Merge branch 'mc-1.15.x' into mc-1.16.x

.gitpod.yml

@@ -0,0 +1,22 @@
+image:
+  file: config/gitpod/Dockerfile
+
+ports:
+  - port: 25565
+    onOpen: notify
+
+vscode:
+  extensions:
+    - eamodio.gitlens
+    - github.vscode-pull-request-github
+    - ms-azuretools.vscode-docker
+    - redhat.java
+    - richardwillis.vscode-gradle
+    - vscjava.vscode-java-debug
+    - vscode.github
+
+tasks:
+  - name: Setup pre-commit hool
+    init: pre-commit install --config config/pre-commit/config.yml --allow-missing-config
+  - name: Install npm packages
+    init: npm ci

CONTRIBUTING.md

@@ -19,6 +19,10 @@ process. When building on Windows, Use `gradlew.bat` instead of `./gradlew`.
  - **Clone the repository:** `git clone https://github.com/SquidDev-CC/CC-Tweaked.git && cd CC-Tweaked`
  - **Setup Forge:** `./gradlew build`
  - **Run Minecraft:** `./gradlew runClient` (or run the `GradleStart` class from your IDE).
+ - **Optionally:** For small PRs (especially those only touching Lua code), it may be easier to use GitPod, which
+   provides a pre-configured environment: [![Gitpod ready-to-code](https://img.shields.io/badge/Gitpod-ready--to--code-2b2b2b?logo=gitpod)](https://gitpod.io/#https://github.com/SquidDev-CC/CC-Tweaked/)
+
+   Do note you will need to download the mod after compiling to test.
 
 If you want to run CC:T in a normal Minecraft instance, run `./gradlew build` and copy the `.jar` from `build/libs`.
 These commands may take a few minutes to run the first time, as the environment is set up, but should be much faster

build.gradle

@@ -1,6 +1,5 @@
 buildscript {
     repositories {
-        jcenter()
         mavenCentral()
         maven {
             name = "forge"
@@ -14,7 +13,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.google.code.gson:gson:2.8.1'
-        classpath 'net.minecraftforge.gradle:ForgeGradle:4.1.9'
+        classpath 'net.minecraftforge.gradle:ForgeGradle:5.0.12'
         classpath 'org.spongepowered:mixingradle:0.7-SNAPSHOT'
     }
 }
@@ -23,10 +22,11 @@ plugins {
     id "checkstyle"
     id "jacoco"
     id "maven-publish"
-    id "com.github.hierynomus.license" version "0.15.0"
+    id "com.github.hierynomus.license" version "0.16.1"
     id "com.matthewprenger.cursegradle" version "1.4.0"
     id "com.github.breadmoirai.github-release" version "2.2.12"
     id "org.jetbrains.kotlin.jvm" version "1.3.72"
+    id "com.modrinth.minotaur" version "1.2.1"
 }
 
 apply plugin: 'net.minecraftforge.gradle'
@@ -37,15 +37,30 @@ version = mod_version
 group = "org.squiddev"
 archivesBaseName = "cc-tweaked-${mc_version}"
 
+def javaVersion = JavaLanguageVersion.of(8)
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(8)
+        languageVersion = javaVersion
     }
 
     withSourcesJar()
     withJavadocJar()
 }
 
+// Tragically java.toolchain.languageVersion doesn't apply to ForgeGradle's
+// tasks, so we force all launchers to use the right Java version.
+tasks.withType(JavaCompile).configureEach {
+    javaCompiler = javaToolchains.compilerFor {
+        languageVersion = javaVersion
+    }
+}
+
+tasks.withType(JavaExec).configureEach {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = javaVersion
+    }
+}
+
 minecraft {
     runs {
         client {
@@ -219,6 +234,7 @@ processResources {
         e.printStackTrace()
     }
     inputs.property "commithash", hash
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
 
     from(sourceSets.main.resources.srcDirs) {
         include 'META-INF/mods.toml'
@@ -235,6 +251,10 @@ processResources {
     }
 }
 
+sourcesJar {
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+}
+
 // Web tasks
 
 
@@ -416,31 +436,31 @@ task checkRelease {
     description "Verifies that everything is ready for a release"
 
     inputs.property "version", mod_version
-    inputs.file("src/main/resources/data/computercraft/lua/rom/help/changelog.txt")
+    inputs.file("src/main/resources/data/computercraft/lua/rom/help/changelog.md")
-    inputs.file("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt")
+    inputs.file("src/main/resources/data/computercraft/lua/rom/help/whatsnew.md")
 
     doLast {
         def ok = true
 
         // Check we're targetting the current version
-        def whatsnew = new File(projectDir, "src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt").readLines()
+        def whatsnew = new File(projectDir, "src/main/resources/data/computercraft/lua/rom/help/whatsnew.md").readLines()
         if (whatsnew[0] != "New features in CC: Tweaked $mod_version") {
             ok = false
-            project.logger.error("Expected `whatsnew.txt' to target $mod_version.")
+            project.logger.error("Expected `whatsnew.md' to target $mod_version.")
         }
 
         // Check "read more" exists and trim it
         def idx = whatsnew.findIndexOf { it == 'Type "help changelog" to see the full version history.' }
         if (idx == -1) {
             ok = false
-            project.logger.error("Must mention the changelog in whatsnew.txt")
+            project.logger.error("Must mention the changelog in whatsnew.md")
         } else {
             whatsnew = whatsnew.getAt(0..<idx)
         }
 
         // Check whatsnew and changelog match.
         def versionChangelog = "# " + whatsnew.join("\n")
-        def changelog = new File(projectDir, "src/main/resources/data/computercraft/lua/rom/help/changelog.txt").getText()
+        def changelog = new File(projectDir, "src/main/resources/data/computercraft/lua/rom/help/changelog.md").getText()
         if (!changelog.startsWith(versionChangelog)) {
             ok = false
             project.logger.error("whatsnew and changelog are not in sync")
@@ -464,6 +484,21 @@ curseforge {
     }
 }
 
+import com.modrinth.minotaur.TaskModrinthUpload
+tasks.register('publishModrinth', TaskModrinthUpload.class).configure {
+    dependsOn('assemble', 'reobfJar')
+    onlyIf {
+        project.hasProperty('modrinthApiKey')
+    }
+
+    token = project.hasProperty('curseForgeApiKey')
+    projectId = 'gu7yAYhd'
+    versionNumber = project.mod_version
+    uploadFile = jar
+    addGameVersion(project.mc_version)
+    addLoader('forge')
+}
+
 tasks.withType(GenerateModuleMetadata) {
     // We can't generate metadata as that includes Forge as a dependency.
     enabled = false
@@ -538,10 +573,10 @@ githubRelease {
     prerelease false
 }
 
-def uploadTasks = ["publish", "curseforge", "githubRelease"]
+def uploadTasks = ["publish", "curseforge", "publishModrinth", "githubRelease"]
 uploadTasks.forEach { tasks.getByName(it).dependsOn checkRelease }
 
 task uploadAll(dependsOn: uploadTasks) {
     group "upload"
-    description "Uploads to all repositories (Maven, Curse, GitHub release)"
+    description "Uploads to all repositories (Maven, Curse, Modrinth, GitHub release)"
 }

config/checkstyle/suppressions.xml

@@ -7,9 +7,6 @@
     <suppress checks="StaticVariableName" files=".*[\\/]ComputerCraft.java" />
     <suppress checks="StaticVariableName" files=".*[\\/]ComputerCraftAPI.java" />
 
-    <!-- Do not check for missing package Javadoc. -->
-    <suppress checks="JavadocStyle" files=".*[\\/]package-info.java" />
-
     <!-- The commands API is documented in Lua. -->
     <suppress checks="SummaryJavadocCheck" files=".*[\\/]CommandAPI.java" />
 </suppressions>

config/gitpod/Dockerfile

@@ -0,0 +1,8 @@
+FROM gitpod/workspace-base
+
+USER gitpod
+
+RUN sudo apt-get -q update \
+ && sudo apt-get install -yq openjdk-8-jdk openjdk-16-jdk python3-pip npm \
+ && sudo pip3 install pre-commit \
+ && sudo update-java-alternatives --set java-1.8.0-openjdk-amd64

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

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

@@ -32,7 +32,7 @@ public final class TransformedModel
     public TransformedModel( @Nonnull IBakedModel model )
     {
         this.model = Objects.requireNonNull( model );
-        this.matrix = TransformationMatrix.identity();
+        matrix = TransformationMatrix.identity();
     }
 
     public static TransformedModel of( @Nonnull ModelResourceLocation location )

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

@@ -30,7 +30,7 @@ public class FileOperationException extends IOException
     public FileOperationException( @Nonnull String message )
     {
         super( Objects.requireNonNull( message, "message cannot be null" ) );
-        this.filename = null;
+        filename = null;
     }
 
     @Nullable

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

@@ -19,14 +19,14 @@ public class LuaException extends Exception
     public LuaException( @Nullable String message )
     {
         super( message );
-        this.hasLevel = false;
+        hasLevel = false;
-        this.level = 1;
+        level = 1;
     }
 
     public LuaException( @Nullable String message, int level )
     {
         super( message );
-        this.hasLevel = true;
+        hasLevel = true;
         this.level = level;
     }
 

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

@@ -30,14 +30,14 @@ public final class MethodResult
 
     private MethodResult( Object[] arguments, ILuaCallback callback )
     {
-        this.result = arguments;
+        result = arguments;
         this.callback = callback;
-        this.adjust = 0;
+        adjust = 0;
     }
 
     private MethodResult( Object[] arguments, ILuaCallback callback, int adjust )
     {
-        this.result = arguments;
+        result = arguments;
         this.callback = callback;
         this.adjust = adjust;
     }

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

@@ -22,6 +22,7 @@ public class ClientHooks
         if( event.getWorld().isClientSide() )
         {
             ClientMonitor.destroyAll();
+            SoundManager.reset();
         }
     }
 

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

@@ -0,0 +1,84 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.audio.ISound;
+import net.minecraft.client.audio.ITickableSound;
+import net.minecraft.client.audio.LocatableSound;
+import net.minecraft.client.audio.SoundHandler;
+import net.minecraft.util.SoundCategory;
+import net.minecraft.util.SoundEvent;
+import net.minecraft.util.math.vector.Vector3d;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+public class SoundManager
+{
+    private static final Map<UUID, MoveableSound> sounds = new HashMap<>();
+
+    public static void playSound( UUID source, Vector3d position, SoundEvent event, float volume, float pitch )
+    {
+        SoundHandler soundManager = Minecraft.getInstance().getSoundManager();
+
+        MoveableSound oldSound = sounds.get( source );
+        if( oldSound != null ) soundManager.stop( oldSound );
+
+        MoveableSound newSound = new MoveableSound( event, position, volume, pitch );
+        sounds.put( source, newSound );
+        soundManager.play( newSound );
+    }
+
+    public static void stopSound( UUID source )
+    {
+        ISound sound = sounds.remove( source );
+        if( sound == null ) return;
+
+        Minecraft.getInstance().getSoundManager().stop( sound );
+    }
+
+    public static void moveSound( UUID source, Vector3d position )
+    {
+        MoveableSound sound = sounds.get( source );
+        if( sound != null ) sound.setPosition( position );
+    }
+
+    public static void reset()
+    {
+        sounds.clear();
+    }
+
+    private static class MoveableSound extends LocatableSound implements ITickableSound
+    {
+        protected MoveableSound( SoundEvent sound, Vector3d position, float volume, float pitch )
+        {
+            super( sound, SoundCategory.RECORDS );
+            setPosition( position );
+            this.volume = volume;
+            this.pitch = pitch;
+        }
+
+        void setPosition( Vector3d position )
+        {
+            x = (float) position.x();
+            y = (float) position.y();
+            z = (float) position.z();
+        }
+
+        @Override
+        public boolean isStopped()
+        {
+            return false;
+        }
+
+        @Override
+        public void tick()
+        {
+        }
+    }
+}

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

@@ -8,8 +8,8 @@ package dan200.computercraft.client.gui;
 import com.mojang.blaze3d.matrix.MatrixStack;
 import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
-import dan200.computercraft.client.gui.widgets.WidgetWrapper;
 import dan200.computercraft.client.render.ComputerBorderRenderer;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -25,7 +25,6 @@ import org.lwjgl.glfw.GLFW;
 import javax.annotation.Nonnull;
 
 import static dan200.computercraft.client.render.ComputerBorderRenderer.BORDER;
-import static dan200.computercraft.client.render.ComputerBorderRenderer.MARGIN;
 
 public final class GuiComputer<T extends ContainerComputerBase> extends ContainerScreen<T>
 {
@@ -34,8 +33,7 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
     private final int termWidth;
     private final int termHeight;
 
