Merge branch 'mc-1.14.x' into mc-1.15.x

This replaces the allow/block lists with a series of rules. Each rule
takes the form

    [[http.rules]]
    host = "127.0.0.0/8"
    action = "block"

This is pretty much the same as the previous config style, in that hosts
may be domains, wildcards or in CIDR notation. However, they may also be
mixed, so you could allow a specific IP, and then block all others.

build.gradle

@@ -9,7 +9,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.google.code.gson:gson:2.8.1'
-        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.154'
+        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.169'
         classpath 'net.sf.proguard:proguard-gradle:6.1.0beta2'
         classpath 'org.ajoberstar.grgit:grgit-gradle:3.0.0'
     }
@@ -47,7 +47,7 @@ minecraft {
         }
 
         server {
-            workingDirectory project.file('run')
+            workingDirectory project.file("run/server-${mc_version}")
             property 'forge.logging.markers', 'SCAN,REGISTRIES,REGISTRYDUMP'
             property 'forge.logging.console.level', 'debug'
 
@@ -99,10 +99,10 @@ dependencies {
 
     minecraft "net.minecraftforge:forge:${mc_version}-${forge_version}"
 
-    compileOnly fg.deobf("mezz.jei:jei-1.14.4:6.0.0.27:api")
-    compileOnly fg.deobf("com.blamejared.crafttweaker:CraftTweaker-1.14.4:5.0.1.162")
+    compileOnly fg.deobf("mezz.jei:jei-1.15.2:6.0.0.3:api")
+    compileOnly fg.deobf("com.blamejared.crafttweaker:CraftTweaker-1.15.2:6.0.0.9")
 
-    runtimeOnly fg.deobf("mezz.jei:jei-1.14.4:6.0.0.27")
+    runtimeOnly fg.deobf("mezz.jei:jei-1.15.2:6.0.0.3")
 
     shade 'org.squiddev:Cobalt:0.5.1-SNAPSHOT'
 
@@ -373,7 +373,7 @@ curseforge {
     apiKey = project.hasProperty('curseForgeApiKey') ? project.curseForgeApiKey : ''
     project {
         id = '282001'
-        releaseType = 'release'
+        releaseType = 'alpha'
         changelog = "Release notes can be found on the GitHub repository (https://github.com/SquidDev-CC/CC-Tweaked/releases/tag/v${mc_version}-${mod_version})."
 
         relations {
@@ -451,7 +451,7 @@ githubRelease {
             .takeWhile { it != 'Type "help changelog" to see the full version history.' }
             .join("\n").trim()
     }
-    prerelease false
+    prerelease true
 }
 
 def uploadTasks = ["uploadArchives", "curseforge", "githubRelease"]

config/checkstyle/checkstyle.xml

@@ -10,6 +10,10 @@
         <property name="file" value="config/checkstyle/suppressions.xml" />
     </module>
 
+    <module name="BeforeExecutionExclusionFileFilter">
+        <property name="fileNamePattern" value="render_old"/>
+    </module>
+
     <module name="TreeWalker">
         <!-- Annotations -->
         <module name="AnnotationLocation" />

gradle.properties

@@ -2,6 +2,6 @@
 mod_version=1.87.0
 
 # Minecraft properties (update mods.toml when changing)
-mc_version=1.14.4
-forge_version=28.1.71
-mappings_version=20191123-1.14.3
+mc_version=1.15.2
+forge_version=31.1.41
+mappings_version=20200410-1.15.1

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

@@ -6,7 +6,7 @@
 package dan200.computercraft;
 
 import dan200.computercraft.api.turtle.event.TurtleAction;
-import dan200.computercraft.core.apis.AddressPredicate;
+import dan200.computercraft.core.apis.http.AddressRule;
 import dan200.computercraft.shared.Config;
 import dan200.computercraft.shared.computer.blocks.BlockComputer;
 import dan200.computercraft.shared.computer.core.ClientComputerRegistry;
@@ -39,8 +39,13 @@ import org.apache.logging.log4j.Logger;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Collections;
 import java.util.EnumSet;
+import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 @Mod( ComputerCraft.MOD_ID )
 public final class ComputerCraft
@@ -50,8 +55,8 @@ public final class ComputerCraft
     public static final int DATAFIXER_VERSION = 0;
 
     // Configuration options
-    public static final String[] DEFAULT_HTTP_WHITELIST = new String[] { "*" };
-    public static final String[] DEFAULT_HTTP_BLACKLIST = new String[] {
+    public static final String[] DEFAULT_HTTP_ALLOW = new String[] { "*" };
+    public static final String[] DEFAULT_HTTP_DENY = new String[] {
         "127.0.0.0/8",
         "10.0.0.0/8",
         "172.16.0.0/12",
@@ -71,10 +76,12 @@ public final class ComputerCraft
     public static long maxMainGlobalTime = TimeUnit.MILLISECONDS.toNanos( 10 );
     public static long maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos( 5 );
 
-    public static boolean http_enable = true;
-    public static boolean http_websocket_enable = true;
-    public static AddressPredicate http_whitelist = new AddressPredicate( DEFAULT_HTTP_WHITELIST );
-    public static AddressPredicate http_blacklist = new AddressPredicate( DEFAULT_HTTP_BLACKLIST );
+    public static boolean httpEnabled = true;
+    public static boolean httpWebsocketEnabled = true;
+    public static List<AddressRule> httpRules = Collections.unmodifiableList( Stream.concat(
+        Stream.of( DEFAULT_HTTP_DENY ).map( x -> AddressRule.parse( x, AddressRule.Action.DENY ) ).filter( Objects::nonNull ),
+        Stream.of( DEFAULT_HTTP_ALLOW ).map( x -> AddressRule.parse( x, AddressRule.Action.ALLOW ) ).filter( Objects::nonNull )
+    ).collect( Collectors.toList() ) );
 
     public static int httpTimeout = 30000;
     public static int httpMaxRequests = 16;

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

@@ -112,31 +112,6 @@ public final class ComputerCraftAPI
         return getInstance().createResourceMount( domain, subPath );
     }
 
-    /**
-     * Creates a file system mount to a resource folder, and returns it.
-     *
-     * Use in conjunction with {@link IComputerAccess#mount} or {@link IComputerAccess#mountWritable} to mount a
-     * resource folder onto a computer's file system.
-     *
-     * The files in this mount will be a combination of files in all mod jar, and data packs that contain
-     * resources with the same domain and path.
-     *
-     * @param klass   The mod class to which the files belong.
-     * @param domain  The domain under which to look for resources. eg: "mymod".
-     * @param subPath The subPath under which to look for resources. eg: "lua/myfiles".
-     * @return The mount, or {@code null} if it could be created for some reason.
-     * @see IComputerAccess#mount(String, IMount)
-     * @see IComputerAccess#mountWritable(String, IWritableMount)
-     * @see IMount
-     * @deprecated Use {@link #createResourceMount(String, String)} instead.
-     */
-    @Nullable
-    @Deprecated
-    public static IMount createResourceMount( Class<?> klass, @Nonnull String domain, @Nonnull String subPath )
-    {
-        return getInstance().createResourceMount( domain, subPath );
-    }
-
     /**
      * Registers a peripheral provider to convert blocks into {@link IPeripheral} implementations.
      *

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

@@ -0,0 +1,61 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.client;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.TransformationMatrix;
+import net.minecraft.client.renderer.model.IBakedModel;
+import net.minecraft.client.renderer.model.ModelManager;
+import net.minecraft.client.renderer.model.ModelResourceLocation;
+import net.minecraft.item.ItemStack;
+
+import javax.annotation.Nonnull;
+import java.util.Objects;
+
+/**
+ * A model to render, combined with a transformation matrix to apply.
+ */
+public final class TransformedModel
+{
+    private final IBakedModel model;
+    private final TransformationMatrix matrix;
+
+    public TransformedModel( @Nonnull IBakedModel model, @Nonnull TransformationMatrix matrix )
+    {
+        this.model = Objects.requireNonNull( model );
+        this.matrix = Objects.requireNonNull( matrix );
+    }
+
+    public TransformedModel( @Nonnull IBakedModel model )
+    {
+        this.model = Objects.requireNonNull( model );
+        this.matrix = TransformationMatrix.identity();
+    }
+
+    public static TransformedModel of( @Nonnull ModelResourceLocation location )
+    {
+        ModelManager modelManager = Minecraft.getInstance().getModelManager();
+        return new TransformedModel( modelManager.getModel( location ) );
+    }
+
+    public static TransformedModel of( @Nonnull ItemStack item, @Nonnull TransformationMatrix transform )
+    {
+        IBakedModel model = Minecraft.getInstance().getItemRenderer().getItemModelMesher().getItemModel( item );
+        return new TransformedModel( model, transform );
+    }
+
+    @Nonnull
+    public IBakedModel getModel()
+    {
+        return model;
+    }
+
+    @Nonnull
+    public TransformationMatrix getMatrix()
+    {
+        return matrix;
+    }
+}

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

@@ -11,8 +11,6 @@ import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
-import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.List;
@@ -23,10 +21,10 @@ import java.util.List;
  *
  * Ready made implementations of this interface can be created using
  * {@link ComputerCraftAPI#createSaveDirMount(World, String, long)} or
- * {@link ComputerCraftAPI#createResourceMount(Class, String, String)}, or you're free to implement it yourselves!
+ * {@link ComputerCraftAPI#createResourceMount(String, String)}, or you're free to implement it yourselves!
  *
  * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
- * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+ * @see ComputerCraftAPI#createResourceMount(String, String)
  * @see IComputerAccess#mount(String, IMount)
  * @see IWritableMount
  */
@@ -68,18 +66,6 @@ public interface IMount
      */
     long getSize( @Nonnull String path ) throws IOException;
 
-    /**
-     * Opens a file with a given path, and returns an {@link InputStream} representing its contents.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream representing the contents of the file.
-     * @throws IOException If the file does not exist, or could not be opened.
-     * @deprecated Use {@link #openChannelForRead(String)} instead
-     */
-    @Nonnull
-    @Deprecated
-    InputStream openForRead( @Nonnull String path ) throws IOException;
-
     /**
      * Opens a file with a given path, and returns an {@link ReadableByteChannel} representing its contents.
      *
@@ -90,10 +76,7 @@ public interface IMount
      * @throws IOException If the file does not exist, or could not be opened.
      */
     @Nonnull
-    default ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForRead( path ) );
-    }
+    ReadableByteChannel openForRead( @Nonnull String path ) throws IOException;
 
     /**
      * Get attributes about the given file.

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

@@ -12,7 +12,6 @@ import net.minecraft.world.World;
 import javax.annotation.Nonnull;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.channels.Channels;
 import java.nio.channels.WritableByteChannel;
 import java.util.OptionalLong;
 
@@ -46,18 +45,6 @@ public interface IWritableMount extends IMount
      */
     void delete( @Nonnull String path ) throws IOException;
 
-    /**
-     * Opens a file with a given path, and returns an {@link OutputStream} for writing to it.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to
-     * @throws IOException If the file could not be opened for writing.
-     * @deprecated Use {@link #openChannelForWrite(String)} instead.
-     */
-    @Nonnull
-    @Deprecated
-    OutputStream openForWrite( @Nonnull String path ) throws IOException;
-
     /**
      * Opens a file with a given path, and returns an {@link OutputStream} for writing to it.
      *
@@ -67,22 +54,7 @@ public interface IWritableMount extends IMount
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    default WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForWrite( path ) );
-    }
-
-    /**
-     * Opens a file with a given path, and returns an {@link OutputStream} for appending to it.
-     *
-     * @param path A file path in normalised format, relative to the mount location. ie: "programs/myprogram".
-     * @return A stream for writing to.
-     * @throws IOException If the file could not be opened for writing.
-     * @deprecated Use {@link #openChannelForAppend(String)} instead.
-     */
-    @Nonnull
-    @Deprecated
-    OutputStream openForAppend( @Nonnull String path ) throws IOException;
+    WritableByteChannel openForWrite( @Nonnull String path ) throws IOException;
 
     /**
      * Opens a file with a given path, and returns an {@link OutputStream} for appending to it.
@@ -93,10 +65,7 @@ public interface IWritableMount extends IMount
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    default WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
-    {
-        return Channels.newChannel( openForAppend( path ) );
-    }
+    WritableByteChannel openForAppend( @Nonnull String path ) throws IOException;
 
     /**
      * Get the amount of free space on the mount, in bytes. You should decrease this value as the user writes to the

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

@@ -79,7 +79,7 @@ public interface IMedia
      * @see IMount
      * @see dan200.computercraft.api.filesystem.IWritableMount
      * @see dan200.computercraft.api.ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see dan200.computercraft.api.ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see dan200.computercraft.api.ComputerCraftAPI#createResourceMount(String, String)
      */
     @Nullable
     default IMount createDataMount( @Nonnull ItemStack stack, @Nonnull World world )

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

@@ -14,7 +14,6 @@ import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Collections;
 import java.util.Map;
 
 /**
@@ -31,9 +30,9 @@ public interface IComputerAccess
      * @param mount           The mount object to mount on the computer.
      * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a
      * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount, String)
      * @see #mountWritable(String, IWritableMount)
      * @see #unmount(String)
@@ -53,9 +52,9 @@ public interface IComputerAccess
      * @param driveName       A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
      * @return The location on the computer's file system where you the mount mounted, or {@code null} if there was already a
      * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #mountWritable(String, IWritableMount)
      * @see #unmount(String)
@@ -71,9 +70,9 @@ public interface IComputerAccess
      * @param mount           The mount object to mount on the computer.
      * @return The location on the computer's file system where you the mount mounted, or null if there was already a
      * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #unmount(String)
      * @see IMount
@@ -92,9 +91,9 @@ public interface IComputerAccess
      * @param driveName       A custom name to give for this mount location, as returned by {@code fs.getDrive()}.
      * @return The location on the computer's file system where you the mount mounted, or null if there was already a
      * file in the desired location. Store this value if you wish to unmount the mount later.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see ComputerCraftAPI#createSaveDirMount(World, String, long)
-     * @see ComputerCraftAPI#createResourceMount(Class, String, String)
+     * @see ComputerCraftAPI#createResourceMount(String, String)
      * @see #mount(String, IMount)
      * @see #unmount(String)
      * @see IMount
@@ -114,8 +113,8 @@ public interface IComputerAccess
      * @param location The desired location in the computers file system of the directory to unmount.
      *                 This must be the location of a directory previously mounted by {@link #mount(String, IMount)} or
      *                 {@link #mountWritable(String, IWritableMount)}, as indicated by their return value.
-     * @throws RuntimeException If the peripheral has been detached.
-     * @throws RuntimeException If the mount does not exist, or was mounted by another peripheral.
+     * @throws NotAttachedException  If the peripheral has been detached.
+     * @throws IllegalStateException If the mount does not exist, or was mounted by another peripheral.
      * @see #mount(String, IMount)
      * @see #mountWritable(String, IWritableMount)
      */
@@ -146,7 +145,7 @@ public interface IComputerAccess
      *                  to lua data types in the same fashion as the return values of IPeripheral.callMethod().
      *
      *                  You may supply {@code null} to indicate that no arguments are to be supplied.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see IPeripheral#callMethod
      */
     void queueEvent( @Nonnull String event, @Nullable Object[] arguments );
@@ -159,7 +158,7 @@ public interface IComputerAccess
      * which peripheral the event came.
      *
      * @return A string unique to the computer, but not globally.
-     * @throws RuntimeException If the peripheral has been detached.
+     * @throws NotAttachedException If the peripheral has been detached.
      */
     @Nonnull
     String getAttachmentName();
@@ -170,14 +169,12 @@ public interface IComputerAccess
      * This may include other peripherals on the wired network or peripherals on other sides of the computer.
      *
      * @return All reachable peripherals
+     * @throws NotAttachedException If the peripheral has been detached.
      * @see #getAttachmentName()
      * @see #getAvailablePeripheral(String)
      */
     @Nonnull
-    default Map<String, IPeripheral> getAvailablePeripherals()
-    {
-        return Collections.emptyMap();
-    }
+    Map<String, IPeripheral> getAvailablePeripherals();
 
     /**
      * Get a reachable peripheral with the given attachment name. This is a equivalent to
@@ -188,10 +185,7 @@ public interface IComputerAccess
      * @see #getAvailablePeripherals()
      */
     @Nullable
-    default IPeripheral getAvailablePeripheral( @Nonnull String name )
-    {
-        return null;
-    }
+    IPeripheral getAvailablePeripheral( @Nonnull String name );
 
     /**
      * Get a {@link IWorkMonitor} for tasks your peripheral might execute on the main (server) thread.
@@ -205,10 +199,8 @@ public interface IComputerAccess
      * thread.
      *
      * @return The work monitor for the main thread, or {@code null} if this computer does not have one.
+     * @throws NotAttachedException If the peripheral has been detached.
      */
-    @Nullable
-    default IWorkMonitor getMainThreadMonitor()
-    {
-        return null;
-    }
+    @Nonnull
+    IWorkMonitor getMainThreadMonitor();
 }

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

@@ -0,0 +1,25 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.peripheral;
+
+/**
+ * Thrown when performing operations on {@link IComputerAccess} when the current peripheral is no longer attached to
+ * the computer.
+ */
+public class NotAttachedException extends IllegalStateException
+{
+    private static final long serialVersionUID = 1221244785535553536L;
+
+    public NotAttachedException()
+    {
+        super( "You are not attached to this Computer" );
+    }
+
+    public NotAttachedException( String s )
+    {
+        super( s );
+    }
+}

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

@@ -3,10 +3,8 @@
  * Copyright Daniel Ratcliffe, 2011-2020. This API may be redistributed unmodified and in full only.
  * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-package dan200.computercraft.api;
+package dan200.computercraft.api.turtle;
 
-import dan200.computercraft.api.turtle.ITurtleUpgrade;
-import dan200.computercraft.api.turtle.TurtleUpgradeType;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.IItemProvider;
 import net.minecraft.util.ResourceLocation;

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

@@ -6,10 +6,10 @@
 package dan200.computercraft.api.turtle;
 
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.turtle.event.TurtleAttackEvent;
 import dan200.computercraft.api.turtle.event.TurtleBlockEvent;
-import net.minecraft.client.renderer.model.IBakedModel;
 import net.minecraft.client.renderer.model.ModelResourceLocation;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Direction;
@@ -18,11 +18,9 @@ import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.api.distmarker.OnlyIn;
 import net.minecraftforge.event.entity.player.AttackEntityEvent;
 import net.minecraftforge.event.world.BlockEvent;
-import org.apache.commons.lang3.tuple.Pair;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import javax.vecmath.Matrix4f;
 
 /**
  * The primary interface for defining an update for Turtles. A turtle update
@@ -126,12 +124,11 @@ public interface ITurtleUpgrade
      *
      * @param turtle Access to the turtle that the upgrade resides on. This will be null when getting item models!
      * @param side   Which side of the turtle (left or right) the upgrade resides on.
-     * @return The model that you wish to be used to render your upgrade, and a transformation to apply to it. Returning
-     * a transformation of {@code null} has the same effect as the identify matrix.
+     * @return The model that you wish to be used to render your upgrade.
      */
     @Nonnull
     @OnlyIn( Dist.CLIENT )
-    Pair<IBakedModel, Matrix4f> getModel( @Nullable ITurtleAccess turtle, @Nonnull TurtleSide side );
+    TransformedModel getModel( @Nullable ITurtleAccess turtle, @Nonnull TurtleSide side );
 
     /**
      * Called once per tick for each turtle which has the upgrade equipped.

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

@@ -17,70 +17,70 @@ public enum TurtleAnimation
     /**
      * An animation which does nothing. This takes no time to complete.
      *
-     * @see #Wait
-     * @see #ShortWait
+     * @see #WAIT
+     * @see #SHORT_WAIT
      */
-    None,
+    NONE,
 
     /**
      * Make the turtle move forward. Note that the animation starts from the block <em>behind</em> it, and
      * moves into this one.
      */
-    MoveForward,
+    MOVE_FORWARD,
 
     /**
      * Make the turtle move backwards. Note that the animation starts from the block <em>in front</em> it, and
      * moves into this one.
      */
-    MoveBack,
+    MOVE_BACK,
 
     /**
      * Make the turtle move backwards. Note that the animation starts from the block <em>above</em> it, and
      * moves into this one.
      */
-    MoveUp,
+    MOVE_UP,
 
     /**
      * Make the turtle move backwards. Note that the animation starts from the block <em>below</em> it, and
      * moves into this one.
      */
-    MoveDown,
+    MOVE_DOWN,
 
     /**
      * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and
      * the turtle turns to face in the current direction.
      */
-    TurnLeft,
+    TURN_LEFT,
 
     /**
      * Turn the turtle to the left. Note that the animation starts with the turtle facing <em>right</em>, and
      * the turtle turns to face in the current direction.
      */
-    TurnRight,
+    TURN_RIGHT,
 
     /**
      * Swing the tool on the left.
      */
-    SwingLeftTool,
+    SWING_LEFT_TOOL,
 
     /**
      * Swing the tool on the right.
      */
-    SwingRightTool,
+    SWING_RIGHT_TOOL,
 
     /**
      * Wait until the animation has finished, performing no movement.
      *
-     * @see #ShortWait
-     * @see #None
+     * @see #SHORT_WAIT
+     * @see #NONE
      */
-    Wait,
+    WAIT,
 
     /**
      * Wait until the animation has finished, performing no movement. This takes 4 ticks to complete.
      *
-     * @see #Wait
-     * @see #None
+     * @see #WAIT
+     * @see #NONE
      */
-    ShortWait,
+    SHORT_WAIT,
 }

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

@@ -13,10 +13,10 @@ public enum TurtleSide
     /**
      * The turtle's left side (where the pickaxe usually is on a Wireless Mining Turtle).
      */
-    Left,
+    LEFT,
 
     /**
      * The turtle's right side (where the modem usually is on a Wireless Mining Turtle).
      */
-    Right,
+    RIGHT,
 }

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

@@ -16,28 +16,28 @@ public enum TurtleUpgradeType
      * A tool is rendered as an item on the side of the turtle, and responds to the {@code turtle.dig()}
      * and {@code turtle.attack()} methods (Such as pickaxe or sword on Mining and Melee turtles).
      */
-    Tool,
+    TOOL,
 
     /**
      * A peripheral adds a special peripheral which is attached to the side of the turtle,
      * and can be interacted with the {@code peripheral} API (Such as the modem on Wireless Turtles).
      */
-    Peripheral,
+    PERIPHERAL,
 
     /**
      * An upgrade which provides both a tool and a peripheral. This can be used when you wish
      * your upgrade to also provide methods. For example, a pickaxe could provide methods
      * determining whether it can break the given block or not.
      */
-    Both;
+    BOTH;
 
     public boolean isTool()
     {
-        return this == Tool || this == Both;
+        return this == TOOL || this == BOTH;
     }
 
     public boolean isPeripheral()
     {
-        return this == Peripheral || this == Both;
+        return this == PERIPHERAL || this == BOTH;
     }
 }

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

@@ -19,10 +19,10 @@ public enum TurtleVerb
     /**
      * The turtle called {@code turtle.dig()}, {@code turtle.digUp()} or {@code turtle.digDown()}.
      */
-    Dig,
+    DIG,
 
     /**
      * The turtle called {@code turtle.attack()}, {@code turtle.attackUp()} or {@code turtle.attackDown()}.
      */
-    Attack,
+    ATTACK,
 }

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

@@ -11,20 +11,19 @@ import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.media.items.ItemDisk;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
-import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.model.IBakedModel;
 import net.minecraft.client.renderer.model.IUnbakedModel;
 import net.minecraft.client.renderer.model.ModelResourceLocation;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
+import net.minecraft.inventory.container.PlayerContainer;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.client.event.ColorHandlerEvent;
 import net.minecraftforge.client.event.ModelBakeEvent;
 import net.minecraftforge.client.event.ModelRegistryEvent;
 import net.minecraftforge.client.event.TextureStitchEvent;
-import net.minecraftforge.client.model.BasicState;
 import net.minecraftforge.client.model.ModelLoader;
 import net.minecraftforge.client.model.ModelLoaderRegistry;
+import net.minecraftforge.client.model.SimpleModelTransform;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
 
@@ -71,13 +70,13 @@ public final class ClientRegistry
     @SubscribeEvent
     public static void registerModels( ModelRegistryEvent event )
     {
-        ModelLoaderRegistry.registerLoader( TurtleModelLoader.INSTANCE );
+        ModelLoaderRegistry.registerLoader( new ResourceLocation( ComputerCraft.MOD_ID, "turtle" ), TurtleModelLoader.INSTANCE );
     }
 
     @SubscribeEvent
     public static void onTextureStitchEvent( TextureStitchEvent.Pre event )
     {
-        if( event.getMap() != Minecraft.getInstance().getTextureMap() ) return;
+        if( !event.getMap().getTextureLocation().equals( PlayerContainer.LOCATION_BLOCKS_TEXTURE ) ) return;
 
         for( String extra : EXTRA_TEXTURES )
         {
@@ -92,29 +91,18 @@ public final class ClientRegistry
         ModelLoader loader = event.getModelLoader();
         Map<ResourceLocation, IBakedModel> registry = event.getModelRegistry();
 
-        for( String model : EXTRA_MODELS )
+        for( String modelName : EXTRA_MODELS )
         {
-            IBakedModel bakedModel = bake( loader, loader.getUnbakedModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/" + model ) ) );
+            ResourceLocation location = new ResourceLocation( ComputerCraft.MOD_ID, "item/" + modelName );
+            IUnbakedModel model = loader.getUnbakedModel( location );
+            model.getTextures( loader::getUnbakedModel, new HashSet<>() );
 
-            if( bakedModel != null )
+            IBakedModel baked = model.bakeModel( loader, ModelLoader.defaultTextureGetter(), SimpleModelTransform.IDENTITY, location );
+            if( baked != null )
             {
-                registry.put(
-                    new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, model ), "inventory" ),
-                    bakedModel
-                );
+                registry.put( new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, modelName ), "inventory" ), baked );
             }
         }
-
-        // And load the custom turtle models in too.
-        registry.put(
-            new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, "turtle_normal" ), "inventory" ),
-            bake( loader, TurtleModelLoader.INSTANCE.loadModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/turtle_normal" ) ) )
-        );
-
-        registry.put(
-            new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, "turtle_advanced" ), "inventory" ),
-            bake( loader, TurtleModelLoader.INSTANCE.loadModel( new ResourceLocation( ComputerCraft.MOD_ID, "item/turtle_advanced" ) ) )
-        );
     }
 
     @SubscribeEvent
@@ -142,7 +130,7 @@ public final class ClientRegistry
                 case 2: // Light colour
                 {
                     int light = ItemPocketComputer.getLightState( stack );
-                    return light == -1 ? Colour.Black.getHex() : light;
+                    return light == -1 ? Colour.BLACK.getHex() : light;
                 }
             }
         }, ComputerCraft.Items.pocketComputerNormal, ComputerCraft.Items.pocketComputerAdvanced );
@@ -153,15 +141,4 @@ public final class ClientRegistry
             ComputerCraft.Blocks.turtleNormal, ComputerCraft.Blocks.turtleAdvanced
         );
     }
-
-    private static IBakedModel bake( ModelLoader loader, IUnbakedModel model )
-    {
-        model.getTextures( loader::getUnbakedModel, new HashSet<>() );
-
-        return model.bake(
-            loader,
-            ModelLoader.defaultTextureGetter(),
-            new BasicState( model.getDefaultState(), false ), DefaultVertexFormats.BLOCK
-        );
-    }
 }

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

@@ -5,15 +5,15 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.client.FrameInfo;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.util.Colour;
 import dan200.computercraft.shared.util.Palette;
 import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.*;
 import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.client.renderer.vertex.VertexFormat;
 import net.minecraft.util.ResourceLocation;
@@ -24,21 +24,10 @@ import javax.annotation.Nullable;
 
 public final class FixedWidthFontRenderer
 {
+    private static final Matrix4f IDENTITY = TransformationMatrix.identity().getMatrix();
+
     private static final ResourceLocation FONT = new ResourceLocation( "computercraft", "textures/gui/term_font.png" );
 
