c, float x1, float y1, float x2, float y2, float z, byte[] rgba, float u1, float v1, float u2, float v2, int light) {
+    private static void quad(QuadEmitter c, float x1, float y1, float x2, float y2, float z, int colour, float u1, float v1, float u2, float v2, int light) {
         var poseMatrix = c.poseMatrix();
         var consumer = c.consumer();
-        byte r = rgba[0], g = rgba[1], b = rgba[2], a = rgba[3];
+        int r = FastColor.ARGB32.red(colour), g = FastColor.ARGB32.green(colour), b = FastColor.ARGB32.blue(colour), a = FastColor.ARGB32.alpha(colour);
 
         consumer.addVertex(poseMatrix, x1, y1, z).setColor(r, g, b, a).setUv(u1, v1).setLight(light);
         consumer.addVertex(poseMatrix, x1, y2, z).setColor(r, g, b, a).setUv(u1, v2).setLight(light);

projects/common/src/client/java/dan200/computercraft/data/client/ClientDataProviders.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.data.client;
 
 import dan200.computercraft.client.gui.GuiSprites;
+import dan200.computercraft.client.model.LecternPrintoutModel;
 import dan200.computercraft.data.DataProviders;
 import dan200.computercraft.shared.turtle.TurtleOverlay;
 import dan200.computercraft.shared.turtle.inventory.UpgradeSlot;
@@ -33,7 +34,8 @@ public final class ClientDataProviders {
         generator.addFromCodec("Block atlases", PackType.CLIENT_RESOURCES, "atlases", SpriteSources.FILE_CODEC, out -> {
             out.accept(ResourceLocation.withDefaultNamespace("blocks"), List.of(
                 new SingleFile(UpgradeSlot.LEFT_UPGRADE, Optional.empty()),
-                new SingleFile(UpgradeSlot.RIGHT_UPGRADE, Optional.empty())
+                new SingleFile(UpgradeSlot.RIGHT_UPGRADE, Optional.empty()),
+                new SingleFile(LecternPrintoutModel.TEXTURE, Optional.empty())
             ));
             out.accept(GuiSprites.SPRITE_SHEET, Stream.of(
                 // Buttons

projects/common/src/generated/resources/assets/computercraft/blockstates/lectern.json

@@ -0,0 +1,8 @@
+{
+  "variants": {
+    "facing=east": {"model": "minecraft:block/lectern", "y": 90},
+    "facing=north": {"model": "minecraft:block/lectern", "y": 0},
+    "facing=south": {"model": "minecraft:block/lectern", "y": 180},
+    "facing=west": {"model": "minecraft:block/lectern", "y": 270}
+  }
+}

projects/common/src/generated/resources/assets/computercraft/blockstates/redstone_relay.json

@@ -0,0 +1,8 @@
+{
+  "variants": {
+    "facing=east": {"model": "computercraft:block/redstone_relay", "y": 90},
+    "facing=north": {"model": "computercraft:block/redstone_relay", "y": 0},
+    "facing=south": {"model": "computercraft:block/redstone_relay", "y": 180},
+    "facing=west": {"model": "computercraft:block/redstone_relay", "y": 270}
+  }
+}

projects/common/src/generated/resources/assets/computercraft/lang/en_us.json

@@ -17,6 +17,7 @@
   "block.computercraft.monitor_advanced": "Advanced Monitor",
   "block.computercraft.monitor_normal": "Monitor",
   "block.computercraft.printer": "Printer",
+  "block.computercraft.redstone_relay": "Redstone Relay",
   "block.computercraft.speaker": "Speaker",
   "block.computercraft.turtle_advanced": "Advanced Turtle",
   "block.computercraft.turtle_advanced.upgraded": "Advanced %s Turtle",
@@ -38,8 +39,6 @@
   "commands.computercraft.generic.additional_rows": "%d additional rows…",
   "commands.computercraft.generic.exception": "Unhandled exception (%s)",
   "commands.computercraft.generic.no": "N",
-  "commands.computercraft.generic.no_position": "<no pos>",
-  "commands.computercraft.generic.position": "%s, %s, %s",
   "commands.computercraft.generic.yes": "Y",
   "commands.computercraft.help.desc": "Displays this help message",
   "commands.computercraft.help.no_children": "%s has no sub-commands",

projects/common/src/generated/resources/assets/computercraft/models/block/redstone_relay.json

@@ -0,0 +1,9 @@
+{
+  "parent": "minecraft:block/orientable_with_bottom",
+  "textures": {
+    "bottom": "computercraft:block/redstone_relay_bottom",
+    "front": "computercraft:block/redstone_relay_front",
+    "side": "computercraft:block/redstone_relay_side",
+    "top": "computercraft:block/redstone_relay_top"
+  }
+}

projects/common/src/generated/resources/assets/computercraft/models/item/redstone_relay.json

@@ -0,0 +1 @@
+{"parent": "computercraft:block/redstone_relay"}

projects/common/src/generated/resources/assets/minecraft/atlases/blocks.json

@@ -1,6 +1,7 @@
 {
   "sources": [
     {"type": "minecraft:single", "resource": "computercraft:gui/turtle_upgrade_left"},
-    {"type": "minecraft:single", "resource": "computercraft:gui/turtle_upgrade_right"}
+    {"type": "minecraft:single", "resource": "computercraft:gui/turtle_upgrade_right"},
+    {"type": "minecraft:single", "resource": "computercraft:entity/printout"}
   ]
 }

projects/common/src/generated/resources/data/computercraft/advancement/recipes/redstone/redstone_relay.json

@@ -0,0 +1,15 @@
+{
+  "parent": "minecraft:recipes/root",
+  "criteria": {
+    "has_cable": {
+      "conditions": {"items": [{"items": "computercraft:wired_modem"}]},
+      "trigger": "minecraft:inventory_changed"
+    },
+    "has_the_recipe": {
+      "conditions": {"recipe": "computercraft:redstone_relay"},
+      "trigger": "minecraft:recipe_unlocked"
+    }
+  },
+  "requirements": [["has_the_recipe", "has_cable"]],
+  "rewards": {"recipes": ["computercraft:redstone_relay"]}
+}

projects/common/src/generated/resources/data/computercraft/loot_table/blocks/lectern.json

@@ -0,0 +1,12 @@
+{
+  "type": "minecraft:block",
+  "pools": [
+    {
+      "bonus_rolls": 0.0,
+      "conditions": [{"condition": "minecraft:survives_explosion"}],
+      "entries": [{"type": "minecraft:item", "name": "minecraft:lectern"}],
+      "rolls": 1.0
+    }
+  ],
+  "random_sequence": "computercraft:blocks/lectern"
+}

projects/common/src/generated/resources/data/computercraft/loot_table/blocks/redstone_relay.json

@@ -0,0 +1,12 @@
+{
+  "type": "minecraft:block",
+  "pools": [
+    {
+      "bonus_rolls": 0.0,
+      "conditions": [{"condition": "minecraft:survives_explosion"}],
+      "entries": [{"type": "minecraft:item", "name": "computercraft:redstone_relay"}],
+      "rolls": 1.0
+    }
+  ],
+  "random_sequence": "computercraft:blocks/redstone_relay"
+}

projects/common/src/generated/resources/data/computercraft/recipe/redstone_relay.json

@@ -0,0 +1,11 @@
+{
+  "type": "minecraft:crafting_shaped",
+  "category": "redstone",
+  "key": {
+    "C": {"item": "computercraft:wired_modem"},
+    "R": {"tag": "c:dusts/redstone"},
+    "S": {"item": "minecraft:stone"}
+  },
+  "pattern": ["SRS", "RCR", "SRS"],
+  "result": {"count": 1, "id": "computercraft:redstone_relay"}
+}

projects/common/src/generated/resources/data/minecraft/tags/block/mineable/axe.json

@@ -0,0 +1 @@
+{"values": ["computercraft:lectern"]}

projects/common/src/generated/resources/data/minecraft/tags/block/mineable/pickaxe.json

@@ -12,6 +12,7 @@
     "computercraft:wireless_modem_normal",
     "computercraft:wireless_modem_advanced",
     "computercraft:wired_modem_full",
-    "computercraft:cable"
+    "computercraft:cable",
+    "computercraft:redstone_relay"
   ]
 }

projects/common/src/main/java/dan200/computercraft/data/BlockModelProvider.java

@@ -23,6 +23,7 @@ import net.minecraft.data.models.BlockModelGenerators;
 import net.minecraft.data.models.blockstates.*;
 import net.minecraft.data.models.model.*;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.state.properties.BlockStateProperties;
 import net.minecraft.world.level.block.state.properties.BooleanProperty;
 import net.minecraft.world.level.block.state.properties.Property;
@@ -96,10 +97,17 @@ class BlockModelProvider {
 
         registerCable(generators);
 
+        registerRedstoneControl(generators);
+
         registerTurtleUpgrade(generators, "block/turtle_crafting_table", "block/turtle_crafty_face");
         registerTurtleUpgrade(generators, "block/turtle_speaker", "block/turtle_speaker_face");
         registerTurtleModem(generators, "block/turtle_modem_normal", "block/wireless_modem_normal_face");
         registerTurtleModem(generators, "block/turtle_modem_advanced", "block/wireless_modem_advanced_face");
+
+        generators.blockStateOutput.accept(MultiVariantGenerator.multiVariant(
+            ModRegistry.Blocks.LECTERN.get(),
+            Variant.variant().with(VariantProperties.MODEL, ModelLocationUtils.getModelLocation(Blocks.LECTERN))
+        ).with(createHorizontalFacingDispatch()));
     }
 
     private static void registerDiskDrive(BlockModelGenerators generators) {
@@ -349,6 +357,18 @@ class BlockModelProvider {
         generators.blockStateOutput.accept(generator);
     }
 