-    private WidgetTerminal terminal;
+    private WidgetTerminal terminal = null;
-    private WidgetWrapper terminalWrapper;
 
     private GuiComputer(
         T container, PlayerInventory player, ITextComponent title, int termWidth, int termHeight
@@ -46,7 +44,9 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
         computer = (ClientComputer) container.getComputer();
         this.termWidth = termWidth;
         this.termHeight = termHeight;
-        terminal = null;
+
+        imageWidth = WidgetTerminal.getWidth( termWidth ) + BORDER * 2 + ComputerSidebar.WIDTH;
+        imageHeight = WidgetTerminal.getHeight( termHeight ) + BORDER * 2;
     }
 
     public static GuiComputer<ContainerComputer> create( ContainerComputer container, PlayerInventory inventory, ITextComponent component )
@@ -77,29 +77,21 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
     @Override
     protected void init()
     {
-        minecraft.keyboardHandler.setSendRepeatsToGui( true );
-
-        int termPxWidth = termWidth * FixedWidthFontRenderer.FONT_WIDTH;
-        int termPxHeight = termHeight * FixedWidthFontRenderer.FONT_HEIGHT;
-
-        imageWidth = termPxWidth + MARGIN * 2 + BORDER * 2;
-        imageHeight = termPxHeight + MARGIN * 2 + BORDER * 2;
-
         super.init();
 
-        terminal = new WidgetTerminal( minecraft, () -> computer, termWidth, termHeight, MARGIN, MARGIN, MARGIN, MARGIN );
+        minecraft.keyboardHandler.setSendRepeatsToGui( true );
-        terminalWrapper = new WidgetWrapper( terminal, MARGIN + BORDER + leftPos, MARGIN + BORDER + topPos, termPxWidth, termPxHeight );
 
-        children.add( terminalWrapper );
+        terminal = addButton( new WidgetTerminal( computer,
-        setFocused( terminalWrapper );
+            leftPos + ComputerSidebar.WIDTH + BORDER, topPos + BORDER, termWidth, termHeight
+        ) );
+        ComputerSidebar.addButtons( this, computer, this::addButton, leftPos, topPos + BORDER );
+        setFocused( terminal );
     }
 
     @Override
     public void removed()
     {
         super.removed();
-        children.remove( terminal );
-        terminal = null;
         minecraft.keyboardHandler.setSendRepeatsToGui( false );
     }
 
@@ -114,7 +106,7 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
     public boolean keyPressed( int key, int scancode, int modifiers )
     {
         // Forward the tab key to the terminal, rather than moving between controls.
-        if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminalWrapper )
+        if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminal )
         {
             return getFocused().keyPressed( key, scancode, modifiers );
         }
@@ -125,16 +117,11 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
     @Override
     public void renderBg( @Nonnull MatrixStack stack, float partialTicks, int mouseX, int mouseY )
     {
-        // Draw terminal
-        terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
-
         // Draw a border around the terminal
         RenderSystem.color4f( 1, 1, 1, 1 );
         minecraft.getTextureManager().bind( ComputerBorderRenderer.getTexture( family ) );
-        ComputerBorderRenderer.render(
+        ComputerBorderRenderer.render( terminal.x, terminal.y, getBlitOffset(), terminal.getWidth(), terminal.getHeight() );
-            terminalWrapper.getX() - MARGIN, terminalWrapper.getY() - MARGIN, getBlitOffset(),
+        ComputerSidebar.renderBackground( stack, leftPos, topPos + BORDER );
-            terminalWrapper.getWidth() + MARGIN * 2, terminalWrapper.getHeight() + MARGIN * 2
-        );
     }
 
     @Override

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

@@ -8,8 +8,9 @@ package dan200.computercraft.client.gui;
 import com.mojang.blaze3d.matrix.MatrixStack;
 import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
-import dan200.computercraft.client.gui.widgets.WidgetWrapper;
+import dan200.computercraft.client.render.ComputerBorderRenderer;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
@@ -21,6 +22,8 @@ import org.lwjgl.glfw.GLFW;
 
 import javax.annotation.Nonnull;
 
+import static dan200.computercraft.shared.turtle.inventory.ContainerTurtle.*;
+
 public class GuiTurtle extends ContainerScreen<ContainerTurtle>
 {
     private static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/turtle_normal.png" );
@@ -32,7 +35,6 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
     private final ClientComputer computer;
 
     private WidgetTerminal terminal;
-    private WidgetWrapper terminalWrapper;
 
     public GuiTurtle( ContainerTurtle container, PlayerInventory player, ITextComponent title )
     {
@@ -52,27 +54,18 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
         super.init();
         minecraft.keyboardHandler.setSendRepeatsToGui( true );
 
-        int termPxWidth = ComputerCraft.turtleTermWidth * FixedWidthFontRenderer.FONT_WIDTH;
+        terminal = addButton( new WidgetTerminal(
-        int termPxHeight = ComputerCraft.turtleTermHeight * FixedWidthFontRenderer.FONT_HEIGHT;
+            computer, leftPos + BORDER + ComputerSidebar.WIDTH, topPos + BORDER,
-
+            ComputerCraft.turtleTermWidth, ComputerCraft.turtleTermHeight
-        terminal = new WidgetTerminal(
+        ) );
-            minecraft, () -> computer,
+        ComputerSidebar.addButtons( this, computer, this::addButton, leftPos, topPos + BORDER );
-            ComputerCraft.turtleTermWidth,
+        setFocused( terminal );
-            ComputerCraft.turtleTermHeight,
-            2, 2, 2, 2
-        );
-        terminalWrapper = new WidgetWrapper( terminal, 2 + 8 + leftPos, 2 + 8 + topPos, termPxWidth, termPxHeight );
-
-        children.add( terminalWrapper );
-        setFocused( terminalWrapper );
     }
 
     @Override
     public void removed()
     {
         super.removed();
-        children.remove( terminal );
-        terminal = null;
         minecraft.keyboardHandler.setSendRepeatsToGui( false );
     }
 
@@ -87,7 +80,7 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
     public boolean keyPressed( int key, int scancode, int modifiers )
     {
         // Forward the tab key to the terminal, rather than moving between controls.
-        if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminalWrapper )
+        if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminal )
         {
             return getFocused().keyPressed( key, scancode, modifiers );
         }
@@ -98,24 +91,21 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
     @Override
     protected void renderBg( @Nonnull MatrixStack transform, float partialTicks, int mouseX, int mouseY )
     {
-        // Draw term
+        boolean advanced = family == ComputerFamily.ADVANCED;
-        ResourceLocation texture = family == ComputerFamily.ADVANCED ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL;
+        minecraft.getTextureManager().bind( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
-        terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
+        blit( transform, leftPos + ComputerSidebar.WIDTH, topPos, 0, 0, imageWidth, imageHeight );
 
-        // Draw border/inventory
+        minecraft.getTextureManager().bind( advanced ? ComputerBorderRenderer.BACKGROUND_ADVANCED : ComputerBorderRenderer.BACKGROUND_NORMAL );
-        RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+        ComputerSidebar.renderBackground( transform, leftPos, topPos + BORDER );
-        minecraft.getTextureManager().bind( texture );
-        blit( transform, leftPos, topPos, 0, 0, imageWidth, imageHeight );
 
-        // Draw selection slot
         int slot = container.getSelectedSlot();
         if( slot >= 0 )
         {
+            RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
             int slotX = slot % 4;
             int slotY = slot / 4;
             blit( transform,
-                leftPos + ContainerTurtle.TURTLE_START_X - 2 + slotX * 18,
+                leftPos + TURTLE_START_X - 2 + slotX * 18, topPos + PLAYER_START_Y - 2 + slotY * 18,
-                topPos + ContainerTurtle.PLAYER_START_Y - 2 + slotY * 18,
                 0, 217, 24, 24
             );
         }

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

@@ -0,0 +1,106 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.gui.widgets;
+
+import com.mojang.blaze3d.matrix.MatrixStack;
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.render.ComputerBorderRenderer;
+import dan200.computercraft.shared.computer.core.ClientComputer;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.widget.Widget;
+import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.text.TextFormatting;
+import net.minecraft.util.text.TranslationTextComponent;
+
+import java.util.Arrays;
+import java.util.function.Consumer;
+
+/**
+ * Registers buttons to interact with a computer.
+ */
+public final class ComputerSidebar
+{
+    private static final ResourceLocation TEXTURE = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/buttons.png" );
+
+    private static final int TEX_SIZE = 64;
+
+    private static final int ICON_WIDTH = 12;
+    private static final int ICON_HEIGHT = 12;
+    private static final int ICON_MARGIN = 2;
+
+    private static final int ICON_TEX_Y_DIFF = 14;
+
+    private static final int CORNERS_BORDER = 3;
+    private static final int FULL_BORDER = CORNERS_BORDER + ICON_MARGIN;
+
+    private static final int BUTTONS = 2;
+    private static final int HEIGHT = (ICON_HEIGHT + ICON_MARGIN * 2) * BUTTONS + CORNERS_BORDER * 2;
+    public static final int WIDTH = 17;
+
+    private ComputerSidebar()
+    {
+    }
+
+    public static void addButtons( Screen screen, ClientComputer computer, Consumer<Widget> add, int x, int y )
+    {
+        x += CORNERS_BORDER + 1;
+        y += CORNERS_BORDER + ICON_MARGIN;
+
+        add.accept( new DynamicImageButton(
+            screen, x, y, ICON_WIDTH, ICON_HEIGHT, () -> computer.isOn() ? 15 : 1, 1, ICON_TEX_Y_DIFF,
+            TEXTURE, TEX_SIZE, TEX_SIZE, b -> toggleComputer( computer ),
+            () -> computer.isOn() ? Arrays.asList(
+                new TranslationTextComponent( "gui.computercraft.tooltip.turn_off" ),
+                new TranslationTextComponent( "gui.computercraft.tooltip.turn_off.key" ).withStyle( TextFormatting.GRAY )
+            ) : Arrays.asList(
+                new TranslationTextComponent( "gui.computercraft.tooltip.turn_on" ),
+                new TranslationTextComponent( "gui.computercraft.tooltip.turn_off.key" ).withStyle( TextFormatting.GRAY )
+            )
+        ) );
+
+        y += ICON_HEIGHT + ICON_MARGIN * 2;
+
+        add.accept( new DynamicImageButton(
+            screen, x, y, ICON_WIDTH, ICON_HEIGHT, 29, 1, ICON_TEX_Y_DIFF,
+            TEXTURE, TEX_SIZE, TEX_SIZE, b -> computer.queueEvent( "terminate" ),
+            Arrays.asList(
+                new TranslationTextComponent( "gui.computercraft.tooltip.terminate" ),
+                new TranslationTextComponent( "gui.computercraft.tooltip.terminate.key" ).withStyle( TextFormatting.GRAY )
+            )
+        ) );
+    }
+
+    public static void renderBackground( MatrixStack transform, int x, int y )
+    {
+        Screen.blit( transform,
+            x, y, 0, 102, WIDTH, FULL_BORDER,
+            ComputerBorderRenderer.TEX_SIZE, ComputerBorderRenderer.TEX_SIZE
+        );
+
+        Screen.blit( transform,
+            x, y + FULL_BORDER, WIDTH, HEIGHT - FULL_BORDER * 2,
+            0, 107, WIDTH, 4,
+            ComputerBorderRenderer.TEX_SIZE, ComputerBorderRenderer.TEX_SIZE
+        );
+
+        Screen.blit( transform,
+            x, y + HEIGHT - FULL_BORDER, 0, 111, WIDTH, FULL_BORDER,
+            ComputerBorderRenderer.TEX_SIZE, ComputerBorderRenderer.TEX_SIZE
+        );
+    }
+
+    private static void toggleComputer( ClientComputer computer )
+    {
+        if( computer.isOn() )
+        {
+            computer.shutdown();
+        }
+        else
+        {
+            computer.turnOn();
+        }
+    }
+}