-    /**
-     * Like {@link DefaultVertexFormats#POSITION_TEX_COLOR}, but flipped. This is backported from 1.15, hence the
-     * custom format.
-     */
-    public static final VertexFormat POSITION_COLOR_TEX = new VertexFormat();
-
-    static
-    {
-        POSITION_COLOR_TEX.addElement( DefaultVertexFormats.POSITION_3F );
-        POSITION_COLOR_TEX.addElement( DefaultVertexFormats.COLOR_4UB );
-        POSITION_COLOR_TEX.addElement( DefaultVertexFormats.TEX_2F );
-    }
-
     public static final int FONT_HEIGHT = 9;
     public static final int FONT_WIDTH = 6;
     public static final float WIDTH = 256.0f;
@@ -46,6 +35,8 @@ public final class FixedWidthFontRenderer
     public static final float BACKGROUND_START = (WIDTH - 6.0f) / WIDTH;
     public static final float BACKGROUND_END = (WIDTH - 4.0f) / WIDTH;
 
+    public static final RenderType TYPE = Type.MAIN;
+
     private FixedWidthFontRenderer()
     {
     }
@@ -61,7 +52,7 @@ public final class FixedWidthFontRenderer
         return i < 0 ? 0 : 15 - i;
     }
 
-    private static void drawChar( BufferBuilder buffer, float x, float y, int index, float r, float g, float b )
+    private static void drawChar( Matrix4f transform, IVertexBuilder buffer, float x, float y, int index, float r, float g, float b )
     {
         // Short circuit to avoid the common case - the texture should be blank here after all.
         if( index == '\0' || index == ' ' ) return;
@@ -72,25 +63,25 @@ public final class FixedWidthFontRenderer
         int xStart = 1 + column * (FONT_WIDTH + 2);
         int yStart = 1 + row * (FONT_HEIGHT + 2);
 
-        buffer.pos( x, y, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, yStart / WIDTH ).endVertex();
-        buffer.pos( x, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
-        buffer.pos( x + FONT_WIDTH, y, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH ).endVertex();
-        buffer.pos( x + FONT_WIDTH, y, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH ).endVertex();
-        buffer.pos( x, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
-        buffer.pos( x + FONT_WIDTH, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
+        buffer.pos( transform, x, y, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, yStart / WIDTH ).endVertex();
+        buffer.pos( transform, x, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
+        buffer.pos( transform, x + FONT_WIDTH, y, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH ).endVertex();
+        buffer.pos( transform, x + FONT_WIDTH, y, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, yStart / WIDTH ).endVertex();
+        buffer.pos( transform, x, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( xStart / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
+        buffer.pos( transform, x + FONT_WIDTH, y + FONT_HEIGHT, 0f ).color( r, g, b, 1.0f ).tex( (xStart + FONT_WIDTH) / WIDTH, (yStart + FONT_HEIGHT) / WIDTH ).endVertex();
     }
 
-    private static void drawQuad( BufferBuilder buffer, float x, float y, float width, float height, float r, float g, float b )
+    private static void drawQuad( Matrix4f transform, IVertexBuilder buffer, float x, float y, float width, float height, float r, float g, float b )
     {
-        buffer.pos( x, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_START ).endVertex();
-        buffer.pos( x, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_END ).endVertex();
-        buffer.pos( x + width, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_START ).endVertex();
-        buffer.pos( x + width, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_START ).endVertex();
-        buffer.pos( x, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_END ).endVertex();
-        buffer.pos( x + width, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_END ).endVertex();
+        buffer.pos( transform, x, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_START ).endVertex();
+        buffer.pos( transform, x, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_END ).endVertex();
+        buffer.pos( transform, x + width, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_START ).endVertex();
+        buffer.pos( transform, x + width, y, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_START ).endVertex();
+        buffer.pos( transform, x, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_START, BACKGROUND_END ).endVertex();
+        buffer.pos( transform, x + width, y + height, 0 ).color( r, g, b, 1.0f ).tex( BACKGROUND_END, BACKGROUND_END ).endVertex();
     }
 
-    private static void drawQuad( BufferBuilder buffer, float x, float y, float width, float height, Palette palette, boolean greyscale, char colourIndex )
+    private static void drawQuad( Matrix4f transform, IVertexBuilder buffer, float x, float y, float width, float height, Palette palette, boolean greyscale, char colourIndex )
     {
         double[] colour = palette.getColour( getColour( colourIndex ) );
         float r, g, b;
@@ -105,23 +96,23 @@ public final class FixedWidthFontRenderer
             b = (float) colour[2];
         }
 
-        drawQuad( buffer, x, y, width, height, r, g, b );
+        drawQuad( transform, buffer, x, y, width, height, r, g, b );
     }
 
     private static void drawBackground(
-        @Nonnull BufferBuilder renderer, float x, float y,
+        @Nonnull Matrix4f transform, @Nonnull IVertexBuilder renderer, float x, float y,
         @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette, boolean greyscale,
         float leftMarginSize, float rightMarginSize, float height
     )
     {
         if( leftMarginSize > 0 )
         {
-            drawQuad( renderer, x - leftMarginSize, y, leftMarginSize, height, palette, greyscale, backgroundColour.charAt( 0 ) );
+            drawQuad( transform, renderer, x - leftMarginSize, y, leftMarginSize, height, palette, greyscale, backgroundColour.charAt( 0 ) );
         }
 
         if( rightMarginSize > 0 )
         {
-            drawQuad( renderer, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, greyscale, backgroundColour.charAt( backgroundColour.length() - 1 ) );
+            drawQuad( transform, renderer, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, greyscale, backgroundColour.charAt( backgroundColour.length() - 1 ) );
         }
 
         // Batch together runs of identical background cells.
@@ -134,7 +125,7 @@ public final class FixedWidthFontRenderer
 
             if( blockColour != '\0' )
             {
-                drawQuad( renderer, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, greyscale, blockColour );
+                drawQuad( transform, renderer, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, greyscale, blockColour );
             }
 
             blockColour = colourIndex;
@@ -143,24 +134,24 @@ public final class FixedWidthFontRenderer
 
         if( blockColour != '\0' )
         {
-            drawQuad( renderer, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, greyscale, blockColour );
+            drawQuad( transform, renderer, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, greyscale, blockColour );
         }
     }
 
     public static void drawString(
-        @Nonnull BufferBuilder renderer, float x, float y,
+        @Nonnull Matrix4f transform, @Nonnull IVertexBuilder renderer, float x, float y,
         @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nullable TextBuffer backgroundColour,
         @Nonnull Palette palette, boolean greyscale, float leftMarginSize, float rightMarginSize
     )
     {
         if( backgroundColour != null )
         {
-            drawBackground( renderer, x, y, backgroundColour, palette, greyscale, leftMarginSize, rightMarginSize, FONT_HEIGHT );
+            drawBackground( transform, renderer, x, y, backgroundColour, palette, greyscale, leftMarginSize, rightMarginSize, FONT_HEIGHT );
         }
 
         for( int i = 0; i < text.length(); i++ )
         {
-            double[] colour = palette.getColour( getColour( textColour.charAt( i ) ) );
+            double[] colour = palette.getColour( 15 - "0123456789abcdef".indexOf( textColour.charAt( i ) ) );
             float r, g, b;
             if( greyscale )
             {
@@ -176,7 +167,7 @@ public final class FixedWidthFontRenderer
             // Draw char
             int index = text.charAt( i );
             if( index > 255 ) index = '?';
-            drawChar( renderer, x + i * FONT_WIDTH, y, index, r, g, b );
+            drawChar( transform, renderer, x + i * FONT_WIDTH, y, index, r, g, b );
         }
 
     }
@@ -188,15 +179,13 @@ public final class FixedWidthFontRenderer
     {
         bindFont();
 
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        begin( buffer );
-        drawString( buffer, x, y, text, textColour, backgroundColour, palette, greyscale, leftMarginSize, rightMarginSize );
-        tessellator.draw();
+        IRenderTypeBuffer.Impl renderer = Minecraft.getInstance().getRenderTypeBuffers().getBufferSource();
+        drawString( IDENTITY, ((IRenderTypeBuffer) renderer).getBuffer( TYPE ), x, y, text, textColour, backgroundColour, palette, greyscale, leftMarginSize, rightMarginSize );
+        renderer.finish();
     }
 
     public static void drawTerminalWithoutCursor(
-        @Nonnull BufferBuilder buffer, float x, float y,
+        @Nonnull Matrix4f transform, @Nonnull IVertexBuilder buffer, float x, float y,
         @Nonnull Terminal terminal, boolean greyscale,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
@@ -206,13 +195,13 @@ public final class FixedWidthFontRenderer
 
         // Top and bottom margins
         drawBackground(
-            buffer, x, y - topMarginSize,
+            transform, buffer, x, y - topMarginSize,
             terminal.getBackgroundColourLine( 0 ), palette, greyscale,
             leftMarginSize, rightMarginSize, topMarginSize
         );
 
         drawBackground(
-            buffer, x, y + height * FONT_HEIGHT,
+            transform, buffer, x, y + height * FONT_HEIGHT,
             terminal.getBackgroundColourLine( height - 1 ), palette, greyscale,
             leftMarginSize, rightMarginSize, bottomMarginSize
         );
@@ -221,7 +210,7 @@ public final class FixedWidthFontRenderer
         for( int i = 0; i < height; i++ )
         {
             drawString(
-                buffer, x, y + FixedWidthFontRenderer.FONT_HEIGHT * i,
+                transform, buffer, x, y + FixedWidthFontRenderer.FONT_HEIGHT * i,
                 terminal.getLine( i ), terminal.getTextColourLine( i ), terminal.getBackgroundColourLine( i ),
                 palette, greyscale, leftMarginSize, rightMarginSize
             );
@@ -229,7 +218,7 @@ public final class FixedWidthFontRenderer
     }
 
     public static void drawCursor(
-        @Nonnull BufferBuilder buffer, float x, float y,
+        @Nonnull Matrix4f transform, @Nonnull IVertexBuilder buffer, float x, float y,
         @Nonnull Terminal terminal, boolean greyscale
     )
     {
@@ -254,75 +243,104 @@ public final class FixedWidthFontRenderer
                 b = (float) colour[2];
             }
 
-            drawChar( buffer, x + cursorX * FONT_WIDTH, y + cursorY * FONT_HEIGHT, '_', r, g, b );
+            drawChar( transform, buffer, x + cursorX * FONT_WIDTH, y + cursorY * FONT_HEIGHT, '_', r, g, b );
         }
     }
 
     public static void drawTerminal(
-        @Nonnull BufferBuilder buffer, float x, float y,
+        @Nonnull Matrix4f transform, @Nonnull IVertexBuilder buffer, float x, float y,
         @Nonnull Terminal terminal, boolean greyscale,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
     {
-        drawTerminalWithoutCursor( buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize );
-        drawCursor( buffer, x, y, terminal, greyscale );
+        drawTerminalWithoutCursor( transform, buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize );
+        drawCursor( transform, buffer, x, y, terminal, greyscale );
+    }
+
+    public static void drawTerminal(
+        @Nonnull Matrix4f transform, float x, float y, @Nonnull Terminal terminal, boolean greyscale,
+        float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
+    )
+    {
+        bindFont();
+
+        IRenderTypeBuffer.Impl renderer = Minecraft.getInstance().getRenderTypeBuffers().getBufferSource();
+        IVertexBuilder buffer = renderer.getBuffer( TYPE );
+        drawTerminal( transform, buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize );
+        renderer.finish( TYPE );
     }
 
     public static void drawTerminal(
         float x, float y, @Nonnull Terminal terminal, boolean greyscale,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
+    {
+        drawTerminal( IDENTITY, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize );
+    }
+
+    public static void drawEmptyTerminal( @Nonnull Matrix4f transform, @Nonnull IRenderTypeBuffer renderer, float x, float y, float width, float height )
+    {
+        Colour colour = Colour.BLACK;
+        drawQuad( transform, renderer.getBuffer( TYPE ), x, y, width, height, colour.getR(), colour.getG(), colour.getB() );
+    }
+
+    public static void drawEmptyTerminal( @Nonnull Matrix4f transform, float x, float y, float width, float height )
     {
         bindFont();
 
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        begin( buffer );
-        drawTerminal( buffer, x, y, terminal, greyscale, topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize );
-        tessellator.draw();
+        IRenderTypeBuffer.Impl renderer = Minecraft.getInstance().getRenderTypeBuffers().getBufferSource();
+        drawEmptyTerminal( transform, renderer, x, y, width, height );
+        renderer.finish();
     }
 
     public static void drawEmptyTerminal( float x, float y, float width, float height )
     {
-        bindFont();
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        begin( buffer );
-
-        Colour colour = Colour.Black;
-        drawQuad( buffer, x, y, width, height, colour.getR(), colour.getG(), colour.getB() );
-
-        tessellator.draw();
+        drawEmptyTerminal( IDENTITY, x, y, width, height );
     }
 
-    public static void drawBlocker( @Nonnull BufferBuilder buffer, float x, float y, float width, float height )
+    public static void drawBlocker( @Nonnull Matrix4f transform, @Nonnull IRenderTypeBuffer renderer, float x, float y, float width, float height )
     {
-        Colour colour = Colour.Black;
-        drawQuad( buffer, x, y, width, height, colour.getR(), colour.getG(), colour.getB() );
+        Colour colour = Colour.BLACK;
+        drawQuad( transform, renderer.getBuffer( Type.BLOCKER ), x, y, width, height, colour.getR(), colour.getG(), colour.getB() );
     }
 
-    public static void drawBlocker( float x, float y, float width, float height )
-    {
-        bindFont();
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        begin( buffer );
-        drawBlocker( buffer, x, y, width, height );
-        tessellator.draw();
-    }
-
-    public static void bindFont()
+    private static void bindFont()
     {
         Minecraft.getInstance().getTextureManager().bindTexture( FONT );
-        GlStateManager.texParameter( GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_CLAMP );
-
-        GlStateManager.enableTexture();
+        RenderSystem.texParameter( GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_CLAMP );
     }
 
-    public static void begin( BufferBuilder buffer )
+    private static final class Type extends RenderState
     {
-        buffer.begin( GL11.GL_TRIANGLES, POSITION_COLOR_TEX );
+        private static final int GL_MODE = GL11.GL_TRIANGLES;
+
+        private static final VertexFormat FORMAT = DefaultVertexFormats.POSITION_COLOR_TEX;
+
+        static final RenderType MAIN = RenderType.makeType(
+            "terminal_font", FORMAT, GL_MODE, 1024,
+            false, false, // useDelegate, needsSorting
+            RenderType.State.getBuilder()
+                .texture( new RenderState.TextureState( FONT, false, false ) ) // blur, minimap
+                .alpha( DEFAULT_ALPHA )
+                .lightmap( LIGHTMAP_DISABLED )
+                .writeMask( COLOR_WRITE )
+                .build( false )
+        );
+
+        static final RenderType BLOCKER = RenderType.makeType(
+            "terminal_blocker", FORMAT, GL_MODE, 256,
+            false, false, // useDelegate, needsSorting
+            RenderType.State.getBuilder()
+                .texture( new RenderState.TextureState( FONT, false, false ) ) // blur, minimap
+                .alpha( DEFAULT_ALPHA )
+                .writeMask( DEPTH_WRITE )
+                .lightmap( LIGHTMAP_DISABLED )
+                .build( false )
+        );
+
+        private Type( String name, Runnable setup, Runnable destroy )
+        {
+            super( name, setup, destroy );
+        }
     }
 }

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

@@ -5,7 +5,7 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.gui.widgets.WidgetWrapper;
@@ -134,17 +134,17 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
         terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
 
         // Draw a border around the terminal
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
+        RenderSystem.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
         switch( m_family )
         {
-            case Normal:
+            case NORMAL:
             default:
                 minecraft.getTextureManager().bindTexture( BACKGROUND_NORMAL );
                 break;
-            case Advanced:
+            case ADVANCED:
                 minecraft.getTextureManager().bindTexture( BACKGROUND_ADVANCED );
                 break;
-            case Command:
+            case COMMAND:
                 minecraft.getTextureManager().bindTexture( BACKGROUND_COMMAND );
                 break;
         }

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

@@ -5,7 +5,7 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
 import net.minecraft.client.gui.screen.inventory.ContainerScreen;
 import net.minecraft.entity.player.PlayerInventory;
@@ -32,7 +32,7 @@ public class GuiDiskDrive extends ContainerScreen<ContainerDiskDrive>
     @Override
     protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
     {
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+        RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
         minecraft.getTextureManager().bindTexture( BACKGROUND );
         blit( guiLeft, guiTop, 0, 0, xSize, ySize );
     }

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

@@ -5,7 +5,7 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
 import net.minecraft.client.gui.screen.inventory.ContainerScreen;
 import net.minecraft.client.resources.I18n;
@@ -33,7 +33,7 @@ public class GuiPrinter extends ContainerScreen<ContainerPrinter>
     @Override
     protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
     {
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+        RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
         minecraft.getTextureManager().bindTexture( BACKGROUND );
         blit( guiLeft, guiTop, 0, 0, xSize, ySize );
 

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

@@ -5,11 +5,15 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.common.ContainerHeldItem;
 import dan200.computercraft.shared.media.items.ItemPrintout;
+import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screen.inventory.ContainerScreen;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.TransformationMatrix;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.util.text.ITextComponent;
 import org.lwjgl.glfw.GLFW;
@@ -18,6 +22,8 @@ import static dan200.computercraft.client.render.PrintoutRenderer.*;
 
 public class GuiPrintout extends ContainerScreen<ContainerHeldItem>
 {
+    private static final Matrix4f IDENTITY = TransformationMatrix.identity().getMatrix();
+
     private final boolean m_book;
     private final int m_pages;
     private final TextBuffer[] m_text;
@@ -88,20 +94,22 @@ public class GuiPrintout extends ContainerScreen<ContainerHeldItem>
     public void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
     {
         // Draw the printout
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableDepthTest();
+        RenderSystem.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
+        RenderSystem.enableDepthTest();
 
-        drawBorder( guiLeft, guiTop, blitOffset, m_page, m_pages, m_book );
-        drawText( guiLeft + X_TEXT_MARGIN, guiTop + Y_TEXT_MARGIN, ItemPrintout.LINES_PER_PAGE * m_page, m_text, m_colours );
+        IRenderTypeBuffer.Impl renderer = Minecraft.getInstance().getRenderTypeBuffers().getBufferSource();
+        drawBorder( IDENTITY, renderer, guiLeft, guiTop, getBlitOffset(), m_page, m_pages, m_book );
+        drawText( IDENTITY, renderer, guiLeft + X_TEXT_MARGIN, guiTop + Y_TEXT_MARGIN, ItemPrintout.LINES_PER_PAGE * m_page, m_text, m_colours );
+        renderer.finish();
     }
 
     @Override
     public void render( int mouseX, int mouseY, float partialTicks )
     {
         // We must take the background further back in order to not overlap with our printed pages.
-        blitOffset--;
+        setBlitOffset( getBlitOffset() - 1 );
         renderBackground();
-        blitOffset++;
+        setBlitOffset( getBlitOffset() + 1 );
 
         super.render( mouseX, mouseY, partialTicks );
         renderHoveredToolTip( mouseX, mouseY );

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

@@ -5,7 +5,7 @@
  */
 package dan200.computercraft.client.gui;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.systems.RenderSystem;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.gui.widgets.WidgetWrapper;
@@ -98,7 +98,7 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
         int slot = m_container.getSelectedSlot();
         if( slot >= 0 )
         {
-            GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+            RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
             int slotX = slot % 4;
             int slotY = slot / 4;
             minecraft.getTextureManager().bindTexture( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
@@ -110,11 +110,11 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
     protected void drawGuiContainerBackgroundLayer( float partialTicks, int mouseX, int mouseY )
     {
         // Draw term
-        boolean advanced = m_family == ComputerFamily.Advanced;
+        boolean advanced = m_family == ComputerFamily.ADVANCED;
         terminal.draw( terminalWrapper.getX(), terminalWrapper.getY() );
 
         // Draw border/inventory
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
+        RenderSystem.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
         minecraft.getTextureManager().bindTexture( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
         blit( guiLeft, guiTop, 0, 0, xSize, ySize );
 

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

@@ -17,6 +17,9 @@ import org.lwjgl.glfw.GLFW;
 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;
+
 public class WidgetTerminal implements IGuiEventListener
 {
     private static final float TERMINATE_TIME = 0.5f;
@@ -173,8 +176,8 @@ public class WidgetTerminal implements IGuiEventListener
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -197,8 +200,8 @@ public class WidgetTerminal implements IGuiEventListener
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -224,8 +227,8 @@ public class WidgetTerminal implements IGuiEventListener
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -249,8 +252,8 @@ public class WidgetTerminal implements IGuiEventListener
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            int charX = (int) (mouseX / FixedWidthFontRenderer.FONT_WIDTH);
-            int charY = (int) (mouseY / FixedWidthFontRenderer.FONT_HEIGHT);
+            int charX = (int) (mouseX / FONT_WIDTH);
+            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -318,19 +321,15 @@ public class WidgetTerminal implements IGuiEventListener
             Terminal terminal = computer != null ? computer.getTerminal() : null;
             if( terminal != null )
             {
-                FixedWidthFontRenderer.drawTerminal(
-                    originX, originY,
-                    terminal, !computer.isColour(), topMargin, bottomMargin, leftMargin, rightMargin
-                );
+                FixedWidthFontRenderer.drawTerminal( originX, originY, terminal, !computer.isColour(), topMargin, bottomMargin, leftMargin, rightMargin );
             }
             else
             {
-                int x = originX - leftMargin;
-                int y = originY - rightMargin;
-                int width = termWidth * FixedWidthFontRenderer.FONT_WIDTH + leftMargin + rightMargin;
-                int height = termHeight * FixedWidthFontRenderer.FONT_HEIGHT + topMargin + bottomMargin;
-
-                FixedWidthFontRenderer.drawEmptyTerminal( x, y, width, height );
+                FixedWidthFontRenderer.drawEmptyTerminal(
+                    originX - leftMargin, originY - rightMargin,
+                    termWidth * FONT_WIDTH + leftMargin + rightMargin,
+                    termHeight * FONT_HEIGHT + topMargin + bottomMargin
+                );
             }
         }
     }

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

@@ -7,7 +7,6 @@ package dan200.computercraft.client.proxy;
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.*;
-import dan200.computercraft.client.render.TileEntityCableRenderer;
 import dan200.computercraft.client.render.TileEntityMonitorRenderer;
 import dan200.computercraft.client.render.TileEntityTurtleRenderer;
 import dan200.computercraft.client.render.TurtlePlayerRenderer;
@@ -15,7 +14,6 @@ import dan200.computercraft.shared.common.ContainerHeldItem;
 import dan200.computercraft.shared.computer.inventory.ContainerComputer;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
-import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
 import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
 import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
 import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
@@ -24,6 +22,8 @@ import dan200.computercraft.shared.turtle.blocks.TileTurtle;
 import dan200.computercraft.shared.turtle.core.TurtlePlayer;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
 import net.minecraft.client.gui.ScreenManager;
+import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.RenderTypeLookup;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.event.world.WorldEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
@@ -40,12 +40,22 @@ public final class ComputerCraftProxyClient
     {
         registerContainers();
 
-        // Setup TESRs
-        ClientRegistry.bindTileEntitySpecialRenderer( TileMonitor.class, new TileEntityMonitorRenderer() );
-        ClientRegistry.bindTileEntitySpecialRenderer( TileCable.class, new TileEntityCableRenderer() );
-        ClientRegistry.bindTileEntitySpecialRenderer( TileTurtle.class, new TileEntityTurtleRenderer() );
+        // While turtles themselves are not transparent, their upgrades may be.
+        RenderTypeLookup.setRenderLayer( ComputerCraft.Blocks.turtleNormal, RenderType.getTranslucent() );
+        RenderTypeLookup.setRenderLayer( ComputerCraft.Blocks.turtleAdvanced, RenderType.getTranslucent() );
 
-        RenderingRegistry.registerEntityRenderingHandler( TurtlePlayer.class, TurtlePlayerRenderer::new );
+        // Monitors' textures have transparent fronts and so count as cutouts.
+        RenderTypeLookup.setRenderLayer( ComputerCraft.Blocks.monitorNormal, RenderType.getCutout() );
+        RenderTypeLookup.setRenderLayer( ComputerCraft.Blocks.monitorAdvanced, RenderType.getCutout() );
+
+        // Setup TESRs
+        ClientRegistry.bindTileEntityRenderer( TileMonitor.FACTORY_NORMAL, TileEntityMonitorRenderer::new );
+        ClientRegistry.bindTileEntityRenderer( TileMonitor.FACTORY_ADVANCED, TileEntityMonitorRenderer::new );
+        ClientRegistry.bindTileEntityRenderer( TileTurtle.FACTORY_NORMAL, TileEntityTurtleRenderer::new );
+        ClientRegistry.bindTileEntityRenderer( TileTurtle.FACTORY_ADVANCED, TileEntityTurtleRenderer::new );
+        // TODO: ClientRegistry.bindTileEntityRenderer( TileCable.FACTORY, x -> new TileEntityCableRenderer() );
+
+        RenderingRegistry.registerEntityRenderingHandler( TurtlePlayer.TYPE, TurtlePlayerRenderer::new );
     }
 
     private static void registerContainers()

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

@@ -5,26 +5,27 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
 import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
 import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.block.BlockState;
-import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.ActiveRenderInfo;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.RenderType;
 import net.minecraft.client.renderer.WorldRenderer;
+import net.minecraft.entity.Entity;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
-import net.minecraft.util.math.RayTraceResult;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.math.shapes.VoxelShape;
 import net.minecraft.world.World;
 import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.DrawBlockHighlightEvent;
+import net.minecraftforge.client.event.DrawHighlightEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
-import org.lwjgl.opengl.GL11;
 
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
 public final class CableHighlightRenderer
@@ -37,14 +38,12 @@ public final class CableHighlightRenderer
      * Draw an outline for a specific part of a cable "Multipart".
      *
      * @param event The event to observe
-     * @see WorldRenderer#drawSelectionBox(ActiveRenderInfo, RayTraceResult, int)
+     * @see WorldRenderer#drawSelectionBox(MatrixStack, IVertexBuilder, Entity, double, double, double, BlockPos, BlockState)
      */
     @SubscribeEvent
-    public static void drawHighlight( DrawBlockHighlightEvent event )
+    public static void drawHighlight( DrawHighlightEvent.HighlightBlock event )
     {
-        if( event.getTarget().getType() != RayTraceResult.Type.BLOCK ) return;
-
-        BlockRayTraceResult hit = (BlockRayTraceResult) event.getTarget();
+        BlockRayTraceResult hit = event.getTarget();
         BlockPos pos = hit.getPos();
         World world = event.getInfo().getRenderViewEntity().getEntityWorld();
         ActiveRenderInfo info = event.getInfo();
@@ -59,31 +58,22 @@ public final class CableHighlightRenderer
 
         event.setCanceled( true );
 
-        Minecraft mc = Minecraft.getInstance();
-
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
-        GlStateManager.lineWidth( Math.max( 2.5F, mc.mainWindow.getFramebufferWidth() / 1920.0F * 2.5F ) );
-        GlStateManager.disableTexture();
-        GlStateManager.depthMask( false );
-        GlStateManager.matrixMode( GL11.GL_PROJECTION );
-        GlStateManager.pushMatrix();
-        GlStateManager.scalef( 1.0F, 1.0F, 0.999F );
-
         VoxelShape shape = WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.getHitVec().subtract( pos.getX(), pos.getY(), pos.getZ() ) )
             ? CableShapes.getModemShape( state )
             : CableShapes.getCableShape( state );
 
         Vec3d cameraPos = info.getProjectedView();
-        WorldRenderer.drawShape(
-            shape, pos.getX() - cameraPos.getX(), pos.getY() - cameraPos.getY(), pos.getZ() - cameraPos.getZ(),
-            0.0F, 0.0F, 0.0F, 0.4F
-        );
+        double xOffset = pos.getX() - cameraPos.getX();
+        double yOffset = pos.getY() - cameraPos.getY();
+        double zOffset = pos.getZ() - cameraPos.getZ();
 
