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
@@ -0,0 +1,158 @@
+// MinecraftPT — DiffuseTracing_FS
+// One diffuse path-tracing ray per pixel at half resolution.
+// Output: colortex6 = noisy diffuse irradiance, colortex10 = motion vectors.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+#include "/Lib/BasicFunctions/LightingConstants.glsl"
+#include "/Lib/GbufferData.glsl"
+#include "/Lib/PathTracing/Tracer/TracingNoise.glsl"
+#include "/Lib/PathTracing/Tracer/TracingUtilities.glsl"
+#include "/Lib/PathTracing/Tracer/ShadowTracing.glsl"
+#include "/Lib/PathTracing/Tracer/SampleIRC.glsl"
+#include "/Lib/PathTracing/Tracer/SpecularTracer.glsl"
+#include "/Lib/BasicFunctions/TemporalNoise.glsl"
+
+uniform sampler2D colortex0; // albedo
+uniform sampler2D colortex1; // normals
+uniform sampler2D colortex3; // lightmap
+
+layout(location = 0) out vec4 diffuseOut;  // colortex6
+layout(location = 1) out vec4 motionOut;   // colortex10
+
+vec3 TraceDiffuseRay(vec3 origin, vec3 dir, float maxDist){
+	vec3 result = vec3(0.0);
+
+	Ray ray = PackRay(origin, dir);
+	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;
+
+	for (int i = 0; i < 128; i++){
+		if (clamp(voxelCoord, vec3(0.0), vec3(voxelResolution - 0.5)) != voxelCoord){
+			// Miss: sample sky
+			result += SampleSkyBox(dir) * (1.0 / 3.14159265);
+			break;
+		}
+
+		if (rayLength > maxDist){
+			result += SampleSkyBox(dir) * (1.0 / 3.14159265);
+			break;
+		}
+
+		vec4 voxelData = texelFetch(voxelData3D, ivec3(voxelCoord), 0);
+		float voxelID = DecodeVoxelID(voxelData.z);
+
+		// Light sphere contribution
+		if (IsLightSphere(voxelID)){
+			result += HitLightShpere(ray, voxelCoord, voxelID, rayLength);
+			rayLength = minVec3(totalStep);
+			tracingNext = step(totalStep, vec3(rayLength));
+			voxelCoord += tracingNext * ray.sdir;
+			totalStep += tracingNext * abs(ray.rdir);
+			continue;
+		}
+
+		bool hit = false;
+		vec3 hitNormal = vec3(0.0);
+
+		if (voxelID >= 999.0){
+			hit = rayLength > 0.0;
+			hitNormal = -step(vec3(rayLength), totalStep - abs(ray.rdir)) * ray.sdir;
+		}else if (voxelID < 1000.0 && voxelID > 1.0){
+			float rawID = 1000.0 - voxelID;
+			rayLength = minVec3(totalStep);
+			hit = HitShape(ray, voxelCoord, rawID, rayLength, hitNormal);
+		}
+
+		if (hit){
+			vec3 hitPos = ray.ori + ray.dir * rayLength;
+			vec2 midCoord = voxelData.xy;
+			vec3 albedo = SampleVoxelAlbedo(midCoord, hitPos, hitNormal);
+			float skylight = Unpack2xU8_Y_from_U16(voxelData.w);
+
+			// Direct sun at hit point
+			vec3 sun = GetSunIrradiance();
+			float shadow = SimpleShadowTracing(hitPos + hitNormal * 0.01, GetSunDirWorld());
+			float NdotL = max(dot(hitNormal, GetSunDirWorld()), 0.0);
+
+			result += albedo * sun * shadow * NdotL;
+
+			// Sky light at hit point (from voxel skylight)
+			result += albedo * GetAtmoIrradiance() * skylight * 0.5;
+
+			// One-bounce: sample IRC
+			result += albedo * SampleIRC(hitPos) * 0.5;
+
+			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 result;
+}
+
+void main(){
+	// Half resolution texel
+	ivec2 texelCoord = ivec2(gl_FragCoord.xy);
+	ivec2 fullCoord = texelCoord * 2;
+
+	// Skip sky
+	float depth = texelFetch(depthtex0, fullCoord, 0).r;
+	if (depth >= 1.0){
+		diffuseOut = vec4(0.0);
+		motionOut = vec4(0.0);
+		return;
+	}
+
+	vec4 albedoData = texelFetch(colortex0, fullCoord, 0);
+	vec4 normalData = texelFetch(colortex1, fullCoord, 0);
+
+	vec3 worldNormal = DecodeNormal(normalData.xy);
+	vec3 viewNormal = mat3(gbufferModelView) * worldNormal;
+
+	// Reconstruct view position
+	vec4 viewPos = gbufferProjectionInverse * vec4(vec2(fullCoord) / screenSize * 2.0 - 1.0, depth * 2.0 - 1.0, 1.0);
+	viewPos.xyz /= viewPos.w;
+
+	vec3 worldPos = gbufferModelViewInverse[3].xyz + viewPos.xyz;
+
+	vec2 noise = GetTracingNoise2(vec2(texelCoord), frameCounter, 0);
+
+	// Cosine-weighted hemisphere sampling
+	vec3 dir = SampleHemisphere(noise, worldNormal);
+
+	// Only trace if there's anything to bounce (skip pure black)
+	vec3 traceResult = TraceDiffuseRay(WorldToVoxel(worldPos + worldNormal * 0.05), dir, PT_DIFFUSE_TRACING_DISTANCE);
+
+	diffuseOut = vec4(traceResult, 1.0);
+
+	// Motion vectors (full res reprojection)
+	vec4 prevViewPos = gbufferPreviousProjection * gbufferPreviousModelView * vec4(worldPos, 1.0);
+	prevViewPos.xyz /= prevViewPos.w;
+	vec2 prevScreen = (prevViewPos.xy * 0.5 + 0.5) * screenSize;
+
+	vec2 motion = vec2(texelCoord) - prevScreen * 0.5;
+
+	motionOut = vec4(motion, 0.0, 1.0);
+}