+    private static void registerRedstoneControl(BlockModelGenerators generators) {
+        var redstoneControl = ModRegistry.Blocks.REDSTONE_RELAY.get();
+        var model = ModelTemplates.CUBE_ORIENTABLE_TOP_BOTTOM.create(
+            redstoneControl, TextureMapping.orientableCube(redstoneControl), generators.modelOutput
+        );
+        generators.blockStateOutput.accept(
+            MultiVariantGenerator.multiVariant(redstoneControl, Variant.variant().with(VariantProperties.MODEL, model))
+                .with(createHorizontalFacingDispatch())
+        );
+    }
+
+
     private static final BooleanProperty[] CABLE_DIRECTIONS = { CableBlock.DOWN, CableBlock.UP, CableBlock.NORTH, CableBlock.SOUTH, CableBlock.WEST, CableBlock.EAST };
     private static final boolean[] BOOLEANS = new boolean[]{ false, true };
 

projects/common/src/main/java/dan200/computercraft/data/LanguageProvider.java

@@ -82,6 +82,7 @@ public final class LanguageProvider implements DataProvider {
         add(ModRegistry.Items.WIRED_MODEM.get(), "Wired Modem");
         add(ModRegistry.Items.CABLE.get(), "Networking Cable");
         add(ModRegistry.Items.WIRED_MODEM_FULL.get(), "Wired Modem");
+        add(ModRegistry.Items.REDSTONE_RELAY.get(), "Redstone Relay");
 
         add(ModRegistry.Items.TURTLE_NORMAL.get(), "Turtle");
         add(ModRegistry.Blocks.TURTLE_NORMAL.get().getDescriptionId() + ".upgraded", "%s Turtle");
@@ -164,8 +165,6 @@ public final class LanguageProvider implements DataProvider {
         add("commands.computercraft.queue.synopsis", "Send a computer_command event to a command computer");
         add("commands.computercraft.queue.desc", "Send a computer_command event to a command computer, passing through the additional arguments. This is mostly designed for map makers, acting as a more computer-friendly version of /trigger. Any player can run the command, which would most likely be done through a text component's click event.");
 
-        add("commands.computercraft.generic.no_position", "<no pos>");
-        add("commands.computercraft.generic.position", "%s, %s, %s");
         add("commands.computercraft.generic.yes", "Y");
         add("commands.computercraft.generic.no", "N");
         add("commands.computercraft.generic.exception", "Unhandled exception (%s)");
@@ -288,7 +287,9 @@ public final class LanguageProvider implements DataProvider {
         return Stream.of(
             BuiltInRegistries.BLOCK.holders()
                 .filter(x -> x.key().location().getNamespace().equals(ComputerCraftAPI.MOD_ID))
-                .map(x -> x.value().getDescriptionId()),
+                .map(x -> x.value().getDescriptionId())
+                // Exclude blocks that just reuse vanilla translations, such as the lectern.
+                .filter(x -> !x.startsWith("block.minecraft.")),
             BuiltInRegistries.ITEM.holders()
                 .filter(x -> x.key().location().getNamespace().equals(ComputerCraftAPI.MOD_ID))
                 .map(x -> x.value().getDescriptionId()),

projects/common/src/main/java/dan200/computercraft/data/LootTableProvider.java

@@ -14,6 +14,7 @@ import dan200.computercraft.shared.peripheral.modem.wired.CableModemVariant;
 import net.minecraft.advancements.critereon.StatePropertiesPredicate;
 import net.minecraft.data.loot.LootTableProvider.SubProviderEntry;
 import net.minecraft.resources.ResourceKey;
+import net.minecraft.world.item.Items;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.storage.loot.LootPool;
 import net.minecraft.world.level.storage.loot.LootTable;
@@ -49,6 +50,7 @@ class LootTableProvider {
         selfDrop(add, ModRegistry.Blocks.WIRED_MODEM_FULL);
         selfDrop(add, ModRegistry.Blocks.WIRELESS_MODEM_NORMAL);
         selfDrop(add, ModRegistry.Blocks.WIRELESS_MODEM_ADVANCED);
+        selfDrop(add, ModRegistry.Blocks.REDSTONE_RELAY);
 
         computerDrop(add, ModRegistry.Blocks.COMPUTER_NORMAL);
         computerDrop(add, ModRegistry.Blocks.COMPUTER_ADVANCED);
@@ -56,6 +58,8 @@ class LootTableProvider {
         computerDrop(add, ModRegistry.Blocks.TURTLE_NORMAL);
         computerDrop(add, ModRegistry.Blocks.TURTLE_ADVANCED);
 
+        blockDrop(add, ModRegistry.Blocks.LECTERN, LootItem.lootTableItem(Items.LECTERN), ExplosionCondition.survivesExplosion());
+
         add.accept(ModRegistry.Blocks.CABLE.get().getLootTable(), LootTable
             .lootTable()
             .withPool(LootPool.lootPool()

projects/common/src/main/java/dan200/computercraft/data/RecipeProvider.java

@@ -491,6 +491,17 @@ final class RecipeProvider extends net.minecraft.data.recipes.RecipeProvider {
             .unlockedBy("has_printer", inventoryChange(ModRegistry.Items.PRINTER.get()))
             .build(x -> new PrintoutRecipe(x, pages, 1))
             .save(add);
+
+        ShapedRecipeBuilder
+            .shaped(RecipeCategory.REDSTONE, ModRegistry.Blocks.REDSTONE_RELAY.get())
+            .pattern("SRS")
+            .pattern("RCR")
+            .pattern("SRS")
+            .define('S', Items.STONE)
+            .define('R', ingredients.redstone())
+            .define('C', ModRegistry.Blocks.CABLE.get())
+            .unlockedBy("has_cable", inventoryChange(ModRegistry.Blocks.CABLE.get()))
+            .save(add);
     }
 
     private static DyeColor ofColour(Colour colour) {

projects/common/src/main/java/dan200/computercraft/data/TagProvider.java

@@ -5,9 +5,9 @@
 package dan200.computercraft.data;
 
 import dan200.computercraft.api.ComputerCraftTags;
-import dan200.computercraft.shared.util.RegistryHelper;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.integration.ExternalModTags;
+import dan200.computercraft.shared.util.RegistryHelper;
 import net.minecraft.core.Registry;
 import net.minecraft.data.tags.ItemTagsProvider;
 import net.minecraft.data.tags.TagsProvider;
@@ -79,9 +79,12 @@ class TagProvider {
             ModRegistry.Blocks.WIRELESS_MODEM_NORMAL.get(),
             ModRegistry.Blocks.WIRELESS_MODEM_ADVANCED.get(),
             ModRegistry.Blocks.WIRED_MODEM_FULL.get(),
-            ModRegistry.Blocks.CABLE.get()
+            ModRegistry.Blocks.CABLE.get(),
+            ModRegistry.Blocks.REDSTONE_RELAY.get()
         );
 
+        tags.tag(BlockTags.MINEABLE_WITH_AXE).add(ModRegistry.Blocks.LECTERN.get());
+
         tags.tag(BlockTags.WITHER_IMMUNE).add(ModRegistry.Blocks.COMPUTER_COMMAND.get());
 
         tags.tag(ExternalModTags.Blocks.CREATE_BRITTLE).add(
@@ -107,6 +110,7 @@ class TagProvider {
             ModRegistry.Items.MONITOR_ADVANCED.get()
         );
 
+        // Allow printed books to be placed in bookshelves.
         tags.tag(ItemTags.BOOKSHELF_BOOKS).add(ModRegistry.Items.PRINTED_BOOK.get());
 
         tags.tag(ComputerCraftTags.Items.TURTLE_CAN_PLACE)

projects/common/src/main/java/dan200/computercraft/impl/ApiFactories.java

@@ -14,7 +14,6 @@ import java.util.Objects;
 /**
  * The global factory for {@link ILuaAPIFactory}s.
  *
- * @see dan200.computercraft.core.ComputerContext.Builder#apiFactories(Collection)
  * @see dan200.computercraft.api.ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
  */
 public final class ApiFactories {

projects/common/src/main/java/dan200/computercraft/impl/detail/DetailRegistryImpl.java

@@ -15,7 +15,7 @@ import java.util.*;
  * @param <T> The type of object that this registry provides details for.
  */
 public class DetailRegistryImpl<T> implements DetailRegistry<T> {
-    private final Collection<DetailProvider<T>> providers = new ArrayList<>();
+    private final Collection<DetailProvider<? super T>> providers = new ArrayList<>();
     private final DetailProvider<T> basic;
 
     public DetailRegistryImpl(DetailProvider<T> basic) {
@@ -24,7 +24,7 @@ public class DetailRegistryImpl<T> implements DetailRegistry<T> {
     }
 
     @Override
-    public synchronized void addProvider(DetailProvider<T> provider) {
+    public synchronized void addProvider(DetailProvider<? super T> provider) {
         Objects.requireNonNull(provider, "provider cannot be null");
         if (!providers.contains(provider)) providers.add(provider);
     }

projects/common/src/main/java/dan200/computercraft/mixin/DataFixersMixin.java

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.mixin;
+
+import com.llamalad7.mixinextras.sugar.Local;
+import com.mojang.datafixers.DataFixUtils;
+import com.mojang.datafixers.DataFixerBuilder;
+import com.mojang.datafixers.schemas.Schema;
+import dan200.computercraft.shared.datafix.TurtleUpgradeComponentizationFix;
+import net.minecraft.util.datafix.DataFixers;
+import net.minecraft.util.datafix.fixes.ItemStackComponentizationFix;
+import net.minecraft.util.datafix.schemas.V3818_5;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
+
+@Mixin(DataFixers.class)
+abstract class DataFixersMixin {
+    /**
+     * Register {@link TurtleUpgradeComponentizationFix} alongside {@link ItemStackComponentizationFix}.
+     * <p>
+     * We use a {@link ModifyArg} to capture the schema passed to {@link ItemStackComponentizationFix}. This is a
+     * little gross, but is the easiest way to obtain the schema without hard-coding local ordinals.
+     *
+     * @param schema  The {@link V3818_5} schema.
+     * @param builder The current datafixer builder
+     * @return The input schema.
+     */
+    @ModifyArg(
+        method = "addFixers",
+        at = @At(value = "INVOKE", target = "Lnet/minecraft/util/datafix/fixes/ItemStackComponentizationFix;<init>(Lcom/mojang/datafixers/schemas/Schema;)V"),
+        index = 0,
+        allow = 1
+    )
+    @SuppressWarnings("UnusedMethod")
+    private static Schema addComponentizationFixes(Schema schema, @Local DataFixerBuilder builder) {
+        assertSchemaVersion(schema, DataFixUtils.makeKey(3818, 5));
+        builder.addFixer(new TurtleUpgradeComponentizationFix(schema));
+        return schema;
+    }
+
+    @Unique
+    private static void assertSchemaVersion(Schema schema, int version) {
+        if (schema.getVersionKey() != version) {
+            throw new IllegalStateException("Unexpected schema version. Expected " + version + ", got " + schema.getVersionKey());
+        }
+    }
+}

projects/common/src/main/java/dan200/computercraft/mixin/ItemStackComponentizationFixMixin.java

