Fix a bunch of stuff, mirroring colors now works correctly

src/main/java/com/simibubi/create/content/optics/Beam.java

@@ -8,44 +8,33 @@ import java.util.Set;
 import javax.annotation.Nullable;
 
 import com.mojang.blaze3d.matrix.MatrixStack;
+import com.simibubi.create.foundation.utility.VecHelper;
 
 import net.minecraft.client.renderer.IRenderTypeBuffer;
+import net.minecraft.item.DyeColor;
+import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.vector.Vector3d;
 
 public class Beam extends ArrayList<BeamSegment> {
-	public final Set<Beam> subBeams;
 	private final Set<ILightHandler<?>> lightEventListeners;
 	private final Vector3d direction;
-	private boolean removed = false;
+	@Nullable
+	private final Beam parent;
 
-	public Beam(Vector3d direction) {
+	public Beam(@Nullable Beam parent, Vector3d direction) {
 		super();
+		this.parent = parent;
 		this.direction = direction;
 		lightEventListeners = new HashSet<>();
-		subBeams = new HashSet<>();
-	}
-
-	public void onRemoved() {
-		lightEventListeners.forEach(handler -> handler.onBeamRemoved(this));
-		subBeams.forEach(Beam::onRemoved);
-		subBeams.clear();
-		removed = true;
-		clear();
 	}
 
 	public void onCreated() {
 		lightEventListeners.stream()
 				.flatMap(handler -> handler.constructSubBeams(this))
-				.forEach(subBeams::add);
+				.forEach(Beam::onCreated);
-	}
-
-	public void registerSubBeam(Beam beam) {
-		subBeams.add(beam);
 	}
 
 	public void render(MatrixStack ms, IRenderTypeBuffer buffer, float partialTicks) {
-		if (removed)
-			throw new IllegalStateException("tried to render removed beam");
 		forEach(beamSegment -> beamSegment.renderSegment(ms, buffer, partialTicks));
 	}
 
@@ -64,11 +53,28 @@ public class Beam extends ArrayList<BeamSegment> {
 		if (o == null || getClass() != o.getClass()) return false;
 		if (!super.equals(o)) return false;
 		Beam that = (Beam) o;
-		return removed == that.removed && subBeams.equals(that.subBeams) && lightEventListeners.equals(that.lightEventListeners) && Objects.equals(direction, that.direction);
+		return lightEventListeners.equals(that.lightEventListeners) && Objects.equals(direction, that.direction);
 	}
 
-	public void removeSubBeam(Beam out) {
+	public boolean isRemoved() {
-		if (subBeams.remove(out))
+		return isEmpty() || get(0).getHandler()
-			out.onRemoved();
+				.getTile()
+				.isRemoved() || !get(0).getHandler()
+				.getOutBeams()
+				.contains(this) || (parent != null && parent.isRemoved());
+	}
+
+	public float[] getColorAt(BlockPos testBlockPos) {
+		float[] out = DyeColor.WHITE.getColorComponentValues();
+		for (BeamSegment segment : this) {
+			if (VecHelper.getCenterOf(testBlockPos)
+					.subtract(segment.getStart())
+					.dotProduct(segment.getNormalized()) > 0)
+				out = segment.getColors();
+			else
+				break;
+		}
+
+		return out;
 	}
 }

src/main/java/com/simibubi/create/content/optics/BeamSegment.java

@@ -120,16 +120,12 @@ public class BeamSegment {
 				beaconBeamModifier = Quaternion.IDENTITY;
 			} else {
 				Vector3f unitVec = axis.getUnitVector();
-				beaconBeamModifier = unitVec.getRadialQuaternion((float) (-Math.acos(dotProd) * Math.signum(new Vector3d(unitVec).dotProduct(getNormalized().crossProduct(UP)))));
+				beaconBeamModifier = unitVec.getRadialQuaternion((float) Math.acos(dotProd) * (new Vector3d(unitVec).dotProduct(getNormalized().crossProduct(UP)) > 0 ? -1 : 1));
 			}
 		}
 		return beaconBeamModifier;
 	}
 
-	public double getTotalSectionLength() {
-		return totalSectionLength.getValue();
-	}
-
 	public long getWorldTick() {
 		World world = getHandler()
 				.getTile()

src/main/java/com/simibubi/create/content/optics/ILightHandler.java

@@ -1,6 +1,7 @@
 package com.simibubi.create.content.optics;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.stream.Stream;
@@ -22,19 +23,19 @@ import net.minecraft.world.World;
 
 public interface ILightHandler<T extends SmartTileEntity & ILightHandler<T>> {
 	@Nullable
-	default Beam constructOutBeam(Vector3d beamDirection) {
+	default Beam constructOutBeam(@Nullable Beam parent, Vector3d beamDirection) {
-		return constructOutBeam(beamDirection, getTile().getPos());
+		return constructOutBeam(parent, beamDirection, getTile().getPos());
 	}
 
 	@Nullable
-	default Beam constructOutBeam(Vector3d beamDirection, BlockPos testBlockPos) {
+	default Beam constructOutBeam(@Nullable Beam parent, Vector3d beamDirection, BlockPos testBlockPos) {
 
-		float[] segmentColor = getSegmentStartColor();
+		float[] segmentColor = parent == null ? DyeColor.WHITE.getColorComponentValues() : parent.getColorAt(testBlockPos);
 		World world = getTile().getWorld();
 		if (world == null)
 			return null;
 		Vector3d direction = VecHelper.step(beamDirection);
-		Beam beam = new Beam(direction);
+		Beam beam = new Beam(parent, direction);
 		Vector3d testPos = VecHelper.getCenterOf(testBlockPos);
 