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

@@ -0,0 +1,101 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.gui.widgets;
+
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.systems.RenderSystem;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.widget.button.Button;
+import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.text.ITextComponent;
+import net.minecraft.util.text.StringTextComponent;
+import net.minecraftforge.common.util.NonNullSupplier;
+
+import javax.annotation.Nonnull;
+import java.util.List;
+import java.util.function.IntSupplier;
+
+/**
+ * Version of {@link net.minecraft.client.gui.widget.button.ImageButton} which allows changing some properties
+ * dynamically.
+ */
+public class DynamicImageButton extends Button
+{
+    private final Screen screen;
+    private final ResourceLocation texture;
+    private final IntSupplier xTexStart;
+    private final int yTexStart;
+    private final int yDiffTex;
+    private final int textureWidth;
+    private final int textureHeight;
+    private final NonNullSupplier<List<ITextComponent>> tooltip;
+
+    public DynamicImageButton(
+        Screen screen, int x, int y, int width, int height, int xTexStart, int yTexStart, int yDiffTex,
+        ResourceLocation texture, int textureWidth, int textureHeight,
+        IPressable onPress, List<ITextComponent> tooltip
+    )
+    {
+        this(
+            screen, x, y, width, height, () -> xTexStart, yTexStart, yDiffTex,
+            texture, textureWidth, textureHeight,
+            onPress, () -> tooltip
+        );
+    }
+
+
+    public DynamicImageButton(
+        Screen screen, int x, int y, int width, int height, IntSupplier xTexStart, int yTexStart, int yDiffTex,
+        ResourceLocation texture, int textureWidth, int textureHeight,
+        IPressable onPress, NonNullSupplier<List<ITextComponent>> tooltip
+    )
+    {
+        super( x, y, width, height, StringTextComponent.EMPTY, onPress );
+        this.screen = screen;
+        this.textureWidth = textureWidth;
+        this.textureHeight = textureHeight;
+        this.xTexStart = xTexStart;
+        this.yTexStart = yTexStart;
+        this.yDiffTex = yDiffTex;
+        this.texture = texture;
+        this.tooltip = tooltip;
+    }
+
+    @Override
+    public void renderButton( @Nonnull MatrixStack stack, int mouseX, int mouseY, float partialTicks )
+    {
+        Minecraft minecraft = Minecraft.getInstance();
+        minecraft.getTextureManager().bind( texture );
+        RenderSystem.disableDepthTest();
+
+        int yTex = yTexStart;
+        if( isHovered() ) yTex += yDiffTex;
+
+        blit( stack, x, y, xTexStart.getAsInt(), yTex, width, height, textureWidth, textureHeight );
+        RenderSystem.enableDepthTest();
+
+        if( isHovered() ) renderToolTip( stack, mouseX, mouseY );
+    }
+
+    @Nonnull
+    @Override
+    public ITextComponent getMessage()
+    {
+        List<ITextComponent> tooltip = this.tooltip.get();
+        return tooltip.isEmpty() ? StringTextComponent.EMPTY : tooltip.get( 0 );
+    }
+
+    @Override
+    public void renderToolTip( @Nonnull MatrixStack stack, int mouseX, int mouseY )
+    {
+        List<ITextComponent> tooltip = this.tooltip.get();
+        if( !tooltip.isEmpty() )
+        {
+            screen.renderWrappedToolTip( stack, tooltip, mouseX, mouseY, screen.getMinecraft().font );
+        }
+    }
+}

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

@@ -5,32 +5,35 @@
  */
 package dan200.computercraft.client.gui.widgets;
 
+import com.mojang.blaze3d.matrix.MatrixStack;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.shared.computer.core.ClientComputer;
-import dan200.computercraft.shared.computer.core.IComputer;
 import net.minecraft.client.Minecraft;
-import net.minecraft.client.gui.IGuiEventListener;
+import net.minecraft.client.gui.widget.Widget;
 import net.minecraft.util.SharedConstants;
+import net.minecraft.util.math.vector.Matrix4f;
+import net.minecraft.util.text.StringTextComponent;
 import org.lwjgl.glfw.GLFW;
 
+import javax.annotation.Nonnull;
 import java.util.BitSet;
-import java.util.function.Supplier;
 
 import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
 import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
+import static dan200.computercraft.client.render.ComputerBorderRenderer.MARGIN;
 
-public class WidgetTerminal implements IGuiEventListener
+public class WidgetTerminal extends Widget
 {
     private static final float TERMINATE_TIME = 0.5f;
 
-    private final Minecraft client;
+    private final ClientComputer computer;
 
-    private boolean focused;
+    // The positions of the actual terminal
-
+    private final int innerX;
-    private final Supplier<ClientComputer> computer;
+    private final int innerY;
-    private final int termWidth;
+    private final int innerWidth;
-    private final int termHeight;
+    private final int innerHeight;
 
     private float terminateTimer = -1;
     private float rebootTimer = -1;
@@ -40,23 +43,18 @@ public class WidgetTerminal implements IGuiEventListener
     private int lastMouseX = -1;
     private int lastMouseY = -1;
 
-    private final int leftMargin;
-    private final int rightMargin;
-    private final int topMargin;
-    private final int bottomMargin;
-
     private final BitSet keysDown = new BitSet( 256 );
 
-    public WidgetTerminal( Minecraft client, Supplier<ClientComputer> computer, int termWidth, int termHeight, int leftMargin, int rightMargin, int topMargin, int bottomMargin )
+    public WidgetTerminal( @Nonnull ClientComputer computer, int x, int y, int termWidth, int termHeight )
     {
-        this.client = client;
+        super( x, y, termWidth * FONT_WIDTH + MARGIN * 2, termHeight * FONT_HEIGHT + MARGIN * 2, StringTextComponent.EMPTY );
+
         this.computer = computer;
-        this.termWidth = termWidth;
+
-        this.termHeight = termHeight;
+        innerX = x + MARGIN;
-        this.leftMargin = leftMargin;
+        innerY = y + MARGIN;
-        this.rightMargin = rightMargin;
+        innerWidth = termWidth * FONT_WIDTH;
-        this.topMargin = topMargin;
+        innerHeight = termHeight * FONT_HEIGHT;
-        this.bottomMargin = bottomMargin;
     }
 
     @Override
@@ -65,7 +63,7 @@ public class WidgetTerminal implements IGuiEventListener
         if( ch >= 32 && ch <= 126 || ch >= 160 && ch <= 255 ) // printable chars in byte range
         {
             // Queue the "char" event
-            queueEvent( "char", Character.toString( ch ) );
+            computer.queueEvent( "char", new Object[] { Character.toString( ch ) } );
         }
 
         return true;
@@ -91,7 +89,7 @@ public class WidgetTerminal implements IGuiEventListener
 
                 case GLFW.GLFW_KEY_V:
                     // Ctrl+V for paste
-                    String clipboard = client.keyboardHandler.getClipboard();
+                    String clipboard = Minecraft.getInstance().keyboardHandler.getClipboard();
                     if( clipboard != null )
                     {
                         // Clip to the first occurrence of \r or \n
@@ -116,7 +114,7 @@ public class WidgetTerminal implements IGuiEventListener
                         {
                             // Clip to 512 characters and queue the event
                             if( clipboard.length() > 512 ) clipboard = clipboard.substring( 0, 512 );
-                            queueEvent( "paste", clipboard );
+                            computer.queueEvent( "paste", new Object[] { clipboard } );
                         }
 
                         return true;
@@ -129,8 +127,7 @@ public class WidgetTerminal implements IGuiEventListener
             // Queue the "key" event and add to the down set
             boolean repeat = keysDown.get( key );
             keysDown.set( key );
-            IComputer computer = this.computer.get();
+            computer.keyDown( key, repeat );
-            if( computer != null ) computer.keyDown( key, repeat );
         }
 
         return true;
@@ -143,8 +140,7 @@ public class WidgetTerminal implements IGuiEventListener
         if( key >= 0 && keysDown.get( key ) )
         {
             keysDown.set( key, false );
-            IComputer computer = this.computer.get();
+            computer.keyUp( key );
-            if( computer != null ) computer.keyUp( key );
         }
 
         switch( key )
@@ -170,14 +166,14 @@ public class WidgetTerminal implements IGuiEventListener
     @Override
     public boolean mouseClicked( double mouseX, double mouseY, int button )
     {
-        ClientComputer computer = this.computer.get();
+        if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !computer.isColour() || button < 0 || button > 2 ) return false;
 
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FONT_WIDTH);
+            int charX = (int) ((mouseX - x) / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
+            int charY = (int) ((mouseY - x) / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -194,14 +190,14 @@ public class WidgetTerminal implements IGuiEventListener
     @Override
     public boolean mouseReleased( double mouseX, double mouseY, int button )
     {
-        ClientComputer computer = this.computer.get();
+        if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !computer.isColour() || button < 0 || button > 2 ) return false;
 
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FONT_WIDTH);
+            int charX = (int) ((mouseX - x) / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
+            int charY = (int) ((mouseY - x) / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -221,14 +217,14 @@ public class WidgetTerminal implements IGuiEventListener
     @Override
     public boolean mouseDragged( double mouseX, double mouseY, int button, double v2, double v3 )
     {
-        ClientComputer computer = this.computer.get();
+        if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( computer == null || !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !computer.isColour() || button < 0 || button > 2 ) return false;
 
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FONT_WIDTH);
+            int charX = (int) ((mouseX - x) / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
+            int charY = (int) ((mouseY - x) / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -246,14 +242,14 @@ public class WidgetTerminal implements IGuiEventListener
     @Override
     public boolean mouseScrolled( double mouseX, double mouseY, double delta )
     {
-        ClientComputer computer = this.computer.get();
+        if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( computer == null || !computer.isColour() || delta == 0 ) return false;
+        if( !computer.isColour() || delta == 0 ) return false;
 
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FONT_WIDTH);
+            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
+            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -266,89 +262,74 @@ public class WidgetTerminal implements IGuiEventListener
         return true;
     }
 
+    private boolean inTermRegion( double mouseX, double mouseY )
+    {
+        return active && visible && mouseX >= innerX && mouseY >= innerY && mouseX < innerX + innerWidth && mouseY < innerY + innerHeight;
+    }
+
     public void update()
     {
         if( terminateTimer >= 0 && terminateTimer < TERMINATE_TIME && (terminateTimer += 0.05f) > TERMINATE_TIME )
         {
-            queueEvent( "terminate" );
+            computer.queueEvent( "terminate" );
         }
 
         if( shutdownTimer >= 0 && shutdownTimer < TERMINATE_TIME && (shutdownTimer += 0.05f) > TERMINATE_TIME )
         {
-            ClientComputer computer = this.computer.get();
+            computer.shutdown();
-            if( computer != null ) computer.shutdown();
         }
 
         if( rebootTimer >= 0 && rebootTimer < TERMINATE_TIME && (rebootTimer += 0.05f) > TERMINATE_TIME )
         {
-            ClientComputer computer = this.computer.get();
+            computer.reboot();
-            if( computer != null ) computer.reboot();
         }
     }
 
     @Override
-    public boolean changeFocus( boolean reversed )
+    public void onFocusedChanged( boolean focused )
     {
-        if( focused )
+        if( !focused )
         {
             // When blurring, we should make all keys go up
             for( int key = 0; key < keysDown.size(); key++ )
             {
-                if( keysDown.get( key ) ) queueEvent( "key_up", key );
+                if( keysDown.get( key ) ) computer.keyUp( key );
             }
             keysDown.clear();
 
             // When blurring, we should make the last mouse button go up
             if( lastMouseButton > 0 )
             {
-                IComputer computer = this.computer.get();
+                computer.mouseUp( lastMouseButton + 1, lastMouseX + 1, lastMouseY + 1 );
-                if( computer != null ) computer.mouseUp( lastMouseButton + 1, lastMouseX + 1, lastMouseY + 1 );
                 lastMouseButton = -1;
             }
 
             shutdownTimer = terminateTimer = rebootTimer = -1;
         }
-        focused = !focused;
-        return true;
-    }
-
-    public void draw( int originX, int originY )
-    {
-        synchronized( computer )
-        {
-            // Draw the screen contents
-            ClientComputer computer = this.computer.get();
-            Terminal terminal = computer != null ? computer.getTerminal() : null;
-            if( terminal != null )
-            {
-                FixedWidthFontRenderer.drawTerminal( originX, originY, terminal, !computer.isColour(), topMargin, bottomMargin, leftMargin, rightMargin );
-            }
-            else
-            {
-                FixedWidthFontRenderer.drawEmptyTerminal(
-                    originX - leftMargin, originY - rightMargin,
-                    termWidth * FONT_WIDTH + leftMargin + rightMargin,
-                    termHeight * FONT_HEIGHT + topMargin + bottomMargin
-                );
-            }
-        }
-    }
-
-    private void queueEvent( String event )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer != null ) computer.queueEvent( event );
-    }
-
-    private void queueEvent( String event, Object... args )
-    {
-        ClientComputer computer = this.computer.get();
-        if( computer != null ) computer.queueEvent( event, args );
     }
 
     @Override
-    public boolean isMouseOver( double x, double y )
+    public void render( @Nonnull MatrixStack transform, int mouseX, int mouseY, float partialTicks )
     {
-        return true;
+        Matrix4f matrix = transform.last().pose();
+        Terminal terminal = computer.getTerminal();
+        if( terminal != null )
+        {
+            FixedWidthFontRenderer.drawTerminal( matrix, innerX, innerY, terminal, !computer.isColour(), MARGIN, MARGIN, MARGIN, MARGIN );
+        }
+        else
+        {
+            FixedWidthFontRenderer.drawEmptyTerminal( matrix, x, y, width, height );
+        }
+    }
+
+    public static int getWidth( int termWidth )
+    {
+        return termWidth * FONT_WIDTH + MARGIN * 2;
+    }
+
+    public static int getHeight( int termHeight )
+    {
+        return termHeight * FONT_HEIGHT + MARGIN * 2;
     }
 }

