Begin on player uniforms

src/main/java/com/jozufozu/flywheel/backend/engine/uniform/FrameUniforms.java

@@ -123,7 +123,7 @@ public class FrameUniforms implements UniformProvider {
 
 		var window = Minecraft.getInstance()
 				.getWindow();
-		ptr = writeVec2(ptr, window.getWidth(), window.getHeight());
+		ptr = Uniforms.writeVec2(ptr, window.getWidth(), window.getHeight());
 
 		// default line width: net.minecraft.client.renderer.RenderStateShard.LineStateShard
 		MemoryUtil.memPutFloat(ptr, Math.max(2.5F, (float) window.getWidth() / 1920.0F * 2.5F));
@@ -187,11 +187,11 @@ public class FrameUniforms implements UniformProvider {
 
 	private static long writeCamera(long ptr, float camX, float camY, float camZ, Vector3f lookVector, float xRot,
 									float yRot) {
-		ptr = writeVec3(ptr, camX, camY, camZ);
+		ptr = Uniforms.writeVec3(ptr, camX, camY, camZ);
 
-		ptr = writeVec3(ptr, lookVector.x, lookVector.y, lookVector.z);
+		ptr = Uniforms.writeVec3(ptr, lookVector.x, lookVector.y, lookVector.z);
 
-		ptr = writeVec2(ptr, xRot, yRot);
+		ptr = Uniforms.writeVec2(ptr, xRot, yRot);
 		return ptr;
 	}
 
@@ -248,20 +248,6 @@ public class FrameUniforms implements UniformProvider {
 		return ptr + 8;
 	}
 
-	private static long writeVec3(long ptr, float camX, float camY, float camZ) {
-		MemoryUtil.memPutFloat(ptr, camX);
-		MemoryUtil.memPutFloat(ptr + 4, camY);
-		MemoryUtil.memPutFloat(ptr + 8, camZ);
-		MemoryUtil.memPutFloat(ptr + 12, 0f); // empty component of vec4 because we don't trust std140
-		return ptr + 16;
-	}
-
-	private static long writeVec2(long ptr, float camX, float camY) {
-		MemoryUtil.memPutFloat(ptr, camX);
-		MemoryUtil.memPutFloat(ptr + 4, camY);
-		return ptr + 8;
-	}
-
 	private static int getConstantAmbientLightFlag(RenderContext context) {
 		var constantAmbientLight = context.level()
 				.effects()

src/main/java/com/jozufozu/flywheel/backend/engine/uniform/PlayerUniforms.java

@@ -0,0 +1,67 @@
+package com.jozufozu.flywheel.backend.engine.uniform;
+
+import org.jetbrains.annotations.Nullable;
+import org.lwjgl.system.MemoryUtil;
+
+import com.jozufozu.flywheel.api.event.RenderContext;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.player.LocalPlayer;
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.item.BlockItem;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.level.LightLayer;
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.phys.Vec3;
+
+public class PlayerUniforms implements UniformProvider {
+	public static final int SIZE = 4 + 8 + 16;
+
+	@Nullable
+	private RenderContext context;
+
+	@Override
+	public int byteSize() {
+		return SIZE;
+	}
+
+	public void setContext(RenderContext context) {
+		this.context = context;
+	}
+
+	@Override
+	public void write(long ptr) {
+		Minecraft mc = Minecraft.getInstance();
+		LocalPlayer player = mc.player;
+		if (context == null || player == null) {
+			MemoryUtil.memSet(ptr, 0, SIZE);
+			return;
+		}
+
+		int luminance = 0;
+		for (InteractionHand hand : InteractionHand.values()) {
+			Item handItem = player.getItemInHand(hand).getItem();
+			if (handItem instanceof BlockItem bitem) {
+				Block block = bitem.getBlock();
+				int blockLight = block.defaultBlockState().getLightEmission(player.clientLevel, BlockPos.ZERO);
+				if (luminance < blockLight) {
+					luminance = blockLight;
+				}
+			}
+		}
+
+		MemoryUtil.memPutFloat(ptr, (float) luminance / 15);
+		ptr += 4;
+
+		Vec3 eyePos = player.getEyePosition(context.partialTick());
+		ptr = Uniforms.writeVec3(ptr, (float) eyePos.x, (float) eyePos.y, (float) eyePos.z);
+
+		int blockBrightness = player.clientLevel.getBrightness(LightLayer.BLOCK, player.blockPosition());
+		int skyBrightness = player.clientLevel.getBrightness(LightLayer.SKY, player.blockPosition());
+		int maxBrightness = player.clientLevel.getMaxLightLevel();
+
+		ptr = Uniforms.writeVec2(ptr, (float) blockBrightness / (float) maxBrightness,
+				(float) skyBrightness / (float) maxBrightness);
+	}
+}