 		BeamSegment segment = new BeamSegment(this, segmentColor, testPos, direction);
@@ -74,18 +75,11 @@ public interface ILightHandler<T extends SmartTileEntity & ILightHandler<T>> {
 	default void setColor(float[] segmentColor) {
 	}
 
-	default float[] getSegmentStartColor() {
-		return DyeColor.WHITE.getColorComponentValues();
-	}
-
 	@Nullable
 	default Direction getBeamRotationAround() {
 		return null;
 	}
 
-	default void onBeamRemoved(Beam beam) {
-	}
-
 	default Stream<Beam> constructSubBeams(Beam beam) {
 		return Stream.empty();
 	}
@@ -97,4 +91,8 @@ public interface ILightHandler<T extends SmartTileEntity & ILightHandler<T>> {
 	default boolean canLightPass() {
 		return false;
 	}
+
+	default Collection<Beam> getOutBeams() {
+		return Collections.emptySet();
+	}
 }

src/main/java/com/simibubi/create/content/optics/mirror/MirrorTileEntity.java

@@ -1,5 +1,6 @@
 package com.simibubi.create.content.optics.mirror;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -20,7 +21,6 @@ import com.simibubi.create.foundation.utility.ServerSpeedProvider;
 import com.simibubi.create.foundation.utility.VecHelper;
 
 import net.minecraft.block.BlockState;
-import net.minecraft.item.DyeColor;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.state.properties.BlockStateProperties;
 import net.minecraft.tileentity.BeaconTileEntity;
@@ -40,7 +40,6 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 	@Nullable
 	private BeaconTileEntity beacon;
 	private Beam beaconBeam = null;
-	private float[] initialColor = DyeColor.WHITE.getColorComponentValues();
 
 	public MirrorTileEntity(TileEntityType<?> typeIn) {
 		super(typeIn);
@@ -93,7 +92,7 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 		angle = newAngle % 360;
 
 		if (angle != prevAngle) {
-			updateReflections();
+			updateBeams();
 		}
 
 		if (beacon != null && beacon.isRemoved())
@@ -105,17 +104,14 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 		beacon = BeaconHelper.getBeaconTE(pos, world)
 				.orElse(null);
 
-		if (beaconBefore == beacon)
-			return;
-
 		if (beaconBefore != null) {
-			beaconBeam.onRemoved();
+			beaconBeam.clear();
 			beaconBeam = null;
-			updateReflections();
+			updateBeams();
 		}
 
 		if (beacon != null) {
-			beaconBeam = constructOutBeam(VecHelper.UP, beacon.getPos());
+			beaconBeam = constructOutBeam(null, VecHelper.UP, beacon.getPos());
 			if (beaconBeam != null) {
 				beaconBeam.addListener(this);
 				beaconBeam.onCreated();
@@ -123,12 +119,18 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 		}
 	}
 
-	private void updateReflections() {
+	private void updateBeams() {
-		new HashMap<>(beams).forEach(Beam::removeSubBeam);
-
 		Map<Beam, Beam> newBeams = new HashMap<>();
-		for (Beam beam : beams.keySet()) {
+		for (Map.Entry<Beam, Beam> entry : beams.entrySet()) {
-			newBeams.put(beam, reflectBeam(beam));
+			if (entry.getKey()
+					.isRemoved())
+				continue;
+
+			Beam reflected = reflectBeam(entry.getKey());
+			if (reflected != null) {
+				newBeams.put(entry.getKey(), reflected);
+				reflected.onCreated();
+			}
 		}
 		beams = newBeams;
 	}
@@ -145,7 +147,7 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 	public void lazyTick() {
 		super.lazyTick();
 		updateBeaconState();
-		updateReflections();
+		updateBeams();
 	}
 
 	@Override
@@ -160,12 +162,6 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 
 	@Override
 	public void setColor(float[] initialColor) {
-		this.initialColor = initialColor;
-	}
-
-	@Override
-	public float[] getSegmentStartColor() {
-		return initialColor;
 	}
 
 	@Nonnull
@@ -205,17 +201,20 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 				.iterator(), beaconIter);
 	}
 
-	@Override
-	public void onBeamRemoved(Beam beam) {
-		beams.remove(beam);
-	}
-
 
 	@Override
 	public Stream<Beam> constructSubBeams(Beam beam) {
+		if (beams.keySet()
+				.stream()
+				.map(Beam::getDirection)
+				.map(Vector3d::normalize)
+				.anyMatch(beam.getDirection()
+						.normalize()::equals))
+			return Stream.empty();
 		Beam reflected = reflectBeam(beam);
 		if (reflected != null) {
 			beams.put(beam, reflected);
+			beam.addListener(this);
 			return Stream.of(reflected);
 		}
 		return Stream.empty();
@@ -223,11 +222,21 @@ public class MirrorTileEntity extends KineticTileEntity implements ILightHandler
 
 
 	private Beam reflectBeam(Beam beam) {
-		Beam reflected = constructOutBeam(getReflectionAngle(beam.getDirection()));
+		Vector3d inDir = beam.getDirection()
-		if (reflected != null) {
+				.normalize();
-			beam.registerSubBeam(reflected);
+		Vector3d outDir = getReflectionAngle(inDir).normalize();
-			reflected.onCreated();
+
-		}
+		if (inDir.subtract(outDir)
-		return reflected;
+				.normalize() == Vector3d.ZERO)
+			return null;
+
+		// TE already has input beam at that direction
+
+		return constructOutBeam(beam, outDir);
+	}
+
+	@Override
+	public Collection<Beam> getOutBeams() {
+		return beams.keySet();
 	}
 }