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

@@ -1,105 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.client.gui.widgets;
-
-import net.minecraft.client.gui.IGuiEventListener;
-
-public class WidgetWrapper implements IGuiEventListener
-{
-    private final IGuiEventListener listener;
-    private final int x;
-    private final int y;
-    private final int width;
-    private final int height;
-
-    public WidgetWrapper( IGuiEventListener listener, int x, int y, int width, int height )
-    {
-        this.listener = listener;
-        this.x = x;
-        this.y = y;
-        this.width = width;
-        this.height = height;
-    }
-
-    @Override
-    public boolean changeFocus( boolean b )
-    {
-        return listener.changeFocus( b );
-    }
-
-    @Override
-    public boolean mouseClicked( double x, double y, int button )
-    {
-        double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseClicked( dx, dy, button );
-    }
-
-    @Override
-    public boolean mouseReleased( double x, double y, int button )
-    {
-        double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseReleased( dx, dy, button );
-    }
-
-    @Override
-    public boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
-    {
-        double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseDragged( dx, dy, button, deltaX, deltaY );
-    }
-
-    @Override
-    public boolean mouseScrolled( double x, double y, double delta )
-    {
-        double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height && listener.mouseScrolled( dx, dy, delta );
-    }
-
-    @Override
-    public boolean keyPressed( int key, int scancode, int modifiers )
-    {
-        return listener.keyPressed( key, scancode, modifiers );
-    }
-
-    @Override
-    public boolean keyReleased( int key, int scancode, int modifiers )
-    {
-        return listener.keyReleased( key, scancode, modifiers );
-    }
-
-    @Override
-    public boolean charTyped( char character, int modifiers )
-    {
-        return listener.charTyped( character, modifiers );
-    }
-
-    public int getX()
-    {
-        return x;
-    }
-
-    public int getY()
-    {
-        return y;
-    }
-
-    public int getWidth()
-    {
-        return width;
-    }
-
-    public int getHeight()
-    {
-        return height;
-    }
-
-    @Override
-    public boolean isMouseOver( double x, double y )
-    {
-        double dx = x - this.x, dy = y - this.y;
-        return dx >= 0 && dx < width && dy >= 0 && dy < height;
-    }
-}

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

@@ -52,7 +52,8 @@ public class ComputerBorderRenderer
 
     public static final int LIGHT_HEIGHT = 8;
 
-    private static final float TEX_SCALE = 1 / 256.0f;
+    public static final int TEX_SIZE = 256;
+    private static final float TEX_SCALE = 1 / (float) TEX_SIZE;
 
     private final Matrix4f transform;
     private final IVertexBuilder builder;

src/main/java/dan200/computercraft/core/apis/HTTPAPI.java

@@ -37,7 +37,7 @@ public class HTTPAPI implements ILuaAPI
 {
     private final IAPIEnvironment apiEnvironment;
 
-    private final ResourceGroup<CheckUrl> checkUrls = new ResourceGroup<>();
+    private final ResourceGroup<CheckUrl> checkUrls = new ResourceGroup<>( ResourceGroup.DEFAULT );
     private final ResourceGroup<HttpRequest> requests = new ResourceQueue<>( () -> ComputerCraft.httpMaxRequests );
     private final ResourceGroup<Websocket> websockets = new ResourceGroup<>( () -> ComputerCraft.httpMaxWebsockets );
 
@@ -127,7 +127,10 @@ public class HTTPAPI implements ILuaAPI
             HttpRequest request = new HttpRequest( requests, apiEnvironment, address, postString, headers, binary, redirect );
 
             // Make the request
-            request.queue( r -> r.request( uri, httpMethod ) );
+            if( !request.queue( r -> r.request( uri, httpMethod ) ) )
+            {
+                throw new LuaException( "Too many ongoing HTTP requests" );
+            }
 
             return new Object[] { true };
         }
@@ -138,12 +141,15 @@ public class HTTPAPI implements ILuaAPI
     }
 
     @LuaFunction
-    public final Object[] checkURL( String address )
+    public final Object[] checkURL( String address ) throws LuaException
     {
         try
         {
             URI uri = HttpRequest.checkUri( address );
-            new CheckUrl( checkUrls, apiEnvironment, address, uri ).queue( CheckUrl::run );
+            if( !new CheckUrl( checkUrls, apiEnvironment, address, uri ).queue( CheckUrl::run ) )
+            {
+                throw new LuaException( "Too many ongoing checkUrl calls" );
+            }
 
             return new Object[] { true };
         }

src/main/java/dan200/computercraft/core/apis/http/Resource.java

@@ -97,7 +97,7 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
         tryClose();
     }
 
-    public boolean queue( Consumer<T> task )
+    public final boolean queue( Consumer<T> task )
     {
         @SuppressWarnings( "unchecked" )
         T thisT = (T) this;

src/main/java/dan200/computercraft/core/apis/http/ResourceGroup.java

@@ -18,6 +18,9 @@ import java.util.function.Supplier;
  */
 public class ResourceGroup<T extends Resource<T>>
 {
+    public static final int DEFAULT_LIMIT = 512;
+    public static final IntSupplier DEFAULT = () -> DEFAULT_LIMIT;
+
     private static final IntSupplier ZERO = () -> 0;
 
     final IntSupplier limit;

src/main/java/dan200/computercraft/core/apis/http/ResourceQueue.java

@@ -38,8 +38,10 @@ public class ResourceQueue<T extends Resource<T>> extends ResourceGroup<T>
     public synchronized boolean queue( Supplier<T> resource )
     {
         if( !active ) return false;
+        if( super.queue( resource ) ) return true;
+        if( pending.size() > DEFAULT_LIMIT ) return false;
 
-        if( !super.queue( resource ) ) pending.add( resource );
+        pending.add( resource );
         return true;
     }
 

src/main/java/dan200/computercraft/core/asm/Generator.java

@@ -11,7 +11,10 @@ import com.google.common.cache.LoadingCache;
 import com.google.common.primitives.Primitives;
 import com.google.common.reflect.TypeToken;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.lua.*;
+import dan200.computercraft.api.lua.IArguments;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.LuaFunction;
+import dan200.computercraft.api.lua.MethodResult;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Type;
@@ -63,7 +66,7 @@ public final class Generator<T>
     {
         this.base = base;
         this.context = context;
-        this.interfaces = new String[] { Type.getInternalName( base ) };
+        interfaces = new String[] { Type.getInternalName( base ) };
         this.wrap = wrap;
 
         StringBuilder methodDesc = new StringBuilder().append( "(Ljava/lang/Object;" );

src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java

@@ -251,6 +251,20 @@ final class ComputerExecutor
      * and then schedule a shutdown.
      */
     void abort()
+    {
+        immediateFail( StateCommand.ABORT );
+    }
+
+    /**
+     * Abort this whole computer due to an internal error. This will immediately destroy the Lua machine,
+     * and then schedule a shutdown.
+     */
+    void fastFail()
+    {
+        immediateFail( StateCommand.ERROR );
+    }
+
+    private void immediateFail( StateCommand command )
     {
         ILuaMachine machine = this.machine;
         if( machine != null ) machine.close();
@@ -258,7 +272,7 @@ final class ComputerExecutor
         synchronized( queueLock )
         {
             if( closed ) return;
-            command = StateCommand.ABORT;
+            this.command = command;
             if( isOn ) enqueue();
         }
     }
@@ -596,6 +610,12 @@ final class ComputerExecutor
                     displayFailure( "Error running computer", TimeoutState.ABORT_MESSAGE );
                     shutdown();
                     break;
+
+                case ERROR:
+                    if( !isOn ) return;
+                    displayFailure( "Error running computer", "An internal error occurred, see logs." );
+                    shutdown();
+                    break;
             }
         }
         else if( event != null )
@@ -644,6 +664,7 @@ final class ComputerExecutor
         SHUTDOWN,
         REBOOT,
         ABORT,
+        ERROR,
     }
 
     private static final class Event

src/main/java/dan200/computercraft/core/computer/ComputerThread.java

@@ -506,6 +506,8 @@ public final class ComputerThread
                 catch( Exception | LinkageError | VirtualMachineError e )
                 {
                     ComputerCraft.log.error( "Error running task on computer #" + executor.getComputer().getID(), e );
+                    // Tear down the computer immediately. There's no guarantee it's well behaved from now on.
+                    executor.fastFail();
                 }
                 finally
                 {

src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java

@@ -10,7 +10,6 @@ import dan200.computercraft.api.lua.*;
 import dan200.computercraft.core.asm.LuaMethod;
 import dan200.computercraft.core.asm.ObjectSource;
 import dan200.computercraft.core.computer.Computer;
-import dan200.computercraft.core.computer.MainThread;
 import dan200.computercraft.core.computer.TimeoutState;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.core.tracking.TrackingField;
@@ -53,7 +52,7 @@ public class CobaltLuaMachine implements ILuaMachine
     private final Computer computer;
     private final TimeoutState timeout;
     private final TimeoutDebugHandler debug;
-    private final ILuaContext context = new CobaltLuaContext();
+    private final ILuaContext context;
 
     private LuaState state;
     private LuaTable globals;
@@ -65,6 +64,7 @@ public class CobaltLuaMachine implements ILuaMachine
     {
         this.computer = computer;
         this.timeout = timeout;
+        context = new LuaContext( computer );
         debug = new TimeoutDebugHandler();
 
         // Create an environment to run in
@@ -509,53 +509,6 @@ public class CobaltLuaMachine implements ILuaMachine
         }
     }
 
-    private class CobaltLuaContext implements ILuaContext
-    {
-        @Override
-        public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
-        {
-            // Issue command
-            final long taskID = MainThread.getUniqueTaskID();
-            final Runnable iTask = () -> {
-                try
-                {
-                    Object[] results = task.execute();
-                    if( results != null )
-                    {
-                        Object[] eventArguments = new Object[results.length + 2];
-                        eventArguments[0] = taskID;
-                        eventArguments[1] = true;
-                        System.arraycopy( results, 0, eventArguments, 2, results.length );
-                        computer.queueEvent( "task_complete", eventArguments );
-                    }
-                    else
-                    {
-                        computer.queueEvent( "task_complete", new Object[] { taskID, true } );
-                    }
-                }
-                catch( LuaException e )
-                {
-                    computer.queueEvent( "task_complete", new Object[] { taskID, false, e.getMessage() } );
-                }
-                catch( Throwable t )
-                {
-                    if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error running task", t );
-                    computer.queueEvent( "task_complete", new Object[] {
-                        taskID, false, "Java Exception Thrown: " + t,
-                    } );
-                }
-            };
-            if( computer.queueMainThread( iTask ) )
-            {
-                return taskID;
-            }
-            else
-            {
-                throw new LuaException( "Task limit exceeded" );
-            }
-        }
-    }
-
     private static final class HardAbortError extends Error
     {
         private static final long serialVersionUID = 7954092008586367501L;

src/main/java/dan200/computercraft/core/lua/LuaContext.java

@@ -0,0 +1,69 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.core.lua;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaTask;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.MainThread;
+
+import javax.annotation.Nonnull;
+
+class LuaContext implements ILuaContext
+{
+    private final Computer computer;
+
+    LuaContext( Computer computer )
+    {
+        this.computer = computer;
+    }
+
+    @Override
+    public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
+    {
+        // Issue command
+        final long taskID = MainThread.getUniqueTaskID();
+        final Runnable iTask = () -> {
+            try
+            {
+                Object[] results = task.execute();
+                if( results != null )
+                {
+                    Object[] eventArguments = new Object[results.length + 2];
+                    eventArguments[0] = taskID;
+                    eventArguments[1] = true;
+                    System.arraycopy( results, 0, eventArguments, 2, results.length );
+                    computer.queueEvent( "task_complete", eventArguments );
+                }
+                else
+                {
+                    computer.queueEvent( "task_complete", new Object[] { taskID, true } );
+                }
+            }
+            catch( LuaException e )
+            {
+                computer.queueEvent( "task_complete", new Object[] { taskID, false, e.getMessage() } );
+            }
+            catch( Exception t )
+            {
+                if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error running task", t );
+                computer.queueEvent( "task_complete", new Object[] {
+                    taskID, false, "Java Exception Thrown: " + t,
+                } );
+            }
+        };
+        if( computer.queueMainThread( iTask ) )
+        {
+            return taskID;
+        }
+        else
+        {
+            throw new LuaException( "Task limit exceeded" );
+        }
+    }
+}

src/main/java/dan200/computercraft/core/terminal/Terminal.java

@@ -44,9 +44,9 @@ public class Terminal
         this.height = height;
         onChanged = changedCallback;
 
-        text = new TextBuffer[this.height];
+        text = new TextBuffer[height];
-        textColour = new TextBuffer[this.height];
+        textColour = new TextBuffer[height];
-        backgroundColour = new TextBuffer[this.height];
+        backgroundColour = new TextBuffer[height];
         for( int i = 0; i < this.height; i++ )
         {
             text[i] = new TextBuffer( ' ', this.width );
@@ -93,9 +93,9 @@ public class Terminal
         this.width = width;
         this.height = height;
 
-        text = new TextBuffer[this.height];
+        text = new TextBuffer[height];
-        textColour = new TextBuffer[this.height];
+        textColour = new TextBuffer[height];
-        backgroundColour = new TextBuffer[this.height];
+        backgroundColour = new TextBuffer[height];
         for( int i = 0; i < this.height; i++ )
         {
             if( i >= oldHeight )

src/main/java/dan200/computercraft/core/terminal/TextBuffer.java

@@ -12,7 +12,7 @@ public class TextBuffer
     public TextBuffer( char c, int length )
     {
         text = new char[length];
-        this.fill( c );
+        fill( c );
     }
 
     public TextBuffer( String text )
@@ -79,6 +79,7 @@ public class TextBuffer
         }
     }
 