@@ -4,14 +4,11 @@
 
 package dan200.computercraft.mixin;
 
-import com.llamalad7.mixinextras.injector.ModifyReturnValue;
 import com.mojang.datafixers.DataFix;
-import com.mojang.datafixers.TypeRewriteRule;
 import com.mojang.datafixers.schemas.Schema;
 import com.mojang.serialization.Dynamic;
-import dan200.computercraft.shared.util.ComponentizationFixers;
+import dan200.computercraft.shared.datafix.ComponentizationFixers;
 import net.minecraft.util.datafix.fixes.ItemStackComponentizationFix;
-import net.minecraft.util.datafix.fixes.References;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
@@ -31,19 +28,8 @@ abstract class ItemStackComponentizationFixMixin extends DataFix {
     }
 
     @Inject(method = "fixItemStack", at = @At("TAIL"))
-    @SuppressWarnings("UnusedMethod")
+    @SuppressWarnings("unused")
     private static void fixItemStack(ItemStackComponentizationFix.ItemStackData data, Dynamic<?> ops, CallbackInfo ci) {
         ComponentizationFixers.fixItemComponents(data, ops);
     }
-
-    @ModifyReturnValue(method = "makeRule", at = @At("RETURN"), remap = false)
-    @SuppressWarnings("UnusedMethod")
-    private TypeRewriteRule wrapMakeRule(TypeRewriteRule existing) {
-        return TypeRewriteRule.seq(existing, fixTypeEverywhereTyped(
-            "Turtle upgrade componentization",
-            getInputSchema().getType(References.BLOCK_ENTITY),
-            getOutputSchema().getType(References.BLOCK_ENTITY),
-            ComponentizationFixers.makeBlockEntityRewrites(getInputSchema(), getOutputSchema())
-        ));
-    }
 }

projects/common/src/main/java/dan200/computercraft/shared/CommonHooks.java

@@ -9,6 +9,7 @@ import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.shared.computer.core.ResourceMount;
 import dan200.computercraft.shared.computer.core.ServerContext;
 import dan200.computercraft.shared.computer.metrics.ComputerMBean;
+import dan200.computercraft.shared.lectern.CustomLecternBlock;
 import dan200.computercraft.shared.peripheral.monitor.MonitorWatcher;
 import dan200.computercraft.shared.util.DropConsumer;
 import dan200.computercraft.shared.util.TickScheduler;
@@ -20,16 +21,23 @@ import net.minecraft.server.dedicated.DedicatedServer;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.server.packs.resources.PreparableReloadListener;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.InteractionResult;
 import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.CreativeModeTab;
 import net.minecraft.world.item.CreativeModeTabs;
 import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.LecternBlock;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.storage.loot.BuiltInLootTables;
 import net.minecraft.world.level.storage.loot.LootPool;
 import net.minecraft.world.level.storage.loot.LootTable;
 import net.minecraft.world.level.storage.loot.entries.NestedLootTable;
 import net.minecraft.world.level.storage.loot.providers.number.ConstantValue;
+import net.minecraft.world.phys.BlockHitResult;
 
 import javax.annotation.Nullable;
 import java.util.Set;
@@ -92,6 +100,20 @@ public final class CommonHooks {
         TickScheduler.onChunkTicketChanged(level, chunkPos, oldLevel, newLevel);
     }
 
+    public static InteractionResult onUseBlock(Player player, Level level, InteractionHand hand, BlockHitResult hitResult) {
+        if (player.isSpectator()) return InteractionResult.PASS;
+
+        var pos = hitResult.getBlockPos();
+        var heldItem = player.getItemInHand(hand);
+        var blockState = level.getBlockState(pos);
+
+        if (blockState.is(Blocks.LECTERN) && !blockState.getValue(LecternBlock.HAS_BOOK)) {
+            return CustomLecternBlock.tryPlaceItem(player, level, pos, blockState, heldItem);
+        }
+
+        return InteractionResult.PASS;
+    }
+
     public static final ResourceKey<LootTable> TREASURE_DISK_LOOT = ResourceKey.create(Registries.LOOT_TABLE, ResourceLocation.fromNamespaceAndPath(ComputerCraftAPI.MOD_ID, "treasure_disk"));
 
     private static final Set<ResourceKey<LootTable>> TREASURE_DISK_LOOT_TABLES = Set.of(

projects/common/src/main/java/dan200/computercraft/shared/ModRegistry.java

@@ -8,6 +8,7 @@ import com.mojang.brigadier.arguments.ArgumentType;
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.MapCodec;
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.component.ComputerComponents;
 import dan200.computercraft.api.detail.DetailProvider;
 import dan200.computercraft.api.detail.VanillaDetailRegistries;
 import dan200.computercraft.api.media.IMedia;
@@ -25,7 +26,7 @@ import dan200.computercraft.shared.command.arguments.TrackingFieldArgumentType;
 import dan200.computercraft.shared.common.ClearColourRecipe;
 import dan200.computercraft.shared.common.ColourableRecipe;
 import dan200.computercraft.shared.common.DefaultBundledRedstoneProvider;
-import dan200.computercraft.shared.common.HeldItemMenu;
+import dan200.computercraft.shared.computer.apis.CommandAPI;
 import dan200.computercraft.shared.computer.blocks.CommandComputerBlock;
 import dan200.computercraft.shared.computer.blocks.ComputerBlock;
 import dan200.computercraft.shared.computer.blocks.ComputerBlockEntity;
@@ -42,12 +43,14 @@ import dan200.computercraft.shared.data.PlayerCreativeLootCondition;
 import dan200.computercraft.shared.details.BlockDetails;
 import dan200.computercraft.shared.details.ItemDetails;
 import dan200.computercraft.shared.integration.PermissionRegistry;
+import dan200.computercraft.shared.lectern.CustomLecternBlock;
+import dan200.computercraft.shared.lectern.CustomLecternBlockEntity;
+import dan200.computercraft.shared.media.PrintoutMenu;
 import dan200.computercraft.shared.media.items.*;
 import dan200.computercraft.shared.media.recipes.DiskRecipe;
 import dan200.computercraft.shared.media.recipes.PrintoutRecipe;
 import dan200.computercraft.shared.network.container.ComputerContainerData;
 import dan200.computercraft.shared.network.container.ContainerData;
-import dan200.computercraft.shared.network.container.HeldItemContainerData;
 import dan200.computercraft.shared.peripheral.diskdrive.DiskDriveBlock;
 import dan200.computercraft.shared.peripheral.diskdrive.DiskDriveBlockEntity;
 import dan200.computercraft.shared.peripheral.diskdrive.DiskDriveMenu;
@@ -59,11 +62,14 @@ import dan200.computercraft.shared.peripheral.monitor.MonitorBlockEntity;
 import dan200.computercraft.shared.peripheral.printer.PrinterBlock;
 import dan200.computercraft.shared.peripheral.printer.PrinterBlockEntity;
 import dan200.computercraft.shared.peripheral.printer.PrinterMenu;
+import dan200.computercraft.shared.peripheral.redstone.RedstoneRelayBlock;
+import dan200.computercraft.shared.peripheral.redstone.RedstoneRelayBlockEntity;
 import dan200.computercraft.shared.peripheral.speaker.SpeakerBlock;
 import dan200.computercraft.shared.peripheral.speaker.SpeakerBlockEntity;
 import dan200.computercraft.shared.platform.PlatformHelper;
 import dan200.computercraft.shared.platform.RegistrationHelper;
 import dan200.computercraft.shared.platform.RegistryEntry;
+import dan200.computercraft.shared.pocket.apis.PocketAPI;
 import dan200.computercraft.shared.pocket.items.PocketComputerItem;
 import dan200.computercraft.shared.pocket.peripherals.PocketModem;
 import dan200.computercraft.shared.pocket.peripherals.PocketSpeaker;
@@ -73,8 +79,10 @@ import dan200.computercraft.shared.recipe.function.CopyComponents;
 import dan200.computercraft.shared.recipe.function.RecipeFunction;
 import dan200.computercraft.shared.turtle.FurnaceRefuelHandler;
 import dan200.computercraft.shared.turtle.TurtleOverlay;
+import dan200.computercraft.shared.turtle.apis.TurtleAPI;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlock;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlockEntity;
+import dan200.computercraft.shared.turtle.core.TurtleAccessInternal;
 import dan200.computercraft.shared.turtle.inventory.TurtleMenu;
 import dan200.computercraft.shared.turtle.items.TurtleItem;
 import dan200.computercraft.shared.turtle.recipes.TurtleUpgradeRecipe;
@@ -82,6 +90,7 @@ import dan200.computercraft.shared.turtle.upgrades.TurtleCraftingTable;
 import dan200.computercraft.shared.turtle.upgrades.TurtleModem;
 import dan200.computercraft.shared.turtle.upgrades.TurtleSpeaker;
 import dan200.computercraft.shared.turtle.upgrades.TurtleTool;
+import dan200.computercraft.shared.util.ComponentMap;
 import dan200.computercraft.shared.util.DataComponentUtil;
 import dan200.computercraft.shared.util.NonNegativeId;
 import net.minecraft.commands.CommandSourceStack;
@@ -108,12 +117,15 @@ import net.minecraft.world.item.crafting.Recipe;
 import net.minecraft.world.item.crafting.RecipeSerializer;
 import net.minecraft.world.item.crafting.SimpleCraftingRecipeSerializer;
 import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.block.SoundType;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockBehaviour;
+import net.minecraft.world.level.block.state.properties.NoteBlockInstrument;
 import net.minecraft.world.level.material.MapColor;
 import net.minecraft.world.level.storage.loot.predicates.LootItemConditionType;
 