src/main/java/com/jozufozu/flywheel/backend/engine/uniform/Uniforms.java

@@ -6,6 +6,7 @@ import com.jozufozu.flywheel.backend.gl.GlStateTracker;
 import com.jozufozu.flywheel.config.DebugMode;
 
 import org.jetbrains.annotations.Nullable;
+import org.lwjgl.system.MemoryUtil;
 
 public class Uniforms {
 	public static boolean frustumPaused = false;
@@ -13,6 +14,7 @@ public class Uniforms {
 	private static @Nullable UniformBuffer<FrameUniforms> frame;
 	private static @Nullable UniformBuffer<FogUniforms> fog;
 	private static @Nullable UniformBuffer<OptionsUniforms> options;
+	private static @Nullable UniformBuffer<PlayerUniforms> player;
 
 	public static UniformBuffer<FrameUniforms> frame() {
 		if (frame == null) {
@@ -35,10 +37,18 @@ public class Uniforms {
 		return options;
 	}
 
+	public static UniformBuffer<PlayerUniforms> player() {
+		if (player == null) {
+			player = new UniformBuffer<>(2, new PlayerUniforms());
+		}
+		return player;
+	}
+
 	public static void bindForDraw() {
 		bindFrame();
 		bindFog();
 		bindOptions();
+		bindPlayer();
 	}
 
 	public static void bindFrame() {
@@ -59,6 +69,12 @@ public class Uniforms {
 		}
 	}
 
+	public static void bindPlayer() {
+		if (player != null) {
+			player.bind();
+		}
+	}
+
 	public static void onFogUpdate() {
 		try (var restoreState = GlStateTracker.getRestoreState()) {
 			fog().update();
@@ -71,6 +87,10 @@ public class Uniforms {
 		ubo.update();
 
 		options();
+
+		var player = player();
+		player.provider.setContext(ctx);
+		player.update();
 	}
 
 	public static void setDebugMode(DebugMode mode) {
@@ -92,5 +112,24 @@ public class Uniforms {
 			options.delete();
 			options = null;
 		}
+
+		if (player != null) {
+			player.delete();
+			player = null;
+		}
+	}
+
+	static long writeVec3(long ptr, float camX, float camY, float camZ) {
+		MemoryUtil.memPutFloat(ptr, camX);
+		MemoryUtil.memPutFloat(ptr + 4, camY);
+		MemoryUtil.memPutFloat(ptr + 8, camZ);
+		MemoryUtil.memPutFloat(ptr + 12, 0f); // empty component of vec4 because we don't trust std140
+		return ptr + 16;
+	}
+
+	static long writeVec2(long ptr, float camX, float camY) {
+		MemoryUtil.memPutFloat(ptr, camX);
+		MemoryUtil.memPutFloat(ptr + 4, camY);
+		return ptr + 8;
 	}
 }

src/main/resources/assets/flywheel/flywheel/internal/uniforms/player.glsl

@@ -0,0 +1,10 @@
+// player.glsl - Holds uniforms for player state.
+
+layout (std140) uniform _FlwPlayerUniforms {
+    float flw_heldLight;
+    vec4 _flw_eyePos;
+    /** The brightness at the player's eye position. */
+    vec2 flw_eyeBrightness;
+};
+
+#define flw_eyePos _flw_eyePos.xyz

src/main/resources/assets/flywheel/flywheel/internal/uniforms/uniforms.glsl

@@ -3,3 +3,4 @@
 #include "flywheel:internal/uniforms/frame.glsl"
 #include "flywheel:internal/uniforms/fog.glsl"
 #include "flywheel:internal/uniforms/options.glsl"
+#include "flywheel:internal/uniforms/player.glsl"