+    @Override
     public String toString()
     {
         return new String( text );

src/main/java/dan200/computercraft/data/LootTables.java

@@ -6,11 +6,11 @@
 package dan200.computercraft.data;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.CommonHooks;
 import dan200.computercraft.shared.Registry;
 import dan200.computercraft.shared.data.BlockNamedEntityLootCondition;
 import dan200.computercraft.shared.data.HasComputerIdLootCondition;
 import dan200.computercraft.shared.data.PlayerCreativeLootCondition;
-import dan200.computercraft.shared.CommonHooks;
 import net.minecraft.block.Block;
 import net.minecraft.data.DataGenerator;
 import net.minecraft.loot.*;

src/main/java/dan200/computercraft/shared/TurtleUpgrades.java

@@ -33,9 +33,9 @@ public final class TurtleUpgrades
         Wrapper( ITurtleUpgrade upgrade )
         {
             this.upgrade = upgrade;
-            this.id = upgrade.getUpgradeID().toString();
+            id = upgrade.getUpgradeID().toString();
-            this.modId = ModLoadingContext.get().getActiveNamespace();
+            modId = ModLoadingContext.get().getActiveNamespace();
-            this.enabled = true;
+            enabled = true;
         }
     }
 

src/main/java/dan200/computercraft/shared/common/ContainerHeldItem.java

@@ -61,7 +61,7 @@ public class ContainerHeldItem extends Container
         public Factory( ContainerType<ContainerHeldItem> type, ItemStack stack, Hand hand )
         {
             this.type = type;
-            this.name = stack.getHoverName();
+            name = stack.getHoverName();
             this.hand = hand;
         }
 

src/main/java/dan200/computercraft/shared/computer/inventory/ContainerViewComputer.java

@@ -25,14 +25,14 @@ public class ContainerViewComputer extends ContainerComputerBase implements ICon
     public ContainerViewComputer( int id, ServerComputer computer )
     {
         super( Registry.ModContainers.VIEW_COMPUTER.get(), id, player -> canInteractWith( computer, player ), computer, computer.getFamily() );
-        this.width = this.height = 0;
+        width = height = 0;
     }
 
     public ContainerViewComputer( int id, PlayerInventory player, ViewComputerContainerData data )
     {
         super( Registry.ModContainers.VIEW_COMPUTER.get(), id, player, data );
-        this.width = data.getWidth();
+        width = data.getWidth();
-        this.height = data.getHeight();
+        height = data.getHeight();
     }
 
     private static boolean canInteractWith( @Nonnull ServerComputer computer, @Nonnull PlayerEntity player )

src/main/java/dan200/computercraft/shared/integration/crafttweaker/actions/AddTurtleTool.java

@@ -99,6 +99,7 @@ public class AddTurtleTool implements IUndoableAction
         return String.format( "Removing turtle upgrade %s.", id );
     }
 
+    @Override
     public boolean validate( ILogger logger )
     {
         TrackingLogger trackLog = new TrackingLogger( logger );

src/main/java/dan200/computercraft/shared/integration/crafttweaker/actions/RemoveTurtleUpgradeByItem.java

@@ -41,7 +41,7 @@ public class RemoveTurtleUpgradeByItem implements IUndoableAction
     @Override
     public void undo()
     {
-        if( this.upgrade != null ) TurtleUpgrades.enable( upgrade );
+        if( upgrade != null ) TurtleUpgrades.enable( upgrade );
     }
 
     @Override

src/main/java/dan200/computercraft/shared/integration/crafttweaker/actions/RemoveTurtleUpgradeByName.java

@@ -40,7 +40,7 @@ public class RemoveTurtleUpgradeByName implements IUndoableAction
     @Override
     public void undo()
     {
-        if( this.upgrade != null ) TurtleUpgrades.enable( upgrade );
+        if( upgrade != null ) TurtleUpgrades.enable( upgrade );
     }
 
     @Override

src/main/java/dan200/computercraft/shared/integration/jei/RecipeResolver.java

@@ -339,17 +339,17 @@ class RecipeResolver implements IRecipeManagerPlugin
         UpgradeInfo( ItemStack stack, ITurtleUpgrade turtle )
         {
             this.stack = stack;
-            this.ingredient = of( stack );
+            ingredient = of( stack );
-            this.upgrade = this.turtle = turtle;
+            upgrade = this.turtle = turtle;
-            this.pocket = null;
+            pocket = null;
         }
 
         UpgradeInfo( ItemStack stack, IPocketUpgrade pocket )
         {
             this.stack = stack;
-            this.ingredient = of( stack );
+            ingredient = of( stack );
-            this.turtle = null;
+            turtle = null;
-            this.upgrade = this.pocket = pocket;
+            upgrade = this.pocket = pocket;
         }
 
         List<Shaped> getRecipes()

src/main/java/dan200/computercraft/shared/network/NetworkHandler.java

@@ -56,6 +56,9 @@ public final class NetworkHandler
         registerMainThread( 13, NetworkDirection.PLAY_TO_CLIENT, ComputerTerminalClientMessage::new );
         registerMainThread( 14, NetworkDirection.PLAY_TO_CLIENT, PlayRecordClientMessage.class, PlayRecordClientMessage::new );
         registerMainThread( 15, NetworkDirection.PLAY_TO_CLIENT, MonitorClientMessage.class, MonitorClientMessage::new );
+        registerMainThread( 16, NetworkDirection.PLAY_TO_CLIENT, SpeakerPlayClientMessage.class, SpeakerPlayClientMessage::new );
+        registerMainThread( 17, NetworkDirection.PLAY_TO_CLIENT, SpeakerStopClientMessage.class, SpeakerStopClientMessage::new );
+        registerMainThread( 18, NetworkDirection.PLAY_TO_CLIENT, SpeakerMoveClientMessage.class, SpeakerMoveClientMessage::new );
     }
 
     public static void sendToPlayer( PlayerEntity player, NetworkMessage packet )

src/main/java/dan200/computercraft/shared/network/client/SpeakerMoveClientMessage.java

@@ -0,0 +1,58 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.client;
+
+import dan200.computercraft.client.SoundManager;
+import dan200.computercraft.shared.network.NetworkMessage;
+import net.minecraft.network.PacketBuffer;
+import net.minecraft.util.math.vector.Vector3d;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+import net.minecraftforge.fml.network.NetworkEvent;
+
+import javax.annotation.Nonnull;
+import java.util.UUID;
+
+/**
+ * Starts a sound on the client.
+ *
+ * Used by speakers to play sounds.
+ *
+ * @see dan200.computercraft.shared.peripheral.speaker.TileSpeaker
+ */
+public class SpeakerMoveClientMessage implements NetworkMessage
+{
+    private final UUID source;
+    private final Vector3d pos;
+
+    public SpeakerMoveClientMessage( UUID source, Vector3d pos )
+    {
+        this.source = source;
+        this.pos = pos;
+    }
+
+    public SpeakerMoveClientMessage( PacketBuffer buf )
+    {
+        source = buf.readUUID();
+        pos = new Vector3d( buf.readDouble(), buf.readDouble(), buf.readDouble() );
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketBuffer buf )
+    {
+        buf.writeUUID( source );
+        buf.writeDouble( pos.x() );
+        buf.writeDouble( pos.y() );
+        buf.writeDouble( pos.z() );
+    }
+
+    @Override
+    @OnlyIn( Dist.CLIENT )
+    public void handle( NetworkEvent.Context context )
+    {
+        SoundManager.moveSound( source, pos );
+    }
+}

src/main/java/dan200/computercraft/shared/network/client/SpeakerPlayClientMessage.java

@@ -0,0 +1,74 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.client;
+
+import dan200.computercraft.client.SoundManager;
+import dan200.computercraft.shared.network.NetworkMessage;
+import net.minecraft.network.PacketBuffer;
+import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.SoundEvent;
+import net.minecraft.util.math.vector.Vector3d;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+import net.minecraftforge.fml.network.NetworkEvent;
+import net.minecraftforge.registries.ForgeRegistries;
+
+import javax.annotation.Nonnull;
+import java.util.UUID;
+
+/**
+ * Starts a sound on the client.
+ *
+ * Used by speakers to play sounds.
+ *
+ * @see dan200.computercraft.shared.peripheral.speaker.TileSpeaker
+ */
+public class SpeakerPlayClientMessage implements NetworkMessage
+{
+    private final UUID source;
+    private final Vector3d pos;
+    private final ResourceLocation sound;
+    private final float volume;
+    private final float pitch;
+
+    public SpeakerPlayClientMessage( UUID source, Vector3d pos, ResourceLocation event, float volume, float pitch )
+    {
+        this.source = source;
+        this.pos = pos;
+        sound = event;
+        this.volume = volume;
+        this.pitch = pitch;
+    }
+
+    public SpeakerPlayClientMessage( PacketBuffer buf )
+    {
+        source = buf.readUUID();
+        pos = new Vector3d( buf.readDouble(), buf.readDouble(), buf.readDouble() );
+        sound = buf.readResourceLocation();
+        volume = buf.readFloat();
+        pitch = buf.readFloat();
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketBuffer buf )
+    {
+        buf.writeUUID( source );
+        buf.writeDouble( pos.x() );
+        buf.writeDouble( pos.y() );
+        buf.writeDouble( pos.z() );
+        buf.writeResourceLocation( sound );
+        buf.writeFloat( volume );
+        buf.writeFloat( pitch );
+    }
+
+    @Override
+    @OnlyIn( Dist.CLIENT )
+    public void handle( NetworkEvent.Context context )
+    {
+        SoundEvent sound = ForgeRegistries.SOUND_EVENTS.getValue( this.sound );
+        if( sound != null ) SoundManager.playSound( source, pos, sound, volume, pitch );
+    }
+}

src/main/java/dan200/computercraft/shared/network/client/SpeakerStopClientMessage.java

@@ -0,0 +1,51 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.client;
+
+import dan200.computercraft.client.SoundManager;
+import dan200.computercraft.shared.network.NetworkMessage;
+import net.minecraft.network.PacketBuffer;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+import net.minecraftforge.fml.network.NetworkEvent;
+
+import javax.annotation.Nonnull;
+import java.util.UUID;
+
+/**
+ * Stops a sound on the client
+ *
+ * Called when a speaker is broken.
+ *
+ * @see dan200.computercraft.shared.peripheral.speaker.TileSpeaker
+ */
+public class SpeakerStopClientMessage implements NetworkMessage
+{
+    private final UUID source;
+
+    public SpeakerStopClientMessage( UUID source )
+    {
+        this.source = source;
+    }
+
+    public SpeakerStopClientMessage( PacketBuffer buf )
+    {
+        source = buf.readUUID();
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketBuffer buf )
+    {
+        buf.writeUUID( source );
+    }
+
+    @Override
+    @OnlyIn( Dist.CLIENT )
+    public void handle( NetworkEvent.Context context )
+    {
+        SoundManager.stopSound( source );
+    }
+}

src/main/java/dan200/computercraft/shared/network/client/TerminalState.java

@@ -54,36 +54,36 @@ public class TerminalState
 
         if( terminal == null )
         {
-            this.width = this.height = 0;
+            width = height = 0;
-            this.buffer = null;
+            buffer = null;
         }
         else
         {
-            this.width = terminal.getWidth();
+            width = terminal.getWidth();
-            this.height = terminal.getHeight();
+            height = terminal.getHeight();
 
-            ByteBuf buf = this.buffer = Unpooled.buffer();
+            ByteBuf buf = buffer = Unpooled.buffer();
             terminal.write( new PacketBuffer( buf ) );
         }
     }
 
     public TerminalState( PacketBuffer buf )
     {
-        this.colour = buf.readBoolean();
+        colour = buf.readBoolean();
-        this.compress = buf.readBoolean();
+        compress = buf.readBoolean();
 
         if( buf.readBoolean() )
         {
-            this.width = buf.readVarInt();
+            width = buf.readVarInt();
-            this.height = buf.readVarInt();
+            height = buf.readVarInt();
 
             int length = buf.readVarInt();
-            this.buffer = readCompressed( buf, length, compress );
+            buffer = readCompressed( buf, length, compress );
         }
         else
         {
-            this.width = this.height = 0;
+            width = height = 0;
-            this.buffer = null;
+            buffer = null;
         }
     }
 

src/main/java/dan200/computercraft/shared/network/container/ComputerContainerData.java

@@ -16,14 +16,14 @@ public class ComputerContainerData implements ContainerData
 
     public ComputerContainerData( ServerComputer computer )
     {
-        this.id = computer.getInstanceID();
+        id = computer.getInstanceID();
-        this.family = computer.getFamily();
+        family = computer.getFamily();
     }
 
     public ComputerContainerData( PacketBuffer buf )
     {
-        this.id = buf.readInt();
+        id = buf.readInt();
-        this.family = buf.readEnum( ComputerFamily.class );
+        family = buf.readEnum( ComputerFamily.class );
     }
 
     @Override

src/main/java/dan200/computercraft/shared/peripheral/generic/SaturatedMethod.java