+import java.util.Objects;
 import java.util.function.BiFunction;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
@@ -135,7 +147,7 @@ public final class ModRegistry {
             return BlockBehaviour.Properties.of().strength(2);
         }
 
-        private static BlockBehaviour.Properties computerProperties() {
+        private static BlockBehaviour.Properties redstoneConductor() {
             // Computers shouldn't conduct redstone through them, so set isRedstoneConductor to false. This still allows
             // redstone to connect to computers though as it's a signal source.
             return properties().isRedstoneConductor((block, level, blockPos) -> false);
@@ -150,11 +162,11 @@ public final class ModRegistry {
         }
 
         public static final RegistryEntry<ComputerBlock<ComputerBlockEntity>> COMPUTER_NORMAL = REGISTRY.register("computer_normal",
-            () -> new ComputerBlock<>(computerProperties().mapColor(MapColor.STONE), BlockEntities.COMPUTER_NORMAL));
+            () -> new ComputerBlock<>(redstoneConductor().mapColor(MapColor.STONE), BlockEntities.COMPUTER_NORMAL));
         public static final RegistryEntry<ComputerBlock<ComputerBlockEntity>> COMPUTER_ADVANCED = REGISTRY.register("computer_advanced",
-            () -> new ComputerBlock<>(computerProperties().mapColor(MapColor.GOLD), BlockEntities.COMPUTER_ADVANCED));
+            () -> new ComputerBlock<>(redstoneConductor().mapColor(MapColor.GOLD), BlockEntities.COMPUTER_ADVANCED));
         public static final RegistryEntry<ComputerBlock<ComputerBlockEntity>> COMPUTER_COMMAND = REGISTRY.register("computer_command",
-            () -> new CommandComputerBlock<>(computerProperties().strength(-1, 6000000.0F), BlockEntities.COMPUTER_COMMAND));
+            () -> new CommandComputerBlock<>(redstoneConductor().strength(-1, 6000000.0F), BlockEntities.COMPUTER_COMMAND));
 
         public static final RegistryEntry<TurtleBlock> TURTLE_NORMAL = REGISTRY.register("turtle_normal",
             () -> new TurtleBlock(turtleProperties().mapColor(MapColor.STONE), BlockEntities.TURTLE_NORMAL));
@@ -178,6 +190,13 @@ public final class ModRegistry {
         public static final RegistryEntry<WiredModemFullBlock> WIRED_MODEM_FULL = REGISTRY.register("wired_modem_full",
             () -> new WiredModemFullBlock(modemProperties().mapColor(MapColor.STONE)));
         public static final RegistryEntry<CableBlock> CABLE = REGISTRY.register("cable", () -> new CableBlock(modemProperties().mapColor(MapColor.STONE)));
+
+        public static final RegistryEntry<CustomLecternBlock> LECTERN = REGISTRY.register("lectern", () -> new CustomLecternBlock(
+            BlockBehaviour.Properties.of().mapColor(MapColor.WOOD).instrument(NoteBlockInstrument.BASS).strength(2.5F).sound(SoundType.WOOD).ignitedByLava()
+        ));
+
+        public static final RegistryEntry<RedstoneRelayBlock> REDSTONE_RELAY = REGISTRY.register("redstone_relay",
+            () -> new RedstoneRelayBlock(redstoneConductor().mapColor(MapColor.STONE)));
     }
 
     public static class BlockEntities {
@@ -219,6 +238,10 @@ public final class ModRegistry {
             ofBlock(Blocks.WIRELESS_MODEM_NORMAL, (p, s) -> new WirelessModemBlockEntity(BlockEntities.WIRELESS_MODEM_NORMAL.get(), p, s, false));
         public static final RegistryEntry<BlockEntityType<WirelessModemBlockEntity>> WIRELESS_MODEM_ADVANCED =
             ofBlock(Blocks.WIRELESS_MODEM_ADVANCED, (p, s) -> new WirelessModemBlockEntity(BlockEntities.WIRELESS_MODEM_ADVANCED.get(), p, s, true));
+
+        public static final RegistryEntry<BlockEntityType<CustomLecternBlockEntity>> LECTERN = ofBlock(Blocks.LECTERN, CustomLecternBlockEntity::new);
+
+        public static final RegistryEntry<BlockEntityType<RedstoneRelayBlockEntity>> REDSTONE_RELAY = ofBlock(Blocks.REDSTONE_RELAY, RedstoneRelayBlockEntity::new);
     }
 
     public static final class Items {
@@ -268,6 +291,7 @@ public final class ModRegistry {
         public static final RegistryEntry<BlockItem> WIRELESS_MODEM_NORMAL = ofBlock(Blocks.WIRELESS_MODEM_NORMAL, BlockItem::new);
         public static final RegistryEntry<BlockItem> WIRELESS_MODEM_ADVANCED = ofBlock(Blocks.WIRELESS_MODEM_ADVANCED, BlockItem::new);
         public static final RegistryEntry<BlockItem> WIRED_MODEM_FULL = ofBlock(Blocks.WIRED_MODEM_FULL, BlockItem::new);
+        public static final RegistryEntry<BlockItem> REDSTONE_RELAY = ofBlock(Blocks.REDSTONE_RELAY, BlockItem::new);
 
         public static final RegistryEntry<CableBlockItem.Cable> CABLE = REGISTRY.register("cable",
             () -> new CableBlockItem.Cable(Blocks.CABLE.get(), properties()));
@@ -422,11 +446,8 @@ public final class ModRegistry {
         public static final RegistryEntry<MenuType<PrinterMenu>> PRINTER = REGISTRY.register("printer",
             () -> new MenuType<>(PrinterMenu::new, FeatureFlags.VANILLA_SET));
 
-        public static final RegistryEntry<MenuType<HeldItemMenu>> PRINTOUT = REGISTRY.register("printout",
-            () -> ContainerData.toType(
-                HeldItemContainerData.STREAM_CODEC,
-                (id, inventory, data) -> new HeldItemMenu(Menus.PRINTOUT.get(), id, inventory.player, data.hand())
-            ));
+        public static final RegistryEntry<MenuType<PrintoutMenu>> PRINTOUT = REGISTRY.register("printout",
+            () -> new MenuType<>((i, c) -> PrintoutMenu.createRemote(i), FeatureFlags.VANILLA_SET));
     }
 
     static class ArgumentTypes {
@@ -533,6 +554,7 @@ public final class ModRegistry {
                 out.accept(Items.CABLE.get());
                 out.accept(Items.WIRED_MODEM.get());
                 out.accept(Items.WIRED_MODEM_FULL.get());
+                out.accept(Items.REDSTONE_RELAY.get());
 
                 out.accept(Items.MONITOR_NORMAL.get());
                 out.accept(Items.MONITOR_ADVANCED.get());
@@ -579,6 +601,22 @@ public final class ModRegistry {
             return null;
         });
 
+        ComputerCraftAPI.registerAPIFactory(computer -> {
+            var turtle = computer.getComponent(ComputerComponents.TURTLE);
+            var metrics = Objects.requireNonNull(computer.getComponent(ComponentMap.METRICS));
+            return turtle == null ? null : new TurtleAPI(metrics, (TurtleAccessInternal) turtle);
+        });
+
+        ComputerCraftAPI.registerAPIFactory(computer -> {
+            var pocket = computer.getComponent(ComputerComponents.POCKET);
+            return pocket == null ? null : new PocketAPI(pocket);
+        });
+
+        ComputerCraftAPI.registerAPIFactory(computer -> {
+            var admin = computer.getComponent(ComputerComponents.ADMIN_COMPUTER);
+            return admin == null ? null : new CommandAPI(computer, admin);
+        });
+
         VanillaDetailRegistries.ITEM_STACK.addProvider(ItemDetails::fill);
         VanillaDetailRegistries.BLOCK_IN_WORLD.addProvider(BlockDetails::fill);
     }

projects/common/src/main/java/dan200/computercraft/shared/command/text/ChatHelpers.java

@@ -39,9 +39,8 @@ public final class ChatHelpers {
         return component;
     }
 
-    public static MutableComponent position(@Nullable BlockPos pos) {
-        if (pos == null) return Component.translatable("commands.computercraft.generic.no_position");
-        return Component.translatable("commands.computercraft.generic.position", pos.getX(), pos.getY(), pos.getZ());
+    public static MutableComponent position(BlockPos pos) {
+        return Component.literal(pos.toShortString());
     }
 
     public static MutableComponent bool(boolean value) {

projects/common/src/main/java/dan200/computercraft/shared/command/text/TableBuilder.java

@@ -63,7 +63,7 @@ public class TableBuilder {
     /**
      * Get the number of columns for this table.
      * <p>
-     * This will be the same as {@link #getHeaders()}'s length if it is is non-{@code null},
+     * This will be the same as {@link #getHeaders()}'s length if it is non-{@code null},
      * otherwise the length of the first column.
      *
      * @return The number of columns.