-        GlStateManager.popMatrix();
-        GlStateManager.matrixMode( GL11.GL_MODELVIEW );
-        GlStateManager.depthMask( true );
-        GlStateManager.enableTexture();
-        GlStateManager.disableBlend();
+        IVertexBuilder buffer = event.getBuffers().getBuffer( RenderType.getLines() );
+        Matrix4f matrix4f = event.getMatrix().getLast().getMatrix();
+        shape.forEachEdge( ( x1, y1, z1, x2, y2, z2 ) -> {
+            buffer.pos( matrix4f, (float) (x1 + xOffset), (float) (y1 + yOffset), (float) (z1 + zOffset) )
+                .color( 0, 0, 0, 0.4f ).endVertex();
+            buffer.pos( matrix4f, (float) (x2 + xOffset), (float) (y2 + yOffset), (float) (z2 + zOffset) )
+                .color( 0, 0, 0, 0.4f ).endVertex();
+        } );
     }
 }

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

@@ -5,9 +5,12 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.entity.player.AbstractClientPlayerEntity;
 import net.minecraft.client.renderer.FirstPersonRenderer;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.client.renderer.Vector3f;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Hand;
@@ -19,99 +22,118 @@ public abstract class ItemMapLikeRenderer
     /**
      * The main rendering method for the item.
      *
-     * @param stack The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPerson(ItemStack)
+     * @param transform The matrix transformation stack
+     * @param render    The buffer to render to
+     * @param stack     The stack to render
+     * @see FirstPersonRenderer#renderItemInFirstPerson(AbstractClientPlayerEntity, float, float, Hand, float, ItemStack, float, MatrixStack, IRenderTypeBuffer, int)
      */
-    protected abstract void renderItem( ItemStack stack );
+    protected abstract void renderItem( MatrixStack transform, IRenderTypeBuffer render, ItemStack stack );
 
-    protected void renderItemFirstPerson( Hand hand, float pitch, float equipProgress, float swingProgress, ItemStack stack )
+    protected void renderItemFirstPerson( MatrixStack transform, IRenderTypeBuffer render, int lightTexture, Hand hand, float pitch, float equipProgress, float swingProgress, ItemStack stack )
     {
         PlayerEntity player = Minecraft.getInstance().player;
 
-        GlStateManager.pushMatrix();
+        transform.push();
         if( hand == Hand.MAIN_HAND && player.getHeldItemOffhand().isEmpty() )
         {
-            renderItemFirstPersonCenter( pitch, equipProgress, swingProgress, stack );
+            renderItemFirstPersonCenter( transform, render, lightTexture, pitch, equipProgress, swingProgress, stack );
         }
         else
         {
             renderItemFirstPersonSide(
+                transform, render, lightTexture,
                 hand == Hand.MAIN_HAND ? player.getPrimaryHand() : player.getPrimaryHand().opposite(),
                 equipProgress, swingProgress, stack
             );
         }
-        GlStateManager.popMatrix();
+        transform.pop();
     }
 
     /**
      * Renders the item to one side of the player.
      *
+     * @param transform     The matrix transformation stack
+     * @param render        The buffer to render to
+     * @param combinedLight The current light level
      * @param side          The side to render on
      * @param equipProgress The equip progress of this item
      * @param swingProgress The swing progress of this item
      * @param stack         The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPersonSide(float, HandSide, float, ItemStack)
+     * @see FirstPersonRenderer#renderMapFirstPersonSide(MatrixStack, IRenderTypeBuffer, int, float, HandSide, float, ItemStack)
      */
-    private void renderItemFirstPersonSide( HandSide side, float equipProgress, float swingProgress, ItemStack stack )
+    private void renderItemFirstPersonSide( MatrixStack transform, IRenderTypeBuffer render, int combinedLight, HandSide side, float equipProgress, float swingProgress, ItemStack stack )
     {
         Minecraft minecraft = Minecraft.getInstance();
         float offset = side == HandSide.RIGHT ? 1f : -1f;
-        GlStateManager.translatef( offset * 0.125f, -0.125f, 0f );
+        transform.translate( offset * 0.125f, -0.125f, 0f );
 
         // If the player is not invisible then render a single arm
         if( !minecraft.player.isInvisible() )
         {
-            GlStateManager.pushMatrix();
-            GlStateManager.rotatef( offset * 10f, 0f, 0f, 1f );
-            minecraft.getFirstPersonRenderer().renderArmFirstPerson( equipProgress, swingProgress, side );
-            GlStateManager.popMatrix();
+            transform.push();
+            transform.rotate( Vector3f.ZP.rotationDegrees( offset * 10f ) );
+            minecraft.getFirstPersonRenderer().renderArmFirstPerson( transform, render, combinedLight, equipProgress, swingProgress, side );
+            transform.pop();
         }
 
         // Setup the appropriate transformations. This is just copied from the
         // corresponding method in ItemRenderer.
-        GlStateManager.pushMatrix();
-        GlStateManager.translatef( offset * 0.51f, -0.08f + equipProgress * -1.2f, -0.75f );
+        transform.push();
+        transform.translate( offset * 0.51f, -0.08f + equipProgress * -1.2f, -0.75f );
         float f1 = MathHelper.sqrt( swingProgress );
         float f2 = MathHelper.sin( f1 * (float) Math.PI );
         float f3 = -0.5f * f2;
         float f4 = 0.4f * MathHelper.sin( f1 * ((float) Math.PI * 2f) );
         float f5 = -0.3f * MathHelper.sin( swingProgress * (float) Math.PI );
-        GlStateManager.translatef( offset * f3, f4 - 0.3f * f2, f5 );
-        GlStateManager.rotatef( f2 * -45f, 1f, 0f, 0f );
-        GlStateManager.rotatef( offset * f2 * -30f, 0f, 1f, 0f );
+        transform.translate( offset * f3, f4 - 0.3f * f2, f5 );
+        transform.rotate( Vector3f.XP.rotationDegrees( f2 * -45f ) );
+        transform.rotate( Vector3f.YP.rotationDegrees( offset * f2 * -30f ) );
 
-        renderItem( stack );
+        renderItem( transform, render, stack );
 
-        GlStateManager.popMatrix();
+        transform.pop();
     }
 
     /**
      * Render an item in the middle of the screen.
      *
+     * @param transform     The matrix transformation stack
+     * @param render        The buffer to render to
+     * @param combinedLight The current light level
      * @param pitch         The pitch of the player
      * @param equipProgress The equip progress of this item
      * @param swingProgress The swing progress of this item
      * @param stack         The stack to render
-     * @see FirstPersonRenderer#renderMapFirstPerson(float, float, float)
+     * @see FirstPersonRenderer#renderMapFirstPerson(MatrixStack, IRenderTypeBuffer, int, float, float, float)
      */
-    private void renderItemFirstPersonCenter( float pitch, float equipProgress, float swingProgress, ItemStack stack )
+    private void renderItemFirstPersonCenter( MatrixStack transform, IRenderTypeBuffer render, int combinedLight, float pitch, float equipProgress, float swingProgress, ItemStack stack )
     {
-        FirstPersonRenderer renderer = Minecraft.getInstance().getFirstPersonRenderer();
+        Minecraft minecraft = Minecraft.getInstance();
+        FirstPersonRenderer renderer = minecraft.getFirstPersonRenderer();
 
         // Setup the appropriate transformations. This is just copied from the
         // corresponding method in ItemRenderer.
         float swingRt = MathHelper.sqrt( swingProgress );
         float tX = -0.2f * MathHelper.sin( swingProgress * (float) Math.PI );
         float tZ = -0.4f * MathHelper.sin( swingRt * (float) Math.PI );
-        GlStateManager.translatef( 0f, -tX / 2f, tZ );
-        float pitchAngle = renderer.getMapAngleFromPitch( pitch );
-        GlStateManager.translatef( 0f, 0.04f + equipProgress * -1.2f + pitchAngle * -0.5f, -0.72f );
-        GlStateManager.rotatef( pitchAngle * -85f, 1f, 0f, 0f );
-        renderer.renderArms();
-        float rX = MathHelper.sin( swingRt * (float) Math.PI );
-        GlStateManager.rotatef( rX * 20f, 1f, 0f, 0f );
-        GlStateManager.scalef( 2f, 2f, 2f );
+        transform.translate( 0, -tX / 2, tZ );
 
-        renderItem( stack );
+        float pitchAngle = renderer.getMapAngleFromPitch( pitch );
+        transform.translate( 0, 0.04F + equipProgress * -1.2f + pitchAngle * -0.5f, -0.72f );
+        transform.rotate( Vector3f.XP.rotationDegrees( pitchAngle * -85.0f ) );
+        if( !minecraft.player.isInvisible() )
+        {
+            transform.push();
+            transform.rotate( Vector3f.YP.rotationDegrees( 90.0F ) );
+            renderer.renderArm( transform, render, combinedLight, HandSide.RIGHT );
+            renderer.renderArm( transform, render, combinedLight, HandSide.LEFT );
+            transform.pop();
+        }
+
+        float rX = MathHelper.sin( swingRt * (float) Math.PI );
+        transform.rotate( Vector3f.XP.rotationDegrees( rX * 20.0F ) );
+        transform.scale( 2.0F, 2.0F, 2.0F );
+
+        renderItem( transform, render, stack );
     }
 }

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

@@ -5,7 +5,9 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.systems.RenderSystem;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
@@ -14,12 +16,11 @@ import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
 import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.*;
 import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.RenderSpecificHandEvent;
+import net.minecraftforge.client.event.RenderHandEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
 import org.lwjgl.opengl.GL11;
@@ -45,17 +46,20 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
     }
 
     @SubscribeEvent
-    public static void renderItem( RenderSpecificHandEvent event )
+    public static void onRenderInHand( RenderHandEvent event )
     {
         ItemStack stack = event.getItemStack();
         if( !(stack.getItem() instanceof ItemPocketComputer) ) return;
 
         event.setCanceled( true );
-        INSTANCE.renderItemFirstPerson( event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack() );
+        INSTANCE.renderItemFirstPerson(
+            event.getMatrixStack(), event.getBuffers(), event.getLight(),
+            event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack()
+        );
     }
 
     @Override
-    protected void renderItem( ItemStack stack )
+    protected void renderItem( MatrixStack transform, IRenderTypeBuffer render, ItemStack stack )
     {
         ClientComputer computer = ItemPocketComputer.createClientComputer( stack );
         Terminal terminal = computer == null ? null : computer.getTerminal();
@@ -77,50 +81,45 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
 
         // Setup various transformations. Note that these are partially adapted from the corresponding method
         // in ItemRenderer
-        GlStateManager.pushMatrix();
+        transform.push();
+        transform.rotate( Vector3f.YP.rotationDegrees( 180f ) );
+        transform.rotate( Vector3f.ZP.rotationDegrees( 180f ) );
+        transform.scale( 0.5f, 0.5f, 0.5f );
 
-        GlStateManager.disableLighting();
-        GlStateManager.disableDepthTest();
-
-        GlStateManager.rotatef( 180f, 0f, 1f, 0f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.5f, 0.5f, 0.5f );
-
-        double scale = 0.75 / Math.max( width + FRAME * 2, height + FRAME * 2 + LIGHT_HEIGHT );
-        GlStateManager.scaled( scale, scale, 0 );
-        GlStateManager.translated( -0.5 * width, -0.5 * height, 0 );
+        float scale = 0.75f / Math.max( width + FRAME * 2, height + FRAME * 2 + LIGHT_HEIGHT );
+        transform.scale( scale, scale, 0 );
+        transform.translate( -0.5 * width, -0.5 * height, 0 );
 
         // Render the main frame
         ItemPocketComputer item = (ItemPocketComputer) stack.getItem();
         ComputerFamily family = item.getFamily();
         int frameColour = item.getColour( stack );
-        renderFrame( family, frameColour, width, height );
+
+        Matrix4f matrix = transform.getLast().getMatrix();
+        renderFrame( matrix, family, frameColour, width, height );
 
         // Render the light
         int lightColour = ItemPocketComputer.getLightState( stack );
-        if( lightColour == -1 ) lightColour = Colour.Black.getHex();
-        renderLight( lightColour, width, height );
+        if( lightColour == -1 ) lightColour = Colour.BLACK.getHex();
+        renderLight( matrix, lightColour, width, height );
 
         if( computer != null && terminal != null )
         {
-            FixedWidthFontRenderer.drawTerminal( MARGIN, MARGIN, terminal, !computer.isColour(), MARGIN, MARGIN, MARGIN, MARGIN );
+            FixedWidthFontRenderer.drawTerminal( matrix, MARGIN, MARGIN, terminal, !computer.isColour(), MARGIN, MARGIN, MARGIN, MARGIN );
         }
         else
         {
-            FixedWidthFontRenderer.drawEmptyTerminal( 0, 0, width, height );
+            FixedWidthFontRenderer.drawEmptyTerminal( matrix, 0, 0, width, height );
         }
 
-        GlStateManager.enableDepthTest();
-        GlStateManager.enableLighting();
-        GlStateManager.popMatrix();
+        transform.pop();
     }
 
-    private static void renderFrame( ComputerFamily family, int colour, int width, int height )
+    private static void renderFrame( Matrix4f transform, ComputerFamily family, int colour, int width, int height )
     {
-
         Minecraft.getInstance().getTextureManager().bindTexture( colour != -1
             ? BACKGROUND_COLOUR
-            : family == ComputerFamily.Normal ? BACKGROUND_NORMAL : BACKGROUND_ADVANCED
+            : family == ComputerFamily.NORMAL ? BACKGROUND_NORMAL : BACKGROUND_ADVANCED
         );
 
         float r = ((colour >>> 16) & 0xFF) / 255.0f;
@@ -129,38 +128,38 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
 
         Tessellator tessellator = Tessellator.getInstance();
         BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX_COLOR );
+        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_COLOR_TEX );
 
         // Top left, middle, right
-        renderTexture( buffer, -FRAME, -FRAME, 12, 28, FRAME, FRAME, r, g, b );
-        renderTexture( buffer, 0, -FRAME, 0, 0, width, FRAME, r, g, b );
-        renderTexture( buffer, width, -FRAME, 24, 28, FRAME, FRAME, r, g, b );
+        renderTexture( transform, buffer, -FRAME, -FRAME, 12, 28, FRAME, FRAME, r, g, b );
+        renderTexture( transform, buffer, 0, -FRAME, 0, 0, width, FRAME, r, g, b );
+        renderTexture( transform, buffer, width, -FRAME, 24, 28, FRAME, FRAME, r, g, b );
 
         // Left and bright border
-        renderTexture( buffer, -FRAME, 0, 0, 28, FRAME, height, r, g, b );
-        renderTexture( buffer, width, 0, 36, 28, FRAME, height, r, g, b );
+        renderTexture( transform, buffer, -FRAME, 0, 0, 28, FRAME, height, r, g, b );
+        renderTexture( transform, buffer, width, 0, 36, 28, FRAME, height, r, g, b );
 
         // Bottom left, middle, right. We do this in three portions: the top inner corners, an extended region for
         // lights, and then the bottom outer corners.
-        renderTexture( buffer, -FRAME, height, 12, 40, FRAME, FRAME / 2, r, g, b );
-        renderTexture( buffer, 0, height, 0, 12, width, FRAME / 2, r, g, b );
-        renderTexture( buffer, width, height, 24, 40, FRAME, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, -FRAME, height, 12, 40, FRAME, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, 0, height, 0, 12, width, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, width, height, 24, 40, FRAME, FRAME / 2, r, g, b );
 
-        renderTexture( buffer, -FRAME, height + FRAME / 2, 12, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
-        renderTexture( buffer, 0, height + FRAME / 2, 0, 16, width, LIGHT_HEIGHT, FRAME, 4, r, g, b );
-        renderTexture( buffer, width, height + FRAME / 2, 24, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+        renderTexture( transform, buffer, -FRAME, height + FRAME / 2, 12, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+        renderTexture( transform, buffer, 0, height + FRAME / 2, 0, 16, width, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+        renderTexture( transform, buffer, width, height + FRAME / 2, 24, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
 
-        renderTexture( buffer, -FRAME, height + LIGHT_HEIGHT + FRAME / 2, 12, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
-        renderTexture( buffer, 0, height + LIGHT_HEIGHT + FRAME / 2, 0, 12 + FRAME / 2, width, FRAME / 2, r, g, b );
-        renderTexture( buffer, width, height + LIGHT_HEIGHT + FRAME / 2, 24, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, -FRAME, height + LIGHT_HEIGHT + FRAME / 2, 12, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, 0, height + LIGHT_HEIGHT + FRAME / 2, 0, 12 + FRAME / 2, width, FRAME / 2, r, g, b );
+        renderTexture( transform, buffer, width, height + LIGHT_HEIGHT + FRAME / 2, 24, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
 
         tessellator.draw();
     }
 
-    private static void renderLight( int colour, int width, int height )
+    private static void renderLight( Matrix4f transform, int colour, int width, int height )
     {
-        GlStateManager.enableBlend();
-        GlStateManager.disableTexture();
+        RenderSystem.enableBlend();
+        RenderSystem.disableTexture();
 
         float r = ((colour >>> 16) & 0xFF) / 255.0f;
         float g = ((colour >>> 8) & 0xFF) / 255.0f;
@@ -169,26 +168,26 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
         Tessellator tessellator = Tessellator.getInstance();
         BufferBuilder buffer = tessellator.getBuffer();
         buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_COLOR );
-        buffer.pos( width - LIGHT_HEIGHT * 2, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
-        buffer.pos( width - LIGHT_HEIGHT * 2, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( transform, width - LIGHT_HEIGHT * 2, height + LIGHT_HEIGHT + FRAME / 2.0f, 0 ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( transform, width, height + LIGHT_HEIGHT + FRAME / 2.0f, 0 ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( transform, width, height + FRAME / 2.0f, 0 ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( transform, width - LIGHT_HEIGHT * 2, height + FRAME / 2.0f, 0 ).color( r, g, b, 1.0f ).endVertex();
 
         tessellator.draw();
-        GlStateManager.enableTexture();
+        RenderSystem.enableTexture();
     }
 
-    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, float r, float g, float b )
+    private static void renderTexture( Matrix4f transform, IVertexBuilder builder, int x, int y, int textureX, int textureY, int width, int height, float r, float g, float b )
     {
-        renderTexture( builder, x, y, textureX, textureY, width, height, width, height, r, g, b );
+        renderTexture( transform, builder, x, y, textureX, textureY, width, height, width, height, r, g, b );
     }
 
-    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, int textureWidth, int textureHeight, float r, float g, float b )
+    private static void renderTexture( Matrix4f transform, IVertexBuilder builder, int x, int y, int textureX, int textureY, int width, int height, int textureWidth, int textureHeight, float r, float g, float b )
     {
         float scale = 1 / 255.0f;
-        builder.pos( x, y + height, 0 ).tex( textureX * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x + width, y + height, 0 ).tex( (textureX + textureWidth) * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x + width, y, 0 ).tex( (textureX + textureWidth) * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
-        builder.pos( x, y, 0 ).tex( textureX * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
+        builder.pos( transform, x, y + height, 0 ).color( r, g, b, 1.0f ).tex( textureX * scale, (textureY + textureHeight) * scale ).endVertex();
+        builder.pos( transform, x + width, y + height, 0 ).color( r, g, b, 1.0f ).tex( (textureX + textureWidth) * scale, (textureY + textureHeight) * scale ).endVertex();
+        builder.pos( transform, x + width, y, 0 ).color( r, g, b, 1.0f ).tex( (textureX + textureWidth) * scale, textureY * scale ).endVertex();
+        builder.pos( transform, x, y, 0 ).color( r, g, b, 1.0f ).tex( textureX * scale, textureY * scale ).endVertex();
     }
 }

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

@@ -5,13 +5,16 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.media.items.ItemPrintout;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.Vector3f;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.client.event.RenderHandEvent;
 import net.minecraftforge.client.event.RenderItemInFrameEvent;
-import net.minecraftforge.client.event.RenderSpecificHandEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
 
@@ -34,30 +37,26 @@ public final class ItemPrintoutRenderer extends ItemMapLikeRenderer
     }
 
     @SubscribeEvent
-    public static void onRenderInHand( RenderSpecificHandEvent event )
+    public static void onRenderInHand( RenderHandEvent event )
     {
         ItemStack stack = event.getItemStack();
         if( !(stack.getItem() instanceof ItemPrintout) ) return;
 
         event.setCanceled( true );
-        INSTANCE.renderItemFirstPerson( event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack() );
+        INSTANCE.renderItemFirstPerson(
+            event.getMatrixStack(), event.getBuffers(), event.getLight(),
+            event.getHand(), event.getInterpolatedPitch(), event.getEquipProgress(), event.getSwingProgress(), event.getItemStack()
+        );
     }
 
     @Override
-    protected void renderItem( ItemStack stack )
+    protected void renderItem( MatrixStack transform, IRenderTypeBuffer render, ItemStack stack )
     {
-        // Setup various transformations. Note that these are partially adapated from the corresponding method
-        // in FirstPersonRenderer.renderFirstPersonMap
-        GlStateManager.disableLighting();
+        transform.rotate( Vector3f.XP.rotationDegrees( 180f ) );
+        transform.scale( 0.42f, 0.42f, -0.42f );
+        transform.translate( -0.5f, -0.48f, 0.0f );
 
-        GlStateManager.rotatef( 180f, 0f, 1f, 0f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.42f, 0.42f, -0.42f );
-        GlStateManager.translatef( -0.5f, -0.48f, 0.0f );
-
-        drawPrintout( stack );
-
-        GlStateManager.enableLighting();
+        drawPrintout( transform, render, stack );
     }
 
     @SubscribeEvent
@@ -65,24 +64,20 @@ public final class ItemPrintoutRenderer extends ItemMapLikeRenderer
     {
         ItemStack stack = event.getItem();
         if( !(stack.getItem() instanceof ItemPrintout) ) return;
-
         event.setCanceled( true );
 
-        GlStateManager.disableLighting();
+        MatrixStack transform = event.getMatrix();
 
         // Move a little bit forward to ensure we're not clipping with the frame
-        GlStateManager.translatef( 0.0f, 0.0f, -0.001f );
-        GlStateManager.rotatef( 180f, 0f, 0f, 1f );
-        GlStateManager.scalef( 0.95f, 0.95f, -0.95f );
-        GlStateManager.translatef( -0.5f, -0.5f, 0.0f );
+        transform.translate( 0.0f, 0.0f, -0.001f );
+        transform.rotate( Vector3f.ZP.rotationDegrees( 180f ) );
+        transform.scale( 0.95f, 0.95f, -0.95f );
+        transform.translate( -0.5f, -0.5f, 0.0f );
 
-        drawPrintout( stack );
-
-        GlStateManager.enableLighting();
-        GlStateManager.disableBlend();
+        drawPrintout( transform, event.getBuffers(), stack );
     }
 
-    private static void drawPrintout( ItemStack stack )
+    private static void drawPrintout( MatrixStack transform, IRenderTypeBuffer render, ItemStack stack )
     {
         int pages = ItemPrintout.getPageCount( stack );
         boolean book = ((ItemPrintout) stack.getItem()).getType() == ItemPrintout.Type.BOOK;
@@ -105,11 +100,14 @@ public final class ItemPrintoutRenderer extends ItemMapLikeRenderer
         double max = Math.max( visualHeight, visualWidth );
 
         // Scale the printout to fit correctly.
-        double scale = 1.0 / max;
-        GlStateManager.scaled( scale, scale, scale );
-        GlStateManager.translated( (max - width) / 2.0, (max - height) / 2.0, 0.0 );
+        float scale = (float) (1.0 / max);
+        transform.scale( scale, scale, scale );
+        transform.translate( (max - width) / 2.0, (max - height) / 2.0, 0.0 );
 
-        drawBorder( 0, 0, -0.01, 0, pages, book );
-        drawText( X_TEXT_MARGIN, Y_TEXT_MARGIN, 0, ItemPrintout.getText( stack ), ItemPrintout.getColours( stack ) );
+        Matrix4f matrix = transform.getLast().getMatrix();
+        drawBorder( matrix, render, 0, 0, -0.01f, 0, pages, book );
+        drawText( matrix, render,
+            X_TEXT_MARGIN, Y_TEXT_MARGIN, 0, ItemPrintout.getText( stack ), ItemPrintout.getColours( stack )
+        );
     }
 }

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

@@ -1,269 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.client.render;
-
-import net.minecraft.client.renderer.model.BakedQuad;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.vertex.VertexFormat;
-import net.minecraft.util.Direction;
-import net.minecraftforge.client.model.pipeline.IVertexConsumer;
-import net.minecraftforge.client.model.pipeline.LightUtil;
-import net.minecraftforge.client.model.pipeline.VertexTransformer;
-import net.minecraftforge.common.model.TRSRTransformation;
-
-import javax.annotation.Nonnull;
-import javax.vecmath.Matrix4f;
-import javax.vecmath.Point3f;
-import javax.vecmath.Vector3f;
-import java.util.List;
-
-/**
- * Transforms vertices of a model, remaining aware of winding order, and rearranging
- * vertices if needed.
- */
-public final class ModelTransformer
-{
-    private static final Matrix4f identity;
-
-    static
-    {
-        identity = new Matrix4f();
-        identity.setIdentity();
-    }
-
-    private ModelTransformer()
-    {
-    }
-
-    public static void transformQuadsTo( List<BakedQuad> output, List<BakedQuad> input, Matrix4f transform )
-    {
-        if( transform == null || transform.equals( identity ) )
-        {
-            output.addAll( input );
-        }
-        else
-        {
-            Matrix4f normalMatrix = new Matrix4f( transform );
-            normalMatrix.invert();
-            normalMatrix.transpose();
-
-            for( BakedQuad quad : input ) output.add( doTransformQuad( quad, transform, normalMatrix ) );
-        }
-    }
-
-    public static BakedQuad transformQuad( BakedQuad input, Matrix4f transform )
-    {
-        if( transform == null || transform.equals( identity ) ) return input;
-
-        Matrix4f normalMatrix = new Matrix4f( transform );
-        normalMatrix.invert();
-        normalMatrix.transpose();
-        return doTransformQuad( input, transform, normalMatrix );
-    }
-
-    private static BakedQuad doTransformQuad( BakedQuad input, Matrix4f positionMatrix, Matrix4f normalMatrix )
-    {
-
-        BakedQuadBuilder builder = new BakedQuadBuilder( input.getFormat() );
-        NormalAwareTransformer transformer = new NormalAwareTransformer( builder, positionMatrix, normalMatrix );
-        input.pipe( transformer );
-
-        if( transformer.areNormalsInverted() )
-        {
-            builder.swap( 1, 3 );
-            transformer.areNormalsInverted();
-        }
-
-        return builder.build();
-    }
-
-    /**
-     * A vertex transformer that tracks whether the normals have been inverted and so the vertices
-     * should be reordered so backface culling works as expected.
-     */
-    private static class NormalAwareTransformer extends VertexTransformer
-    {
-        private final Matrix4f positionMatrix;
-        private final Matrix4f normalMatrix;
-
-        private int vertexIndex = 0, elementIndex = 0;
-        private final Point3f[] before = new Point3f[4];
-        private final Point3f[] after = new Point3f[4];
-
-        NormalAwareTransformer( IVertexConsumer parent, Matrix4f positionMatrix, Matrix4f normalMatrix )
-        {
-            super( parent );
-            this.positionMatrix = positionMatrix;
-            this.normalMatrix = normalMatrix;
-        }
-
-        @Override
-        public void setQuadOrientation( @Nonnull Direction orientation )
-        {
-            super.setQuadOrientation( orientation == null ? orientation : TRSRTransformation.rotate( positionMatrix, orientation ) );
-        }
-
-        @Override
-        public void put( int element, @Nonnull float... data )
-        {
-            switch( getVertexFormat().getElement( element ).getUsage() )
-            {
-                case POSITION:
-                {
-                    Point3f vec = new Point3f( data );
-                    Point3f newVec = new Point3f();
-                    positionMatrix.transform( vec, newVec );
-
-                    float[] newData = new float[4];
-                    newVec.get( newData );
-                    super.put( element, newData );
-
-
-                    before[vertexIndex] = vec;
-                    after[vertexIndex] = newVec;
-                    break;
-                }
-                case NORMAL:
-                {
-                    Vector3f vec = new Vector3f( data );
-                    normalMatrix.transform( vec );
-
-                    float[] newData = new float[4];
-                    vec.get( newData );
-                    super.put( element, newData );
-                    break;
-                }
-                default:
-                    super.put( element, data );
-                    break;
-            }
-
-            elementIndex++;
-            if( elementIndex == getVertexFormat().getElementCount() )
-            {
-                vertexIndex++;
-                elementIndex = 0;
-            }
-        }
-
-        public boolean areNormalsInverted()
-        {
-            Vector3f temp1 = new Vector3f(), temp2 = new Vector3f();
-            Vector3f crossBefore = new Vector3f(), crossAfter = new Vector3f();
-
-            // Determine what cross product we expect to have
-            temp1.sub( before[1], before[0] );
-            temp2.sub( before[1], before[2] );
-            crossBefore.cross( temp1, temp2 );
-            normalMatrix.transform( crossBefore );
-
-            // And determine what cross product we actually have
-            temp1.sub( after[1], after[0] );
-            temp2.sub( after[1], after[2] );
-            crossAfter.cross( temp1, temp2 );
-
-            // If the angle between expected and actual cross product is greater than
-            // pi/2 radians then we will need to reorder our quads.
-            return Math.abs( crossBefore.angle( crossAfter ) ) >= Math.PI / 2;
-        }
-    }
-
-    /**
-     * A vertex consumer which is capable of building {@link BakedQuad}s.
-     *
-     * Equivalent to {@link net.minecraftforge.client.model.pipeline.UnpackedBakedQuad.Builder} but more memory
-     * efficient.
-     *
-     * This also provides the ability to swap vertices through {@link #swap(int, int)} to allow reordering.
-     */
-    private static final class BakedQuadBuilder implements IVertexConsumer
-    {
-        private final VertexFormat format;
-
-        private final int[] vertexData;
-        private int vertexIndex = 0, elementIndex = 0;
-
-        private Direction orientation;
-        private int quadTint;
-        private boolean diffuse;
-        private TextureAtlasSprite texture;
-
-        private BakedQuadBuilder( VertexFormat format )
-        {
-            this.format = format;
-            vertexData = new int[format.getSize()];
-        }
-
-        @Nonnull
-        @Override
-        public VertexFormat getVertexFormat()
-        {
-            return format;
-        }
-
-        @Override
-        public void setQuadTint( int tint )
-        {
-            quadTint = tint;
-        }
-
-        @Override
-        public void setQuadOrientation( @Nonnull Direction orientation )
-        {
-            this.orientation = orientation;
-        }
-
-        @Override
-        public void setApplyDiffuseLighting( boolean diffuse )
-        {
-            this.diffuse = diffuse;
-        }
-
-        @Override
-        public void setTexture( @Nonnull TextureAtlasSprite texture )
-        {
-            this.texture = texture;
-        }
-
-        @Override
-        public void put( int element, @Nonnull float... data )
-        {
-            LightUtil.pack( data, vertexData, format, vertexIndex, element );
-
-            elementIndex++;
-            if( elementIndex == getVertexFormat().getElementCount() )
-            {
-                vertexIndex++;
-                elementIndex = 0;
-            }
-        }
-
-        public void swap( int a, int b )
-        {
-            int length = vertexData.length / 4;
-            for( int i = 0; i < length; i++ )
-            {
-                int temp = vertexData[a * length + i];
-                vertexData[a * length + i] = vertexData[b * length + i];
-                vertexData[b * length + i] = temp;
-            }
-        }
-
-        public BakedQuad build()
-        {
-            if( elementIndex != 0 || vertexIndex != 4 )
-            {
-                throw new IllegalStateException( "Got an unexpected number of elements/vertices" );
-            }
-            if( texture == null )
-            {
-                throw new IllegalStateException( "Texture has not been set" );
-            }
-
-            return new BakedQuad( vertexData, quadTint, orientation, texture, diffuse, format );
-        }
-    }
-}

