Uniforms: support shadowLightPosition

src/main/java/net/coderbot/iris/mixin/MixinWorldRenderer.java

@@ -5,6 +5,7 @@
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Slice;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import net.minecraft.client.gl.GlProgramManager;
@@ -22,7 +23,10 @@
 @Environment(EnvType.CLIENT)
 public class MixinWorldRenderer {
 	private static final String RENDER = "render(Lnet/minecraft/client/util/math/MatrixStack;FJZLnet/minecraft/client/render/Camera;Lnet/minecraft/client/render/GameRenderer;Lnet/minecraft/client/render/LightmapTextureManager;Lnet/minecraft/util/math/Matrix4f;)V";
+	private static final String RENDER_SKY = "renderSky(Lnet/minecraft/client/util/math/MatrixStack;F)V";
 	private static final String PROFILER_SWAP = "Lnet/minecraft/util/profiler/Profiler;swap(Ljava/lang/String;)V";
+	private static final String POSITIVE_Y = "Lnet/minecraft/client/util/math/Vector3f;POSITIVE_Y:Lnet/minecraft/client/util/math/Vector3f;";
+	private static final String PEEK = "Lnet/minecraft/client/util/math/MatrixStack;peek()Lnet/minecraft/client/util/math/MatrixStack$Entry;";
 
 	@Inject(method = RENDER, at = @At(value = "INVOKE_STRING", target = PROFILER_SWAP, args = "ldc=terrain"))
 	private void setupTerrainShaders(MatrixStack matrices, float tickDelta, long limitTime, boolean renderBlockOutline, Camera camera, GameRenderer gameRenderer, LightmapTextureManager lightmapTextureManager, Matrix4f matrix4f, CallbackInfo callback) {
@@ -34,4 +38,11 @@ private void setupTerrainShaders(MatrixStack matrices, float tickDelta, long lim
 	private void stopUsingTerrainShaders(MatrixStack matrices, float tickDelta, long limitTime, boolean renderBlockOutline, Camera camera, GameRenderer gameRenderer, LightmapTextureManager lightmapTextureManager, Matrix4f matrix4f, CallbackInfo callback) {
 		GlProgramManager.useProgram(0);
 	}
+
+	@Inject(method = RENDER_SKY,
+			slice = @Slice(from = @At(value = "FIELD", target = POSITIVE_Y)),
+			at = @At(value = "INVOKE:FIRST", target = PEEK))
+	private void iris$renderSky$postCelestialRotate(MatrixStack matrices, float tickDelta, CallbackInfo callback) {
+		CapturedRenderingState.INSTANCE.setCelestialModelView(matrices.peek().getModel().copy());
+	}
 }

src/main/java/net/coderbot/iris/uniforms/CapturedRenderingState.java

@@ -8,6 +8,11 @@ public class CapturedRenderingState {
 	private Matrix4f gbufferModelView;
 	private Matrix4f gbufferProjection;
 
+	/**
+	 * The state of the modelview matrix right after the sky angle rotation has been applied
+	 */
+	private Matrix4f celestialModelView;
+
 	private CapturedRenderingState() {
 	}
 
@@ -26,4 +31,12 @@ public Matrix4f getGbufferProjection() {
 	public void setGbufferProjection(Matrix4f gbufferProjection) {
 		this.gbufferProjection = gbufferProjection;
 	}
+
+	public Matrix4f getCelestialModelView() {
+		return celestialModelView;
+	}
+
+	public void setCelestialModelView(Matrix4f celestialModelView) {
+		this.celestialModelView = celestialModelView;
+	}
 }

src/main/java/net/coderbot/iris/uniforms/Uniforms.java

@@ -8,6 +8,8 @@
 
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.gl.GlProgram;
+import net.minecraft.client.util.math.Vector3f;
+import net.minecraft.client.util.math.Vector4f;
 import net.minecraft.util.math.Matrix4f;
 import net.minecraft.util.math.Vec3d;
 
@@ -22,6 +24,8 @@ public class Uniforms {
 
 	private int cameraPosition;
 
+	private int shadowLightPosition;
+
 	public Uniforms(GlProgram program) {
 		int programId = program.getProgramRef();
 
@@ -34,6 +38,8 @@ public Uniforms(GlProgram program) {
 		gbufferProjectionInverse = GL21.glGetUniformLocation(programId, "gbufferProjectionInverse");
 
 		cameraPosition = GL21.glGetUniformLocation(programId, "cameraPosition");
+
+		shadowLightPosition = GL21.glGetUniformLocation(programId, "shadowLightPosition");
 	}
 
 	public void update() {
@@ -46,8 +52,22 @@ public void update() {
 		updateMatrix(gbufferProjection, CapturedRenderingState.INSTANCE.getGbufferProjection());
 		updateMatrix(gbufferProjectionInverse, invertedCopy(CapturedRenderingState.INSTANCE.getGbufferProjection()));
 
-		Vec3d cameraPos = MinecraftClient.getInstance().gameRenderer.getCamera().getPos();
-		GL21.glUniform3f(cameraPosition, (float) cameraPos.x, (float) cameraPos.y, (float) cameraPos.z);
+		updateVector(cameraPosition, MinecraftClient.getInstance().gameRenderer.getCamera().getPos());
+
+		// TODO: Simplify this
+		Vector4f shadowLightPositionVector;
+
+		if (MinecraftClient.getInstance().world.isDay()) {
+			// Sun position
+			shadowLightPositionVector = new Vector4f(0.0F, 100.0F, 0.0F, 0.0F);
+		} else {
+			// Moon position
+			shadowLightPositionVector = new Vector4f(0.0F, -100.0F, 0.0F, 0.0F);
+		}
+
+		shadowLightPositionVector.transform(CapturedRenderingState.INSTANCE.getCelestialModelView());
+
+		updateVector(shadowLightPosition, new Vector3f(0.0F, 100.0F, 0.0F));
 	}
 
 	private void updateMatrix(int location, Matrix4f instance) {
@@ -59,6 +79,14 @@ private void updateMatrix(int location, Matrix4f instance) {
 		GL21.glUniformMatrix4fv(location, false, buffer);
 	}
 
+	private void updateVector(int location, Vec3d instance) {
+		GL21.glUniform3f(location, (float) instance.x, (float) instance.y, (float) instance.z);
+	}
+
+	private void updateVector(int location, Vector3f instance) {
+		GL21.glUniform3f(location, instance.getX(), instance.getY(), instance.getZ());
+	}
+
 	private Matrix4f invertedCopy(Matrix4f matrix) {
 		// PERF: Don't copy this matrix every time
 		Matrix4f copy = matrix.copy();