@@ -24,7 +24,7 @@ final class SaturatedMethod
     SaturatedMethod( Object target, NamedMethod<PeripheralMethod> method )
     {
         this.target = target;
-        this.name = method.getName();
+        name = method.getName();
         this.method = method.getMethod();
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileCable.java

@@ -53,7 +53,7 @@ public class TileCable extends TileGeneric
         @Override
         public World getWorld()
         {
-            return TileCable.this.getLevel();
+            return getLevel();
         }
 
         @Nonnull

src/main/java/dan200/computercraft/shared/peripheral/speaker/SpeakerPeripheral.java

@@ -10,17 +10,23 @@ import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.lua.LuaFunction;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.client.SpeakerMoveClientMessage;
+import dan200.computercraft.shared.network.client.SpeakerPlayClientMessage;
 import net.minecraft.network.play.server.SPlaySoundPacket;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.state.properties.NoteBlockInstrument;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.ResourceLocationException;
 import net.minecraft.util.SoundCategory;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.MathHelper;
 import net.minecraft.util.math.vector.Vector3d;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import java.util.Optional;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static dan200.computercraft.api.lua.LuaValues.checkFinite;
@@ -32,20 +38,44 @@ import static dan200.computercraft.api.lua.LuaValues.checkFinite;
  */
 public abstract class SpeakerPeripheral implements IPeripheral
 {
+    private static final int MIN_TICKS_BETWEEN_SOUNDS = 1;
+
     private long clock = 0;
     private long lastPlayTime = 0;
     private final AtomicInteger notesThisTick = new AtomicInteger();
 
+    private long lastPositionTime;
+    private Vector3d lastPosition;
+
     public void update()
     {
         clock++;
         notesThisTick.set( 0 );
+
+        // Push position updates to any speakers which have ever played a note,
+        // have moved by a non-trivial amount and haven't had a position update
+        // in the last second.
+        if( lastPlayTime > 0 && (clock - lastPositionTime) >= 20 )
+        {
+            Vector3d position = getPosition();
+            if( lastPosition == null || lastPosition.distanceToSqr( position ) >= 0.1 )
+            {
+                lastPosition = position;
+                lastPositionTime = clock;
+                NetworkHandler.sendToAllTracking(
+                    new SpeakerMoveClientMessage( getSource(), position ),
+                    getWorld().getChunkAt( new BlockPos( position ) )
+                );
+            }
+        }
     }
 
     public abstract World getWorld();
 
     public abstract Vector3d getPosition();
 
+    protected abstract UUID getSource();
+
     public boolean madeSound( long ticks )
     {
         return clock - lastPlayTime <= ticks;
@@ -135,26 +165,37 @@ public abstract class SpeakerPeripheral implements IPeripheral
 
     private synchronized boolean playSound( ILuaContext context, ResourceLocation name, float volume, float pitch, boolean isNote ) throws LuaException
     {
-        if( clock - lastPlayTime < TileSpeaker.MIN_TICKS_BETWEEN_SOUNDS &&
+        if( clock - lastPlayTime < MIN_TICKS_BETWEEN_SOUNDS )
-            (!isNote || clock - lastPlayTime != 0 || notesThisTick.get() >= ComputerCraft.maxNotesPerTick) )
         {
-            // Rate limiting occurs when we've already played a sound within the last tick, or we've
+            // Rate limiting occurs when we've already played a sound within the last tick.
-            // played more notes than allowable within the current tick.
+            if( !isNote ) return false;
-            return false;
+            // Or we've played more notes than allowable within the current tick.
+            if( clock - lastPlayTime != 0 || notesThisTick.get() >= ComputerCraft.maxNotesPerTick ) return false;
         }
 
         World world = getWorld();
         Vector3d pos = getPosition();
 
+        float range = MathHelper.clamp( volume, 1.0f, 3.0f ) * 16;
+
         context.issueMainThreadTask( () -> {
             MinecraftServer server = world.getServer();
             if( server == null ) return null;
 
-            float adjVolume = Math.min( volume, 3.0f );
+            if( isNote )
+            {
                 server.getPlayerList().broadcast(
-                null, pos.x, pos.y, pos.z, adjVolume > 1.0f ? 16 * adjVolume : 16.0, world.dimension(),
+                    null, pos.x, pos.y, pos.z, range, world.dimension(),
-                new SPlaySoundPacket( name, SoundCategory.RECORDS, pos, adjVolume, pitch )
+                    new SPlaySoundPacket( name, SoundCategory.RECORDS, pos, range, pitch )
                 );
+            }
+            else
+            {
+                NetworkHandler.sendToAllAround(
+                    new SpeakerPlayClientMessage( getSource(), pos, name, range, pitch ),
+                    world, pos, range
+                );
+            }
             return null;
         } );
 

src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java

@@ -7,6 +7,8 @@ package dan200.computercraft.shared.peripheral.speaker;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.common.TileGeneric;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.client.SpeakerStopClientMessage;
 import dan200.computercraft.shared.util.CapabilityUtil;
 import net.minecraft.tileentity.ITickableTileEntity;
 import net.minecraft.tileentity.TileEntityType;
@@ -19,15 +21,15 @@ import net.minecraftforge.common.util.LazyOptional;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.UUID;
 
 import static dan200.computercraft.shared.Capabilities.CAPABILITY_PERIPHERAL;
 
 public class TileSpeaker extends TileGeneric implements ITickableTileEntity
 {
-    public static final int MIN_TICKS_BETWEEN_SOUNDS = 1;
-
     private final SpeakerPeripheral peripheral;
     private LazyOptional<IPeripheral> peripheralCap;
+    private final UUID source = UUID.randomUUID();
 
     public TileSpeaker( TileEntityType<TileSpeaker> type )
     {
@@ -41,6 +43,13 @@ public class TileSpeaker extends TileGeneric implements ITickableTileEntity
         peripheral.update();
     }
 
+    @Override
+    public void setRemoved()
+    {
+        super.setRemoved();
+        NetworkHandler.sendToAllPlayers( new SpeakerStopClientMessage( source ) );
+    }
+
     @Nonnull
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> cap, @Nullable Direction side )
@@ -83,6 +92,12 @@ public class TileSpeaker extends TileGeneric implements ITickableTileEntity
             return new Vector3d( pos.getX(), pos.getY(), pos.getZ() );
         }
 
+        @Override
+        protected UUID getSource()
+        {
+            return speaker.source;
+        }
+
         @Override
         public boolean equals( @Nullable IPeripheral other )
         {

src/main/java/dan200/computercraft/shared/peripheral/speaker/UpgradeSpeakerPeripheral.java

@@ -0,0 +1,33 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.peripheral.speaker;
+
+import dan200.computercraft.api.peripheral.IComputerAccess;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.client.SpeakerStopClientMessage;
+
+import javax.annotation.Nonnull;
+import java.util.UUID;
+
+/**
+ * A speaker peripheral which is used on an upgrade, and so is only attached to one computer.
+ */
+public abstract class UpgradeSpeakerPeripheral extends SpeakerPeripheral
+{
+    private final UUID source = UUID.randomUUID();
+
+    @Override
+    protected final UUID getSource()
+    {
+        return source;
+    }
+
+    @Override
+    public void detach( @Nonnull IComputerAccess computer )
+    {
+        NetworkHandler.sendToAllPlayers( new SpeakerStopClientMessage( source ) );
+    }
+}

src/main/java/dan200/computercraft/shared/pocket/inventory/ContainerPocketComputer.java

@@ -46,7 +46,7 @@ public final class ContainerPocketComputer extends ContainerComputerBase
         public Factory( ServerComputer computer, ItemStack stack, ItemPocketComputer item, Hand hand )
         {
             this.computer = computer;
-            this.name = stack.getHoverName();
+            name = stack.getHoverName();
             this.item = item;
             this.hand = hand;
         }

src/main/java/dan200/computercraft/shared/pocket/peripherals/PocketSpeakerPeripheral.java

@@ -6,11 +6,11 @@
 package dan200.computercraft.shared.pocket.peripherals;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.shared.peripheral.speaker.SpeakerPeripheral;
+import dan200.computercraft.shared.peripheral.speaker.UpgradeSpeakerPeripheral;
 import net.minecraft.util.math.vector.Vector3d;
 import net.minecraft.world.World;
 
-public class PocketSpeakerPeripheral extends SpeakerPeripheral
+public class PocketSpeakerPeripheral extends UpgradeSpeakerPeripheral
 {
     private World world = null;
     private Vector3d position = Vector3d.ZERO;

src/main/java/dan200/computercraft/shared/turtle/apis/TurtleAPI.java

@@ -715,7 +715,6 @@ public class TurtleAPI implements ILuaAPI
      *                 more information about the item at the cost of taking longer to run.
      * @return The command result.
      * @throws LuaException If the slot is out of range.
-     * @see InventoryMethods#getItemDetail Describes the information returned by a detailed query.
      * @cc.treturn nil|table Information about the given slot, or {@code nil} if it is empty.
      * @cc.usage Print the current slot, assuming it contains 13 dirt.
      *
@@ -726,6 +725,7 @@ public class TurtleAPI implements ILuaAPI
      * --  count = 13,
      * -- }
      * }</pre>
+     * @see InventoryMethods#getItemDetail Describes the information returned by a detailed query.
      */
     @LuaFunction
     public final MethodResult getItemDetail( ILuaContext context, Optional<Integer> slot, Optional<Boolean> detailed ) throws LuaException

src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java

@@ -503,20 +503,15 @@ public class TurtleBrain implements ITurtleAccess
         setFuelLevel( getFuelLevel() + addition );
     }
 
-    private int issueCommand( ITurtleCommand command )
-    {
-        commandQueue.offer( new TurtleCommandQueueEntry( ++commandsIssued, command ) );
-        return commandsIssued;
-    }
-
     @Nonnull
     @Override
     public MethodResult executeCommand( @Nonnull ITurtleCommand command )
     {
         if( getWorld().isClientSide ) throw new UnsupportedOperationException( "Cannot run commands on the client" );
+        if( commandQueue.size() > 16 ) return MethodResult.of( false, "Too many ongoing turtle commands" );
 
-        // Issue command
+        commandQueue.offer( new TurtleCommandQueueEntry( ++commandsIssued, command ) );
-        int commandID = issueCommand( command );
+        int commandID = commandsIssued;
         return new CommandCallback( commandID ).pull;
     }
 

src/main/java/dan200/computercraft/shared/turtle/inventory/ContainerTurtle.java

@@ -5,6 +5,7 @@
  */
 package dan200.computercraft.shared.turtle.inventory;
 
+import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.shared.Registry;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.IComputer;
@@ -27,8 +28,10 @@ import java.util.function.Predicate;
 
 public class ContainerTurtle extends ContainerComputerBase
 {
+    public static final int BORDER = 8;
     public static final int PLAYER_START_Y = 134;
-    public static final int TURTLE_START_X = 175;
+    public static final int TURTLE_START_X = ComputerSidebar.WIDTH + 175;
+    public static final int PLAYER_START_X = ComputerSidebar.WIDTH + BORDER;
 
     private final IIntArray properties;
 
@@ -56,14 +59,14 @@ public class ContainerTurtle extends ContainerComputerBase
         {
             for( int x = 0; x < 9; x++ )
             {
-                addSlot( new Slot( playerInventory, x + y * 9 + 9, 8 + x * 18, PLAYER_START_Y + 1 + y * 18 ) );
+                addSlot( new Slot( playerInventory, x + y * 9 + 9, PLAYER_START_X + x * 18, PLAYER_START_Y + 1 + y * 18 ) );
             }
         }
 
         // Player hotbar
         for( int x = 0; x < 9; x++ )
         {
-            addSlot( new Slot( playerInventory, x, 8 + x * 18, PLAYER_START_Y + 3 * 18 + 5 ) );
+            addSlot( new Slot( playerInventory, x, PLAYER_START_X + x * 18, PLAYER_START_Y + 3 * 18 + 5 ) );
         }
     }
 

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleSpeaker.java

@@ -12,7 +12,7 @@ import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.api.turtle.TurtleUpgradeType;
 import dan200.computercraft.shared.Registry;
-import dan200.computercraft.shared.peripheral.speaker.SpeakerPeripheral;
+import dan200.computercraft.shared.peripheral.speaker.UpgradeSpeakerPeripheral;
 import net.minecraft.client.renderer.model.ModelResourceLocation;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.math.BlockPos;
@@ -28,7 +28,7 @@ public class TurtleSpeaker extends AbstractTurtleUpgrade
     private static final ModelResourceLocation leftModel = new ModelResourceLocation( "computercraft:turtle_speaker_upgrade_left", "inventory" );
     private static final ModelResourceLocation rightModel = new ModelResourceLocation( "computercraft:turtle_speaker_upgrade_right", "inventory" );
 
-    private static class Peripheral extends SpeakerPeripheral
+    private static class Peripheral extends UpgradeSpeakerPeripheral
     {
         ITurtleAccess turtle;
 

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleTool.java

@@ -65,7 +65,7 @@ public class TurtleTool extends AbstractTurtleUpgrade
     public TurtleTool( ResourceLocation id, ItemStack craftItem, ItemStack toolItem )
     {
         super( id, TurtleUpgradeType.TOOL, craftItem );
-        this.item = toolItem;
+        item = toolItem;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/util/FakeNetHandler.java

