Initial commit: Minecraft 光追着色器包（从零实现的 path tracing）

2026-09-19 12:06:22 +08:00
commit 59e30822f8
314 changed files with 9259 additions and 0 deletions
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+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+// MinecraftPT — Shadow Tracing
+// Direct sunlight shadow rays: march from surface toward the sun through the
+// voxel grid. Soft penumbra via distance-weighted ray length.
+
+#ifndef SHADOW_TRACING_GLSL
+#define SHADOW_TRACING_GLSL
+
+#include "/Lib/PathTracing/Tracer/TracingUtilities.glsl"
+
+float ShadowTracing(vec3 viewPos, vec3 worldPos, vec3 vertexNormal, vec3 lightVector, float lightMap){
+	float shadow = 1.0;
+
+	vec3 voxelPos = WorldToVoxel(worldPos);
+	voxelPos += vertexNormal * (-viewPos.z * 0.0003);
+
+	if (clamp(voxelPos, vec3(0.0), vec3(voxelResolution)) == voxelPos){
+		lightMap = saturate(1.0 - lightMap * 2.0);
+		vec2 shadowWeight = vec2(
+			4.0 - 2.0 * saturate(lightMap - viewPos.z * 0.01),
+			0.2 + 0.5 * saturate(lightMap - viewPos.z * 0.01)
+		);
+
+		Ray ray = PackRay(voxelPos, lightVector);
+
+		vec3 voxelCoord = floor(ray.ori);
+		vec3 totalStep = (ray.sdir * (voxelCoord - ray.ori + 0.5) + 0.5) * abs(ray.rdir);
+		float rayLength = 0.0;
+		vec3 tracingNext;
+
+		bool hit = false;
+
+		for (int i = 0; i < 64; i++){
+			if (clamp(voxelCoord, vec3(0.0), vec3(voxelResolution - 0.5)) != voxelCoord) break;
+
+			vec4 voxelData = texelFetch(voxelData3D, ivec3(voxelCoord), 0);
+			float voxelID = DecodeVoxelID(voxelData.z);
+
+			// Full block or cutout shape
+			if (voxelID >= 999.0){
+				hit = rayLength > 0.0;
+			}else if (voxelID < 1000.0 && voxelID > 1.0){
+				float rawID = 1000.0 - voxelID;
+				rayLength = minVec3(totalStep);
+				hit = HitShape_Lite(ray, voxelCoord, rawID, rayLength);
+			}
+
+			if (hit){
+				shadow = saturate((rayLength - shadowWeight.y) * shadowWeight.x);
+				break;
+			}
+
+			// Sparse skip
+			float marker = voxelData.z;
+			if (marker > 0.60 && marker < 0.92){
+				float skipSize = marker > 0.90 ? 8.0 : (marker > 0.70 ? 4.0 : 2.0);
+				vec3 nextBoundary = floor((voxelCoord + 1.0) / skipSize) * skipSize;
+				vec3 distToBoundary = (nextBoundary - voxelCoord) * abs(ray.rdir);
+				float tSkip = minVec3(distToBoundary) + 1e-4;
+				rayLength += tSkip;
+				vec3 stepVec = ray.sdir * abs(ray.rdir) * tSkip;
+				ray.ori += stepVec;
+				voxelCoord = floor(ray.ori);
+				totalStep = (ray.sdir * (voxelCoord - ray.ori + 0.5) + 0.5) * abs(ray.rdir);
+				continue;
+			}
+
+			rayLength = minVec3(totalStep);
+			tracingNext = step(totalStep, vec3(rayLength));
+			voxelCoord += tracingNext * ray.sdir;
+			totalStep += tracingNext * abs(ray.rdir);
+		}
+	}
+
+	return shadow;
+}
+
+// Simplified version for IRC / light sampling (no soft penumbra)
+float SimpleShadowTracing(vec3 voxelPos, vec3 lightVector){
+	Ray ray = PackRay(voxelPos, lightVector);
+
+	vec3 voxelCoord = floor(ray.ori);
+	vec3 totalStep = (ray.sdir * (voxelCoord - ray.ori + 0.5) + 0.5) * abs(ray.rdir);
+	float rayLength = 0.0;
+	vec3 tracingNext;
+
+	bool hit = false;
+
+	for (int i = 0; i < 64; i++){
+		if (clamp(voxelCoord, vec3(0.0), vec3(voxelResolution - 0.5)) != voxelCoord) break;
+
+		vec4 voxelData = texelFetch(voxelData3D, ivec3(voxelCoord), 0);
+		float voxelID = DecodeVoxelID(voxelData.z);
+
+		if (voxelID >= 999.0){
+			hit = rayLength > 0.0;
+		}else if (voxelID < 1000.0 && voxelID > 1.0){
+			float rawID = 1000.0 - voxelID;
+			rayLength = minVec3(totalStep);
+			hit = HitShape_Lite(ray, voxelCoord, rawID, rayLength);
+		}
+
+		if (hit) break;
+
+		// Sparse skip
+		float marker = voxelData.z;
+		if (marker > 0.60 && marker < 0.92){
+			float skipSize = marker > 0.90 ? 8.0 : (marker > 0.70 ? 4.0 : 2.0);
+			vec3 nextBoundary = floor((voxelCoord + 1.0) / skipSize) * skipSize;
+			vec3 distToBoundary = (nextBoundary - voxelCoord) * abs(ray.rdir);
+			float tSkip = minVec3(distToBoundary) + 1e-4;
+			rayLength += tSkip;
+			vec3 stepVec = ray.sdir * abs(ray.rdir) * tSkip;
+			ray.ori += stepVec;
+			voxelCoord = floor(ray.ori);
+			totalStep = (ray.sdir * (voxelCoord - ray.ori + 0.5) + 0.5) * abs(ray.rdir);
+			continue;
+		}
+
+		rayLength = minVec3(totalStep);
+		tracingNext = step(totalStep, vec3(rayLength));
+		voxelCoord += tracingNext * ray.sdir;
+		totalStep += tracingNext * abs(ray.rdir);
+	}
+
+	return float(!hit);
+}
+
+#endif