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

@@ -5,49 +5,45 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.RenderType;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.BlockRayTraceResult;
-import net.minecraft.util.math.RayTraceResult;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.event.DrawBlockHighlightEvent;
+import net.minecraftforge.client.event.DrawHighlightEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
-import org.lwjgl.opengl.GL11;
 
 import java.util.EnumSet;
 
 import static net.minecraft.util.Direction.*;
 
+/**
+ * Overrides monitor highlighting to only render the outline of the <em>whole</em> monitor, rather than the current
+ * block. This means you do not get an intrusive outline on top of the screen.
+ */
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
 public final class MonitorHighlightRenderer
 {
-    private static final float EXPAND = 0.002f;
-
     private MonitorHighlightRenderer()
     {
     }
 
     @SubscribeEvent
-    public static void drawHighlight( DrawBlockHighlightEvent event )
+    public static void drawHighlight( DrawHighlightEvent.HighlightBlock event )
     {
-        if( event.getTarget().getType() != RayTraceResult.Type.BLOCK || event.getInfo().getRenderViewEntity().isSneaking() )
-        {
-            return;
-        }
+        // Preserve normal behaviour when crouching.
+        if( event.getInfo().getRenderViewEntity().isCrouching() ) return;
 
         World world = event.getInfo().getRenderViewEntity().getEntityWorld();
-        BlockPos pos = ((BlockRayTraceResult) event.getTarget()).getPos();
+        BlockPos pos = event.getTarget().getPos();
 
         TileEntity tile = world.getTileEntity( pos );
         if( !(tile instanceof TileMonitor) ) return;
@@ -64,53 +60,37 @@ public final class MonitorHighlightRenderer
         if( monitor.getYIndex() != 0 ) faces.remove( monitor.getDown().getOpposite() );
         if( monitor.getYIndex() != monitor.getHeight() - 1 ) faces.remove( monitor.getDown() );
 
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
-        GlStateManager.lineWidth( Math.max( 2.5F, (float) Minecraft.getInstance().mainWindow.getFramebufferWidth() / 1920.0F * 2.5F ) );
-        GlStateManager.disableTexture();
-        GlStateManager.depthMask( false );
-        GlStateManager.pushMatrix();
-
+        MatrixStack transformStack = event.getMatrix();
         Vec3d cameraPos = event.getInfo().getProjectedView();
-        GlStateManager.translated( pos.getX() - cameraPos.getX(), pos.getY() - cameraPos.getY(), pos.getZ() - cameraPos.getZ() );
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_LINES, DefaultVertexFormats.POSITION_COLOR );
+        transformStack.push();
+        transformStack.translate( pos.getX() - cameraPos.getX(), pos.getY() - cameraPos.getY(), pos.getZ() - cameraPos.getZ() );
 
         // I wish I could think of a better way to do this
-        if( faces.contains( NORTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 0, UP );
-        if( faces.contains( SOUTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 1, UP );
-        if( faces.contains( NORTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 0, UP );
-        if( faces.contains( SOUTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 1, UP );
-        if( faces.contains( NORTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, EAST );
-        if( faces.contains( SOUTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 1, EAST );
-        if( faces.contains( NORTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, EAST );
-        if( faces.contains( SOUTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 1, EAST );
-        if( faces.contains( WEST ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, SOUTH );
-        if( faces.contains( EAST ) || faces.contains( DOWN ) ) line( buffer, 1, 0, 0, SOUTH );
-        if( faces.contains( WEST ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, SOUTH );
-        if( faces.contains( EAST ) || faces.contains( UP ) ) line( buffer, 1, 1, 0, SOUTH );
+        IVertexBuilder buffer = event.getBuffers().getBuffer( RenderType.getLines() );
+        Matrix4f transform = transformStack.getLast().getMatrix();
+        if( faces.contains( NORTH ) || faces.contains( WEST ) ) line( buffer, transform, 0, 0, 0, UP );
+        if( faces.contains( SOUTH ) || faces.contains( WEST ) ) line( buffer, transform, 0, 0, 1, UP );
+        if( faces.contains( NORTH ) || faces.contains( EAST ) ) line( buffer, transform, 1, 0, 0, UP );
+        if( faces.contains( SOUTH ) || faces.contains( EAST ) ) line( buffer, transform, 1, 0, 1, UP );
+        if( faces.contains( NORTH ) || faces.contains( DOWN ) ) line( buffer, transform, 0, 0, 0, EAST );
+        if( faces.contains( SOUTH ) || faces.contains( DOWN ) ) line( buffer, transform, 0, 0, 1, EAST );
+        if( faces.contains( NORTH ) || faces.contains( UP ) ) line( buffer, transform, 0, 1, 0, EAST );
+        if( faces.contains( SOUTH ) || faces.contains( UP ) ) line( buffer, transform, 0, 1, 1, EAST );
+        if( faces.contains( WEST ) || faces.contains( DOWN ) ) line( buffer, transform, 0, 0, 0, SOUTH );
+        if( faces.contains( EAST ) || faces.contains( DOWN ) ) line( buffer, transform, 1, 0, 0, SOUTH );
+        if( faces.contains( WEST ) || faces.contains( UP ) ) line( buffer, transform, 0, 1, 0, SOUTH );
+        if( faces.contains( EAST ) || faces.contains( UP ) ) line( buffer, transform, 1, 1, 0, SOUTH );
 
-        tessellator.draw();
-
-        GlStateManager.popMatrix();
-        GlStateManager.depthMask( true );
-        GlStateManager.enableTexture();
-        GlStateManager.disableBlend();
+        transformStack.pop();
     }
 
-    private static void line( BufferBuilder buffer, int x, int y, int z, Direction direction )
+    private static void line( IVertexBuilder buffer, Matrix4f transform, float x, float y, float z, Direction direction )
     {
-        double minX = x == 0 ? -EXPAND : 1 + EXPAND;
-        double minY = y == 0 ? -EXPAND : 1 + EXPAND;
-        double minZ = z == 0 ? -EXPAND : 1 + EXPAND;
-
-        buffer.pos( minX, minY, minZ ).color( 0, 0, 0, 0.4f ).endVertex();
-        buffer.pos(
-            minX + direction.getXOffset() * (1 + EXPAND * 2),
-            minY + direction.getYOffset() * (1 + EXPAND * 2),
-            minZ + direction.getZOffset() * (1 + EXPAND * 2)
+        buffer.pos( transform, x, y, z ).color( 0, 0, 0, 0.4f ).endVertex();
+        buffer.pos( transform,
+            x + direction.getXOffset(),
+            y + direction.getYOffset(),
+            z + direction.getZOffset()
         ).color( 0, 0, 0, 0.4f ).endVertex();
     }
 }

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

@@ -5,15 +5,14 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
-import com.mojang.blaze3d.platform.GlStateManager.DestFactor;
-import com.mojang.blaze3d.platform.GlStateManager.SourceFactor;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.util.Palette;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.RenderState;
+import net.minecraft.client.renderer.RenderType;
 import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.util.ResourceLocation;
 import org.lwjgl.opengl.GL11;
@@ -24,7 +23,7 @@ import static dan200.computercraft.shared.media.items.ItemPrintout.LINES_PER_PAG
 public final class PrintoutRenderer
 {
     private static final ResourceLocation BG = new ResourceLocation( "computercraft", "textures/gui/printout.png" );
-    private static final double BG_SIZE = 256.0;
+    private static final float BG_SIZE = 256.0f;
 
     /**
      * Width of a page.
@@ -61,27 +60,24 @@ public final class PrintoutRenderer
 
     private PrintoutRenderer() {}
 
-    public static void drawText( int x, int y, int start, TextBuffer[] text, TextBuffer[] colours )
+    public static void drawText( Matrix4f transform, IRenderTypeBuffer renderer, int x, int y, int start, TextBuffer[] text, TextBuffer[] colours )
     {
+        IVertexBuilder buffer = renderer.getBuffer( FixedWidthFontRenderer.TYPE );
         for( int line = 0; line < LINES_PER_PAGE && line < text.length; line++ )
         {
-            FixedWidthFontRenderer.drawString(
+            FixedWidthFontRenderer.drawString( transform, buffer,
                 x, y + line * FONT_HEIGHT, text[start + line], colours[start + line], null, Palette.DEFAULT,
                 false, 0, 0
             );
         }
     }
 
-    public static void drawText( int x, int y, int start, String[] text, String[] colours )
+    public static void drawText( Matrix4f transform, IRenderTypeBuffer renderer, int x, int y, int start, String[] text, String[] colours )
     {
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableBlend();
-        GlStateManager.enableTexture();
-        GlStateManager.blendFuncSeparate( SourceFactor.SRC_ALPHA, DestFactor.ONE_MINUS_SRC_ALPHA, SourceFactor.ONE, DestFactor.ZERO );
-
+        IVertexBuilder buffer = renderer.getBuffer( FixedWidthFontRenderer.TYPE );
         for( int line = 0; line < LINES_PER_PAGE && line < text.length; line++ )
         {
-            FixedWidthFontRenderer.drawString(
+            FixedWidthFontRenderer.drawString( transform, buffer,
                 x, y + line * FONT_HEIGHT,
                 new TextBuffer( text[start + line] ), new TextBuffer( colours[start + line] ),
                 null, Palette.DEFAULT, false, 0, 0
@@ -89,55 +85,46 @@ public final class PrintoutRenderer
         }
     }
 
-    public static void drawBorder( double x, double y, double z, int page, int pages, boolean isBook )
+    public static void drawBorder( Matrix4f transform, IRenderTypeBuffer renderer, float x, float y, float z, int page, int pages, boolean isBook )
     {
-        GlStateManager.color4f( 1.0f, 1.0f, 1.0f, 1.0f );
-        GlStateManager.enableBlend();
-        GlStateManager.enableTexture();
-        GlStateManager.blendFuncSeparate( SourceFactor.SRC_ALPHA, DestFactor.ONE_MINUS_SRC_ALPHA, SourceFactor.ONE, DestFactor.ZERO );
-
-        Minecraft.getInstance().getTextureManager().bindTexture( BG );
-
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX );
-
         int leftPages = page;
         int rightPages = pages - page - 1;
 
+        IVertexBuilder buffer = renderer.getBuffer( Type.TYPE );
+
         if( isBook )
         {
             // Border
-            double offset = offsetAt( pages );
-            final double left = x - 4 - offset;
-            final double right = x + X_SIZE + offset - 4;
+            float offset = offsetAt( pages );
+            float left = x - 4 - offset;
+            float right = x + X_SIZE + offset - 4;
 
             // Left and right border
-            drawTexture( buffer, left - 4, y - 8, z - 0.02, COVER_X, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
-            drawTexture( buffer, right, y - 8, z - 0.02, COVER_X + COVER_SIZE, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
+            drawTexture( transform, buffer, left - 4, y - 8, z - 0.02f, COVER_X, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
+            drawTexture( transform, buffer, right, y - 8, z - 0.02f, COVER_X + COVER_SIZE, 0, COVER_SIZE, Y_SIZE + COVER_SIZE * 2 );
 
             // Draw centre panel (just stretched texture, sorry).
-            drawTexture( buffer,
-                x - offset, y, z - 0.02, X_SIZE + offset * 2, Y_SIZE,
+            drawTexture( transform, buffer,
+                x - offset, y, z - 0.02f, X_SIZE + offset * 2, Y_SIZE,
                 COVER_X + COVER_SIZE / 2.0f, COVER_SIZE, COVER_SIZE, Y_SIZE
             );
 
-            double borderX = left;
+            float borderX = left;
             while( borderX < right )
             {
                 double thisWidth = Math.min( right - borderX, X_SIZE );
-                drawTexture( buffer, borderX, y - 8, z - 0.02, 0, COVER_Y, thisWidth, COVER_SIZE );
-                drawTexture( buffer, borderX, y + Y_SIZE - 4, z - 0.02, 0, COVER_Y + COVER_SIZE, thisWidth, COVER_SIZE );
+                drawTexture( transform, buffer, borderX, y - 8, z - 0.02f, 0, COVER_Y, (float) thisWidth, COVER_SIZE );
+                drawTexture( transform, buffer, borderX, y + Y_SIZE - 4, z - 0.02f, 0, COVER_Y + COVER_SIZE, (float) thisWidth, COVER_SIZE );
                 borderX += thisWidth;
             }
         }
 
         // Left half
-        drawTexture( buffer, x, y, z, X_FOLD_SIZE * 2, 0, X_SIZE / 2.0f, Y_SIZE );
+        drawTexture( transform, buffer, x, y, z, X_FOLD_SIZE * 2, 0, X_SIZE / 2.0f, Y_SIZE );
         for( int n = 0; n <= leftPages; n++ )
         {
-            drawTexture( buffer,
-                x - offsetAt( n ), y, z - 1e-3 * n,
+            drawTexture( transform, buffer,
+                x - offsetAt( n ), y, z - 1e-3f * n,
                 // Use the left "bold" fold for the outermost page
                 n == leftPages ? 0 : X_FOLD_SIZE, 0,
                 X_FOLD_SIZE, Y_SIZE
@@ -145,38 +132,54 @@ public final class PrintoutRenderer
         }
 
         // Right half
-        drawTexture( buffer, x + X_SIZE / 2.0f, y, z, X_FOLD_SIZE * 2 + X_SIZE / 2.0f, 0, X_SIZE / 2.0f, Y_SIZE );
+        drawTexture( transform, buffer, x + X_SIZE / 2.0f, y, z, X_FOLD_SIZE * 2 + X_SIZE / 2.0f, 0, X_SIZE / 2.0f, Y_SIZE );
         for( int n = 0; n <= rightPages; n++ )
         {
-            drawTexture( buffer,
-                x + (X_SIZE - X_FOLD_SIZE) + offsetAt( n ), y, z - 1e-3 * n,
+            drawTexture( transform, buffer,
+                x + (X_SIZE - X_FOLD_SIZE) + offsetAt( n ), y, z - 1e-3f * n,
                 // Two folds, then the main page. Use the right "bold" fold for the outermost page.
                 X_FOLD_SIZE * 2 + X_SIZE + (n == rightPages ? X_FOLD_SIZE : 0), 0,
                 X_FOLD_SIZE, Y_SIZE
             );
         }
-
-        tessellator.draw();
     }
 
-    private static void drawTexture( BufferBuilder buffer, double x, double y, double z, double u, double v, double width, double height )
+    private static void drawTexture( Matrix4f matrix, IVertexBuilder buffer, float x, float y, float z, float u, float v, float width, float height )
     {
-        buffer.pos( x, y + height, z ).tex( u / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y + height, z ).tex( (u + width) / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y, z ).tex( (u + width) / BG_SIZE, v / BG_SIZE ).endVertex();
-        buffer.pos( x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x, y + height, z ).tex( u / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x + width, y + height, z ).tex( (u + width) / BG_SIZE, (v + height) / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x + width, y, z ).tex( (u + width) / BG_SIZE, v / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
     }
 
-    private static void drawTexture( BufferBuilder buffer, double x, double y, double z, double width, double height, double u, double v, double tWidth, double tHeight )
+    private static void drawTexture( Matrix4f matrix, IVertexBuilder buffer, float x, float y, float z, float width, float height, float u, float v, float tWidth, float tHeight )
     {
-        buffer.pos( x, y + height, z ).tex( u / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y + height, z ).tex( (u + tWidth) / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
-        buffer.pos( x + width, y, z ).tex( (u + tWidth) / BG_SIZE, v / BG_SIZE ).endVertex();
-        buffer.pos( x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x, y + height, z ).tex( u / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x + width, y + height, z ).tex( (u + tWidth) / BG_SIZE, (v + tHeight) / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x + width, y, z ).tex( (u + tWidth) / BG_SIZE, v / BG_SIZE ).endVertex();
+        buffer.pos( matrix, x, y, z ).tex( u / BG_SIZE, v / BG_SIZE ).endVertex();
     }
 
-    public static double offsetAt( int page )
+    public static float offsetAt( int page )
     {
-        return 32 * (1 - Math.pow( 1.2, -page ));
+        return (float) (32 * (1 - Math.pow( 1.2, -page )));
+    }
+
+    private static final class Type extends RenderState
+    {
+        static final RenderType TYPE = RenderType.makeType(
+            "printout_background", DefaultVertexFormats.POSITION_TEX, GL11.GL_QUADS, 1024,
+            false, false, // useDelegate, needsSorting
+            RenderType.State.getBuilder()
+                .texture( new RenderState.TextureState( BG, false, false ) ) // blur, minimap
+                .alpha( DEFAULT_ALPHA )
+                .lightmap( LIGHTMAP_DISABLED )
+                .build( false )
+        );
+
+        private Type( String name, Runnable setup, Runnable destroy )
+        {
+            super( name, setup, destroy );
+        }
     }
 }

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

@@ -1,140 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.client.render;
-
-import com.mojang.blaze3d.platform.GlStateManager;
-import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
-import dan200.computercraft.shared.peripheral.modem.wired.CableModemVariant;
-import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
-import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
-import dan200.computercraft.shared.util.WorldUtil;
-import net.minecraft.block.Block;
-import net.minecraft.block.BlockState;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
-import net.minecraft.client.renderer.WorldRenderer;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.util.BlockRenderLayer;
-import net.minecraft.util.ResourceLocation;
-import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.BlockRayTraceResult;
-import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.world.World;
-import net.minecraftforge.client.ForgeHooksClient;
-import net.minecraftforge.client.model.data.EmptyModelData;
-import org.lwjgl.opengl.GL11;
-
-import javax.annotation.Nonnull;
-import java.util.Random;
-
-/**
- * Render breaking animation only over part of a {@link TileCable}.
- */
-public class TileEntityCableRenderer extends TileEntityRenderer<TileCable>
-{
-    private static final ResourceLocation[] DESTROY_STAGES = new ResourceLocation[10];
-    private static final Random random = new Random();
-
-    static
-    {
-        for( int i = 0; i < DESTROY_STAGES.length; i++ )
-        {
-            DESTROY_STAGES[i] = new ResourceLocation( "block/destroy_stage_" + i );
-        }
-    }
-
-    @Override
-    public void render( @Nonnull TileCable te, double x, double y, double z, float partialTicks, int destroyStage )
-    {
-        if( destroyStage < 0 ) return;
-
-        BlockPos pos = te.getPos();
-
-        Minecraft mc = Minecraft.getInstance();
-
-        RayTraceResult hit = mc.objectMouseOver;
-        if( hit == null || hit.getType() != RayTraceResult.Type.BLOCK || !((BlockRayTraceResult) hit).getPos().equals( pos ) )
-        {
-            return;
-        }
-
-        World world = te.getWorld();
-        BlockState state = world.getBlockState( pos );
-        Block block = state.getBlock();
-        if( block != ComputerCraft.Blocks.cable ) return;
-
-        state = WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.getHitVec().subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-            ? block.getDefaultState().with( BlockCable.MODEM, state.get( BlockCable.MODEM ) )
-            : state.with( BlockCable.MODEM, CableModemVariant.None );
-
-        IBakedModel model = mc.getBlockRendererDispatcher().getModelForState( state );
-
-        preRenderDamagedBlocks();
-
-        ForgeHooksClient.setRenderLayer( block.getRenderLayer() );
-
-        // See BlockRendererDispatcher#renderBlockDamage
-        TextureAtlasSprite breakingTexture = mc.getTextureMap().getSprite( DESTROY_STAGES[destroyStage] );
-
-        BufferBuilder buffer = Tessellator.getInstance().getBuffer();
-        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.BLOCK );
-        buffer.setTranslation( x - pos.getX(), y - pos.getY(), z - pos.getZ() );
-        buffer.noColor();
-
-        mc.getBlockRendererDispatcher().getBlockModelRenderer().renderModel(
-            world,
-            ForgeHooksClient.getDamageModel( model, breakingTexture, state, world, pos, 0 ),
-            state, pos, buffer, true, random, state.getPositionRandom( pos ), EmptyModelData.INSTANCE
-        );
-
-        ForgeHooksClient.setRenderLayer( BlockRenderLayer.SOLID );
-
-        buffer.setTranslation( 0, 0, 0 );
-        Tessellator.getInstance().draw();
-
-        postRenderDamagedBlocks();
-    }
-
-    /**
-     * Set up the state for rendering block-breaking progress.
-     *
-     * @see WorldRenderer#preRenderDamagedBlocks()
-     */
-    private void preRenderDamagedBlocks()
-    {
-        GlStateManager.disableLighting();
-
-        GlStateManager.enableBlend();
-        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.DST_COLOR, GlStateManager.DestFactor.SRC_COLOR, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
-        GlStateManager.enableBlend();
-        GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 0.5F );
-        GlStateManager.polygonOffset( -3.0F, -3.0F );
-        GlStateManager.enablePolygonOffset();
-        GlStateManager.alphaFunc( 516, 0.1F );
-        GlStateManager.enableAlphaTest();
-        GlStateManager.pushMatrix();
-    }
-
-    /**
-     * Tear down the state for rendering block-breaking progress.
-     *
-     * @see WorldRenderer#postRenderDamagedBlocks()
-     */
-    private void postRenderDamagedBlocks()
-    {
-        GlStateManager.disableAlphaTest();
-        GlStateManager.polygonOffset( 0.0F, 0.0F );
-        GlStateManager.disablePolygonOffset();
-        GlStateManager.disablePolygonOffset();
-        GlStateManager.depthMask( true );
-        GlStateManager.popMatrix();
-    }
-}

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

@@ -5,8 +5,8 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GLX;
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
 import dan200.computercraft.client.FrameInfo;
 import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
@@ -14,25 +14,32 @@ import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
 import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
 import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
 import dan200.computercraft.shared.util.DirectionUtil;
-import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.*;
 import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
+import net.minecraft.client.renderer.tileentity.TileEntityRendererDispatcher;
 import net.minecraft.client.renderer.vertex.VertexBuffer;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
-import org.lwjgl.opengl.GL11;
 
 import javax.annotation.Nonnull;
 
-import static dan200.computercraft.shared.peripheral.monitor.TileMonitor.RENDER_MARGIN;
-
 public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
 {
+    /**
+     * {@link TileMonitor#RENDER_MARGIN}, but a tiny bit of additional padding to ensure that there is no space between
+     * the monitor frame and contents.
+     */
     private static final float MARGIN = (float) (TileMonitor.RENDER_MARGIN * 1.1);
 
+    private static final Matrix4f IDENTITY = TransformationMatrix.identity().getMatrix();
+
+    public TileEntityMonitorRenderer( TileEntityRendererDispatcher rendererDispatcher )
+    {
+        super( rendererDispatcher );
+    }
+
     @Override
-    public void render( @Nonnull TileMonitor monitor, double posX, double posY, double posZ, float f, int i )
+    public void render( @Nonnull TileMonitor monitor, float partialTicks, @Nonnull MatrixStack transform, @Nonnull IRenderTypeBuffer renderer, int lightmapCoord, int overlayLight )
     {
         // Render from the origin monitor
         ClientMonitor originTerminal = monitor.getClientMonitor();
@@ -54,9 +61,6 @@ public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
         originTerminal.lastRenderPos = monitorPos;
 
         BlockPos originPos = origin.getPos();
-        posX += originPos.getX() - monitorPos.getX();
-        posY += originPos.getY() - monitorPos.getY();
-        posZ += originPos.getZ() - monitorPos.getZ();
 
         // Determine orientation
         Direction dir = origin.getDirection();
@@ -64,130 +68,94 @@ public class TileEntityMonitorRenderer extends TileEntityRenderer<TileMonitor>
         float yaw = dir.getHorizontalAngle();
         float pitch = DirectionUtil.toPitchAngle( front );
 
-        GlStateManager.pushMatrix();
-
         // Setup initial transform
-        GlStateManager.translated( posX + 0.5, posY + 0.5, posZ + 0.5 );
-        GlStateManager.rotatef( -yaw, 0.0f, 1.0f, 0.0f );
-        GlStateManager.rotatef( pitch, 1.0f, 0.0f, 0.0f );
-        GlStateManager.translated(
-            -0.5 + TileMonitor.RENDER_BORDER + RENDER_MARGIN,
-            origin.getHeight() - 0.5 - (TileMonitor.RENDER_BORDER + RENDER_MARGIN) + 0,
+        transform.push();
+        transform.translate(
+            originPos.getX() - monitorPos.getX() + 0.5,
+            originPos.getY() - monitorPos.getY() + 0.5,
+            originPos.getZ() - monitorPos.getZ() + 0.5
+        );
+
+        transform.rotate( Vector3f.YN.rotationDegrees( yaw ) );
+        transform.rotate( Vector3f.XP.rotationDegrees( pitch ) );
+        transform.translate(
+            -0.5 + TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN,
+            origin.getHeight() - 0.5 - (TileMonitor.RENDER_BORDER + TileMonitor.RENDER_MARGIN) + 0,
             0.5
         );
-        double xSize = origin.getWidth() - 2.0 * (RENDER_MARGIN + TileMonitor.RENDER_BORDER);
-        double ySize = origin.getHeight() - 2.0 * (RENDER_MARGIN + TileMonitor.RENDER_BORDER);
-
-        // Get renderers
-        Minecraft mc = Minecraft.getInstance();
-
-        // Set up render state for monitors. We disable writing to the depth buffer (we draw a "blocker" later),
-        // and setup lighting so that we render with a glow.
-        GlStateManager.depthMask( false );
-        GLX.glMultiTexCoord2f( GLX.GL_TEXTURE1, 0xFFFF, 0xFFFF );
-        GlStateManager.disableLighting();
-        mc.gameRenderer.disableLightmap();
+        double xSize = origin.getWidth() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
+        double ySize = origin.getHeight() - 2.0 * (TileMonitor.RENDER_MARGIN + TileMonitor.RENDER_BORDER);
 