@@ -318,7 +318,7 @@ public class FakeNetHandler extends ServerPlayNetHandler
         @Override
         public void disconnect( @Nonnull ITextComponent message )
         {
-            this.closeReason = message;
+            closeReason = message;
         }
 
         @Nonnull

src/main/resources/assets/computercraft/lang/en_us.json

@@ -110,5 +110,11 @@
     "tracking_field.computercraft.coroutines_dead.name": "Coroutines disposed",
     "gui.computercraft.tooltip.copy": "Copy to clipboard",
     "gui.computercraft.tooltip.computer_id": "Computer ID: %s",
-    "gui.computercraft.tooltip.disk_id": "Disk ID: %s"
+    "gui.computercraft.tooltip.disk_id": "Disk ID: %s",
+    "gui.computercraft.tooltip.turn_on": "Turn this computer on",
+    "gui.computercraft.tooltip.turn_on.key": "Hold Ctrl+R",
+    "gui.computercraft.tooltip.turn_off": "Turn this computer off",
+    "gui.computercraft.tooltip.turn_off.key": "Hold Ctrl+S",
+    "gui.computercraft.tooltip.terminate": "Stop the currently running code",
+    "gui.computercraft.tooltip.terminate.key": "Hold Ctrl+T"
 }

src/main/resources/data/computercraft/lua/rom/apis/help.lua

@@ -27,21 +27,24 @@ function setPath(_sPath)
     sPath = _sPath
 end
 
+local extensions = { "", ".md", ".txt" }
+
 --- Returns the location of the help file for the given topic.
 --
 -- @tparam string topic The topic to find
 -- @treturn string|nil The path to the given topic's help file, or `nil` if it
 -- cannot be found.
 -- @usage help.lookup("disk")
-function lookup(_sTopic)
+function lookup(topic)
-    expect(1, _sTopic, "string")
+    expect(1, topic, "string")
     -- Look on the path variable
-    for sPath in string.gmatch(sPath, "[^:]+") do
+    for path in string.gmatch(sPath, "[^:]+") do
-        sPath = fs.combine(sPath, _sTopic)
+        path = fs.combine(path, topic)
-        if fs.exists(sPath) and not fs.isDir(sPath) then
+        for _, extension in ipairs(extensions) do
-            return sPath
+            local file = path .. extension
-        elseif fs.exists(sPath .. ".txt") and not fs.isDir(sPath .. ".txt") then
+            if fs.exists(file) and not fs.isDir(file) then
-            return sPath .. ".txt"
+                return file
+            end
         end
     end
 
@@ -66,8 +69,11 @@ function topics()
             for _, sFile in pairs(tList) do
                 if string.sub(sFile, 1, 1) ~= "." then
                     if not fs.isDir(fs.combine(sPath, sFile)) then
-                        if #sFile > 4 and sFile:sub(-4) == ".txt" then
+                        for i = 2, #extensions do
-                            sFile = sFile:sub(1, -5)
+                            local extension = extensions[i]
+                            if #sFile > #extension and sFile:sub(-#extension) == extension then
+                                sFile = sFile:sub(1, -#extension - 1)
+                            end
                         end
                         tItems[sFile] = true
                     end

src/main/resources/data/computercraft/lua/rom/help/craft.txt

@@ -1,5 +1,5 @@
 craft is a program for Crafty Turtles. Craft will craft a stack of items using the current inventory.
 
 ex:
-"craft" will craft as many items as possible
+"craft all" will craft as many items as possible
 "craft 5" will craft at most 5 times

src/main/resources/data/computercraft/lua/rom/modules/main/cc/shell/completion.lua

@@ -29,8 +29,8 @@ local completion = require "cc.completion"
 
 --- Complete the name of a file relative to the current working directory.
 --
--- @tparam table shell The shell we're completing in
+-- @tparam table shell The shell we're completing in.
--- @tparam { string... } choices The list of choices to complete from.
+-- @tparam string text Current text to complete.
 -- @treturn { string... } A list of suffixes of matching files.
 local function file(shell, text)
     return fs.complete(text, shell.dir(), true, false)
@@ -38,8 +38,8 @@ end
 
 --- Complete the name of a directory relative to the current working directory.
 --
--- @tparam table shell The shell we're completing in
+-- @tparam table shell The shell we're completing in.
--- @tparam { string... } choices The list of choices to complete from.
+-- @tparam string text Current text to complete.
 -- @treturn { string... } A list of suffixes of matching directories.
 local function dir(shell, text)
     return fs.complete(text, shell.dir(), false, true)
@@ -48,8 +48,8 @@ end
 --- Complete the name of a file or directory relative to the current working
 -- directory.
 --
--- @tparam table shell The shell we're completing in
+-- @tparam table shell The shell we're completing in.
--- @tparam { string... } choices The list of choices to complete from.
+-- @tparam string text Current text to complete.
 -- @tparam { string... } previous The shell arguments before this one.
 -- @tparam[opt] boolean add_space Whether to add a space after the completed item.
 -- @treturn { string... } A list of suffixes of matching files and directories.
@@ -74,14 +74,46 @@ end
 
 --- Complete the name of a program.
 --
--- @tparam table shell The shell we're completing in
+-- @tparam table shell The shell we're completing in.
--- @tparam { string... } choices The list of choices to complete from.
+-- @tparam string text Current text to complete.
 -- @treturn { string... } A list of suffixes of matching programs.
 -- @see shell.completeProgram
 local function program(shell, text)
     return shell.completeProgram(text)
 end
 
+--- Complete arguments of a program.
+--
+-- @tparam table shell The shell we're completing in.
+-- @tparam string text Current text to complete.
+-- @tparam { string... } previous The shell arguments before this one.
+-- @tparam number starting Which argument index this program and args start at.
+-- @treturn { string... } A list of suffixes of matching programs or arguments.
+local function programWithArgs(shell, text, previous, starting)
+    if #previous + 1 == starting then
+        local tCompletionInfo = shell.getCompletionInfo()
+        if text:sub(-1) ~= "/" and tCompletionInfo[shell.resolveProgram(text)] then
+            return { " " }
+        else
+            local results = shell.completeProgram(text)
+            for n = 1, #results do
+                local sResult = results[n]
+                if sResult:sub(-1) ~= "/" and tCompletionInfo[shell.resolveProgram(text .. sResult)] then
+                    results[n] = sResult .. " "
+                end
+            end
+            return results
+        end
+    else
+        local program = previous[starting]
+        local resolved = shell.resolveProgram(program)
+        if not resolved then return end
+        local tCompletion = shell.getCompletionInfo()[resolved]
+        if not tCompletion then return end
+        return tCompletion.fnComplete(shell, #previous - starting + 1, text, { program, table.unpack(previous, starting + 1, #previous) })
+    end
+end
+
 --[[- A helper function for building shell completion arguments.
 
 This accepts a series of single-argument completion functions, and combines
@@ -144,6 +176,7 @@ return {
     dir = dir,
     dirOrFile = dirOrFile,
     program = program,
+    programWithArgs = programWithArgs,
 
     -- Re-export various other functions
     help = wrap(help.completeTopic), --- Wraps @{help.completeTopic} as a @{build} compatible function.

src/main/resources/data/computercraft/lua/rom/programs/help.lua

@@ -14,16 +14,127 @@ if sTopic == "index" then
 end
 
 local strings = require "cc.strings"
-local function word_wrap(text, width)
+
-    local lines = strings.wrap(text, width)
+local function min_of(a, b, default)
+    if not a and not b then return default end
+    if not a then return b end
+    if not b then return a end
+    return math.min(a, b)
+end
+
+--[[- Parse a markdown string, extracting headings and highlighting some basic
+constructs.
+
+The implementation of this is horrible. SquidDev shouldn't be allowed to write
+parsers, especially ones they think might be "performance critical".
+]]
+local function parse_markdown(text)
+    local len = #text
+    local oob = len + 1
+
+    -- Some patterns to match headers and bullets on the start of lines.
+    -- The `%f[^\n\0]` is some wonderful logic to match the start of a line /or/
+    -- the start of the document.
+    local heading = "%f[^\n\0](#+ +)([^\n]*)"
+    local bullet = "%f[^\n\0]( *)[.*]( +)"
+    local code = "`([^`]+)`"
+
+    local new_text, fg, bg = "", "", ""
+    local function append(txt, fore, back)
+        new_text = new_text .. txt
+        fg = fg .. (fore or "0"):rep(#txt)
+        bg = bg .. (back or "f"):rep(#txt)
+    end
+
+    local next_header = text:find(heading)
+    local next_bullet = text:find(bullet)
+    local next_block = min_of(next_header, next_bullet, oob)
+
+    local next_code, next_code_end = text:find(code)
+
+    local sections = {}
+
+    local start = 1
+    while start <= len do
+        if start == next_block then
+            if start == next_header then
+                local _, fin, head, content = text:find(heading, start)
+                sections[#new_text + 1] = content
+                append(head .. content, "4", "f")
+                start = fin + 1
+
+                next_header = text:find(heading, start)
+            else
+                local _, fin, space, content = text:find(bullet, start)
+                append(space .. "\7" .. content)
+                start = fin + 1
+
+                next_bullet = text:find(bullet, start)
+            end
+
+            next_block = min_of(next_header, next_bullet, oob)
+        elseif next_code and next_code_end < next_block then
+            -- Basic inline code blocks
+            if start < next_code then append(text:sub(start, next_code - 1)) end
+            local content = text:match(code, next_code)
+            append(content, "0", "7")
+
+            start = next_code_end + 1
+            next_code, next_code_end = text:find(code, start)
+        else
+            -- Normal text
+            append(text:sub(start, next_block - 1))
+            start = next_block
+
+            -- Rescan for a new code block
+            if next_code then next_code, next_code_end = text:find(code, start) end
+        end
+    end
+
+    return new_text, fg, bg, sections
+end
+
+local function word_wrap_basic(text, width)
+    local lines, fg, bg = strings.wrap(text, width), {}, {}
+    local fg_line, bg_line = ("0"):rep(width), ("f"):rep(width)
 
     -- Normalise the strings suitable for use with blit. We could skip this and
     -- just use term.write, but saves us a clearLine call.
     for k, line in pairs(lines) do
         lines[k] = strings.ensure_width(line, width)
+        fg[k] = fg_line
+        bg[k] = bg_line
     end
 
-    return lines
+    return lines, fg, bg, {}
+end
+
+local function word_wrap_markdown(text, width)
+    -- Add in styling for Markdown-formatted text.
+    local text, fg, bg, sections = parse_markdown(text)
+
+    local lines = strings.wrap(text, width)
+    local fglines, bglines, section_list, section_n = {}, {}, {}, 1
+
+    -- Normalise the strings suitable for use with blit. We could skip this and
+    -- just use term.write, but saves us a clearLine call.
+    local start = 1
+    for k, line in pairs(lines) do
+        -- I hate this with a burning passion, but it works!
+        local pos = text:find(line, start, true)
+        lines[k], fglines[k], bglines[k] =
+            strings.ensure_width(line, width),
+            strings.ensure_width(fg:sub(pos, pos + #line), width),
+            strings.ensure_width(bg:sub(pos, pos + #line), width)
+
+        if sections[pos] then
+            section_list[section_n], section_n = { content = sections[pos], offset = k - 1 }, section_n + 1
+        end
+
+        start = pos + 1
+    end
+
+    return lines, fglines, bglines, section_list
 end
 
 local sFile = help.lookup(sTopic)
@@ -33,31 +144,40 @@ if not file then
     return
 end
 
-local contents = file:read("*a"):gsub("(\n *)[-*]( +)", "%1\7%2")
+local contents = file:read("*a")
 file:close()
 
+local word_wrap = sFile:sub(-3) == ".md" and word_wrap_markdown or word_wrap_basic
 local width, height = term.getSize()
-local lines = word_wrap(contents, width)
+local lines, fg, bg, sections = word_wrap(contents, width)
 local print_height = #lines
 
 -- If we fit within the screen, just display without pagination.
 if print_height <= height then
-    print(contents)
+    local _, y = term.getCursorPos()
+    for i = 1, print_height do
+        if y + i - 1 > height then
+            term.scroll(1)
+            term.setCursorPos(1, height)
+        else
+            term.setCursorPos(1, y + i - 1)
+        end
+
+        term.blit(lines[i], fg[i], bg[i])
+    end
     return
 end
 
+local current_section = nil
 local offset = 0
 
-local function draw()
+--- Find the currently visible seciton, or nil if this document has no sections.
-    local fg, bg = ("0"):rep(width), ("f"):rep(width)
+--
-    for y = 1, height - 1 do
+-- This could potentially be a binary search, but right now it's not worth it.
-        term.setCursorPos(1, y)
+local function find_section()
-        if y + offset > print_height then
+    for i = #sections, 1, -1 do
-            -- Should only happen if we resize the terminal to a larger one
+        if sections[i].offset <= offset then
-            -- than actually needed for the current text.
+            return i
-            term.clearLine()
-        else
-            term.blit(lines[y + offset], fg, bg)
         end
     end
 end
@@ -68,7 +188,10 @@ local function draw_menu()
     term.clearLine()
 
     local tag = "Help: " .. sTopic
-    term.write("Help: " .. sTopic)
+    if current_section then
+        tag = tag .. (" (%s)"):format(sections[current_section].content)
+    end
+    term.write(tag)
 
     if width >= #tag + 16 then
         term.setCursorPos(width - 14, height)
@@ -76,11 +199,31 @@ local function draw_menu()
     end
 end
 
