Auto-generate monitor models

I didn't think it was worth it, and then I found myself needing to
update a dozen of them. The code isn't especially pretty, but it works,
so that's fine.

Also fixes several issues with us using the wrong texture (closes #572).
I've put together a wiki page[1] which describes each texture in a
little more detail.

[1] https://github.com/SquidDev-CC/CC-Tweaked/wiki/Monitor-texture-reference

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

@@ -0,0 +1,109 @@
+/*
+ * 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.data;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.Registry;
+import dan200.computercraft.shared.peripheral.monitor.BlockMonitor;
+import dan200.computercraft.shared.peripheral.monitor.MonitorEdgeState;
+import net.minecraft.block.Block;
+import net.minecraft.data.DataGenerator;
+import net.minecraft.util.Direction;
+import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.client.model.generators.*;
+
+import javax.annotation.Nonnull;
+
+public class BlockModelProvider extends BlockStateProvider
+{
+    private final ModelFile root;
+
+    public BlockModelProvider( DataGenerator generator, ExistingFileHelper existingFileHelper )
+    {
+        super( generator, ComputerCraft.MOD_ID, existingFileHelper );
+        root = models().getExistingFile( new ResourceLocation( ComputerCraft.MOD_ID, "block/monitor_base" ) );
+    }
+
+    @Nonnull
+    @Override
+    public String getName()
+    {
+        return "Block states and models";
+    }
+
+    @Override
+    protected void registerStatesAndModels()
+    {
+        registerMonitors( Registry.ModBlocks.MONITOR_NORMAL.get() );
+        registerMonitors( Registry.ModBlocks.MONITOR_ADVANCED.get() );
+    }
+
+    private void registerMonitors( Block block )
+    {
+        String name = block.getRegistryName().getPath();
+        registerMonitorModel( name, "", 16, 4, 0, 32 );
+        registerMonitorModel( name, "_d", 20, 7, 0, 36 );
+        registerMonitorModel( name, "_l", 19, 4, 1, 33 );
+        registerMonitorModel( name, "_ld", 31, 7, 1, 45 );
+        registerMonitorModel( name, "_lr", 18, 4, 2, 34 );
+        registerMonitorModel( name, "_lrd", 30, 7, 2, 46 );
+        registerMonitorModel( name, "_lru", 24, 5, 2, 40 );
+        registerMonitorModel( name, "_lrud", 27, 6, 2, 43 );
+        registerMonitorModel( name, "_lu", 25, 5, 1, 39 );
+        registerMonitorModel( name, "_lud", 28, 6, 1, 42 );
+        registerMonitorModel( name, "_r", 17, 4, 3, 35 );
+        registerMonitorModel( name, "_rd", 29, 7, 3, 47 );
+        registerMonitorModel( name, "_ru", 23, 5, 3, 41 );
+        registerMonitorModel( name, "_rud", 26, 6, 3, 44 );
+        registerMonitorModel( name, "_u", 22, 5, 0, 38 );
+        registerMonitorModel( name, "_ud", 21, 6, 0, 37 );
+
+        VariantBlockStateBuilder builder = getVariantBuilder( block );
+        for( MonitorEdgeState edge : BlockMonitor.STATE.getAllowedValues() )
+        {
+            String suffix = edge == MonitorEdgeState.NONE ? "" : "_" + edge.getName();
+            ResourceLocation modelName = new ResourceLocation( ComputerCraft.MOD_ID, "block/" + name + suffix );
+            ModelFile model = models().getBuilder( modelName.toString() );
+
+            for( Direction facing : BlockMonitor.FACING.getAllowedValues() )
+            {
+                for( Direction orientation : BlockMonitor.ORIENTATION.getAllowedValues() )
+                {
+                    builder.partialState()
+                        .with( BlockMonitor.STATE, edge )
+                        .with( BlockMonitor.FACING, facing )
+                        .with( BlockMonitor.ORIENTATION, orientation )
+                        .addModels( new ConfiguredModel( model, toXAngle( orientation ), 180 - (int) facing.getHorizontalAngle(), false ) );
+                }
+            }
+        }
+    }
+
+    private void registerMonitorModel( String prefix, String corners, int front, int side, int top, int back )
+    {
+        String texturePrefix = ComputerCraft.MOD_ID + ":block/" + prefix + "_";
+        models().getBuilder( prefix + corners )
+            .parent( root )
+            .texture( "front", texturePrefix + front )
+            .texture( "side", texturePrefix + side )
+            .texture( "top", texturePrefix + top )
+            .texture( "back", texturePrefix + back );
+    }
+
+    private int toXAngle( Direction direction )
+    {
+        switch( direction )
+        {
+            default:
+                return 0;
+            case UP:
+                return 270;
+            case DOWN:
+                return 90;
+        }
+    }
+}

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

@@ -24,5 +24,6 @@ public class Generators
         generator.addProvider( new Recipes( generator ) );
         generator.addProvider( new LootTables( generator ) );
         generator.addProvider( new Tags( generator ) );
+        generator.addProvider( new BlockModelProvider( generator, event.getExistingFileHelper() ) );
     }
 }

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

@@ -32,7 +32,7 @@ public class BlockMonitor extends BlockGeneric
 
     public static final DirectionProperty FACING = BlockStateProperties.HORIZONTAL_FACING;
 
-    static final EnumProperty<MonitorEdgeState> STATE = EnumProperty.create( "state", MonitorEdgeState.class );
+    public static final EnumProperty<MonitorEdgeState> STATE = EnumProperty.create( "state", MonitorEdgeState.class );
 
     public BlockMonitor( Properties settings, RegistryObject<? extends TileEntityType<? extends TileMonitor>> type )
     {

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

@@ -57,6 +57,12 @@ public enum MonitorEdgeState implements IStringSerializable
         return BY_FLAG[(up ? UP : 0) | (down ? DOWN : 0) | (left ? LEFT : 0) | (right ? RIGHT : 0)];
     }
 
+    @Override
+    public String toString()
+    {
+        return getName();
+    }
+
     @Nonnull
     @Override
     public String getName()