+        // Draw the contents
         Terminal terminal = originTerminal.getTerminal();
         if( terminal != null )
         {
+            boolean redraw = originTerminal.pollTerminalChanged();
+            if( originTerminal.buffer == null )
+            {
+                originTerminal.createBuffer( MonitorRenderer.VBO );
+                redraw = true;
+            }
+            VertexBuffer vbo = originTerminal.buffer;
+
             // Draw a terminal
             double xScale = xSize / (terminal.getWidth() * FixedWidthFontRenderer.FONT_WIDTH);
             double yScale = ySize / (terminal.getHeight() * FixedWidthFontRenderer.FONT_HEIGHT);
+            transform.push();
+            transform.scale( (float) xScale, (float) -yScale, 1.0f );
 
-            GlStateManager.pushMatrix();
-            GlStateManager.scaled( (float) xScale, (float) -yScale, 1.0f );
+            float xMargin = (float) (MARGIN / xScale);
+            float yMargin = (float) (MARGIN / yScale);
 
-            renderTerminal( originTerminal, (float) (MARGIN / xScale), (float) (MARGIN / yScale) );
+            Matrix4f matrix = transform.getLast().getMatrix();
 
-            GlStateManager.popMatrix();
+            if( redraw )
+            {
+                Tessellator tessellator = Tessellator.getInstance();
+                BufferBuilder builder = tessellator.getBuffer();
+                builder.begin( FixedWidthFontRenderer.TYPE.getDrawMode(), FixedWidthFontRenderer.TYPE.getVertexFormat() );
+                FixedWidthFontRenderer.drawTerminalWithoutCursor(
+                    IDENTITY, builder, 0, 0,
+                    terminal, !originTerminal.isColour(), yMargin, yMargin, xMargin, xMargin
+                );
+
+                builder.finishDrawing();
+                vbo.upload( builder );
+            }
+
+            // Sneaky hack here: we get a buffer now in order to flush existing ones and set up the appropriate
+            // render state. I've no clue how well this'll work in future versions of Minecraft, but it does the trick
+            // for now.
+            IVertexBuilder buffer = renderer.getBuffer( FixedWidthFontRenderer.TYPE );
+            FixedWidthFontRenderer.TYPE.setupRenderState();
+
+            vbo.bindBuffer();
+            FixedWidthFontRenderer.TYPE.getVertexFormat().setupBufferState( 0L );
+            vbo.draw( matrix, FixedWidthFontRenderer.TYPE.getDrawMode() );
+            VertexBuffer.unbindBuffer();
+            FixedWidthFontRenderer.TYPE.getVertexFormat().clearBufferState();
+
+            // We don't draw the cursor with the VBO, as it's dynamic and so we'll end up refreshing far more than is
+            // reasonable.
+            FixedWidthFontRenderer.drawCursor( matrix, buffer, 0, 0, terminal, !originTerminal.isColour() );
+
+            transform.pop();
         }
         else
         {
             FixedWidthFontRenderer.drawEmptyTerminal(
+                transform.getLast().getMatrix(), renderer,
                 -MARGIN, MARGIN,
                 (float) (xSize + 2 * MARGIN), (float) -(ySize + MARGIN * 2)
             );
         }
 
-        // Tear down render state for monitors.
-        GlStateManager.depthMask( true );
-        mc.gameRenderer.enableLightmap();
-        GlStateManager.enableLighting();
-
-        // Draw the depth blocker
-        GlStateManager.colorMask( false, false, false, false );
         FixedWidthFontRenderer.drawBlocker(
+            transform.getLast().getMatrix(), renderer,
             (float) -TileMonitor.RENDER_MARGIN, (float) TileMonitor.RENDER_MARGIN,
             (float) (xSize + 2 * TileMonitor.RENDER_MARGIN), (float) -(ySize + TileMonitor.RENDER_MARGIN * 2)
         );
-        GlStateManager.colorMask( true, true, true, true );
 
-        GlStateManager.popMatrix();
-    }
-
-    private static void renderTerminal( ClientMonitor monitor, float xMargin, float yMargin )
-    {
-        Tessellator tessellator = Tessellator.getInstance();
-        BufferBuilder buffer = tessellator.getBuffer();
-
-        boolean redraw = monitor.pollTerminalChanged();
-
-        // Setup the buffers if needed. We get the renderer here, to avoid the (unlikely) race condition between
-        // creating the buffers and rendering.
-        MonitorRenderer renderer = MonitorRenderer.current();
-        if( monitor.createBuffer( renderer ) ) redraw = true;
-
-        FixedWidthFontRenderer.bindFont();
-
-        switch( renderer )
-        {
-            case VBO:
-            {
-                VertexBuffer vbo = monitor.buffer;
-                if( redraw )
-                {
-                    renderTerminalTo( monitor, buffer, xMargin, yMargin );
-                    buffer.finishDrawing();
-                    buffer.reset();
-                    vbo.bufferData( buffer.getByteBuffer() );
-                }
-
-                vbo.bindBuffer();
-                setupBufferFormat();
-                vbo.drawArrays( GL11.GL_TRIANGLES );
-                VertexBuffer.unbindBuffer();
-
-                break;
-            }
-        }
-
-        // We don't draw the cursor with a buffer, as it's dynamic and so we'll end up refreshing far more than is
-        // reasonable.
-        FixedWidthFontRenderer.begin( buffer );
-        FixedWidthFontRenderer.drawCursor( buffer, 0, 0, monitor.getTerminal(), !monitor.isColour() );
-        tessellator.draw();
-    }
-
-    private static void renderTerminalTo( ClientMonitor monitor, BufferBuilder buffer, float xMargin, float yMargin )
-    {
-        FixedWidthFontRenderer.begin( buffer );
-        FixedWidthFontRenderer.drawTerminalWithoutCursor(
-            buffer, 0, 0,
-            monitor.getTerminal(), !monitor.isColour(), yMargin, yMargin, xMargin, xMargin
-        );
-    }
-
-    public static void setupBufferFormat()
-    {
-        int stride = FixedWidthFontRenderer.POSITION_COLOR_TEX.getSize();
-        GlStateManager.vertexPointer( 3, GL11.GL_FLOAT, stride, 0 );
-        GlStateManager.enableClientState( GL11.GL_VERTEX_ARRAY );
-
-        GlStateManager.colorPointer( 4, GL11.GL_UNSIGNED_BYTE, stride, 12 );
-        GlStateManager.enableClientState( GL11.GL_COLOR_ARRAY );
-
-        GlStateManager.texCoordPointer( 2, GL11.GL_FLOAT, stride, 16 );
-        GlStateManager.enableClientState( GL11.GL_TEXTURE_COORD_ARRAY );
+        transform.pop();
     }
 }

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

@@ -5,7 +5,9 @@
  */
 package dan200.computercraft.client.render;
 
-import com.mojang.blaze3d.platform.GlStateManager;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import com.mojang.blaze3d.vertex.IVertexBuilder;
+import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -13,31 +15,26 @@ import dan200.computercraft.shared.turtle.blocks.TileTurtle;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.Holiday;
 import dan200.computercraft.shared.util.HolidayUtil;
-import net.minecraft.block.BlockState;
 import net.minecraft.client.Minecraft;
-import net.minecraft.client.renderer.BufferBuilder;
-import net.minecraft.client.renderer.GameRenderer;
-import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.gui.FontRenderer;
+import net.minecraft.client.renderer.Atlases;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.client.renderer.Matrix4f;
+import net.minecraft.client.renderer.Vector3f;
 import net.minecraft.client.renderer.model.BakedQuad;
 import net.minecraft.client.renderer.model.IBakedModel;
 import net.minecraft.client.renderer.model.ModelManager;
 import net.minecraft.client.renderer.model.ModelResourceLocation;
-import net.minecraft.client.renderer.texture.AtlasTexture;
 import net.minecraft.client.renderer.tileentity.TileEntityRenderer;
-import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
-import net.minecraft.client.renderer.vertex.VertexFormat;
+import net.minecraft.client.renderer.tileentity.TileEntityRendererDispatcher;
 import net.minecraft.util.Direction;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.util.math.RayTraceResult;
 import net.minecraft.util.math.Vec3d;
-import net.minecraftforge.client.ForgeHooksClient;
 import net.minecraftforge.client.model.data.EmptyModelData;
-import net.minecraftforge.client.model.pipeline.LightUtil;
-import org.apache.commons.lang3.tuple.Pair;
-import org.lwjgl.opengl.GL11;
 
-import javax.vecmath.Matrix4f;
+import javax.annotation.Nonnull;
 import java.util.List;
 import java.util.Random;
 
@@ -48,189 +45,147 @@ public class TileEntityTurtleRenderer extends TileEntityRenderer<TileTurtle>
     private static final ModelResourceLocation COLOUR_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_colour", "inventory" );
     private static final ModelResourceLocation ELF_OVERLAY_MODEL = new ModelResourceLocation( "computercraft:turtle_elf_overlay", "inventory" );
 
-    @Override
-    public void render( TileTurtle tileEntity, double posX, double posY, double posZ, float partialTicks, int breaking )
+    private final Random random = new Random( 0 );
+
+    public TileEntityTurtleRenderer( TileEntityRendererDispatcher renderDispatcher )
     {
-        if( tileEntity != null ) renderTurtleAt( tileEntity, posX, posY, posZ, partialTicks );
+        super( renderDispatcher );
     }
 
     public static ModelResourceLocation getTurtleModel( ComputerFamily family, boolean coloured )
     {
         switch( family )
         {
-            case Normal:
+            case NORMAL:
             default:
                 return coloured ? COLOUR_TURTLE_MODEL : NORMAL_TURTLE_MODEL;
-            case Advanced:
+            case ADVANCED:
                 return coloured ? COLOUR_TURTLE_MODEL : ADVANCED_TURTLE_MODEL;
         }
     }
 
     public static ModelResourceLocation getTurtleOverlayModel( ResourceLocation overlay, boolean christmas )
     {
-        if( overlay != null )
-        {
-            return new ModelResourceLocation( overlay, "inventory" );
-        }
-        else if( christmas )
-        {
-            return ELF_OVERLAY_MODEL;
-        }
-        else
-        {
-            return null;
-        }
+        if( overlay != null ) return new ModelResourceLocation( overlay, "inventory" );
+        if( christmas ) return ELF_OVERLAY_MODEL;
+        return null;
     }
 
-    private void renderTurtleAt( TileTurtle turtle, double posX, double posY, double posZ, float partialTicks )
+    @Override
+    public void render( @Nonnull TileTurtle turtle, float partialTicks, @Nonnull MatrixStack transform, @Nonnull IRenderTypeBuffer renderer, int lightmapCoord, int overlayLight )
     {
         // Render the label
         String label = turtle.createProxy().getLabel();
-        RayTraceResult hit = rendererDispatcher.cameraHitResult;
+        RayTraceResult hit = renderDispatcher.cameraHitResult;
         if( label != null && hit.getType() == RayTraceResult.Type.BLOCK && turtle.getPos().equals( ((BlockRayTraceResult) hit).getPos() ) )
         {
-            setLightmapDisabled( true );
-            GameRenderer.drawNameplate(
-                getFontRenderer(), label,
-                (float) posX + 0.5F, (float) posY + 1.2F, (float) posZ + 0.5F, 0,
-                rendererDispatcher.renderInfo.getYaw(), rendererDispatcher.renderInfo.getPitch(), false
-            );
-            setLightmapDisabled( false );
+            Minecraft mc = Minecraft.getInstance();
+            FontRenderer font = renderDispatcher.fontRenderer;
+
+            transform.push();
+            transform.translate( 0.5, 1.2, 0.5 );
+            transform.rotate( mc.getRenderManager().getCameraOrientation() );
+            transform.scale( -0.025f, -0.025f, 0.025f );
+
+            Matrix4f matrix = transform.getLast().getMatrix();
+            int opacity = (int) (mc.gameSettings.getTextBackgroundOpacity( 0.25f ) * 255) << 24;
+            float width = -font.getStringWidth( label ) / 2.0f;
+            font.renderString( label, width, (float) 0, 0x20ffffff, false, matrix, renderer, true, opacity, lightmapCoord );
+            font.renderString( label, width, (float) 0, 0xffffffff, false, matrix, renderer, false, 0, lightmapCoord );
+
+            transform.pop();
         }
 
-        GlStateManager.pushMatrix();
-        try
+        transform.push();
+
+        // Setup the transform.
+        Vec3d offset = turtle.getRenderOffset( partialTicks );
+        float yaw = turtle.getRenderYaw( partialTicks );
+        transform.translate( offset.x, offset.y, offset.z );
+
+        transform.translate( 0.5f, 0.5f, 0.5f );
+        transform.rotate( Vector3f.YP.rotationDegrees( 180.0f - yaw ) );
+        if( label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" )) )
         {
-            BlockState state = turtle.getBlockState();
-            // Setup the transform
-            Vec3d offset = turtle.getRenderOffset( partialTicks );
-            float yaw = turtle.getRenderYaw( partialTicks );
-            GlStateManager.translated( posX + offset.x, posY + offset.y, posZ + offset.z );
-            // Render the turtle
-            GlStateManager.translatef( 0.5f, 0.5f, 0.5f );
-            GlStateManager.rotatef( 180.0f - yaw, 0.0f, 1.0f, 0.0f );
-            if( label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" )) )
-            {
-                // Flip the model and swap the cull face as winding order will have changed.
-                GlStateManager.scalef( 1.0f, -1.0f, 1.0f );
-                GlStateManager.cullFace( GlStateManager.CullFace.FRONT );
-            }
-            GlStateManager.translatef( -0.5f, -0.5f, -0.5f );
-            // Render the turtle
-            int colour = turtle.getColour();
-            ComputerFamily family = turtle.getFamily();
-            ResourceLocation overlay = turtle.getOverlay();
-
-            renderModel( state, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
-
-            // Render the overlay
-            ModelResourceLocation overlayModel = getTurtleOverlayModel(
-                overlay,
-                HolidayUtil.getCurrentHoliday() == Holiday.Christmas
-            );
-            if( overlayModel != null )
-            {
-                GlStateManager.disableCull();
-                GlStateManager.enableBlend();
-                GlStateManager.blendFunc( GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA );
-                try
-                {
-                    renderModel( state, overlayModel, null );
-                }
-                finally
-                {
-                    GlStateManager.disableBlend();
-                    GlStateManager.enableCull();
-                }
-            }
-
-            // Render the upgrades
-            renderUpgrade( state, turtle, TurtleSide.Left, partialTicks );
-            renderUpgrade( state, turtle, TurtleSide.Right, partialTicks );
+            // Flip the model
+            transform.scale( 1.0f, -1.0f, 1.0f );
         }
-        finally
+        transform.translate( -0.5f, -0.5f, -0.5f );
+
+        // Render the turtle
+        int colour = turtle.getColour();
+        ComputerFamily family = turtle.getFamily();
+        ResourceLocation overlay = turtle.getOverlay();
+
+        IVertexBuilder buffer = renderer.getBuffer( Atlases.getTranslucentCullBlockType() );
+        renderModel( transform, buffer, lightmapCoord, overlayLight, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
+
+        // Render the overlay
+        ModelResourceLocation overlayModel = getTurtleOverlayModel( overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS );
+        if( overlayModel != null )
         {
-            GlStateManager.popMatrix();
-            GlStateManager.cullFace( GlStateManager.CullFace.BACK );
+            renderModel( transform, buffer, lightmapCoord, overlayLight, overlayModel, null );
         }
+
+        // Render the upgrades
+        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks );
+        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks );
+
+        transform.pop();
     }
 
-    private void renderUpgrade( BlockState state, TileTurtle turtle, TurtleSide side, float f )
+    private void renderUpgrade( @Nonnull MatrixStack transform, @Nonnull IVertexBuilder renderer, int lightmapCoord, int overlayLight, TileTurtle turtle, TurtleSide side, float f )
     {
         ITurtleUpgrade upgrade = turtle.getUpgrade( side );
-        if( upgrade != null )
-        {
-            GlStateManager.pushMatrix();
-            try
-            {
-                float toolAngle = turtle.getToolRenderAngle( side, f );
-                GlStateManager.translatef( 0.0f, 0.5f, 0.5f );
-                GlStateManager.rotatef( -toolAngle, 1.0f, 0.0f, 0.0f );
-                GlStateManager.translatef( 0.0f, -0.5f, -0.5f );
+        if( upgrade == null ) return;
+        transform.push();
 
-                Pair<IBakedModel, Matrix4f> pair = upgrade.getModel( turtle.getAccess(), side );
-                if( pair != null )
-                {
-                    if( pair.getRight() != null )
-                    {
-                        ForgeHooksClient.multiplyCurrentGlMatrix( pair.getRight() );
-                    }
-                    if( pair.getLeft() != null )
-                    {
-                        renderModel( state, pair.getLeft(), null );
-                    }
-                }
-            }
-            finally
-            {
-                GlStateManager.popMatrix();
-            }
-        }
+        float toolAngle = turtle.getToolRenderAngle( side, f );
+        transform.translate( 0.0f, 0.5f, 0.5f );
+        transform.rotate( Vector3f.XN.rotationDegrees( toolAngle ) );
+        transform.translate( 0.0f, -0.5f, -0.5f );
+
+        TransformedModel model = upgrade.getModel( turtle.getAccess(), side );
+        model.getMatrix().push( transform );
+        renderModel( transform, renderer, lightmapCoord, overlayLight, model.getModel(), null );
+        transform.pop();
+
+        transform.pop();
     }
 
-    private void renderModel( BlockState state, ModelResourceLocation modelLocation, int[] tints )
+    private void renderModel( @Nonnull MatrixStack transform, @Nonnull IVertexBuilder renderer, int lightmapCoord, int overlayLight, ModelResourceLocation modelLocation, int[] tints )
     {
-        Minecraft mc = Minecraft.getInstance();
-        ModelManager modelManager = mc.getItemRenderer().getItemModelMesher().getModelManager();
-        renderModel( state, modelManager.getModel( modelLocation ), tints );
+        ModelManager modelManager = Minecraft.getInstance().getItemRenderer().getItemModelMesher().getModelManager();
+        renderModel( transform, renderer, lightmapCoord, overlayLight, modelManager.getModel( modelLocation ), tints );
     }
 
-    private void renderModel( BlockState state, IBakedModel model, int[] tints )
+    private void renderModel( @Nonnull MatrixStack transform, @Nonnull IVertexBuilder renderer, int lightmapCoord, int overlayLight, IBakedModel model, int[] tints )
     {
-        Random random = new Random( 0 );
-        Tessellator tessellator = Tessellator.getInstance();
-        rendererDispatcher.textureManager.bindTexture( AtlasTexture.LOCATION_BLOCKS_TEXTURE );
-        renderQuads( tessellator, model.getQuads( state, null, random, EmptyModelData.INSTANCE ), tints );
+        random.setSeed( 0 );
+        renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, null, random, EmptyModelData.INSTANCE ), tints );
         for( Direction facing : DirectionUtil.FACINGS )
         {
-            renderQuads( tessellator, model.getQuads( state, facing, random, EmptyModelData.INSTANCE ), tints );
+            renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, facing, random, EmptyModelData.INSTANCE ), tints );
         }
     }
 
-    private static void renderQuads( Tessellator tessellator, List<BakedQuad> quads, int[] tints )
+    private static void renderQuads( @Nonnull MatrixStack transform, @Nonnull IVertexBuilder buffer, int lightmapCoord, int overlayLight, List<BakedQuad> quads, int[] tints )
     {
-        BufferBuilder buffer = tessellator.getBuffer();
-        VertexFormat format = DefaultVertexFormats.ITEM;
-        buffer.begin( GL11.GL_QUADS, format );
-        for( BakedQuad quad : quads )
+        MatrixStack.Entry matrix = transform.getLast();
+
+        for( BakedQuad bakedquad : quads )
         {
-            VertexFormat quadFormat = quad.getFormat();
-            if( quadFormat != format )
+            int tint = -1;
+            if( tints != null && bakedquad.hasTintIndex() )
             {
-                tessellator.draw();
-                format = quadFormat;
-                buffer.begin( GL11.GL_QUADS, format );
+                int idx = bakedquad.getTintIndex();
+                if( idx >= 0 && idx < tints.length ) tint = tints[bakedquad.getTintIndex()];
             }
 
-            int colour = 0xFFFFFFFF;
-            if( quad.hasTintIndex() && tints != null )
-            {
-                int index = quad.getTintIndex();
-                if( index >= 0 && index < tints.length ) colour = tints[index] | 0xFF000000;
-            }
-
-            LightUtil.renderQuadColor( buffer, quad, colour );
+            float f = (float) (tint >> 16 & 255) / 255.0F;
+            float f1 = (float) (tint >> 8 & 255) / 255.0F;
+            float f2 = (float) (tint & 255) / 255.0F;
+            buffer.addVertexData( matrix, bakedquad, f, f1, f2, lightmapCoord, overlayLight, true );
         }
-        tessellator.draw();
     }
 }

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

@@ -5,28 +5,27 @@
  */
 package dan200.computercraft.client.render;
 
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonObject;
+import com.mojang.datafixers.util.Pair;
 import dan200.computercraft.ComputerCraft;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.IUnbakedModel;
-import net.minecraft.client.renderer.model.ModelBakery;
-import net.minecraft.client.renderer.texture.ISprite;
+import net.minecraft.client.renderer.model.*;
 import net.minecraft.client.renderer.texture.TextureAtlasSprite;
-import net.minecraft.client.renderer.vertex.VertexFormat;
 import net.minecraft.resources.IResourceManager;
+import net.minecraft.util.JSONUtils;
 import net.minecraft.util.ResourceLocation;
-import net.minecraftforge.client.model.ICustomModelLoader;
+import net.minecraftforge.client.model.IModelConfiguration;
+import net.minecraftforge.client.model.IModelLoader;
+import net.minecraftforge.client.model.geometry.IModelGeometry;
 
 import javax.annotation.Nonnull;
-import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Set;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 
-public final class TurtleModelLoader implements ICustomModelLoader
+public final class TurtleModelLoader implements IModelLoader<TurtleModelLoader.TurtleModel>
 {
-    private static final ResourceLocation NORMAL_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_normal" );
-    private static final ResourceLocation ADVANCED_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_advanced" );
     private static final ResourceLocation COLOUR_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_colour" );
 
     public static final TurtleModelLoader INSTANCE = new TurtleModelLoader();
@@ -40,32 +39,15 @@ public final class TurtleModelLoader implements ICustomModelLoader
     {
     }
 
-    @Override
-    public boolean accepts( @Nonnull ResourceLocation name )
-    {
-        return name.getNamespace().equals( ComputerCraft.MOD_ID )
-            && (name.getPath().equals( "item/turtle_normal" ) || name.getPath().equals( "item/turtle_advanced" ));
-    }
-
     @Nonnull
     @Override
-    public IUnbakedModel loadModel( @Nonnull ResourceLocation name )
+    public TurtleModel read( @Nonnull JsonDeserializationContext deserializationContext, @Nonnull JsonObject modelContents )
     {
-        if( name.getNamespace().equals( ComputerCraft.MOD_ID ) )
-        {
-            switch( name.getPath() )
-            {
-                case "item/turtle_normal":
-                    return new TurtleModel( NORMAL_TURTLE_MODEL );
-                case "item/turtle_advanced":
-                    return new TurtleModel( ADVANCED_TURTLE_MODEL );
-            }
-        }
-
-        throw new IllegalStateException( "Loader does not accept " + name );
+        ResourceLocation model = new ResourceLocation( JSONUtils.getString( modelContents, "model" ) );
+        return new TurtleModel( model );
     }
 
-    private static final class TurtleModel implements IUnbakedModel
+    public static final class TurtleModel implements IModelGeometry<TurtleModel>
     {
         private final ResourceLocation family;
 
@@ -74,29 +56,21 @@ public final class TurtleModelLoader implements ICustomModelLoader
             this.family = family;
         }
 
-        @Nonnull
         @Override
-        public Collection<ResourceLocation> getDependencies()
+        public Collection<Material> getTextures( IModelConfiguration owner, Function<ResourceLocation, IUnbakedModel> modelGetter, Set<Pair<String, String>> missingTextureErrors )
         {
-            return Arrays.asList( family, COLOUR_TURTLE_MODEL );
+            Set<Material> materials = new HashSet<>();
+            materials.addAll( modelGetter.apply( family ).getTextures( modelGetter, missingTextureErrors ) );
+            materials.addAll( modelGetter.apply( COLOUR_TURTLE_MODEL ).getTextures( modelGetter, missingTextureErrors ) );
+            return materials;
         }
 
-        @Nonnull
         @Override
-        public Collection<ResourceLocation> getTextures( @Nonnull Function<ResourceLocation, IUnbakedModel> modelGetter, @Nonnull Set<String> missingTextureErrors )
-        {
-            return getDependencies().stream()
-                .flatMap( x -> modelGetter.apply( x ).getTextures( modelGetter, missingTextureErrors ).stream() )
-                .collect( Collectors.toSet() );
-        }
-
-        @Nonnull
-        @Override
-        public IBakedModel bake( @Nonnull ModelBakery bakery, @Nonnull Function<ResourceLocation, TextureAtlasSprite> spriteGetter, @Nonnull ISprite sprite, @Nonnull VertexFormat format )
+        public IBakedModel bake( IModelConfiguration owner, ModelBakery bakery, Function<Material, TextureAtlasSprite> spriteGetter, IModelTransform transform, ItemOverrideList overrides, ResourceLocation modelLocation )
         {
             return new TurtleSmartItemModel(
-                bakery.getBakedModel( family, sprite, spriteGetter, format ),
-                bakery.getBakedModel( COLOUR_TURTLE_MODEL, sprite, spriteGetter, format )
+                bakery.getBakedModel( family, transform, spriteGetter ),
+                bakery.getBakedModel( COLOUR_TURTLE_MODEL, transform, spriteGetter )
             );
         }
     }

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

@@ -5,7 +5,9 @@
  */
 package dan200.computercraft.client.render;
 
+import dan200.computercraft.api.client.TransformedModel;
 import net.minecraft.block.BlockState;
+import net.minecraft.client.renderer.TransformationMatrix;
 import net.minecraft.client.renderer.model.BakedQuad;
 import net.minecraft.client.renderer.model.IBakedModel;
 import net.minecraft.client.renderer.model.ItemOverrideList;
@@ -13,32 +15,29 @@ import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.util.Direction;
 import net.minecraftforge.client.model.data.EmptyModelData;
 import net.minecraftforge.client.model.data.IModelData;
+import net.minecraftforge.client.model.pipeline.BakedQuadBuilder;
+import net.minecraftforge.client.model.pipeline.TRSRTransformer;
 
 import javax.annotation.Nonnull;
-import javax.vecmath.Matrix4f;
 import java.util.*;
 
 public class TurtleMultiModel implements IBakedModel
 {
     private final IBakedModel m_baseModel;
     private final IBakedModel m_overlayModel;
-    private final Matrix4f m_generalTransform;
-    private final IBakedModel m_leftUpgradeModel;
-    private final Matrix4f m_leftUpgradeTransform;
-    private final IBakedModel m_rightUpgradeModel;
-    private final Matrix4f m_rightUpgradeTransform;
+    private final TransformationMatrix m_generalTransform;
+    private final TransformedModel m_leftUpgradeModel;
+    private final TransformedModel m_rightUpgradeModel;
     private List<BakedQuad> m_generalQuads = null;
     private Map<Direction, List<BakedQuad>> m_faceQuads = new EnumMap<>( Direction.class );
 