projects/common/src/main/java/dan200/computercraft/shared/common/HeldItemMenu.java

@@ -1,68 +0,0 @@
-// Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
-//
-// SPDX-License-Identifier: LicenseRef-CCPL
-
-package dan200.computercraft.shared.common;
-
-import net.minecraft.network.chat.Component;
-import net.minecraft.world.InteractionHand;
-import net.minecraft.world.MenuProvider;
-import net.minecraft.world.entity.player.Inventory;
-import net.minecraft.world.entity.player.Player;
-import net.minecraft.world.inventory.AbstractContainerMenu;
-import net.minecraft.world.inventory.MenuType;
-import net.minecraft.world.item.ItemStack;
-
-import javax.annotation.Nullable;
-
-public class HeldItemMenu extends AbstractContainerMenu {
-    private final ItemStack stack;
-    private final InteractionHand hand;
-
-    public HeldItemMenu(MenuType<? extends HeldItemMenu> type, int id, Player player, InteractionHand hand) {
-        super(type, id);
-
-        this.hand = hand;
-        stack = player.getItemInHand(hand).copy();
-    }
-
-    public ItemStack getStack() {
-        return stack;
-    }
-
-    @Override
-    public ItemStack quickMoveStack(Player player, int slot) {
-        return ItemStack.EMPTY;
-    }
-
-    @Override
-    public boolean stillValid(Player player) {
-        if (!player.isAlive()) return false;
-
-        var stack = player.getItemInHand(hand);
-        return stack == this.stack || !stack.isEmpty() && !this.stack.isEmpty() && stack.getItem() == this.stack.getItem();
-    }
-
-    public static class Factory implements MenuProvider {
-        private final MenuType<HeldItemMenu> type;
-        private final Component name;
-        private final InteractionHand hand;
-
-        public Factory(MenuType<HeldItemMenu> type, ItemStack stack, InteractionHand hand) {
-            this.type = type;
-            name = stack.getHoverName();
-            this.hand = hand;
-        }
-
-        @Override
-        public Component getDisplayName() {
-            return name;
-        }
-
-        @Nullable
-        @Override
-        public AbstractContainerMenu createMenu(int id, Inventory inventory, Player player) {
-            return new HeldItemMenu(type, id, player, hand);
-        }
-    }
-}

projects/common/src/main/java/dan200/computercraft/shared/computer/apis/CommandAPI.java

@@ -6,11 +6,11 @@ package dan200.computercraft.shared.computer.apis;
 
 import com.mojang.brigadier.tree.CommandNode;
 import com.mojang.brigadier.tree.LiteralCommandNode;
+import dan200.computercraft.api.component.AdminComputer;
 import dan200.computercraft.api.detail.BlockReference;
 import dan200.computercraft.api.detail.VanillaDetailRegistries;
 import dan200.computercraft.api.lua.*;
 import dan200.computercraft.core.Logging;
-import dan200.computercraft.shared.computer.core.ServerComputer;
 import dan200.computercraft.shared.util.NBTUtil;
 import net.minecraft.commands.CommandSource;
 import net.minecraft.commands.CommandSourceStack;
@@ -35,11 +35,13 @@ import java.util.*;
 public class CommandAPI implements ILuaAPI {
     private static final Logger LOG = LoggerFactory.getLogger(CommandAPI.class);
 
-    private final ServerComputer computer;
+    private final IComputerSystem computer;
+    private final AdminComputer admin;
     private final OutputReceiver receiver = new OutputReceiver();
 
-    public CommandAPI(ServerComputer computer) {
+    public CommandAPI(IComputerSystem computer, AdminComputer admin) {
         this.computer = computer;
+        this.admin = admin;
     }
 
     @Override
@@ -254,7 +256,7 @@ public class CommandAPI implements ILuaAPI {
      * Get some basic information about a block.
      * <p>
      * The returned table contains the current name, metadata and block state (as
-     * with [`turtle.inspect`]). If there is a tile entity for that block, its NBT
+     * with [`turtle.inspect`]). If there is a block entity for that block, its NBT
      * will also be returned.
      *
      * @param x         The x position of the block to query.
@@ -295,7 +297,7 @@ public class CommandAPI implements ILuaAPI {
 
         return new CommandSourceStack(receiver,
             Vec3.atCenterOf(computer.getPosition()), Vec2.ZERO,
-            computer.getLevel(), 2,
+            computer.getLevel(), admin.permissionLevel(),
             name, Component.literal(name),
             computer.getLevel().getServer(), null
         );

projects/common/src/main/java/dan200/computercraft/shared/computer/blocks/AbstractComputerBlockEntity.java

@@ -39,7 +39,7 @@ import javax.annotation.Nullable;
 import java.util.Objects;
 import java.util.UUID;
 
-public abstract class AbstractComputerBlockEntity extends BlockEntity implements IComputerBlockEntity, Nameable, MenuProvider {
+public abstract class AbstractComputerBlockEntity extends BlockEntity implements Nameable, MenuProvider {
     private static final String NBT_ID = "ComputerId";
     private static final String NBT_LABEL = "Label";
     private static final String NBT_ON = "On";
@@ -111,7 +111,7 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         fresh = false;
         computerID = computer.getID();
 
-        // If the on state has changed, mark as as dirty.
+        // If the on state has changed, mark as dirty.
         var newOn = computer.isOn();
         if (on != newOn) {
             on = newOn;
@@ -128,7 +128,7 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         // Update the block state if needed.
         updateBlockState(computer.getState());
 
-        var changes = computer.pollAndResetChanges();
+        var changes = computer.pollRedstoneChanges();
         if (changes != 0) {
             for (var direction : DirectionUtil.FACINGS) {
                 if ((changes & (1 << remapToLocalSide(direction).ordinal())) != 0) updateRedstoneTo(direction);
@@ -221,8 +221,10 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         var offsetSide = dir.getOpposite();
         var localDir = remapToLocalSide(dir);
 
-        computer.setRedstoneInput(localDir, RedstoneUtil.getRedstoneInput(getLevel(), targetPos, dir));
-        computer.setBundledRedstoneInput(localDir, BundledRedstone.getOutput(getLevel(), targetPos, offsetSide));
+        computer.setRedstoneInput(localDir,
+            RedstoneUtil.getRedstoneInput(getLevel(), targetPos, dir),
+            BundledRedstone.getOutput(getLevel(), targetPos, offsetSide)
+        );
     }
 
     /**
@@ -326,17 +328,14 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         for (var dir : DirectionUtil.FACINGS) updateRedstoneTo(dir);
     }
 
-    @Override
     public final int getComputerID() {
         return computerID;
     }
 
-    @Override
     public final @Nullable String getLabel() {
         return label;
     }
 
-    @Override
     public final void setComputerID(int id) {
         if (getLevel().isClientSide || computerID == id) return;
 
@@ -344,7 +343,6 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         BlockEntityHelpers.updateBlock(this);
     }
 
-    @Override
     public final void setLabel(@Nullable String label) {
         if (getLevel().isClientSide || Objects.equals(this.label, label)) return;
 
@@ -354,7 +352,6 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         BlockEntityHelpers.updateBlock(this);
     }
 
-    @Override
     public ComputerFamily getFamily() {
         return family;
     }

projects/common/src/main/java/dan200/computercraft/shared/computer/blocks/ComputerBlockEntity.java

@@ -12,6 +12,7 @@ import dan200.computercraft.shared.computer.core.ComputerState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
 import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
 import dan200.computercraft.shared.config.Config;
+import dan200.computercraft.shared.util.ComponentMap;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.server.level.ServerLevel;
@@ -34,7 +35,8 @@ public class ComputerBlockEntity extends AbstractComputerBlockEntity {
     protected ServerComputer createComputer(int id) {
         return new ServerComputer(
             (ServerLevel) getLevel(), getBlockPos(), id, label,
-            getFamily(), Config.computerTermWidth, Config.computerTermHeight
+            getFamily(), Config.computerTermWidth, Config.computerTermHeight,
+            ComponentMap.empty()
         );
     }
 

projects/common/src/main/java/dan200/computercraft/shared/computer/blocks/IComputerBlockEntity.java

@@ -1,22 +0,0 @@
-// Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
-//
-// SPDX-License-Identifier: LicenseRef-CCPL
-
-package dan200.computercraft.shared.computer.blocks;
-
-import dan200.computercraft.shared.computer.core.ComputerFamily;
-
-import javax.annotation.Nullable;
-
-public interface IComputerBlockEntity {
-    int getComputerID();
-
-    void setComputerID(int id);
-
-    @Nullable
-    String getLabel();
-
-    void setLabel(@Nullable String label);
-
-    ComputerFamily getFamily();
-}

projects/common/src/main/java/dan200/computercraft/shared/computer/core/ComputerSystem.java

