Add a custom renderer for monitor block highlights (#220)

This only renders the bounding box on non-screen edges of the monitor,
meaning you have an uninterrupted view of the screen when hovering
hover.

Closes #219

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

@@ -29,13 +29,13 @@ import net.minecraftforge.fml.relauncher.Side;
 import org.lwjgl.opengl.GL11;
 
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Side.CLIENT )
-public final class RenderOverlayCable
+public final class CableHighlightRenderer
 {
     private static final float EXPAND = 0.002f;
     private static final double MIN = CableBounds.MIN - EXPAND;
     private static final double MAX = CableBounds.MAX + EXPAND;
 
-    private RenderOverlayCable()
+    private CableHighlightRenderer()
     {
     }
 

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

@@ -0,0 +1,118 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.client.render;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
+import net.minecraft.client.renderer.BufferBuilder;
+import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.tileentity.TileEntity;
+import net.minecraft.util.EnumFacing;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.RayTraceResult;
+import net.minecraft.world.World;
+import net.minecraftforge.client.event.DrawBlockHighlightEvent;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
+import net.minecraftforge.fml.relauncher.Side;
+import org.lwjgl.opengl.GL11;
+
+import java.util.EnumSet;
+
+import static net.minecraft.util.EnumFacing.*;
+
+@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Side.CLIENT )
+public final class MonitorHighlightRenderer
+{
+    private static final float EXPAND = 0.002f;
+
+    private MonitorHighlightRenderer()
+    {
+    }
+
+    @SubscribeEvent
+    public static void drawHighlight( DrawBlockHighlightEvent event )
+    {
+        if( event.getTarget().typeOfHit != RayTraceResult.Type.BLOCK || event.getPlayer().isSneaking() ) return;
+
+        World world = event.getPlayer().getEntityWorld();
+        BlockPos pos = event.getTarget().getBlockPos();
+
+        if( world.getBlockState( pos ).getBlock() != ComputerCraft.Blocks.peripheral ) return;
+
+        TileEntity tile = world.getTileEntity( pos );
+        if( !(tile instanceof TileMonitor) ) return;
+
+        TileMonitor monitor = (TileMonitor) tile;
+        event.setCanceled( true );
+
+        // Determine which sides are part of the external faces of the monitor, and so which need to be rendered.
+        EnumSet<EnumFacing> faces = EnumSet.allOf( EnumFacing.class );
+        EnumFacing front = monitor.getFront();
+        faces.remove( front );
+        if( monitor.getXIndex() != 0 ) faces.remove( monitor.getRight().getOpposite() );
+        if( monitor.getXIndex() != monitor.getWidth() - 1 ) faces.remove( monitor.getRight() );
+        if( monitor.getYIndex() != 0 ) faces.remove( monitor.getDown().getOpposite() );
+        if( monitor.getYIndex() != monitor.getHeight() - 1 ) faces.remove( monitor.getDown() );
+
+        GlStateManager.enableBlend();
+        GlStateManager.tryBlendFuncSeparate( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
+        GL11.glLineWidth( 2.0F );
+        GlStateManager.disableTexture2D();
+        GlStateManager.depthMask( false );
+        GlStateManager.pushMatrix();
+
+        EntityPlayer player = event.getPlayer();
+        double x = player.lastTickPosX + (player.posX - player.lastTickPosX) * event.getPartialTicks();
+        double y = player.lastTickPosY + (player.posY - player.lastTickPosY) * event.getPartialTicks();
+        double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * event.getPartialTicks();
+
+        GlStateManager.translate( -x + pos.getX(), -y + pos.getY(), -z + pos.getZ() );
+
+        Tessellator tessellator = Tessellator.getInstance();
+        BufferBuilder buffer = tessellator.getBuffer();
+        buffer.begin( GL11.GL_LINES, DefaultVertexFormats.POSITION_COLOR );
+
+        // 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 );
+
+        tessellator.draw();
+
+        GlStateManager.popMatrix();
+        GlStateManager.depthMask( true );
+        GlStateManager.enableTexture2D();
+        GlStateManager.disableBlend();
+    }
+
+    private static void line( BufferBuilder buffer, int x, int y, int z, EnumFacing direction )
+    {
+        double minX = x == 0 ? -EXPAND : 1 + EXPAND;
+        double minY = y == 0 ? -EXPAND : 1 + EXPAND;
+        double minZ = z == 0 ? -EXPAND : 1 + EXPAND;
+
+        buffer.pos( minX, minY, minZ ).color( 0, 0, 0, 0.4f ).endVertex();
+        buffer.pos(
+            minX + direction.getXOffset() * (1 + EXPAND * 2),
+            minY + direction.getYOffset() * (1 + EXPAND * 2),
+            minZ + direction.getZOffset() * (1 + EXPAND * 2)
+        ).color( 0, 0, 0, 0.4f ).endVertex();
+    }
+}

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

@@ -339,7 +339,7 @@ public class TileMonitor extends TileGeneric implements ITilePeripheral, IPeriph
         return EnumFacing.WEST;
     }
 
-    private EnumFacing getDown()
+    public EnumFacing getDown()
     {
         int dir = getDir();
         if( dir <= 5 ) return EnumFacing.UP;