-    public TurtleMultiModel( IBakedModel baseModel, IBakedModel overlayModel, Matrix4f generalTransform, IBakedModel leftUpgradeModel, Matrix4f leftUpgradeTransform, IBakedModel rightUpgradeModel, Matrix4f rightUpgradeTransform )
+    public TurtleMultiModel( IBakedModel baseModel, IBakedModel overlayModel, TransformationMatrix generalTransform, TransformedModel leftUpgradeModel, TransformedModel rightUpgradeModel )
     {
         // Get the models
         m_baseModel = baseModel;
         m_overlayModel = overlayModel;
         m_leftUpgradeModel = leftUpgradeModel;
-        m_leftUpgradeTransform = leftUpgradeTransform;
         m_rightUpgradeModel = rightUpgradeModel;
-        m_rightUpgradeTransform = rightUpgradeTransform;
         m_generalTransform = generalTransform;
     }
 
@@ -69,30 +68,22 @@ public class TurtleMultiModel implements IBakedModel
     private List<BakedQuad> buildQuads( BlockState state, Direction side, Random rand )
     {
         ArrayList<BakedQuad> quads = new ArrayList<>();
-        ModelTransformer.transformQuadsTo( quads, m_baseModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
+
+
+        transformQuadsTo( quads, m_baseModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
         if( m_overlayModel != null )
         {
-            ModelTransformer.transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
+            transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
         }
         if( m_leftUpgradeModel != null )
         {
-            Matrix4f upgradeTransform = m_generalTransform;
-            if( m_leftUpgradeTransform != null )
-            {
-                upgradeTransform = new Matrix4f( m_generalTransform );
-                upgradeTransform.mul( m_leftUpgradeTransform );
-            }
-            ModelTransformer.transformQuadsTo( quads, m_leftUpgradeModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
+            TransformationMatrix upgradeTransform = m_generalTransform.compose( m_leftUpgradeModel.getMatrix() );
+            transformQuadsTo( quads, m_leftUpgradeModel.getModel().getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
         }
         if( m_rightUpgradeModel != null )
         {
-            Matrix4f upgradeTransform = m_generalTransform;
-            if( m_rightUpgradeTransform != null )
-            {
-                upgradeTransform = new Matrix4f( m_generalTransform );
-                upgradeTransform.mul( m_rightUpgradeTransform );
-            }
-            ModelTransformer.transformQuadsTo( quads, m_rightUpgradeModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
+            TransformationMatrix upgradeTransform = m_generalTransform.compose( m_rightUpgradeModel.getMatrix() );
+            transformQuadsTo( quads, m_rightUpgradeModel.getModel().getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
         }
         quads.trimToSize();
         return quads;
@@ -116,6 +107,12 @@ public class TurtleMultiModel implements IBakedModel
         return m_baseModel.isBuiltInRenderer();
     }
 
+    @Override
+    public boolean func_230044_c_()
+    {
+        return m_baseModel.func_230044_c_();
+    }
+
     @Nonnull
     @Override
     @Deprecated
@@ -138,4 +135,15 @@ public class TurtleMultiModel implements IBakedModel
     {
         return ItemOverrideList.EMPTY;
     }
+
+    private void transformQuadsTo( List<BakedQuad> output, List<BakedQuad> quads, TransformationMatrix transform )
+    {
+        for( BakedQuad quad : quads )
+        {
+            BakedQuadBuilder builder = new BakedQuadBuilder();
+            TRSRTransformer transformer = new TRSRTransformer( builder, transform );
+            quad.pipe( transformer );
+            output.add( builder.build() );
+        }
+    }
 }

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

@@ -6,14 +6,15 @@
 
 package dan200.computercraft.client.render;
 
-import dan200.computercraft.ComputerCraft;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import dan200.computercraft.client.gui.GuiComputer;
 import dan200.computercraft.shared.turtle.core.TurtlePlayer;
+import net.minecraft.client.renderer.IRenderTypeBuffer;
 import net.minecraft.client.renderer.entity.EntityRenderer;
 import net.minecraft.client.renderer.entity.EntityRendererManager;
 import net.minecraft.util.ResourceLocation;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 
 public class TurtlePlayerRenderer extends EntityRenderer<TurtlePlayer>
 {
@@ -22,16 +23,15 @@ public class TurtlePlayerRenderer extends EntityRenderer<TurtlePlayer>
         super( renderManager );
     }
 
+    @Nonnull
     @Override
-    public void doRender( @Nonnull TurtlePlayer entity, double x, double y, double z, float entityYaw, float partialTicks )
+    public ResourceLocation getEntityTexture( @Nonnull TurtlePlayer entity )
     {
-        ComputerCraft.log.error( "Rendering TurtlePlayer on the client side, at {}", entity.getPosition() );
+        return GuiComputer.BACKGROUND_NORMAL;
     }
 
-    @Nullable
     @Override
-    protected ResourceLocation getEntityTexture( @Nonnull TurtlePlayer entity )
+    public void render( @Nonnull TurtlePlayer entityIn, float entityYaw, float partialTicks, @Nonnull MatrixStack transform, @Nonnull IRenderTypeBuffer buffer, int packedLightIn )
     {
-        return null;
     }
 }

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

@@ -6,6 +6,8 @@
 package dan200.computercraft.client.render;
 
 import com.google.common.base.Objects;
+import com.mojang.blaze3d.matrix.MatrixStack;
+import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.turtle.items.ItemTurtle;
@@ -13,6 +15,7 @@ import dan200.computercraft.shared.util.Holiday;
 import dan200.computercraft.shared.util.HolidayUtil;
 import net.minecraft.block.BlockState;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.TransformationMatrix;
 import net.minecraft.client.renderer.model.*;
 import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.entity.LivingEntity;
@@ -21,28 +24,25 @@ import net.minecraft.util.Direction;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.world.World;
 import net.minecraftforge.client.model.data.IModelData;
-import org.apache.commons.lang3.tuple.Pair;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import javax.vecmath.Matrix4f;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Random;
 
 public class TurtleSmartItemModel implements IBakedModel
 {
-    private static final Matrix4f s_identity, s_flip;
+    private static final TransformationMatrix identity, flip;
 
     static
     {
-        s_identity = new Matrix4f();
-        s_identity.setIdentity();
+        MatrixStack stack = new MatrixStack();
+        stack.scale( 0, -1, 0 );
+        stack.translate( 0, 0, 1 );
 
-        s_flip = new Matrix4f();
-        s_flip.setIdentity();
-        s_flip.m11 = -1; // Flip on the y axis
-        s_flip.m13 = 1; // Models go from (0,0,0) to (1,1,1), so push back up.
+        identity = TransformationMatrix.identity();
+        flip = new TransformationMatrix( stack.getLast().getMatrix() );
     }
 
     private static class TurtleModelCombination
@@ -97,15 +97,14 @@ public class TurtleSmartItemModel implements IBakedModel
     private final IBakedModel familyModel;
     private final IBakedModel colourModel;
 
-    private HashMap<TurtleModelCombination, IBakedModel> m_cachedModels;
-    private ItemOverrideList m_overrides;
+    private final HashMap<TurtleModelCombination, IBakedModel> m_cachedModels = new HashMap<>();
+    private final ItemOverrideList m_overrides;
 
     public TurtleSmartItemModel( IBakedModel familyModel, IBakedModel colourModel )
     {
         this.familyModel = familyModel;
         this.colourModel = colourModel;
 
-        m_cachedModels = new HashMap<>();
         m_overrides = new ItemOverrideList()
         {
             @Nonnull
@@ -114,10 +113,10 @@ public class TurtleSmartItemModel implements IBakedModel
             {
                 ItemTurtle turtle = (ItemTurtle) stack.getItem();
                 int colour = turtle.getColour( stack );
-                ITurtleUpgrade leftUpgrade = turtle.getUpgrade( stack, TurtleSide.Left );
-                ITurtleUpgrade rightUpgrade = turtle.getUpgrade( stack, TurtleSide.Right );
+                ITurtleUpgrade leftUpgrade = turtle.getUpgrade( stack, TurtleSide.LEFT );
+                ITurtleUpgrade rightUpgrade = turtle.getUpgrade( stack, TurtleSide.RIGHT );
                 ResourceLocation overlay = turtle.getOverlay( stack );
-                boolean christmas = HolidayUtil.getCurrentHoliday() == Holiday.Christmas;
+                boolean christmas = HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS;
                 String label = turtle.getLabel( stack );
                 boolean flip = label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" ));
                 TurtleModelCombination combo = new TurtleModelCombination( colour != -1, leftUpgrade, rightUpgrade, overlay, christmas, flip );
@@ -144,25 +143,10 @@ public class TurtleSmartItemModel implements IBakedModel
 
         IBakedModel baseModel = combo.m_colour ? colourModel : familyModel;
         IBakedModel overlayModel = overlayModelLocation != null ? modelManager.getModel( overlayModelLocation ) : null;
-        Matrix4f transform = combo.m_flip ? s_flip : s_identity;
-        Pair<IBakedModel, Matrix4f> leftModel = combo.m_leftUpgrade != null ? combo.m_leftUpgrade.getModel( null, TurtleSide.Left ) : null;
-        Pair<IBakedModel, Matrix4f> rightModel = combo.m_rightUpgrade != null ? combo.m_rightUpgrade.getModel( null, TurtleSide.Right ) : null;
-        if( leftModel != null && rightModel != null )
-        {
-            return new TurtleMultiModel( baseModel, overlayModel, transform, leftModel.getLeft(), leftModel.getRight(), rightModel.getLeft(), rightModel.getRight() );
-        }
-        else if( leftModel != null )
-        {
-            return new TurtleMultiModel( baseModel, overlayModel, transform, leftModel.getLeft(), leftModel.getRight(), null, null );
-        }
-        else if( rightModel != null )
-        {
-            return new TurtleMultiModel( baseModel, overlayModel, transform, null, null, rightModel.getLeft(), rightModel.getRight() );
-        }
-        else
-        {
-            return new TurtleMultiModel( baseModel, overlayModel, transform, null, null, null, null );
-        }
+        TransformationMatrix transform = combo.m_flip ? flip : identity;
+        TransformedModel leftModel = combo.m_leftUpgrade != null ? combo.m_leftUpgrade.getModel( null, TurtleSide.LEFT ) : null;
+        TransformedModel rightModel = combo.m_rightUpgrade != null ? combo.m_rightUpgrade.getModel( null, TurtleSide.RIGHT ) : null;
+        return new TurtleMultiModel( baseModel, overlayModel, transform, leftModel, rightModel );
     }
 
     @Nonnull
@@ -199,6 +183,12 @@ public class TurtleSmartItemModel implements IBakedModel
         return familyModel.isBuiltInRenderer();
     }
 
+    @Override
+    public boolean func_230044_c_()
+    {
+        return familyModel.func_230044_c_();
+    }
+
     @Nonnull
     @Override
     @Deprecated

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

@@ -1,181 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.core.apis;
-
-import com.google.common.net.InetAddresses;
-import dan200.computercraft.ComputerCraft;
-
-import java.net.Inet6Address;
-import java.net.InetAddress;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.regex.Pattern;
-
-/**
- * Used to determine whether a domain or IP address matches a series of patterns.
- */
-public class AddressPredicate
-{
-    private static final class HostRange
-    {
-        private final byte[] min;
-        private final byte[] max;
-
-        private HostRange( byte[] min, byte[] max )
-        {
-            this.min = min;
-            this.max = max;
-        }
-
-        public boolean contains( InetAddress address )
-        {
-            byte[] entry = address.getAddress();
-            if( entry.length != min.length ) return false;
-
-            for( int i = 0; i < entry.length; i++ )
-            {
-                int value = 0xFF & entry[i];
-                if( value < (0xFF & min[i]) || value > (0xFF & max[i]) ) return false;
-            }
-
-            return true;
-        }
-    }
-
-    private final List<Pattern> wildcards;
-    private final List<HostRange> ranges;
-
-    public AddressPredicate( String... filters )
-    {
-        this( Arrays.asList( filters ) );
-    }
-
-    public AddressPredicate( Iterable<? extends String> filters )
-    {
-        List<Pattern> wildcards = this.wildcards = new ArrayList<>();
-        List<HostRange> ranges = this.ranges = new ArrayList<>();
-
-        for( String filter : filters )
-        {
-            int cidr = filter.indexOf( '/' );
-            if( cidr >= 0 )
-            {
-                String addressStr = filter.substring( 0, cidr );
-                String prefixSizeStr = filter.substring( cidr + 1 );
-
-                int prefixSize;
-                try
-                {
-                    prefixSize = Integer.parseInt( prefixSizeStr );
-                }
-                catch( NumberFormatException e )
-                {
-                    ComputerCraft.log.error(
-                        "Malformed http whitelist/blacklist entry '{}': Cannot extract size of CIDR mask from '{}'.",
-                        filter, prefixSizeStr
-                    );
-                    continue;
-                }
-
-                InetAddress address;
-                try
-                {
-                    address = InetAddresses.forString( addressStr );
-                }
-                catch( IllegalArgumentException e )
-                {
-                    ComputerCraft.log.error(
-                        "Malformed http whitelist/blacklist entry '{}': Cannot extract IP address from '{}'.",
-                        filter, prefixSizeStr
-                    );
-                    continue;
-                }
-
-                // Mask the bytes of the IP address.
-                byte[] minBytes = address.getAddress(), maxBytes = address.getAddress();
-                int size = prefixSize;
-                for( int i = 0; i < minBytes.length; i++ )
-                {
-                    if( size <= 0 )
-                    {
-                        minBytes[i] &= 0;
-                        maxBytes[i] |= 0xFF;
-                    }
-                    else if( size < 8 )
-                    {
-                        minBytes[i] &= 0xFF << (8 - size);
-                        maxBytes[i] |= ~(0xFF << (8 - size));
-                    }
-
-                    size -= 8;
-                }
-
-                ranges.add( new HostRange( minBytes, maxBytes ) );
-            }
-            else
-            {
-                wildcards.add( Pattern.compile( "^\\Q" + filter.replaceAll( "\\*", "\\\\E.*\\\\Q" ) + "\\E$" ) );
-            }
-        }
-    }
-
-    /**
-     * Determine whether a host name matches a series of patterns.
-     *
-     * This is intended to allow early exiting, before one has to look up the IP address. You should use
-     * {@link #matches(InetAddress)} instead of/in addition to this one.
-     *
-     * @param domain The domain to match.
-     * @return Whether the patterns were matched.
-     */
-    public boolean matches( String domain )
-    {
-        for( Pattern domainPattern : wildcards )
-        {
-            if( domainPattern.matcher( domain ).matches() ) return true;
-        }
-
-        return false;
-    }
-
-    private boolean matchesAddress( InetAddress address )
-    {
-        String addressString = address.getHostAddress();
-        for( Pattern domainPattern : wildcards )
-        {
-            if( domainPattern.matcher( addressString ).matches() ) return true;
-        }
-
-        for( HostRange range : ranges )
-        {
-            if( range.contains( address ) ) return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Determine whether the given address matches a series of patterns.
-     *
-     * @param address The address to check.
-     * @return Whether it matches any of these patterns.
-     */
-    public boolean matches( InetAddress address )
-    {
-        // Match the host name
-        String host = address.getHostName();
-        if( host != null && matches( host ) ) return true;
-
-        // Match the normal address
-        if( matchesAddress( address ) ) return true;
-
-        // If we're an IPv4 address in disguise then let's check that.
-        return address instanceof Inet6Address && InetAddresses.is6to4Address( (Inet6Address) address )
-            && matchesAddress( InetAddresses.get6to4IPv4Address( (Inet6Address) address ) );
-
-    }
-}

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

@@ -1,117 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.core.apis;
-
-import dan200.computercraft.api.lua.LuaException;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-import java.util.Map;
-
-/**
- * A stub for any mods which depended on this version of the argument helper.
- *
- * @deprecated Use {@link dan200.computercraft.api.lua.ArgumentHelper}.
- */
-@Deprecated
-public final class ArgumentHelper
-{
-    private ArgumentHelper()
-    {
-    }
-
-    @Nonnull
-    public static String getType( @Nullable Object type )
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getType( type );
-    }
-
-    @Nonnull
-    public static LuaException badArgument( int index, @Nonnull String expected, @Nullable Object actual )
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.badArgumentOf( index, expected, actual );
-    }
-
-    @Nonnull
-    public static LuaException badArgument( int index, @Nonnull String expected, @Nonnull String actual )
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.badArgument( index, expected, actual );
-    }
-
-    public static double getNumber( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getDouble( args, index );
-    }
-
-    public static int getInt( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getInt( args, index );
-    }
-
-    public static long getLong( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getLong( args, index );
-    }
-
-    public static double getReal( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getFiniteDouble( args, index );
-    }
-
-    public static boolean getBoolean( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getBoolean( args, index );
-    }
-
-    @Nonnull
-    public static String getString( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.getString( args, index );
-    }
-
-    @Nonnull
-    @SuppressWarnings( "unchecked" )
-    public static Map<Object, Object> getTable( @Nonnull Object[] args, int index ) throws LuaException
-    {
-        return (Map<Object, Object>) dan200.computercraft.api.lua.ArgumentHelper.getTable( args, index );
-    }
-
-    public static double optNumber( @Nonnull Object[] args, int index, double def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optDouble( args, index, def );
-    }
-
-    public static int optInt( @Nonnull Object[] args, int index, int def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optInt( args, index, def );
-    }
-
-    public static long optLong( @Nonnull Object[] args, int index, long def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optLong( args, index, def );
-    }
-
-    public static double optReal( @Nonnull Object[] args, int index, double def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optFiniteDouble( args, index, def );
-    }
-
-    public static boolean optBoolean( @Nonnull Object[] args, int index, boolean def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optBoolean( args, index, def );
-    }
-
-    public static String optString( @Nonnull Object[] args, int index, String def ) throws LuaException
-    {
-        return dan200.computercraft.api.lua.ArgumentHelper.optString( args, index, def );
-    }
-
-    @SuppressWarnings( "unchecked" )
-    public static Map<Object, Object> optTable( @Nonnull Object[] args, int index, Map<Object, Object> def ) throws LuaException
-    {
-        return (Map<Object, Object>) dan200.computercraft.api.lua.ArgumentHelper.optTable( args, index, def );
-    }
-}

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

@@ -13,7 +13,6 @@ import dan200.computercraft.core.filesystem.FileSystem;
 import dan200.computercraft.core.filesystem.FileSystemException;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
@@ -123,7 +122,7 @@ public abstract class ComputerAccess implements IComputerAccess
         m_environment.queueEvent( event, arguments );
     }
 
-    @Nullable
+    @Nonnull
     @Override
     public IWorkMonitor getMainThreadMonitor()
     {

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

@@ -173,7 +173,7 @@ public class HTTPAPI implements ILuaAPI
                 String address = getString( args, 0 );
                 Map<?, ?> headerTbl = optTable( args, 1, Collections.emptyMap() );
 
-                if( !ComputerCraft.http_websocket_enable )
+                if( !ComputerCraft.httpWebsocketEnabled )
                 {
                     throw new LuaException( "Websocket connections are disabled" );
                 }

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

@@ -1,24 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.core.apis;
-
-/**
- * This exists purely to ensure binary compatibility.
- *
- * @see dan200.computercraft.api.lua.ILuaAPI
- * @deprecated Use the version in the public API. Only exists for compatibility with CCEmuX.
- */
-@Deprecated
-public interface ILuaAPI extends dan200.computercraft.api.lua.ILuaAPI
-{
-    void advance( double v );
-
-    @Override
-    default void update()
-    {
-        advance( 0.05 );
-    }
-}

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

@@ -103,7 +103,7 @@ public class OSAPI implements ILuaAPI
                     double t = alarm.m_day * 24.0 + alarm.m_time;
                     if( now >= t )
                     {
-                        queueLuaEvent( "alarm", new Object[] { entry.getKey() } );
+                        queueLuaEvent( "alarm", new Object[] { entry.getIntKey() } );
                         it.remove();
                     }
                 }

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

@@ -11,6 +11,8 @@ import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.peripheral.IWorkMonitor;
+import dan200.computercraft.api.peripheral.NotAttachedException;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.tracking.TrackingField;
 
@@ -122,53 +124,35 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         @Override
         public synchronized String mount( @Nonnull String desiredLoc, @Nonnull IMount mount, @Nonnull String driveName )
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
-
+            if( !m_attached ) throw new NotAttachedException();
             return super.mount( desiredLoc, mount, driveName );
         }
 
         @Override
         public synchronized String mountWritable( @Nonnull String desiredLoc, @Nonnull IWritableMount mount, @Nonnull String driveName )
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
-
+            if( !m_attached ) throw new NotAttachedException();
             return super.mountWritable( desiredLoc, mount, driveName );
         }
 
         @Override
         public synchronized void unmount( String location )
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
-
+            if( !m_attached ) throw new NotAttachedException();
             super.unmount( location );
         }
 
         @Override
         public int getID()
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
+            if( !m_attached ) throw new NotAttachedException();
             return super.getID();
         }
 
         @Override
         public void queueEvent( @Nonnull final String event, final Object[] arguments )
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
+            if( !m_attached ) throw new NotAttachedException();
             super.queueEvent( event, arguments );
         }
 
@@ -176,10 +160,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         @Override
         public String getAttachmentName()
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
+            if( !m_attached ) throw new NotAttachedException();
             return m_side;
         }
 
@@ -187,10 +168,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         @Override
         public Map<String, IPeripheral> getAvailablePeripherals()
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
+            if( !m_attached ) throw new NotAttachedException();
 
             Map<String, IPeripheral> peripherals = new HashMap<>();
             for( PeripheralWrapper wrapper : m_peripherals )
@@ -208,10 +186,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         @Override
         public IPeripheral getAvailablePeripheral( @Nonnull String name )
         {
-            if( !m_attached )
-            {
-                throw new RuntimeException( "You are not attached to this Computer" );
-            }
+            if( !m_attached ) throw new NotAttachedException();
 
             for( PeripheralWrapper wrapper : m_peripherals )
             {
@@ -222,6 +197,14 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             }
             return null;
         }
+
+        @Nonnull
+        @Override
+        public IWorkMonitor getMainThreadMonitor()
+        {
+            if( !m_attached ) throw new NotAttachedException();
+            return super.getMainThreadMonitor();
+        }
     }
 
     private final IAPIEnvironment m_environment;

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

@@ -0,0 +1,167 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2020. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.core.apis.http;
+
+import com.google.common.net.InetAddresses;
+import dan200.computercraft.ComputerCraft;
+
+import javax.annotation.Nullable;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.util.regex.Pattern;
+
+/**
+ * A pattern which matches an address, and controls whether it is accessible or not.
+ */
+public final class AddressRule
+{
+    private static final class HostRange
+    {
+        private final byte[] min;
+        private final byte[] max;
+
+        private HostRange( byte[] min, byte[] max )
+        {
+            this.min = min;
+            this.max = max;
+        }
+
+        public boolean contains( InetAddress address )
+        {
+            byte[] entry = address.getAddress();
+            if( entry.length != min.length ) return false;
+
+            for( int i = 0; i < entry.length; i++ )
+            {
+                int value = 0xFF & entry[i];
+                if( value < (0xFF & min[i]) || value > (0xFF & max[i]) ) return false;
+            }
+
+            return true;
+        }
+    }
+
+    public enum Action
+    {
+        ALLOW,
+        DENY,
+    }
+
+    private final HostRange ip;
+    private final Pattern domainPattern;
+    private final Action action;
+
+    private AddressRule( HostRange ip, Pattern domainPattern, Action action )
+    {
+        this.ip = ip;
+        this.domainPattern = domainPattern;
+        this.action = action;
+    }
+
+    @Nullable
+    public static AddressRule parse( String filter, Action action )
+    {
+        int cidr = filter.indexOf( '/' );
+        if( cidr >= 0 )
+        {
+            String addressStr = filter.substring( 0, cidr );
+            String prefixSizeStr = filter.substring( cidr + 1 );
+
+            int prefixSize;
+            try
+            {
+                prefixSize = Integer.parseInt( prefixSizeStr );
+            }
+            catch( NumberFormatException e )
+            {
+                ComputerCraft.log.error(
+                    "Malformed http whitelist/blacklist entry '{}': Cannot extract size of CIDR mask from '{}'.",
+                    filter, prefixSizeStr
+                );
+                return null;
+            }
+
+            InetAddress address;
+            try
+            {
+                address = InetAddresses.forString( addressStr );
+            }
+            catch( IllegalArgumentException e )
+            {
+                ComputerCraft.log.error(
+                    "Malformed http whitelist/blacklist entry '{}': Cannot extract IP address from '{}'.",
+                    filter, prefixSizeStr
+                );
+                return null;
+            }
+
+            // Mask the bytes of the IP address.
+            byte[] minBytes = address.getAddress(), maxBytes = address.getAddress();
+            int size = prefixSize;
+            for( int i = 0; i < minBytes.length; i++ )
+            {
+                if( size <= 0 )
+                {
+                    minBytes[i] &= 0;
+                    maxBytes[i] |= 0xFF;
+                }
+                else if( size < 8 )
+                {
+                    minBytes[i] &= 0xFF << (8 - size);
+                    maxBytes[i] |= ~(0xFF << (8 - size));
+                }
+
+                size -= 8;
+            }
+
+            return new AddressRule( new HostRange( minBytes, maxBytes ), null, action );
+        }
+        else
+        {
+            Pattern pattern = Pattern.compile( "^\\Q" + filter.replaceAll( "\\*", "\\\\E.*\\\\Q" ) + "\\E$" );
+            return new AddressRule( null, pattern, action );
+        }
+    }
+
+    /**
+     * Determine whether the given address matches a series of patterns.
+     *
+     * @param domain  The domain to match
+     * @param address The address to check.
+     * @return Whether it matches any of these patterns.
+     */
+    public boolean matches( String domain, InetAddress address )
+    {
+        if( domainPattern != null )
+        {
+            if( domainPattern.matcher( domain ).matches() ) return true;
+            if( domainPattern.matcher( address.getHostName() ).matches() ) return true;
+        }
+
+        // Match the normal address
+        if( matchesAddress( address ) ) return true;
+
+        // If we're an IPv4 address in disguise then let's check that.
+        return address instanceof Inet6Address && InetAddresses.is6to4Address( (Inet6Address) address )
+            && matchesAddress( InetAddresses.get6to4IPv4Address( (Inet6Address) address ) );
+    }
+
+    private boolean matchesAddress( InetAddress address )
+    {
+        if( domainPattern != null && domainPattern.matcher( address.getHostAddress() ).matches() ) return true;
+        return ip != null && ip.contains( address );
+    }
+
+    public static Action apply( Iterable<? extends AddressRule> rules, String domain, InetAddress address )
+    {
+        for( AddressRule rule : rules )
+        {
+            if( rule.matches( domain, address ) ) return rule.action;
+        }
+
+        return Action.DENY;
+    }
+}

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

@@ -97,20 +97,6 @@ public final class NetworkUtils
         }
     }
 
-    /**
-     * Checks a host is allowed.
-     *
-     * @param host The domain to check against
-     * @throws HTTPRequestException If the host is not permitted.
-     */
-    public static void checkHost( String host ) throws HTTPRequestException
-    {
-        if( !ComputerCraft.http_whitelist.matches( host ) || ComputerCraft.http_blacklist.matches( host ) )
-        {
-            throw new HTTPRequestException( "Domain not permitted" );
-        }
-    }
-
     /**
      * Create a {@link InetSocketAddress} from the resolved {@code host} and port.
      *
@@ -130,7 +116,7 @@ public final class NetworkUtils
         if( socketAddress.isUnresolved() ) throw new HTTPRequestException( "Unknown host" );
 
         InetAddress address = socketAddress.getAddress();
-        if( !ComputerCraft.http_whitelist.matches( address ) || ComputerCraft.http_blacklist.matches( address ) )
+        if( AddressRule.apply( ComputerCraft.httpRules, host, address ) == AddressRule.Action.DENY )
         {
             throw new HTTPRequestException( "Domain not permitted" );
         }

src/main/java/dan200/computercraft/core/apis/http/request/HttpRequest.java

@@ -119,8 +119,6 @@ public class HttpRequest extends Resource<HttpRequest>
         {
             throw new HTTPRequestException( "Invalid protocol '" + scheme + "'" );
         }
-
-        NetworkUtils.checkHost( url.getHost() );
     }
 
     public void request( URI uri, HttpMethod method )

src/main/java/dan200/computercraft/core/apis/http/websocket/Websocket.java

@@ -110,7 +110,6 @@ public class Websocket extends Resource<Websocket>
             throw new HTTPRequestException( "Invalid scheme '" + scheme + "'" );
         }
 