@@ -0,0 +1,101 @@
+// SPDX-FileCopyrightText: 2019 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.computer.core;
+
+import dan200.computercraft.api.component.ComputerComponent;
+import dan200.computercraft.api.lua.IComputerSystem;
+import dan200.computercraft.api.lua.ILuaAPIFactory;
+import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.core.apis.ComputerAccess;
+import dan200.computercraft.core.apis.IAPIEnvironment;
+import dan200.computercraft.core.computer.ApiLifecycle;
+import dan200.computercraft.shared.util.ComponentMap;
+import net.minecraft.core.BlockPos;
+import net.minecraft.server.level.ServerLevel;
+
+import javax.annotation.Nullable;
+import java.util.Map;
+
+/**
+ * Implementation of {@link IComputerSystem} for usage by externally registered APIs.
+ *
+ * @see ILuaAPIFactory
+ */
+final class ComputerSystem extends ComputerAccess implements IComputerSystem, ApiLifecycle {
+    private final ServerComputer computer;
+    private final IAPIEnvironment environment;
+    private final ComponentMap components;
+
+    private boolean active;
+
+    ComputerSystem(ServerComputer computer, IAPIEnvironment environment, ComponentMap components) {
+        super(environment);
+        this.computer = computer;
+        this.environment = environment;
+        this.components = components;
+    }
+
+    void activate() {
+        active = true;
+    }
+
+    @Override
+    public void shutdown() {
+        unmountAll();
+    }
+
+    @Override
+    public String getAttachmentName() {
+        return "computer";
+    }
+
+    @Override
+    public ServerLevel getLevel() {
+        if (!active) {
+            throw new IllegalStateException("""
+                Cannot access level when constructing the API. Computers are not guaranteed to stay in one place and
+                APIs should not rely on the level remaining constant. Instead, call this method when needed.
+                """.replace('\n', ' ').strip()
+            );
+        }
+        return computer.getLevel();
+    }
+
+    @Override
+    public BlockPos getPosition() {
+        if (!active) {
+            throw new IllegalStateException("""
+                Cannot access computer position when constructing the API. Computers are not guaranteed to stay in one
+                place and APIs should not rely on the position remaining constant. Instead, call this method when
+                needed.
+                """.replace('\n', ' ').strip()
+            );
+        }
+        return computer.getPosition();
+    }
+
+    @Nullable
+    @Override
+    public String getLabel() {
+        return environment.getLabel();
+    }
+
+    @Override
+    public Map<String, IPeripheral> getAvailablePeripherals() {
+        // TODO: Should this return peripherals on the current computer?
+        return Map.of();
+    }
+
+    @Nullable
+    @Override
+    public IPeripheral getAvailablePeripheral(String name) {
+        return null;
+    }
+
+    @Override
+    public <T> @Nullable T getComponent(ComputerComponent<T> component) {
+        return components.get(component);
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java

@@ -5,15 +5,16 @@
 package dan200.computercraft.shared.computer.core;
 
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.component.AdminComputer;
+import dan200.computercraft.api.component.ComputerComponents;
 import dan200.computercraft.api.filesystem.WritableMount;
-import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.WorkMonitor;
 import dan200.computercraft.core.computer.Computer;
 import dan200.computercraft.core.computer.ComputerEnvironment;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.metrics.MetricsObserver;
-import dan200.computercraft.shared.computer.apis.CommandAPI;
+import dan200.computercraft.impl.ApiFactories;
 import dan200.computercraft.shared.computer.menu.ComputerMenu;
 import dan200.computercraft.shared.computer.terminal.NetworkedTerminal;
 import dan200.computercraft.shared.computer.terminal.TerminalState;
@@ -22,6 +23,7 @@ import dan200.computercraft.shared.network.NetworkMessage;
 import dan200.computercraft.shared.network.client.ClientNetworkContext;
 import dan200.computercraft.shared.network.client.ComputerTerminalClientMessage;
 import dan200.computercraft.shared.network.server.ServerNetworking;
+import dan200.computercraft.shared.util.ComponentMap;
 import net.minecraft.core.BlockPos;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.entity.player.Player;
@@ -48,7 +50,8 @@ public class ServerComputer implements InputHandler, ComputerEnvironment {
     private int ticksSincePing;
 
     public ServerComputer(
-        ServerLevel level, BlockPos position, int computerID, @Nullable String label, ComputerFamily family, int terminalWidth, int terminalHeight
+        ServerLevel level, BlockPos position, int computerID, @Nullable String label, ComputerFamily family, int terminalWidth, int terminalHeight,
+        ComponentMap baseComponents
     ) {
         this.level = level;
         this.position = position;
@@ -58,10 +61,27 @@ public class ServerComputer implements InputHandler, ComputerEnvironment {
         terminal = new NetworkedTerminal(terminalWidth, terminalHeight, family != ComputerFamily.NORMAL, this::markTerminalChanged);
         metrics = context.metrics().createMetricObserver(this);
 
+        var componentBuilder = ComponentMap.builder();
+        componentBuilder.add(ComponentMap.METRICS, metrics);
+        if (family == ComputerFamily.COMMAND) {
+            componentBuilder.add(ComputerComponents.ADMIN_COMPUTER, new AdminComputer() {
+            });
+        }
+        componentBuilder.add(baseComponents);
+        var components = componentBuilder.build();
+
         computer = new Computer(context.computerContext(), this, terminal, computerID);
         computer.setLabel(label);
 
-        if (family == ComputerFamily.COMMAND) addAPI(new CommandAPI(this));
+        // Load in the externally registered APIs.
+        for (var factory : ApiFactories.getAll()) {
+            var system = new ComputerSystem(this, computer.getAPIEnvironment(), components);
+            var api = factory.create(system);
+            if (api == null) continue;
+
+            system.activate();
+            computer.addApi(api, system);
+        }
     }
 
     public ComputerFamily getFamily() {
@@ -112,8 +132,8 @@ public class ServerComputer implements InputHandler, ComputerEnvironment {
      *
      * @return What sides on the computer have changed.
      */
-    public int pollAndResetChanges() {
-        return computer.pollAndResetChanges();
+    public int pollRedstoneChanges() {
+        return computer.pollRedstoneChanges();
     }
 
     public UUID register() {
@@ -196,23 +216,15 @@ public class ServerComputer implements InputHandler, ComputerEnvironment {
     }
 
     public int getRedstoneOutput(ComputerSide side) {
-        return computer.getEnvironment().getExternalRedstoneOutput(side);
+        return computer.isOn() ? computer.getRedstone().getExternalOutput(side) : 0;
     }
 
-    public void setRedstoneInput(ComputerSide side, int level) {
-        computer.getEnvironment().setRedstoneInput(side, level);
+    public void setRedstoneInput(ComputerSide side, int level, int bundledState) {
+        computer.getRedstone().setInput(side, level, bundledState);
     }
 
     public int getBundledRedstoneOutput(ComputerSide side) {
-        return computer.getEnvironment().getExternalBundledRedstoneOutput(side);
-    }
-
-    public void setBundledRedstoneInput(ComputerSide side, int combination) {
-        computer.getEnvironment().setBundledRedstoneInput(side, combination);
-    }
-
-    public void addAPI(ILuaAPI api) {
-        computer.addApi(api);
+        return computer.isOn() ? computer.getRedstone().getExternalBundledOutput(side) : 0;
     }
 
     public void setPeripheral(ComputerSide side, @Nullable IPeripheral peripheral) {

projects/common/src/main/java/dan200/computercraft/shared/computer/core/ServerContext.java

@@ -17,7 +17,6 @@ import dan200.computercraft.core.lua.ILuaMachine;
 import dan200.computercraft.core.methods.MethodSupplier;
 import dan200.computercraft.core.methods.PeripheralMethod;
 import dan200.computercraft.impl.AbstractComputerCraftAPI;
-import dan200.computercraft.impl.ApiFactories;
 import dan200.computercraft.impl.GenericSources;
 import dan200.computercraft.shared.CommonHooks;
 import dan200.computercraft.shared.computer.metrics.GlobalMetrics;
@@ -74,7 +73,6 @@ public final class ServerContext {
             .computerThreads(ConfigSpec.computerThreads.get())
             .mainThreadScheduler(mainThread)
             .luaFactory(luaMachine)
-            .apiFactories(ApiFactories.getAll())
             .genericMethods(GenericSources.getAllMethods())
             .build();
         idAssigner = new IDAssigner(storageDir.resolve("ids.json"));

projects/common/src/main/java/dan200/computercraft/shared/config/AddressRuleConfig.java

@@ -69,6 +69,13 @@ class AddressRuleConfig {
         );
     }
 
+    public static UnmodifiableConfig newRule() {
+        return makeRule(config -> {
+            config.add("host", "example.com");
+            config.add("action", Action.DENY.name().toLowerCase(Locale.ROOT));
+        });
+    }
+
     private static UnmodifiableConfig makeRule(Consumer<CommentedConfig> setup) {
         var config = InMemoryCommentedFormat.defaultInstance().createConfig(LinkedHashMap::new);
         setup.accept(config);

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigFile.java

@@ -126,7 +126,7 @@ public interface ConfigFile {
 
         public abstract ConfigFile.Value<Integer> defineInRange(String path, int defaultValue, int min, int max);
 
-        public abstract <T> ConfigFile.Value<List<? extends T>> defineList(String path, List<? extends T> defaultValue, Predicate<Object> elementValidator);
+        public abstract <T> ConfigFile.Value<List<? extends T>> defineList(String path, List<? extends T> defaultValue, Supplier<T> newValue, Predicate<Object> elementValidator);
 
         public abstract <V extends Enum<V>> ConfigFile.Value<V> defineEnum(String path, V defaultValue);
 

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigSpec.java

@@ -145,7 +145,7 @@ public final class ConfigSpec {
                     or a single method (computercraft:inventory#pushItems).
                     """)
                 .worldRestart()
-                .defineList("disabled_generic_methods", List.of(), x -> x instanceof String);
+                .defineList("disabled_generic_methods", List.of(), () -> "", x -> x instanceof String);
         }
 
         {
@@ -214,7 +214,7 @@ public final class ConfigSpec {
                      - "max_websocket_message" (optional): The maximum size (in bytes) that a computer can send or
                        receive in one websocket packet.
                      - "use_proxy" (optional): Enable use of the HTTP/SOCKS proxy if it is configured.""")
-                .defineList("rules", AddressRuleConfig.defaultRules(), x -> x instanceof UnmodifiableConfig);
+                .defineList("rules", AddressRuleConfig.defaultRules(), AddressRuleConfig::newRule, x -> x instanceof UnmodifiableConfig);
 
             httpMaxRequests = builder
                 .comment("""

projects/common/src/main/java/dan200/computercraft/shared/data/HasComputerIdLootCondition.java