+
+local function draw()
+    for y = 1, height - 1 do
+        term.setCursorPos(1, y)
+        if y + offset > print_height then
+            -- Should only happen if we resize the terminal to a larger one
+            -- than actually needed for the current text.
+            term.clearLine()
+        else
+            term.blit(lines[y + offset], fg[y + offset], bg[y + offset])
+        end
+    end
+
+    local new_section = find_section()
+    if new_section ~= current_section then
+        current_section = new_section
+        draw_menu()
+    end
+end
+
 draw()
 draw_menu()
 
 while true do
-    local event, param = os.pullEvent()
+    local event, param = os.pullEventRaw()
     if event == "key" then
         if param == keys.up and offset > 0 then
             offset = offset - 1
@@ -97,6 +240,12 @@ while true do
         elseif param == keys.home then
             offset = 0
             draw()
+        elseif param == keys.left and current_section and current_section > 1 then
+            offset = sections[current_section - 1].offset
+            draw()
+        elseif param == keys.right and current_section and current_section < #sections then
+            offset = sections[current_section + 1].offset
+            draw()
         elseif param == keys["end"] then
             offset = print_height - height
             draw()
@@ -124,6 +273,8 @@ while true do
         offset = math.max(math.min(offset, print_height - height), 0)
         draw()
         draw_menu()
+    elseif event == "terminate" then
+        break
     end
 end
 

src/main/resources/data/computercraft/lua/rom/programs/http/wget.lua

@@ -51,7 +51,7 @@ local function get(sUrl)
 
     local sResponse = response.readAll()
     response.close()
-    return sResponse
+    return sResponse or ""
 end
 
 if run then
@@ -79,7 +79,12 @@ else
     local res = get(url)
     if not res then return end
 
-    local file = fs.open(sPath, "wb")
+    local file, err = fs.open(sPath, "wb")
+    if not file then
+        printError("Cannot save file: " .. err)
+        return
+    end
+
     file.write(res)
     file.close()
 

src/main/resources/data/computercraft/lua/rom/programs/monitor.lua

@@ -7,7 +7,7 @@ local function printUsage()
 end
 
 local tArgs = { ... }
-if #tArgs < 2 then
+if #tArgs < 2 or tArgs[1] == "scale" and #tArgs < 3 then
     printUsage()
     return
 end
@@ -21,7 +21,7 @@ if tArgs[1] == "scale" then
 
     local nRes = tonumber(tArgs[3])
     if nRes == nil or nRes < 0.5 or nRes > 5 then
-        print("Invalid scale: " .. nRes)
+        print("Invalid scale: " .. tArgs[3])
         return
     end
 

src/main/resources/data/computercraft/lua/rom/programs/turtle/craft.lua

@@ -9,20 +9,19 @@ if not turtle.craft then
 end
 
 local tArgs = { ... }
-local nLimit = nil
+local nLimit = tonumber(tArgs[1])
-if #tArgs < 1 then
+
+if not nLimit and tArgs[1] ~= "all" then
     local programName = arg[0] or fs.getName(shell.getRunningProgram())
-    print("Usage: " .. programName .. " [number]")
+    print("Usage: " .. programName .. " all|<number>")
     return
-else
-    nLimit = tonumber(tArgs[1])
 end
 
 local nCrafted = 0
 local nOldCount = turtle.getItemCount(turtle.getSelectedSlot())
 if turtle.craft(nLimit) then
     local nNewCount = turtle.getItemCount(turtle.getSelectedSlot())
-    if nOldCount <= nLimit then
+    if not nLimit or nOldCount <= nLimit then
         nCrafted = nNewCount
     else
         nCrafted = nOldCount - nNewCount

src/main/resources/data/computercraft/lua/rom/startup.lua

@@ -81,9 +81,17 @@ shell.setCompletionFunction("rom/programs/monitor.lua", completion.build(
         if previous[2] == "scale" then
             return completion.peripheral(shell, text, previous, true)
         else
-            return completion.program(shell, text, previous)
+            return completion.programWithArgs(shell, text, previous, 3)
         end
+    end,
+    {
+        function(shell, text, previous)
+            if previous[2] ~= "scale" then
+                return completion.programWithArgs(shell, text, previous, 3)
             end
+        end,
+        many = true,
+    }
 ))
 
 shell.setCompletionFunction("rom/programs/move.lua", completion.build(
@@ -98,11 +106,11 @@ shell.setCompletionFunction("rom/programs/rename.lua", completion.build(
     { completion.dirOrFile, true },
     completion.dirOrFile
 ))
-shell.setCompletionFunction("rom/programs/shell.lua", completion.build(completion.program))
+shell.setCompletionFunction("rom/programs/shell.lua", completion.build({ completion.programWithArgs, 2, many = true }))
 shell.setCompletionFunction("rom/programs/type.lua", completion.build(completion.dirOrFile))
 shell.setCompletionFunction("rom/programs/set.lua", completion.build({ completion.setting, true }))
-shell.setCompletionFunction("rom/programs/advanced/bg.lua", completion.build(completion.program))
+shell.setCompletionFunction("rom/programs/advanced/bg.lua", completion.build({ completion.programWithArgs, 2, many = true }))
-shell.setCompletionFunction("rom/programs/advanced/fg.lua", completion.build(completion.program))
+shell.setCompletionFunction("rom/programs/advanced/fg.lua", completion.build({ completion.programWithArgs, 2, many = true }))
 shell.setCompletionFunction("rom/programs/fun/dj.lua", completion.build(
     { completion.choice, { "play", "play ", "stop " } },
     completion.peripheral

src/test/java/dan200/computercraft/core/apis/http/options/AddressRuleTest.java

@@ -32,7 +32,7 @@ public class AddressRuleTest
     @ParameterizedTest
     @ValueSource( strings = {
         "0.0.0.0", "[::]",
-        "localhost", "lvh.me", "127.0.0.1", "[::1]",
+        "localhost", "127.0.0.1.nip.io", "127.0.0.1", "[::1]",
         "172.17.0.1", "192.168.1.114", "[0:0:0:0:0:ffff:c0a8:172]", "10.0.0.1"
     } )
     public void blocksLocalDomains( String domain )

src/test/resources/test-rom/spec/apis/help_spec.lua

@@ -18,5 +18,10 @@ describe("The help library", function()
             help.completeTopic("")
             expect.error(help.completeTopic, nil):eq("bad argument #1 (expected string, got nil)")
         end)
+
+        it("completes topics without extensions", function()
+            expect(help.completeTopic("changel")):same { "og" }
+            expect(help.completeTopic("turt")):same { "le" }
+        end)
     end)
 end)

src/test/resources/test-rom/spec/modules/cc/shell/completion_spec.lua

@@ -17,6 +17,30 @@ describe("cc.shell.completion", function()
         end)
     end)
 
+    describe("program", function()
+        it("completes programs", function()
+            expect(c.program(shell, "rom/")):same {
+                "apis/", "autorun/", "help/", "modules/", "motd.txt", "programs/", "startup.lua",
+            }
+        end)
+    end)
+
+    describe("programWithArgs", function()
+        it("completes program name", function()
+            shell.setCompletionFunction("rom/motd.txt", function() end)
+            expect(c.programWithArgs(shell, "rom/", { "rom/programs/shell.lua" }, 2)):same {
+                "apis/", "autorun/", "help/", "modules/", "motd.txt ", "programs/", "startup.lua",
+            }
+        end)
+
+        it("completes program arguments", function()
+            expect(c.programWithArgs(shell, "", { "rom/programs/shell.lua", "pastebin" }, 2)):same {
+                "put ", "get ", "run ",
+            }
+        end)
+
+    end)
+
     describe("build", function()
         it("completes multiple arguments", function()
             local spec = c.build(

src/test/resources/test-rom/spec/programs/http/wget_spec.lua

@@ -1,7 +1,8 @@
 local capture = require "test_helpers".capture_program
 
 describe("The wget program", function()
-    local function setup_request()
+    local default_contents = [[print("Hello", ...)]]
+    local function setup_request(contents)
         stub(_G, "http", {
             checkURL = function()
                 return true
@@ -9,7 +10,7 @@ describe("The wget program", function()
             get = function()
                 return {
                     readAll = function()
-                        return [[print("Hello", ...)]]
+                        return contents
                     end,
                     close = function()
                     end,
@@ -19,28 +20,52 @@ describe("The wget program", function()
     end
 
     it("downloads one file", function()
-        setup_request()
+        fs.delete("/example.com")
+        setup_request(default_contents)
+
         capture(stub, "wget", "https://example.com")
 
         expect(fs.exists("/example.com")):eq(true)
     end)
 
     it("downloads one file with given filename", function()
-        setup_request()
+        fs.delete("/test-files/download")
+        setup_request(default_contents)
+
         capture(stub, "wget", "https://example.com /test-files/download")
 
         expect(fs.exists("/test-files/download")):eq(true)
     end)
 
+    it("downloads empty files", function()
+        fs.delete("/test-files/download")
+        setup_request(nil)
+
+        capture(stub, "wget", "https://example.com", "/test-files/download")
+
+        expect(fs.exists("/test-files/download")):eq(true)
+        expect(fs.getSize("/test-files/download")):eq(0)
+    end)
+
+    it("cannot save to rom", function()
+        setup_request(default_contents)
+
+        expect(capture(stub, "wget", "https://example.com", "/rom/a-file.txt")):matches {
+            ok = true,
+            output = "Connecting to https://example.com... Success.\n",
+            error = "Cannot save file: /rom/a-file.txt: Access denied\n",
+        }
+    end)
+
     it("runs a program from the internet", function()
-        setup_request()
+        setup_request(default_contents)
 
         expect(capture(stub, "wget", "run", "http://test.com", "a", "b", "c"))
             :matches { ok = true, output = "Connecting to http://test.com... Success.\nHello a b c\n", error = "" }
     end)
 
     it("displays its usage when given no arguments", function()
-        setup_request()
+        setup_request(default_contents)
 
         expect(capture(stub, "wget"))
             :matches { ok = true, output = "Usage:\nwget <url> [filename]\nwget run <url>\n", error = "" }

src/test/resources/test-rom/spec/programs/monitor_spec.lua

@@ -21,4 +21,24 @@ describe("The monitor program", function()
             :matches { ok = true, output = "", error = "" }
         expect(r):equals(0.5)
     end)
+
+    it("displays correct error messages", function()
+        local r = 1
+        stub(peripheral, "call", function(s, f, t) r = t end)
+        stub(peripheral, "getType", function(side) return side == "left" and "monitor" or nil end)
+        expect(capture(stub, "monitor", "scale", "left"))
+            :matches {
+                ok = true,
+                output =
+                    "Usage:\n" ..
+                    "  monitor <name> <program> <arguments>\n" ..
+                    "  monitor scale <name> <scale>\n",
+                error = "",
+            }
+        expect(capture(stub, "monitor", "scale", "top", "0.5"))
+            :matches { ok = true, output = "No monitor named top\n", error = "" }
+        expect(capture(stub, "monitor", "scale", "left", "aaa"))
+            :matches { ok = true, output = "Invalid scale: aaa\n", error = "" }
+        expect(r):equals(1)
+    end)
 end)

src/test/resources/test-rom/spec/programs/turtle/craft_spec.lua

@@ -19,7 +19,14 @@ describe("The craft program", function()
         stub(_G, "turtle", { craft = function() end })
 
         expect(capture(stub, "/rom/programs/turtle/craft.lua"))
-            :matches { ok = true, output = "Usage: /rom/programs/turtle/craft.lua [number]\n", error = "" }
+            :matches { ok = true, output = "Usage: /rom/programs/turtle/craft.lua all|<number>\n", error = "" }
+    end)
+
+    it("displays its usage when given incorrect arguments", function()
+        stub(_G, "turtle", { craft = function() end })
+
+        expect(capture(stub, "/rom/programs/turtle/craft.lua a"))
+            :matches { ok = true, output = "Usage: /rom/programs/turtle/craft.lua all|<number>\n", error = "" }
     end)
 
     it("crafts multiple items", function()
@@ -66,4 +73,17 @@ describe("The craft program", function()
         expect(capture(stub, "/rom/programs/turtle/craft.lua 1"))
             :matches { ok = true, output = "No items crafted\n", error = "" }
     end)
+
+    it("crafts all items", function()
+        stub(_G, "turtle", {
+            craft = function()
+                return true
+            end,
+            getItemCount = function() return 17 end,
+            getSelectedSlot = function() return 1 end,
+        })
+
+        expect(capture(stub, "/rom/programs/turtle/craft.lua all"))
+            :matches { ok = true, output = "17 items crafted\n", error = "" }
+    end)
 end)