-        NetworkUtils.checkHost( uri.getHost() );
         return uri;
     }
 

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

@@ -171,7 +171,7 @@ final class ComputerExecutor
         apis.add( new FSAPI( environment ) );
         apis.add( new PeripheralAPI( environment ) );
         apis.add( new OSAPI( environment ) );
-        if( ComputerCraft.http_enable ) apis.add( new HTTPAPI( environment ) );
+        if( ComputerCraft.httpEnabled ) apis.add( new HTTPAPI( environment ) );
 
         // Load in the externally registered APIs.
         for( ILuaAPIFactory factory : ApiFactories.getAll() )
@@ -611,7 +611,7 @@ final class ComputerExecutor
         terminal.reset();
 
         // Display our primary error message
-        if( colour ) terminal.setTextColour( 15 - Colour.Red.ordinal() );
+        if( colour ) terminal.setTextColour( 15 - Colour.RED.ordinal() );
         terminal.write( message );
 
         if( extra != null )
@@ -624,7 +624,7 @@ final class ComputerExecutor
 
         // And display our generic "CC may be installed incorrectly" message.
         terminal.setCursorPos( 0, terminal.getCursorY() + 1 );
-        if( colour ) terminal.setTextColour( 15 - Colour.White.ordinal() );
+        if( colour ) terminal.setTextColour( 15 - Colour.WHITE.ordinal() );
         terminal.write( "ComputerCraft may be installed incorrectly" );
     }
 

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

@@ -9,12 +9,15 @@ import dan200.computercraft.api.filesystem.IFileSystem;
 import dan200.computercraft.api.lua.IComputerSystem;
 import dan200.computercraft.api.lua.ILuaAPIFactory;
 import dan200.computercraft.api.peripheral.IComputerAccess;
+import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.core.apis.ComputerAccess;
 import dan200.computercraft.core.apis.IAPIEnvironment;
 import dan200.computercraft.core.filesystem.FileSystem;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.Collections;
+import java.util.Map;
 
 /**
  * Implementation of {@link IComputerAccess}/{@link IComputerSystem} for usage by externally registered APIs.
@@ -54,4 +57,19 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     {
         return environment.getLabel();
     }
+
+    @Nonnull
+    @Override
+    public Map<String, IPeripheral> getAvailablePeripherals()
+    {
+        // TODO: Should this return peripherals on the current computer?
+        return Collections.emptyMap();
+    }
+
+    @Nullable
+    @Override
+    public IPeripheral getAvailablePeripheral( @Nonnull String name )
+    {
+        return null;
+    }
 }

src/main/java/dan200/computercraft/core/filesystem/ComboMount.java

@@ -10,7 +10,6 @@ import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
@@ -116,8 +115,7 @@ public class ComboMount implements IMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         for( int i = m_parts.length - 1; i >= 0; --i )
         {
@@ -130,21 +128,6 @@ public class ComboMount implements IMount
         throw new FileOperationException( path, "No such file" );
     }
 
-    @Nonnull
-    @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
-    {
-        for( int i = m_parts.length - 1; i >= 0; --i )
-        {
-            IMount part = m_parts[i];
-            if( part.exists( path ) && !part.isDirectory( path ) )
-            {
-                return part.openChannelForRead( path );
-            }
-        }
-        throw new FileOperationException( path, "No such file" );
-    }
-
     @Nonnull
     @Override
     public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException

src/main/java/dan200/computercraft/core/filesystem/EmptyMount.java

@@ -10,7 +10,6 @@ import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
 import java.nio.channels.ReadableByteChannel;
 import java.util.List;
 
@@ -41,16 +40,7 @@ public class EmptyMount implements IMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
-    {
-        throw new FileOperationException( path, "No such file" );
-    }
-
-    @Nonnull
-    @Override
-    @Deprecated
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         throw new FileOperationException( path, "No such file" );
     }

src/main/java/dan200/computercraft/core/filesystem/FileMount.java

@@ -11,7 +11,8 @@ import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IWritableMount;
 
 import javax.annotation.Nonnull;
-import java.io.*;
+import java.io.File;
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.*;
 import java.nio.file.*;
@@ -200,21 +201,7 @@ public class FileMount implements IWritableMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
-    {
-        if( created() )
-        {
-            File file = getRealPath( path );
-            if( file.exists() && !file.isDirectory() ) return new FileInputStream( file );
-        }
-
-        throw new FileOperationException( path, "No such file" );
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         if( created() )
         {
@@ -313,23 +300,7 @@ public class FileMount implements IWritableMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public OutputStream openForWrite( @Nonnull String path ) throws IOException
-    {
-        return Channels.newOutputStream( openChannelForWrite( path ) );
-    }
-
-    @Nonnull
-    @Override
-    @Deprecated
-    public OutputStream openForAppend( @Nonnull String path ) throws IOException
-    {
-        return Channels.newOutputStream( openChannelForAppend( path ) );
-    }
-
-    @Nonnull
-    @Override
-    public WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
+    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
     {
         create();
         File file = getRealPath( path );
@@ -350,7 +321,7 @@ public class FileMount implements IWritableMount
 
     @Nonnull
     @Override
-    public WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
+    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
     {
         if( !created() )
         {

src/main/java/dan200/computercraft/core/filesystem/FileSystemWrapperMount.java

@@ -9,9 +9,6 @@ import dan200.computercraft.api.filesystem.IFileSystem;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
 import java.util.Collections;
@@ -55,7 +52,7 @@ public class FileSystemWrapperMount implements IFileSystem
 
     @Nonnull
     @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         try
         {
@@ -70,7 +67,7 @@ public class FileSystemWrapperMount implements IFileSystem
 
     @Nonnull
     @Override
-    public WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
+    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
     {
         try
         {
@@ -84,7 +81,7 @@ public class FileSystemWrapperMount implements IFileSystem
 
     @Nonnull
     @Override
-    public WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
+    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
     {
         try
         {
@@ -96,30 +93,6 @@ public class FileSystemWrapperMount implements IFileSystem
         }
     }
 
-    @Nonnull
-    @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
-    {
-        return Channels.newInputStream( openChannelForRead( path ) );
-    }
-
-    @Nonnull
-    @Override
-    @Deprecated
-    public OutputStream openForWrite( @Nonnull String path ) throws IOException
-    {
-        return Channels.newOutputStream( openChannelForWrite( path ) );
-    }
-
-    @Nonnull
-    @Override
-    @Deprecated
-    public OutputStream openForAppend( @Nonnull String path ) throws IOException
-    {
-        return Channels.newOutputStream( openChannelForAppend( path ) );
-    }
-
     @Override
     public long getRemainingSpace() throws IOException
     {

src/main/java/dan200/computercraft/core/filesystem/JarMount.java

@@ -184,15 +184,7 @@ public class JarMount implements IMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
-    {
-        return Channels.newInputStream( openChannelForRead( path ) );
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         FileEntry file = get( path );
         if( file != null && !file.isDirectory() )

src/main/java/dan200/computercraft/core/filesystem/MountWrapper.java

@@ -20,11 +20,11 @@ import java.util.OptionalLong;
 
 class MountWrapper
 {
-    private String label;
-    private String location;
+    private final String label;
+    private final String location;
 
-    private IMount mount;
-    private IWritableMount writableMount;
+    private final IMount mount;
+    private final IWritableMount writableMount;
 
     MountWrapper( String label, String location, IMount mount )
     {
@@ -36,7 +36,9 @@ class MountWrapper
 
     MountWrapper( String label, String location, IWritableMount mount )
     {
-        this( label, location, (IMount) mount );
+        this.label = label;
+        this.location = location;
+        this.mount = mount;
         writableMount = mount;
     }
 
@@ -154,7 +156,7 @@ class MountWrapper
         {
             if( mount.exists( path ) && !mount.isDirectory( path ) )
             {
-                return mount.openChannelForRead( path );
+                return mount.openForRead( path );
             }
             else
             {
@@ -232,7 +234,7 @@ class MountWrapper
                         writableMount.makeDirectory( dir );
                     }
                 }
-                return writableMount.openChannelForWrite( path );
+                return writableMount.openForWrite( path );
             }
         }
         catch( AccessDeniedException e )
@@ -262,7 +264,7 @@ class MountWrapper
                         writableMount.makeDirectory( dir );
                     }
                 }
-                return writableMount.openChannelForWrite( path );
+                return writableMount.openForWrite( path );
             }
             else if( mount.isDirectory( path ) )
             {
@@ -270,7 +272,7 @@ class MountWrapper
             }
             else
             {
-                return writableMount.openChannelForAppend( path );
+                return writableMount.openForAppend( path );
             }
         }
         catch( AccessDeniedException e )

src/main/java/dan200/computercraft/core/filesystem/ResourceMount.java

@@ -223,15 +223,7 @@ public final class ResourceMount implements IMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
-    {
-        return Channels.newInputStream( openChannelForRead( path ) );
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         FileEntry file = get( path );
         if( file != null && !file.isDirectory() )

src/main/java/dan200/computercraft/core/filesystem/SubMount.java

@@ -9,7 +9,6 @@ import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
-import java.io.InputStream;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.List;
@@ -51,19 +50,11 @@ public class SubMount implements IMount
 
     @Nonnull
     @Override
-    @Deprecated
-    public InputStream openForRead( @Nonnull String path ) throws IOException
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
         return parent.openForRead( getFullPath( path ) );
     }
 
-    @Nonnull
-    @Override
-    public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
-    {
-        return parent.openChannelForRead( getFullPath( path ) );
-    }
-
     @Nonnull
     @Override
     public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException

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

@@ -312,19 +312,6 @@ public class Terminal
         return null;
     }
 
-    /**
-     * Determine whether this terminal has changed.
-     *
-     * @return If this terminal is dirty.
-     * @deprecated All {@code *Changed()} methods are deprecated: one should pass in a callback
-     * instead.
-     */
-    @Deprecated
-    public final boolean getChanged()
-    {
-        return m_changed;
-    }
-
     public final void setChanged()
     {
         m_changed = true;

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

@@ -14,9 +14,10 @@ import net.minecraft.data.DataGenerator;
 import net.minecraft.data.DirectoryCache;
 import net.minecraft.data.IDataProvider;
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.world.storage.loot.LootParameterSets;
 import net.minecraft.world.storage.loot.LootTable;
 import net.minecraft.world.storage.loot.LootTableManager;
-import net.minecraft.world.storage.loot.ValidationResults;
+import net.minecraft.world.storage.loot.ValidationTracker;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
@@ -42,17 +43,17 @@ public abstract class LootTableProvider implements IDataProvider
     @Override
     public void act( @Nonnull DirectoryCache cache )
     {
-
-        ValidationResults validation = new ValidationResults();
         Map<ResourceLocation, LootTable> tables = new HashMap<>();
+        ValidationTracker validation = new ValidationTracker( LootParameterSets.GENERIC, x -> null, tables::get );
+
         registerLoot( ( id, table ) -> {
-            if( tables.containsKey( id ) ) validation.addProblem( "Duplicate loot tables for " + id );
+            if( tables.containsKey( id ) ) validation.func_227530_a_( "Duplicate loot tables for " + id );
             tables.put( id, table );
         } );
 
-        tables.forEach( ( key, value ) -> LootTableManager.func_215302_a( validation, key, value, tables::get ) );
+        tables.forEach( ( key, value ) -> LootTableManager.func_227508_a_( validation, key, value ) );
 
-        Multimap<String, String> problems = validation.getProblems();
+        Multimap<String, String> problems = validation.func_227527_a_();
         if( !problems.isEmpty() )
         {
             problems.forEach( ( child, problem ) ->

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

@@ -6,12 +6,13 @@
 package dan200.computercraft.shared;
 
 import com.electronwill.nightconfig.core.CommentedConfig;
+import com.electronwill.nightconfig.core.UnmodifiableConfig;
 import com.electronwill.nightconfig.core.file.CommentedFileConfig;
 import com.google.common.base.CaseFormat;
 import com.google.common.base.Converter;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.turtle.event.TurtleAction;
-import dan200.computercraft.core.apis.AddressPredicate;
+import dan200.computercraft.core.apis.http.AddressRule;
 import dan200.computercraft.core.apis.http.websocket.Websocket;
 import net.minecraftforge.common.ForgeConfigSpec;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
@@ -19,13 +20,14 @@ import net.minecraftforge.fml.ModLoadingContext;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.fml.config.ModConfig;
 
-import java.util.Arrays;
+import javax.annotation.Nullable;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
-import static dan200.computercraft.ComputerCraft.DEFAULT_HTTP_BLACKLIST;
-import static dan200.computercraft.ComputerCraft.DEFAULT_HTTP_WHITELIST;
 import static net.minecraftforge.common.ForgeConfigSpec.Builder;
 import static net.minecraftforge.common.ForgeConfigSpec.ConfigValue;
 
@@ -50,8 +52,7 @@ public final class Config
 
     private static final ConfigValue<Boolean> httpEnabled;
     private static final ConfigValue<Boolean> httpWebsocketEnabled;
-    private static final ConfigValue<List<? extends String>> httpWhitelist;
-    private static final ConfigValue<List<? extends String>> httpBlacklist;
+    private static final ConfigValue<List<? extends UnmodifiableConfig>> httpRules;
 
     private static final ConfigValue<Integer> httpTimeout;
     private static final ConfigValue<Integer> httpMaxRequests;
@@ -151,25 +152,25 @@ public final class Config
             builder.push( "http" );
 
             httpEnabled = builder
-                .comment( "Enable the \"http\" API on Computers (see \"http_whitelist\" and \"http_blacklist\" for more " +
-                    "fine grained control than this)" )
-                .define( "enabled", ComputerCraft.http_enable );
+                .comment( "Enable the \"http\" API on Computers (see \"rules\" for more fine grained control than this)." )
+                .define( "enabled", ComputerCraft.httpEnabled );
 
             httpWebsocketEnabled = builder
                 .comment( "Enable use of http websockets. This requires the \"http_enable\" option to also be true." )
-                .define( "websocket_enabled", ComputerCraft.http_websocket_enable );
+                .define( "websocket_enabled", ComputerCraft.httpWebsocketEnabled );
 
-            httpWhitelist = builder
-                .comment( "A list of wildcards for domains or IP ranges that can be accessed through the \"http\" API on Computers.\n" +
-                    "Set this to \"*\" to access to the entire internet. Example: \"*.pastebin.com\" will restrict access to just subdomains of pastebin.com.\n" +
-                    "You can use domain names (\"pastebin.com\"), wilcards (\"*.pastebin.com\") or CIDR notation (\"127.0.0.0/8\")." )
-                .defineList( "whitelist", Arrays.asList( DEFAULT_HTTP_WHITELIST ), x -> true );
-
-            httpBlacklist = builder
-                .comment( "A list of wildcards for domains or IP ranges that cannot be accessed through the \"http\" API on Computers.\n" +
-                    "If this is empty then all whitelisted domains will be accessible. Example: \"*.github.com\" will block access to all subdomains of github.com.\n" +
-                    "You can use domain names (\"pastebin.com\"), wilcards (\"*.pastebin.com\") or CIDR notation (\"127.0.0.0/8\")." )
-                .defineList( "blacklist", Arrays.asList( DEFAULT_HTTP_BLACKLIST ), x -> true );
+            httpRules = builder
+                .comment( "A list of rules which control which domains or IPs are allowed through the \"http\" API on computers.\n" +
+                    "Each rule is an item with a 'host' to match against, and an action. " +
+                    "The host may be a domain name (\"pastebin.com\"),\n" +
+                    "wildcard (\"*.pastebin.com\") or CIDR notation (\"127.0.0.0/8\"). 'action' maybe 'allow' or 'block'. If no rules" +
+                    "match, the domain will be blocked." )
+                .defineList( "rules",
+                    Stream.concat(
+                        Stream.of( ComputerCraft.DEFAULT_HTTP_DENY ).map( x -> makeRule( x, "deny" ) ),
+                        Stream.of( ComputerCraft.DEFAULT_HTTP_ALLOW ).map( x -> makeRule( x, "allow" ) )
+                    ).collect( Collectors.toList() ),
+                    x -> x instanceof UnmodifiableConfig && parseRule( (UnmodifiableConfig) x ) != null );
 
             httpTimeout = builder
                 .comment( "The period of time (in milliseconds) to wait before a HTTP request times out. Set to 0 for unlimited." )
@@ -286,10 +287,10 @@ public final class Config
         ComputerCraft.maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos( maxMainComputerTime.get() );
 
         // HTTP
-        ComputerCraft.http_enable = httpEnabled.get();
-        ComputerCraft.http_websocket_enable = httpWebsocketEnabled.get();
-        ComputerCraft.http_whitelist = new AddressPredicate( httpWhitelist.get() );
-        ComputerCraft.http_blacklist = new AddressPredicate( httpBlacklist.get() );
+        ComputerCraft.httpEnabled = httpEnabled.get();
+        ComputerCraft.httpWebsocketEnabled = httpWebsocketEnabled.get();
+        ComputerCraft.httpRules = Collections.unmodifiableList( httpRules.get().stream()
+            .map( Config::parseRule ).filter( Objects::nonNull ).collect( Collectors.toList() ) );
 
         ComputerCraft.httpTimeout = httpTimeout.get();
         ComputerCraft.httpMaxRequests = httpMaxRequests.get();
@@ -324,7 +325,7 @@ public final class Config
     }
 
     @SubscribeEvent
-    public static void sync( ModConfig.ConfigReloading event )
+    public static void sync( ModConfig.Reloading event )
     {
         // Ensure file configs are reloaded. Forge should probably do this, so worth checking in the future.
         CommentedConfig config = event.getConfig().getConfigData();
@@ -346,4 +347,28 @@ public final class Config
             return null;
         }
     }
+
+    private static UnmodifiableConfig makeRule( String host, String action )
+    {
+        com.electronwill.nightconfig.core.Config config = com.electronwill.nightconfig.core.Config.inMemory();
+        config.add( "host", host );
+        config.add( "action", action );
+        return config;
+    }
+
+    @Nullable
+    private static AddressRule parseRule( UnmodifiableConfig builder )
+    {
+        Object hostObj = builder.get( "host" );
+        Object actionObj = builder.get( "action" );
+        if( !(hostObj instanceof String) || !(actionObj instanceof String) ) return null;
+
+        String host = (String) hostObj, action = (String) actionObj;
+        for( AddressRule.Action candiate : AddressRule.Action.values() )
+        {
+            if( candiate.name().equalsIgnoreCase( action ) ) return AddressRule.parse( host, candiate );
+        }
+
+        return null;
+    }
 }

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

@@ -84,17 +84,17 @@ public final class Registry
         // Computers
         ComputerCraft.Blocks.computerNormal = new BlockComputer(
             Block.Properties.create( Material.ROCK ).hardnessAndResistance( 2.0f ),
-            ComputerFamily.Normal, TileComputer.FACTORY_NORMAL
+            ComputerFamily.NORMAL, TileComputer.FACTORY_NORMAL
         );
 
         ComputerCraft.Blocks.computerAdvanced = new BlockComputer(
             Block.Properties.create( Material.ROCK ).hardnessAndResistance( 2.0f ),
-            ComputerFamily.Advanced, TileComputer.FACTORY_ADVANCED
+            ComputerFamily.ADVANCED, TileComputer.FACTORY_ADVANCED
         );
 
         ComputerCraft.Blocks.computerCommand = new BlockComputer(
             Block.Properties.create( Material.ROCK ).hardnessAndResistance( -1, 6000000.0F ),
-            ComputerFamily.Command, TileCommandComputer.FACTORY
+            ComputerFamily.COMMAND, TileCommandComputer.FACTORY
         );
 
         registry.registerAll(
@@ -106,12 +106,12 @@ public final class Registry
         // Turtles
         ComputerCraft.Blocks.turtleNormal = new BlockTurtle(
             Block.Properties.create( Material.ROCK ).hardnessAndResistance( 2.5f ),
-            ComputerFamily.Normal, TileTurtle.FACTORY_NORMAL
+            ComputerFamily.NORMAL, TileTurtle.FACTORY_NORMAL
         );
 
         ComputerCraft.Blocks.turtleAdvanced = new BlockTurtle(
             Block.Properties.create( Material.ROCK ).hardnessAndResistance( 2.5f ),
-            ComputerFamily.Advanced, TileTurtle.FACTORY_ADVANCED
+            ComputerFamily.ADVANCED, TileTurtle.FACTORY_ADVANCED
         );
 
         registry.registerAll(
@@ -234,8 +234,8 @@ public final class Registry
         );
 
         // Pocket computer
-        ComputerCraft.Items.pocketComputerNormal = new ItemPocketComputer( defaultItem().maxStackSize( 1 ), ComputerFamily.Normal );
-        ComputerCraft.Items.pocketComputerAdvanced = new ItemPocketComputer( defaultItem().maxStackSize( 1 ), ComputerFamily.Advanced );
+        ComputerCraft.Items.pocketComputerNormal = new ItemPocketComputer( defaultItem().maxStackSize( 1 ), ComputerFamily.NORMAL );
+        ComputerCraft.Items.pocketComputerAdvanced = new ItemPocketComputer( defaultItem().maxStackSize( 1 ), ComputerFamily.ADVANCED );
 
         registry.registerAll(
             ComputerCraft.Items.pocketComputerNormal.setRegistryName( new ResourceLocation( ComputerCraft.MOD_ID, "pocket_computer_normal" ) ),

src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java

@@ -205,7 +205,7 @@ public final class CommandComputerCraft
                     int queued = 0;
                     for( ServerComputer computer : computers )
                     {
-                        if( computer.getFamily() == ComputerFamily.Command && computer.isOn() )
+                        if( computer.getFamily() == ComputerFamily.COMMAND && computer.isOn() )
                         {
                             computer.queueEvent( "computer_command", rest );
                             queued++;

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

@@ -11,12 +11,14 @@ import net.minecraft.block.BlockState;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.tileentity.TileEntityType;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Hand;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.world.IBlockReader;
 import net.minecraft.world.IWorldReader;
 import net.minecraft.world.World;
+import net.minecraft.world.server.ServerWorld;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -45,12 +47,13 @@ public abstract class BlockGeneric extends Block
         if( tile instanceof TileGeneric ) ((TileGeneric) tile).destroy();
     }
 
+    @Nonnull
     @Override
     @Deprecated
-    public final boolean onBlockActivated( BlockState state, World world, BlockPos pos, PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public final ActionResultType onBlockActivated( BlockState state, World world, BlockPos pos, PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
         TileEntity tile = world.getTileEntity( pos );
-        return tile instanceof TileGeneric && ((TileGeneric) tile).onActivate( player, hand, hit );
+        return tile instanceof TileGeneric ? ((TileGeneric) tile).onActivate( player, hand, hit ) : ActionResultType.PASS;
     }
 
     @Override
@@ -70,7 +73,7 @@ public abstract class BlockGeneric extends Block
 
     @Override
     @Deprecated
-    public void tick( BlockState state, World world, BlockPos pos, Random rand )
+    public void tick( BlockState state, ServerWorld world, BlockPos pos, Random rand )
     {
         TileEntity te = world.getTileEntity( pos );
         if( te instanceof TileGeneric ) ((TileGeneric) te).blockTick();

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

@@ -12,6 +12,7 @@ import net.minecraft.network.NetworkManager;
 import net.minecraft.network.play.server.SUpdateTileEntityPacket;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.tileentity.TileEntityType;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Hand;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
@@ -37,9 +38,10 @@ public abstract class TileGeneric extends TileEntity
         getWorld().notifyBlockUpdate( pos, state, state, 3 );
     }
 
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    @Nonnull
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        return false;
+        return ActionResultType.PASS;
     }
 
     public void onNeighbourChange( @Nonnull BlockPos neighbour )

src/main/java/dan200/computercraft/shared/computer/blocks/TileCommandComputer.java

@@ -32,7 +32,7 @@ public class TileCommandComputer extends TileComputer
 {
     public static final NamedTileEntityType<TileCommandComputer> FACTORY = NamedTileEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "command_computer" ),
-        f -> new TileCommandComputer( ComputerFamily.Command, f )
+        f -> new TileCommandComputer( ComputerFamily.COMMAND, f )
     );
 
     public class CommandReceiver implements ICommandSource

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java

@@ -27,12 +27,12 @@ public class TileComputer extends TileComputerBase
 {
     public static final NamedTileEntityType<TileComputer> FACTORY_NORMAL = NamedTileEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "computer_normal" ),
-        f -> new TileComputer( ComputerFamily.Normal, f )
+        f -> new TileComputer( ComputerFamily.NORMAL, f )
     );
 
     public static final NamedTileEntityType<TileComputer> FACTORY_ADVANCED = NamedTileEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "computer_advanced" ),
-        f -> new TileComputer( ComputerFamily.Advanced, f )
+        f -> new TileComputer( ComputerFamily.ADVANCED, f )
     );
 
     private ComputerProxy m_proxy;

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java

@@ -30,6 +30,7 @@ import net.minecraft.item.Items;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.tileentity.ITickableTileEntity;
 import net.minecraft.tileentity.TileEntityType;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Direction;
 import net.minecraft.util.Hand;
 import net.minecraft.util.INameable;
@@ -102,8 +103,9 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
         return false;
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
         ItemStack currentItem = player.getHeldItem( hand );
         if( !currentItem.isEmpty() && currentItem.getItem() == Items.NAME_TAG && canNameWithTag( player ) && currentItem.hasDisplayName() )
@@ -114,9 +116,9 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
                 setLabel( currentItem.getDisplayName().getString() );
                 currentItem.shrink( 1 );
             }
-            return true;
+            return ActionResultType.SUCCESS;
         }
-        else if( !player.isSneaking() )
+        else if( !player.isCrouching() )
         {
             // Regular right click to activate computer
             if( !getWorld().isRemote && isUsable( player, false ) )
@@ -124,9 +126,9 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
                 createServerComputer().turnOn();
                 new ComputerContainerData( createServerComputer() ).open( player, this );
             }
-            return true;
+            return ActionResultType.SUCCESS;
         }
-        return false;
+        return ActionResultType.PASS;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/computer/core/ComputerFamily.java

@@ -7,7 +7,7 @@ package dan200.computercraft.shared.computer.core;
 
 public enum ComputerFamily
 {
-    Normal,
-    Advanced,
-    Command
+    NORMAL,
+    ADVANCED,
+    COMMAND
 }

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

@@ -50,7 +50,7 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
 
     public ServerComputer( World world, int computerID, String label, int instanceID, ComputerFamily family, int terminalWidth, int terminalHeight )
     {
-        super( family != ComputerFamily.Normal, terminalWidth, terminalHeight );
+        super( family != ComputerFamily.NORMAL, terminalWidth, terminalHeight );
         m_instanceID = instanceID;
 
         m_world = world;

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

@@ -48,7 +48,7 @@ public class ContainerViewComputer extends ContainerComputerBase implements ICon
         }
 
         // If we're a command computer then ensure we're in creative
-        if( computer.getFamily() == ComputerFamily.Command )
+        if( computer.getFamily() == ComputerFamily.COMMAND )
         {
             MinecraftServer server = player.getServer();
             if( server == null || !server.isCommandBlockEnabled() )

src/main/java/dan200/computercraft/shared/computer/items/ComputerItemFactory.java

@@ -29,11 +29,11 @@ public final class ComputerItemFactory
     {
         switch( family )
         {
-            case Normal:
+            case NORMAL:
                 return ComputerCraft.Items.computerNormal.create( id, label );
-            case Advanced:
+            case ADVANCED:
                 return ComputerCraft.Items.computerAdvanced.create( id, label );
-            case Command:
+            case COMMAND:
                 return ComputerCraft.Items.computerCommand.create( id, label );
             default:
                 return ItemStack.EMPTY;

src/main/java/dan200/computercraft/shared/computer/items/ItemComputerBase.java

@@ -80,7 +80,7 @@ public abstract class ItemComputerBase extends BlockItem implements IComputerIte
     public IMount createDataMount( @Nonnull ItemStack stack, @Nonnull World world )
     {
         ComputerFamily family = getFamily();
-        if( family != ComputerFamily.Command )
+        if( family != ComputerFamily.COMMAND )
         {
             int id = getComputerID( stack );
             if( id >= 0 )