@@ -5,7 +5,7 @@
 package dan200.computercraft.shared.data;
 
 import dan200.computercraft.shared.ModRegistry;
-import dan200.computercraft.shared.computer.blocks.IComputerBlockEntity;
+import dan200.computercraft.shared.computer.blocks.AbstractComputerBlockEntity;
 import net.minecraft.world.level.storage.loot.LootContext;
 import net.minecraft.world.level.storage.loot.parameters.LootContextParam;
 import net.minecraft.world.level.storage.loot.parameters.LootContextParams;
@@ -15,7 +15,7 @@ import net.minecraft.world.level.storage.loot.predicates.LootItemConditionType;
 import java.util.Set;
 
 /**
- * A loot condition which checks if the tile entity has a non-0 ID.
+ * A loot condition which checks if the block entity has a computer ID.
  */
 public final class HasComputerIdLootCondition implements LootItemCondition {
     public static final HasComputerIdLootCondition INSTANCE = new HasComputerIdLootCondition();
@@ -27,7 +27,7 @@ public final class HasComputerIdLootCondition implements LootItemCondition {
     @Override
     public boolean test(LootContext lootContext) {
         var tile = lootContext.getParamOrNull(LootContextParams.BLOCK_ENTITY);
-        return tile instanceof IComputerBlockEntity computer && computer.getComputerID() >= 0;
+        return tile instanceof AbstractComputerBlockEntity computer && computer.getComputerID() >= 0;
     }
 
     @Override

projects/common/src/main/java/dan200/computercraft/shared/datafix/ComponentizationFixers.java

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
-package dan200.computercraft.shared.util;
+package dan200.computercraft.shared.datafix;
 
 import com.mojang.datafixers.DSL;
 import com.mojang.datafixers.Typed;
@@ -48,7 +48,7 @@ public class ComponentizationFixers {
 
     private static final Set<String> DYEABLE = Stream.concat(
         Stream.of(TURTLES, POCKET_COMPUTERS).flatMap(Set::stream),
-        Stream.of(DISK, TREASURE_DISK)
+        Stream.of(DISK)
     ).collect(Collectors.toUnmodifiableSet());
 
     /**
@@ -62,13 +62,7 @@ public class ComponentizationFixers {
         if (item.is(ALL_COMPUTERS)) item.moveTagToComponent("ComputerId", "computercraft:computer_id");
 
         // Set dyed colour
-        if (item.is(DYEABLE)) {
-            item.removeTag("Color").asNumber().result().map(Number::intValue).ifPresent(col ->
-                item.setComponent("minecraft:dyed_color", ops.emptyMap()
-                    .set("rgb", ops.createInt(col))
-                    .set("show_in_tooltip", ops.createBoolean(false))
-                ));
-        }
+        if (item.is(DYEABLE)) moveColourToComponent(item, ops, "Color");
 
         if (item.is(POCKET_COMPUTERS)) {
             item.moveTagToComponent("On", "computercraft:on");
@@ -89,7 +83,7 @@ public class ComponentizationFixers {
             moveUpgradeToComponent(item, ops, "RightUpgrade", "RightUpgradeNbt", "computercraft:right_turtle_upgrade");
         }
 
-        if (item.is(DISK)) item.moveTagToComponent("DiskId", "computercraft:disk");
+        if (item.is(DISK)) item.moveTagToComponent("DiskId", "computercraft:disk_id");
 
         if (item.is(TREASURE_DISK)) {
             var name = item.removeTag("Title").asString().result();
@@ -99,6 +93,8 @@ public class ComponentizationFixers {
                     .set("name", ops.createString(name.get()))
                     .set("path", ops.createString(path.get())));
             }
+
+            moveColourToComponent(item, ops, "Colour");
         }
 
         if (item.is(PRINTOUTS)) movePrintoutToComponent(item, ops);
@@ -111,6 +107,14 @@ public class ComponentizationFixers {
         data.setComponent(component, createUpgradeData(ops, upgrade, data.removeTag(dataKey)));
     }
 
+    private static void moveColourToComponent(ItemStackComponentizationFix.ItemStackData item, Dynamic<?> ops, String key) {
+        item.removeTag(key).asNumber().result().map(Number::intValue).ifPresent(col ->
+            item.setComponent("minecraft:dyed_color", ops.emptyMap()
+                .set("rgb", ops.createInt(col))
+                .set("show_in_tooltip", ops.createBoolean(false))
+            ));
+    }
+
     /**
      * Move printout data to a component.
      *

projects/common/src/main/java/dan200/computercraft/shared/datafix/TurtleUpgradeComponentizationFix.java

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.datafix;
+
+import com.mojang.datafixers.DataFix;
+import com.mojang.datafixers.TypeRewriteRule;
+import com.mojang.datafixers.schemas.Schema;
+import net.minecraft.util.datafix.fixes.References;
+
+/**
+ * Rewrites turtle block entities to store upgrades as components.
+ *
+ * @see ComponentizationFixers#makeBlockEntityRewrites(Schema, Schema)
+ */
+public class TurtleUpgradeComponentizationFix extends DataFix {
+    public TurtleUpgradeComponentizationFix(Schema outputSchema) {
+        super(outputSchema, true);
+    }
+
+    @Override
+    protected TypeRewriteRule makeRule() {
+        return fixTypeEverywhereTyped(
+            "Turtle upgrade componentization",
+            getInputSchema().getType(References.BLOCK_ENTITY),
+            getOutputSchema().getType(References.BLOCK_ENTITY),
+            ComponentizationFixers.makeBlockEntityRewrites(getInputSchema(), getOutputSchema())
+        );
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/details/ItemDetails.java

@@ -53,7 +53,9 @@ public class ItemDetails {
         data.put("itemGroups", getItemGroups(stack));
 
         var lore = stack.get(DataComponents.LORE);
-        if (lore != null) data.put("lore", lore.lines().stream().map(Component::getString).toList());
+        if (lore != null && !lore.lines().isEmpty()) {
+            data.put("lore", lore.lines().stream().map(Component::getString).toList());
+        }
 
         var enchants = getAllEnchants(stack);
         if (!enchants.isEmpty()) data.put("enchantments", enchants);

projects/common/src/main/java/dan200/computercraft/shared/integration/CreateIntegration.java

@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.integration;
+
+import com.simibubi.create.content.contraptions.BlockMovementChecks;
+import com.simibubi.create.content.contraptions.BlockMovementChecks.CheckResult;
+import dan200.computercraft.shared.peripheral.modem.wired.CableBlock;
+import dan200.computercraft.shared.peripheral.modem.wireless.WirelessModemBlock;
+
+/**
+ * Integration with Create.
+ */
+public final class CreateIntegration {
+    public static final String ID = "create";
+
+    private CreateIntegration() {
+    }
+
+    public static void setup() {
+        // Allow modems to be treated as "attached" to their adjacent block.
+        BlockMovementChecks.registerAttachedCheck((state, world, pos, direction) -> {
+            var block = state.getBlock();
+            if (block instanceof WirelessModemBlock) {
+                return CheckResult.of(state.getValue(WirelessModemBlock.FACING) == direction);
+            } else if (block instanceof CableBlock) {
+                return CheckResult.of(state.getValue(CableBlock.MODEM).getFacing() == direction);
+            } else {
+                return CheckResult.PASS;
+            }
+        });
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/integration/ExternalModTags.java

@@ -8,6 +8,7 @@ import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.tags.TagKey;
 import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.block.state.BlockState;
 
 /**
  * Tags defined by external mods.
@@ -26,9 +27,9 @@ public final class ExternalModTags {
         /**
          * Create's "brittle" tag, used to determine if this block needs to be moved before its neighbours.
          *
-         * @see <a href="https://github.com/Creators-of-Create/Create/blob/mc1.20.1/dev/src/main/java/com/simibubi/create/content/contraptions/BlockMovementChecks.java">{@code BlockMovementChecks}</a>
+         * @see com.simibubi.create.content.contraptions.BlockMovementChecks#isBrittle(BlockState)
          */
-        public static final TagKey<Block> CREATE_BRITTLE = make("create", "brittle");
+        public static final TagKey<Block> CREATE_BRITTLE = make(CreateIntegration.ID, "brittle");
 
         private static TagKey<Block> make(String mod, String name) {
             return TagKey.create(Registries.BLOCK, ResourceLocation.fromNamespaceAndPath(mod, name));

projects/common/src/main/java/dan200/computercraft/shared/lectern/CustomLecternBlock.java

@@ -0,0 +1,163 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.lectern;
+
+import dan200.computercraft.shared.ModRegistry;
+import dan200.computercraft.shared.media.items.PrintoutItem;
+import net.minecraft.core.BlockPos;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.stats.Stats;
+import net.minecraft.util.RandomSource;
+import net.minecraft.world.InteractionResult;
+import net.minecraft.world.entity.item.ItemEntity;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.item.context.UseOnContext;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.LevelReader;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.LecternBlock;
+import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.phys.BlockHitResult;
+
+/**
+ * Extends {@link LecternBlock} with support for {@linkplain PrintoutItem printouts}.
+ * <p>
+ * Unlike the vanilla lectern, this block is never empty. If the book is removed from the lectern, it converts back to
+ * its vanilla version (see {@link #clearLectern(Level, BlockPos, BlockState)}).
+ *
+ * @see PrintoutItem#useOn(UseOnContext) Placing books into a lectern.
+ */
+public class CustomLecternBlock extends LecternBlock {
+    public CustomLecternBlock(Properties properties) {
+        super(properties);
+        registerDefaultState(defaultBlockState().setValue(HAS_BOOK, true));
+    }
+
+    /**
+     * Attempt to place an item onto an (empty) lectern.
+     *
+     * @param player     The player placing the item.
+     * @param level      The current level.
+     * @param pos        The position of the lectern.
+     * @param blockState The current state of the lectern.
+     * @param item       The item to place in the custom lectern.
+     * @return Whether the item was placed or not.
+     */
+    public static InteractionResult tryPlaceItem(Player player, Level level, BlockPos pos, BlockState blockState, ItemStack item) {
+        if (item.getItem() instanceof PrintoutItem) {
+            if (!level.isClientSide) replaceLectern(player, level, pos, blockState, item);
+            return InteractionResult.sidedSuccess(level.isClientSide);
+        }
+
+        return InteractionResult.PASS;
+    }
+
+    /**
+     * Replace a vanilla lectern with a custom one.
+     *
+     * @param player     The player placing the item.
+     * @param level      The current level.
+     * @param pos        The position of the lectern.
+     * @param blockState The current state of the lectern.
+     * @param item       The item to place in the custom lectern.
+     */
+    private static void replaceLectern(Player player, Level level, BlockPos pos, BlockState blockState, ItemStack item) {
+        level.setBlockAndUpdate(pos, ModRegistry.Blocks.LECTERN.get().defaultBlockState()
+            .setValue(HAS_BOOK, true)
+            .setValue(FACING, blockState.getValue(FACING))
+            .setValue(POWERED, blockState.getValue(POWERED)));
+
+        if (level.getBlockEntity(pos) instanceof CustomLecternBlockEntity be) {
+            be.setItem(item.consumeAndReturn(1, player));
+        }
+    }
+
+    /**
+     * Remove a custom lectern and replace it with an empty vanilla one.
+     *
+     * @param level      The current level.
+     * @param pos        The position of the lectern.
+     * @param blockState The current state of the lectern.
+     */
+    static void clearLectern(Level level, BlockPos pos, BlockState blockState) {
+        level.setBlockAndUpdate(pos, Blocks.LECTERN.defaultBlockState()
+            .setValue(HAS_BOOK, false)
+            .setValue(FACING, blockState.getValue(FACING))
+            .setValue(POWERED, blockState.getValue(POWERED)));
+    }
+
+    @Override
+    @Deprecated
+    public ItemStack getCloneItemStack(LevelReader level, BlockPos pos, BlockState state) {
+        return new ItemStack(Items.LECTERN);
+    }
+
+    @Override
+    public void tick(BlockState state, ServerLevel level, BlockPos pos, RandomSource random) {
+        // If we've no lectern, remove it.
+        if (level.getBlockEntity(pos) instanceof CustomLecternBlockEntity lectern && lectern.getItem().isEmpty()) {
+            clearLectern(level, pos, state);
+            return;
+        }
+
+        super.tick(state, level, pos, random);
+    }
+
+    @Override
+    public void onRemove(BlockState state, Level level, BlockPos pos, BlockState newState, boolean isMoving) {
+        if (state.is(newState.getBlock())) return;
+
+        if (level.getBlockEntity(pos) instanceof CustomLecternBlockEntity lectern) {
+            dropItem(level, pos, state, lectern.getItem().copy());
+        }
+
+        super.onRemove(state, level, pos, newState, isMoving);
+    }
+
+    private static void dropItem(Level level, BlockPos pos, BlockState state, ItemStack stack) {
+        if (stack.isEmpty()) return;
+
+        var direction = state.getValue(FACING);
+        var dx = 0.25 * direction.getStepX();
+        var dz = 0.25 * direction.getStepZ();
+        var entity = new ItemEntity(level, pos.getX() + 0.5 + dx, pos.getY() + 1, pos.getZ() + 0.5 + dz, stack);
+        entity.setDefaultPickUpDelay();
+        level.addFreshEntity(entity);
+    }
+
+    @Override
+    public String getDescriptionId() {
+        return Blocks.LECTERN.getDescriptionId();
+    }
+
+    @Override
+    public CustomLecternBlockEntity newBlockEntity(BlockPos pos, BlockState state) {
+        return new CustomLecternBlockEntity(pos, state);
+    }
+
+    @Override
+    public int getAnalogOutputSignal(BlockState blockState, Level level, BlockPos pos) {
+        return level.getBlockEntity(pos) instanceof CustomLecternBlockEntity lectern ? lectern.getRedstoneSignal() : 0;
+    }
+
+    @Override
+    public InteractionResult useWithoutItem(BlockState state, Level level, BlockPos pos, Player player, BlockHitResult hit) {
+        if (!level.isClientSide && level.getBlockEntity(pos) instanceof CustomLecternBlockEntity lectern) {
+            if (player.isSecondaryUseActive()) {
+                // When shift+clicked with an empty hand, drop the item and replace with the normal lectern.
+                clearLectern(level, pos, state);
+            } else {
+                // Otherwise open the screen.
+                player.openMenu(lectern);
+            }
+
+            player.awardStat(Stats.INTERACT_WITH_LECTERN);
+        }
+
+        return InteractionResult.sidedSuccess(level.isClientSide);
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/lectern/CustomLecternBlockEntity.java

@@ -0,0 +1,195 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.lectern;
+
+import dan200.computercraft.shared.ModRegistry;
+import dan200.computercraft.shared.container.BasicContainer;
+import dan200.computercraft.shared.container.SingleContainerData;
+import dan200.computercraft.shared.media.PrintoutMenu;
+import dan200.computercraft.shared.media.items.PrintoutData;
+import dan200.computercraft.shared.media.items.PrintoutItem;
+import dan200.computercraft.shared.util.BlockEntityHelpers;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.Tag;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ClientGamePacketListener;
+import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
+import net.minecraft.util.Mth;
+import net.minecraft.world.Container;
+import net.minecraft.world.MenuProvider;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ContainerData;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.block.LecternBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.LecternBlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.AbstractList;
+import java.util.List;
+
+/**
+ * The block entity for our {@link CustomLecternBlock}.
+ *
+ * @see LecternBlockEntity
+ */
+public final class CustomLecternBlockEntity extends BlockEntity implements MenuProvider {
+    private static final String NBT_ITEM = "Item";
+    private static final String NBT_PAGE = "Page";
+
+    private ItemStack item = ItemStack.EMPTY;
+    private int page, pageCount;
+
+    public CustomLecternBlockEntity(BlockPos pos, BlockState blockState) {
+        super(ModRegistry.BlockEntities.LECTERN.get(), pos, blockState);
+    }
+
+    public ItemStack getItem() {
+        return item;
+    }
+
+    void setItem(ItemStack item) {
+        this.item = item;
+        itemChanged();
+        BlockEntityHelpers.updateBlock(this);
+    }
+
+    int getRedstoneSignal() {
+        if (item.getItem() instanceof PrintoutItem) {
+            var progress = pageCount > 1 ? (float) page / (pageCount - 1) : 1F;
+            return Mth.floor(progress * 14f) + 1;
+        }
+
+        return 15;
+    }
+
+    /**
+     * Called after the item has changed. This sets up the state for the new item.
+     */
+    private void itemChanged() {
+        if (item.getItem() instanceof PrintoutItem) {
+            pageCount = PrintoutData.getOrEmpty(item).pages();
+            page = Mth.clamp(page, 0, pageCount - 1);
+        } else {
+            pageCount = page = 0;
+        }
+    }
+
+    /**
+     * Set the current page, emitting a redstone pulse if needed.
+     *
+     * @param page The new page.
+     */
+    private void setPage(int page) {
+        if (this.page == page) return;
+
+        this.page = page;
+        setChanged();
+        if (getLevel() != null) LecternBlock.signalPageChange(getLevel(), getBlockPos(), getBlockState());
+    }
+
+    @Override
+    public void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+        super.loadAdditional(tag, registries);
+
+        item = tag.contains(NBT_ITEM, Tag.TAG_COMPOUND) ? ItemStack.parseOptional(registries, tag.getCompound(NBT_ITEM)) : ItemStack.EMPTY;
+        page = tag.getInt(NBT_PAGE);
+        itemChanged();
+    }
+
+    @Override
+    protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+        super.saveAdditional(tag, registries);
+
+        if (!item.isEmpty()) tag.put(NBT_ITEM, item.save(registries));
+        if (item.getItem() instanceof PrintoutItem) tag.putInt(NBT_PAGE, page);
+    }
+
+    @Override
+    public Packet<ClientGamePacketListener> getUpdatePacket() {
+        return ClientboundBlockEntityDataPacket.create(this);
+    }
+
+    @Override
+    public CompoundTag getUpdateTag(HolderLookup.Provider registries) {
+        var tag = super.getUpdateTag(registries);
+        if (!item.isEmpty()) tag.put(NBT_ITEM, item.save(registries));
+        return tag;
+    }
+
+    @Nullable
+    @Override
+    public AbstractContainerMenu createMenu(int containerId, Inventory playerInventory, Player player) {
+        var item = getItem();
+        if (item.getItem() instanceof PrintoutItem) {
+            return new PrintoutMenu(
+                containerId, new LecternContainer(), 0,
+                p -> Container.stillValidBlockEntity(this, player, Container.DEFAULT_DISTANCE_BUFFER),
+                new PrintoutContainerData()
+            );
+        }
+
+        return null;
+    }
+
+    @Override
+    public Component getDisplayName() {
+        return getItem().getDisplayName();
+    }
+
+    /**
+     * A read-only container storing the lectern's contents.
+     */
+    private final class LecternContainer implements BasicContainer {
+        private final List<ItemStack> itemView = new AbstractList<>() {
+            @Override
+            public ItemStack get(int index) {
+                if (index != 0) throw new IndexOutOfBoundsException("Inventory only has one slot");
+                return item;
+            }
+
+            @Override
+            public int size() {
+                return 1;
+            }
+        };
+
+        @Override
+        public List<ItemStack> getItems() {
+            return itemView;
+        }
+
+        @Override
+        public void setChanged() {
+            // Should never happen, so a no-op.
+        }
+
+        @Override
+        public boolean stillValid(Player player) {
+            return !isRemoved();
+        }
+    }
+
+    /**
+     * {@link ContainerData} for a {@link PrintoutMenu}. This provides a read/write view of the current page.
+     */
+    private final class PrintoutContainerData implements SingleContainerData {
+        @Override
+        public int get() {
+            return page;
+        }
+
+        @Override
+        public void set(int index, int value) {
+            if (index == 0) setPage(value);
+        }
+    }
+}