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

@@ -116,8 +116,8 @@ public class JEIComputerCraft implements IModPlugin
         StringBuilder name = new StringBuilder();
 
         // Add left and right upgrades to the identifier
-        ITurtleUpgrade left = turtle.getUpgrade( stack, TurtleSide.Left );
-        ITurtleUpgrade right = turtle.getUpgrade( stack, TurtleSide.Right );
+        ITurtleUpgrade left = turtle.getUpgrade( stack, TurtleSide.LEFT );
+        ITurtleUpgrade right = turtle.getUpgrade( stack, TurtleSide.RIGHT );
         if( left != null ) name.append( left.getUpgradeID() );
         if( left != null && right != null ) name.append( '|' );
         if( right != null ) name.append( right.getUpgradeID() );

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

@@ -37,7 +37,7 @@ import static net.minecraft.util.NonNullList.from;
 
 class RecipeResolver implements IRecipeManagerPlugin
 {
-    static final ComputerFamily[] MAIN_FAMILIES = new ComputerFamily[] { ComputerFamily.Normal, ComputerFamily.Advanced };
+    static final ComputerFamily[] MAIN_FAMILIES = new ComputerFamily[] { ComputerFamily.NORMAL, ComputerFamily.ADVANCED };
 
     private final Map<Item, List<UpgradeInfo>> upgradeItemLookup = new HashMap<>();
     private final List<UpgradeInfo> pocketUpgrades = new ArrayList<>();
@@ -150,8 +150,8 @@ class RecipeResolver implements IRecipeManagerPlugin
         {
             // Suggest possible upgrades which can be applied to this turtle
             ITurtleItem item = (ITurtleItem) stack.getItem();
-            ITurtleUpgrade left = item.getUpgrade( stack, TurtleSide.Left );
-            ITurtleUpgrade right = item.getUpgrade( stack, TurtleSide.Right );
+            ITurtleUpgrade left = item.getUpgrade( stack, TurtleSide.LEFT );
+            ITurtleUpgrade right = item.getUpgrade( stack, TurtleSide.RIGHT );
             if( left != null && right != null ) return Collections.emptyList();
 
             List<Shaped> recipes = new ArrayList<>();
@@ -231,8 +231,8 @@ class RecipeResolver implements IRecipeManagerPlugin
             ITurtleItem item = (ITurtleItem) stack.getItem();
             List<Shaped> recipes = new ArrayList<>( 0 );
 
-            ITurtleUpgrade left = item.getUpgrade( stack, TurtleSide.Left );
-            ITurtleUpgrade right = item.getUpgrade( stack, TurtleSide.Right );
+            ITurtleUpgrade left = item.getUpgrade( stack, TurtleSide.LEFT );
+            ITurtleUpgrade right = item.getUpgrade( stack, TurtleSide.RIGHT );
 
             // The turtle is facing towards us, so upgrades on the left are actually crafted on the right.
             if( left != null )

src/main/java/dan200/computercraft/shared/media/items/ItemDisk.java

@@ -126,6 +126,6 @@ public class ItemDisk extends Item implements IMedia, IColouredItem
     public int getColour( @Nonnull ItemStack stack )
     {
         int colour = IColouredItem.getColourBasic( stack );
-        return colour == -1 ? Colour.White.getHex() : colour;
+        return colour == -1 ? Colour.WHITE.getHex() : colour;
     }
 }

src/main/java/dan200/computercraft/shared/media/items/ItemTreasureDisk.java

@@ -134,6 +134,6 @@ public class ItemTreasureDisk extends Item implements IMedia
     public static int getColour( @Nonnull ItemStack stack )
     {
         CompoundNBT nbt = stack.getTag();
-        return nbt != null && nbt.contains( NBT_COLOUR ) ? nbt.getInt( NBT_COLOUR ) : Colour.Blue.getHex();
+        return nbt != null && nbt.contains( NBT_COLOUR ) ? nbt.getInt( NBT_COLOUR ) : Colour.BLUE.getHex();
     }
 }

src/main/java/dan200/computercraft/shared/media/recipes/DiskRecipe.java

@@ -87,7 +87,7 @@ public class DiskRecipe extends SpecialRecipe
             }
         }
 
-        return ItemDisk.createFromIDAndColour( -1, null, tracker.hasColour() ? tracker.getColour() : Colour.Blue.getHex() );
+        return ItemDisk.createFromIDAndColour( -1, null, tracker.hasColour() ? tracker.getColour() : Colour.BLUE.getHex() );
     }
 
     @Override
@@ -100,7 +100,7 @@ public class DiskRecipe extends SpecialRecipe
     @Override
     public ItemStack getRecipeOutput()
     {
-        return ItemDisk.createFromIDAndColour( -1, null, Colour.Blue.getHex() );
+        return ItemDisk.createFromIDAndColour( -1, null, Colour.BLUE.getHex() );
     }
 
     @Nonnull

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

@@ -76,12 +76,10 @@ public final class NetworkHandler
     {
         for( ServerPlayerEntity player : ServerLifecycleHooks.getCurrentServer().getPlayerList().getPlayers() )
         {
-            if( player.getEntityWorld() != world ) continue;
-
-            double x = pos.x - player.posX;
-            double y = pos.y - player.posY;
-            double z = pos.z - player.posZ;
-            if( x * x + y * y + z * z < range * range ) sendToPlayer( player, packet );
+            if( player.getEntityWorld() == world && player.getDistanceSq( pos ) < range * range )
+            {
+                sendToPlayer( player, packet );
+            }
         }
     }
 

src/main/java/dan200/computercraft/shared/peripheral/diskdrive/TileDiskDrive.java

@@ -99,26 +99,27 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         }
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        if( player.isSneaking() )
+        if( player.isCrouching() )
         {
             // Try to put a disk into the drive
             ItemStack disk = player.getHeldItem( hand );
-            if( disk.isEmpty() ) return false;
+            if( disk.isEmpty() ) return ActionResultType.PASS;
             if( !getWorld().isRemote && getStackInSlot( 0 ).isEmpty() && MediaProviders.get( disk ) != null )
             {
                 setDiskStack( disk );
                 player.setHeldItem( hand, ItemStack.EMPTY );
             }
-            return true;
+            return ActionResultType.SUCCESS;
         }
         else
         {
             // Open the GUI
             if( !getWorld().isRemote ) NetworkHooks.openGui( (ServerPlayerEntity) player, this );
-            return true;
+            return ActionResultType.SUCCESS;
         }
     }
 

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

@@ -250,11 +250,4 @@ public class BlockCable extends BlockGeneric implements IWaterLoggable
                 .with( WEST, false ).with( UP, false ).with( DOWN, false );
         }
     }
-
-    @Override
-    @Deprecated
-    public boolean hasCustomBreakingProgress( BlockState state )
-    {
-        return true;
-    }
 }

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

@@ -24,6 +24,7 @@ import net.minecraft.block.BlockState;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.CompoundNBT;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Direction;
 import net.minecraft.util.Hand;
 import net.minecraft.util.ResourceLocation;
@@ -238,12 +239,14 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         }
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        if( !canAttachPeripheral() || player.isSneaking() ) return false;
+        if( player.isCrouching() ) return ActionResultType.PASS;
+        if( !canAttachPeripheral() ) return ActionResultType.FAIL;
 
-        if( getWorld().isRemote ) return true;
+        if( getWorld().isRemote ) return ActionResultType.SUCCESS;
 
         String oldName = m_peripheral.getConnectedName();
         togglePeripheralAccess();
@@ -262,7 +265,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
             }
         }
 
-        return true;
+        return ActionResultType.SUCCESS;
     }
 
     @Override

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

@@ -22,6 +22,7 @@ import dan200.computercraft.shared.wired.CapabilityWiredElement;
 import net.minecraft.block.BlockState;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.nbt.CompoundNBT;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Direction;
 import net.minecraft.util.Hand;
 import net.minecraft.util.ResourceLocation;
@@ -184,10 +185,11 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
         }
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        if( getWorld().isRemote ) return true;
+        if( getWorld().isRemote ) return ActionResultType.SUCCESS;
 
         // On server, we interacted if a peripheral was found
         Set<String> oldPeriphNames = getConnectedPeripheralNames();
@@ -200,7 +202,7 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
             sendPeripheralChanges( player, "chat.computercraft.wired_modem.peripheral_connected", periphNames );
         }
 
-        return true;
+        return ActionResultType.SUCCESS;
     }
 
     private static void sendPeripheralChanges( PlayerEntity player, String kind, Collection<String> peripherals )

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

@@ -374,7 +374,7 @@ public abstract class WiredModemPeripheral extends ModemPeripheral implements IW
             m_computer.queueEvent( event, arguments );
         }
 
-        @Nullable
+        @Nonnull
         @Override
         public IWorkMonitor getMainThreadMonitor()
         {

src/main/java/dan200/computercraft/shared/peripheral/monitor/BlockMonitor.java

@@ -18,12 +18,10 @@ import net.minecraft.state.EnumProperty;
 import net.minecraft.state.StateContainer;
 import net.minecraft.state.properties.BlockStateProperties;
 import net.minecraft.tileentity.TileEntity;
-import net.minecraft.util.BlockRenderLayer;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
 
-import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 public class BlockMonitor extends BlockGeneric
@@ -38,28 +36,13 @@ public class BlockMonitor extends BlockGeneric
     public BlockMonitor( Properties settings, NamedTileEntityType<? extends TileGeneric> type )
     {
         super( settings, type );
+        // TODO: Test underwater - do we need isSolid at all?
         setDefaultState( getStateContainer().getBaseState()
             .with( ORIENTATION, Direction.NORTH )
             .with( FACING, Direction.NORTH )
             .with( STATE, MonitorEdgeState.NONE ) );
     }
 
-    @Nonnull
-    @Override
-    public BlockRenderLayer getRenderLayer()
-    {
-        // We use the CUTOUT layer, as otherwise monitor rendering will cause flickering.
-        return BlockRenderLayer.CUTOUT;
-    }
-
-    @Override
-    @Deprecated
-    public boolean isSolid( BlockState state )
-    {
-        // We override isSolid, as our overriding of getRenderLayer means that it would otherwise return false.
-        return true;
-    }
-
     @Override
     protected void fillStateContainer( StateContainer.Builder<Block, BlockState> builder )
     {

src/main/java/dan200/computercraft/shared/peripheral/monitor/ClientMonitor.java

@@ -54,7 +54,7 @@ public final class ClientMonitor extends ClientTerminal
                 if( buffer != null ) return false;
 
                 deleteBuffers();
-                buffer = new VertexBuffer( FixedWidthFontRenderer.POSITION_COLOR_TEX );
+                buffer = new VertexBuffer( FixedWidthFontRenderer.TYPE.getVertexFormat() );
                 addMonitor();
                 return true;
 
@@ -75,7 +75,7 @@ public final class ClientMonitor extends ClientTerminal
     {
         if( buffer != null )
         {
-            buffer.deleteGlBuffers();
+            buffer.close();
             buffer = null;
         }
     }

src/main/java/dan200/computercraft/shared/peripheral/monitor/MonitorRenderer.java

@@ -6,7 +6,6 @@
 
 package dan200.computercraft.shared.peripheral.monitor;
 
-import com.mojang.blaze3d.platform.GLX;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.render.TileEntityMonitorRenderer;
 
@@ -73,22 +72,7 @@ public enum MonitorRenderer
     public static MonitorRenderer current()
     {
         MonitorRenderer current = ComputerCraft.monitorRenderer;
-        switch( current )
-        {
-            case BEST:
-                return best();
-            case VBO:
-                if( !GLX.useVbo() )
-                {
-                    ComputerCraft.log.warn( "VBOs are not supported on your graphics card. Falling back to default." );
-                    ComputerCraft.monitorRenderer = BEST;
-                    return best();
-                }
-
-                return VBO;
-            default:
-                return current;
-        }
+        return current == MonitorRenderer.BEST ? best() : current;
     }
 
     private static MonitorRenderer best()

src/main/java/dan200/computercraft/shared/peripheral/monitor/TileMonitor.java

@@ -18,9 +18,11 @@ import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.tileentity.TileEntityType;
+import net.minecraft.util.ActionResultType;
 import net.minecraft.util.Direction;
 import net.minecraft.util.Hand;
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.math.AxisAlignedBB;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.world.World;
@@ -104,10 +106,11 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
         if( m_clientMonitor != null && m_xIndex == 0 && m_yIndex == 0 ) m_clientMonitor.destroy();
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        if( !player.isSneaking() && getFront() == hit.getFace() )
+        if( !player.isCrouching() && getFront() == hit.getFace() )
         {
             if( !getWorld().isRemote )
             {
@@ -117,10 +120,10 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
                     (float) (hit.getHitVec().z - hit.getPos().getZ())
                 );
             }
-            return true;
+            return ActionResultType.SUCCESS;
         }
 
-        return false;
+        return ActionResultType.PASS;
     }
 
     @Nonnull
@@ -651,13 +654,12 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
         m_computers.remove( computer );
     }
 
-    /*
     @Nonnull
     @Override
     public AxisAlignedBB getRenderBoundingBox()
     {
         TileMonitor start = getNeighbour( 0, 0 );
-        TileMonitor end = getNeighbour( width - 1, height - 1 );
+        TileMonitor end = getNeighbour( m_width - 1, m_height - 1 );
         if( start != null && end != null )
         {
             BlockPos startPos = start.getPos();
@@ -676,5 +678,4 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
             return new AxisAlignedBB( pos.getX(), pos.getY(), pos.getZ(), pos.getX() + 1, pos.getY() + 1, pos.getZ() + 1 );
         }
     }
-    */
 }

src/main/java/dan200/computercraft/shared/peripheral/printer/TilePrinter.java

@@ -25,8 +25,8 @@ import net.minecraft.inventory.container.INamedContainerProvider;
 import net.minecraft.item.*;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.util.*;
-import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
+import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.TranslationTextComponent;
 import net.minecraftforge.common.capabilities.Capability;
@@ -94,13 +94,14 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         }
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
-        if( player.isSneaking() ) return false;
+        if( player.isCrouching() ) return ActionResultType.PASS;
 
         if( !getWorld().isRemote ) NetworkHooks.openGui( (ServerPlayerEntity) player, this );
-        return true;
+        return ActionResultType.SUCCESS;
     }
 
     @Override
@@ -424,11 +425,7 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
                 setInventorySlotContents( i, ItemStack.EMPTY );
 
                 // Spawn the item in the world
-                BlockPos pos = getPos();
-                double x = pos.getX() + 0.5;
-                double y = pos.getY() + 0.75;
-                double z = pos.getZ() + 0.5;
-                WorldUtil.dropItemStack( stack, getWorld(), x, y, z );
+                WorldUtil.dropItemStack( stack, getWorld(), new Vec3d( getPos() ).add( 0.5, 0.75, 0.5 ) );
             }
         }
     }

src/main/java/dan200/computercraft/shared/pocket/apis/PocketAPI.java

@@ -80,7 +80,7 @@ public class PocketAPI implements ILuaAPI
                             stack = InventoryUtil.storeItems( stack, new PlayerMainInvWrapper( inventory ), inventory.currentItem );
                             if( !stack.isEmpty() )
                             {
-                                WorldUtil.dropItemStack( stack, player.getEntityWorld(), player.posX, player.posY, player.posZ );
+                                WorldUtil.dropItemStack( stack, player.getEntityWorld(), player.getPositionVec() );
                             }
                         }
                     }
@@ -111,7 +111,7 @@ public class PocketAPI implements ILuaAPI
                         stack = InventoryUtil.storeItems( stack, new PlayerMainInvWrapper( inventory ), inventory.currentItem );
                         if( stack.isEmpty() )
                         {
-                            WorldUtil.dropItemStack( stack, player.getEntityWorld(), player.posX, player.posY, player.posZ );
+                            WorldUtil.dropItemStack( stack, player.getEntityWorld(), player.getPositionVec() );
                         }
                     }
 

src/main/java/dan200/computercraft/shared/pocket/items/PocketComputerItemFactory.java

@@ -21,9 +21,9 @@ public final class PocketComputerItemFactory
     {
         switch( family )
         {
-            case Normal:
+            case NORMAL:
                 return ComputerCraft.Items.pocketComputerNormal.create( id, label, colour, upgrade );
-            case Advanced:
+            case ADVANCED:
                 return ComputerCraft.Items.pocketComputerAdvanced.create( id, label, colour, upgrade );
             default:
                 return ItemStack.EMPTY;

src/main/java/dan200/computercraft/shared/pocket/recipes/PocketComputerUpgradeRecipe.java

@@ -37,7 +37,7 @@ public final class PocketComputerUpgradeRecipe extends SpecialRecipe
     @Override
     public ItemStack getRecipeOutput()
     {
-        return PocketComputerItemFactory.create( -1, null, -1, ComputerFamily.Normal, null );
+        return PocketComputerItemFactory.create( -1, null, -1, ComputerFamily.NORMAL, null );
     }
 
     @Override

src/main/java/dan200/computercraft/shared/proxy/ComputerCraftProxyCommon.java

@@ -11,7 +11,6 @@ import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.peripheral.IPeripheralTile;
 import dan200.computercraft.core.computer.MainThread;
 import dan200.computercraft.core.tracking.Tracking;
-import dan200.computercraft.shared.Config;
 import dan200.computercraft.shared.command.CommandComputerCraft;
 import dan200.computercraft.shared.command.arguments.ArgumentSerializers;
 import dan200.computercraft.shared.common.DefaultBundledRedstoneProvider;
@@ -36,7 +35,6 @@ import net.minecraft.world.storage.loot.conditions.LootConditionManager;
 import net.minecraftforge.event.TickEvent;
 import net.minecraftforge.event.entity.player.PlayerContainerEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.client.event.ConfigChangedEvent;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
 import net.minecraftforge.fml.event.server.FMLServerStartedEvent;
@@ -133,12 +131,6 @@ public final class ComputerCraftProxyCommon
             }
         }
 
-        @SubscribeEvent
-        public static void onConfigChanged( ConfigChangedEvent.OnConfigChangedEvent event )
-        {
-            if( event.getModID().equals( ComputerCraft.MOD_ID ) ) Config.sync();
-        }
-
         @SubscribeEvent
         public static void onContainerOpen( PlayerContainerEvent.Open event )
         {

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

@@ -133,11 +133,11 @@ public class TurtleAPI implements ILuaAPI
         }
         else if( side.equalsIgnoreCase( "left" ) )
         {
-            return TurtleSide.Left;
+            return TurtleSide.LEFT;
         }
         else if( side.equalsIgnoreCase( "right" ) )
         {
-            return TurtleSide.Right;
+            return TurtleSide.RIGHT;
         }
         else
         {
@@ -152,58 +152,58 @@ public class TurtleAPI implements ILuaAPI
         {
             case 0: // forward
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleMoveCommand( MoveDirection.Forward ) );
+                return tryCommand( context, new TurtleMoveCommand( MoveDirection.FORWARD ) );
             case 1: // back
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleMoveCommand( MoveDirection.Back ) );
+                return tryCommand( context, new TurtleMoveCommand( MoveDirection.BACK ) );
             case 2: // up
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleMoveCommand( MoveDirection.Up ) );
+                return tryCommand( context, new TurtleMoveCommand( MoveDirection.UP ) );
             case 3: // down
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleMoveCommand( MoveDirection.Down ) );
+                return tryCommand( context, new TurtleMoveCommand( MoveDirection.DOWN ) );
             case 4: // turnLeft
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleTurnCommand( TurnDirection.Left ) );
+                return tryCommand( context, new TurtleTurnCommand( TurnDirection.LEFT ) );
             case 5: // turnRight
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleTurnCommand( TurnDirection.Right ) );
+                return tryCommand( context, new TurtleTurnCommand( TurnDirection.RIGHT ) );
             case 6:
             {
                 // dig
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.Forward, side ) );
+                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.FORWARD, side ) );
             }
             case 7:
             {
                 // digUp
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.Up, side ) );
+                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.UP, side ) );
             }
             case 8:
             {
                 // digDown
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.Down, side ) );
+                return tryCommand( context, TurtleToolCommand.dig( InteractDirection.DOWN, side ) );
             }
             case 9: // place
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.Forward, args ) );
+                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.FORWARD, args ) );
             case 10: // placeUp
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.Up, args ) );
+                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.UP, args ) );
             case 11: // placeDown
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.Down, args ) );
+                return tryCommand( context, new TurtlePlaceCommand( InteractDirection.DOWN, args ) );
             case 12:
             {
                 // drop
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleDropCommand( InteractDirection.Forward, count ) );
+                return tryCommand( context, new TurtleDropCommand( InteractDirection.FORWARD, count ) );
             }
             case 13:
             {
@@ -229,72 +229,72 @@ public class TurtleAPI implements ILuaAPI
                 return new Object[] { stack.isEmpty() ? 64 : Math.min( stack.getMaxStackSize(), 64 ) - stack.getCount() };
             }
             case 16: // detect
-                return tryCommand( context, new TurtleDetectCommand( InteractDirection.Forward ) );
+                return tryCommand( context, new TurtleDetectCommand( InteractDirection.FORWARD ) );
             case 17: // detectUp
-                return tryCommand( context, new TurtleDetectCommand( InteractDirection.Up ) );
+                return tryCommand( context, new TurtleDetectCommand( InteractDirection.UP ) );
             case 18: // detectDown
-                return tryCommand( context, new TurtleDetectCommand( InteractDirection.Down ) );
+                return tryCommand( context, new TurtleDetectCommand( InteractDirection.DOWN ) );
             case 19: // compare
-                return tryCommand( context, new TurtleCompareCommand( InteractDirection.Forward ) );
+                return tryCommand( context, new TurtleCompareCommand( InteractDirection.FORWARD ) );
             case 20: // compareUp
-                return tryCommand( context, new TurtleCompareCommand( InteractDirection.Up ) );
+                return tryCommand( context, new TurtleCompareCommand( InteractDirection.UP ) );
             case 21: // compareDown
-                return tryCommand( context, new TurtleCompareCommand( InteractDirection.Down ) );
+                return tryCommand( context, new TurtleCompareCommand( InteractDirection.DOWN ) );
             case 22:
             {
                 // attack
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.Forward, side ) );
+                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.FORWARD, side ) );
             }
             case 23:
             {
                 // attackUp
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.Up, side ) );
+                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.UP, side ) );
             }
             case 24:
             {
                 // attackDown
                 TurtleSide side = parseSide( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.Down, side ) );
+                return tryCommand( context, TurtleToolCommand.attack( InteractDirection.DOWN, side ) );
             }
             case 25:
             {
                 // dropUp
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleDropCommand( InteractDirection.Up, count ) );
+                return tryCommand( context, new TurtleDropCommand( InteractDirection.UP, count ) );
             }
             case 26:
             {
                 // dropDown
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleDropCommand( InteractDirection.Down, count ) );
+                return tryCommand( context, new TurtleDropCommand( InteractDirection.DOWN, count ) );
             }
             case 27:
             {
                 // suck
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleSuckCommand( InteractDirection.Forward, count ) );
+                return tryCommand( context, new TurtleSuckCommand( InteractDirection.FORWARD, count ) );
             }
             case 28:
             {
                 // suckUp
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleSuckCommand( InteractDirection.Up, count ) );
+                return tryCommand( context, new TurtleSuckCommand( InteractDirection.UP, count ) );
             }
             case 29:
             {
                 // suckDown
                 int count = parseCount( args, 0 );
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleSuckCommand( InteractDirection.Down, count ) );
+                return tryCommand( context, new TurtleSuckCommand( InteractDirection.DOWN, count ) );
             }
             case 30: // getFuelLevel
                 return new Object[] { m_turtle.isFuelNeeded() ? m_turtle.getFuelLevel() : "unlimited" };
@@ -324,16 +324,16 @@ public class TurtleAPI implements ILuaAPI
                 return new Object[] { m_turtle.isFuelNeeded() ? m_turtle.getFuelLimit() : "unlimited" };
             case 36: // equipLeft
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleEquipCommand( TurtleSide.Left ) );
+                return tryCommand( context, new TurtleEquipCommand( TurtleSide.LEFT ) );
             case 37: // equipRight
                 m_environment.addTrackingChange( TrackingField.TURTLE_OPS );
-                return tryCommand( context, new TurtleEquipCommand( TurtleSide.Right ) );
+                return tryCommand( context, new TurtleEquipCommand( TurtleSide.RIGHT ) );
             case 38: // inspect
-                return tryCommand( context, new TurtleInspectCommand( InteractDirection.Forward ) );
+                return tryCommand( context, new TurtleInspectCommand( InteractDirection.FORWARD ) );
             case 39: // inspectUp
-                return tryCommand( context, new TurtleInspectCommand( InteractDirection.Up ) );
+                return tryCommand( context, new TurtleInspectCommand( InteractDirection.UP ) );
             case 40: // inspectDown
-                return tryCommand( context, new TurtleInspectCommand( InteractDirection.Down ) );
+                return tryCommand( context, new TurtleInspectCommand( InteractDirection.DOWN ) );
             case 41: // getItemDetail
             {
                 // FIXME: There's a race condition here if the stack is being modified (mutating NBT, etc...)

src/main/java/dan200/computercraft/shared/turtle/blocks/BlockTurtle.java

@@ -152,7 +152,7 @@ public class BlockTurtle extends BlockComputerBase<TileTurtle> implements IWater
     @Override
     public float getExplosionResistance( BlockState state, IWorldReader world, BlockPos pos, @Nullable Entity exploder, Explosion explosion )
     {
-        if( getFamily() == ComputerFamily.Advanced || exploder instanceof LivingEntity || exploder instanceof DamagingProjectileEntity )
+        if( getFamily() == ComputerFamily.ADVANCED || exploder instanceof LivingEntity || exploder instanceof DamagingProjectileEntity )
         {
             return 2000;
         }

src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java

@@ -33,10 +33,7 @@ import net.minecraft.item.Items;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.nbt.ListNBT;
 import net.minecraft.tileentity.TileEntityType;
-import net.minecraft.util.Direction;
-import net.minecraft.util.Hand;
-import net.minecraft.util.NonNullList;
-import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.*;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.util.math.Vec3d;
@@ -60,12 +57,12 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
 
     public static final NamedTileEntityType<TileTurtle> FACTORY_NORMAL = NamedTileEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "turtle_normal" ),
-        type -> new TileTurtle( type, ComputerFamily.Normal )
+        type -> new TileTurtle( type, ComputerFamily.NORMAL )
     );
 
     public static final NamedTileEntityType<TileTurtle> FACTORY_ADVANCED = NamedTileEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "turtle_advanced" ),
-        type -> new TileTurtle( type, ComputerFamily.Advanced )
+        type -> new TileTurtle( type, ComputerFamily.ADVANCED )
     );
 
     enum MoveState
@@ -164,8 +161,9 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         }
     }
 
+    @Nonnull
     @Override
-    public boolean onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
+    public ActionResultType onActivate( PlayerEntity player, Hand hand, BlockRayTraceResult hit )
     {
         // Apply dye
         ItemStack currentItem = player.getHeldItem( hand );
@@ -186,7 +184,7 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
                         }
                     }
                 }
-                return true;
+                return ActionResultType.SUCCESS;
             }
             else if( currentItem.getItem() == Items.WATER_BUCKET && m_brain.getColour() != -1 )
             {
@@ -203,7 +201,7 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
                         }
                     }
                 }
-                return true;
+                return ActionResultType.SUCCESS;
             }
         }
 
@@ -528,10 +526,10 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         switch( side )
         {
             case RIGHT:
-                upgrade = getUpgrade( TurtleSide.Right );
+                upgrade = getUpgrade( TurtleSide.RIGHT );
                 break;
             case LEFT:
-                upgrade = getUpgrade( TurtleSide.Left );
+                upgrade = getUpgrade( TurtleSide.LEFT );
                 break;
             default:
                 return false;

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

@@ -10,20 +10,20 @@ import net.minecraft.util.Direction;
 
 public enum InteractDirection
 {
-    Forward,
-    Up,
-    Down;
+    FORWARD,
+    UP,
+    DOWN;
 
     public Direction toWorldDir( ITurtleAccess turtle )
     {
         switch( this )
         {
-            case Forward:
+            case FORWARD:
             default:
                 return turtle.getDirection();
-            case Up:
+            case UP:
                 return Direction.UP;
-            case Down:
+            case DOWN:
                 return Direction.DOWN;
         }
     }