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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+// MinecraftPT — IRC_CS (Irradiance Cache Update)
+// Updates the 3D irradiance cache: traces a few rays per cell toward the sky,
+// stores ambient + direct light contributions, blends over time.
+
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+#include "/Lib/BasicFunctions/LightingConstants.glsl"
+#include "/Lib/PathTracing/Voxelizer/VoxelProfile.glsl"
+#include "/Lib/PathTracing/Tracer/ShadowTracing.glsl"
+#include "/Lib/BasicFunctions/PrecomputedAtmosphere.glsl"
+
+#ifdef PT_IRC
+
+
+const ivec3 workGroups = ivec3(int(ceil(float(ircResolution) / 4.0)));
+layout (local_size_x = 4, local_size_y = 4, local_size_z = 4) in;
+
+layout (rgba16f) uniform writeonly image3D img_irradianceCache3D;
+layout (rgba16f) uniform readonly image3D img_irradianceCache3D_Alt;
+
+uniform sampler3D voxelData3D;
+
+void main(){
+	ivec3 texel = ivec3(gl_GlobalInvocationID.xyz);
+
+	if (any(greaterThanEqual(texel, ivec3(ircResolution)))){
+		return;
+	}
+
+	// World position of this cache cell
+	vec3 cellPos = (vec3(texel) + 0.5) / float(ircResolution);
+	vec3 worldPos = (cellPos - 0.5) * voxelDistance + cameraPosition;
+
+	// Voxel occupancy check — don't cache inside solid blocks
+	vec3 voxelCoord = cellPos * voxelResolution;
+	vec4 voxelData = texelFetch(voxelData3D, ivec3(clamp(voxelCoord, vec3(0.0), vec3(voxelResolution - 1.0))), 0);
+	float voxelID = DecodeVoxelID(voxelData.z);
+
+	if (voxelID > 1.0 && voxelID < 999.0){
+		// Solid — keep old value
+		return;
+	}
+
+	// Sample sky irradiance from multiple directions (hemisphere)
+	vec3 irradiance = vec3(0.0);
+
+	for (int i = 0; i < PT_IRC_SPP; i++){
+		// Deterministic sample directions over hemisphere
+		float phi = 6.28318 * hash1(vec3(texel) + float(i) * 1.7);
+		float cosTheta = hash1(vec3(texel) * 2.0 + float(i) * 3.1);
+		float sinTheta = sqrt(1.0 - cosTheta * cosTheta);
+
+		vec3 dir = vec3(cos(phi) * sinTheta, cosTheta, sin(phi) * sinTheta);
+
+		// Trace toward sky — if not blocked, add sky light
+		vec3 voxelPos = WorldToVoxel(worldPos) + dir * 0.5;
+		float visibility = SimpleShadowTracing(voxelPos, dir);
+
+		// Sky radiance in this direction (analytic)
+		vec3 skyRadiance = GetSkyRadiance(dir, GetSunDirWorld());
+
+		irradiance += skyRadiance * visibility;
+	}
+
+	irradiance /= float(PT_IRC_SPP);
+
+	// Sun contribution (direct)
+	vec3 sunDir = GetSunDirWorld();
+	float sunVis = SimpleShadowTracing(WorldToVoxel(worldPos), sunDir);
+	irradiance += GetSunIrradiance() * sunVis * max(sunDir.y, 0.0);
+
+	// Blend with previous (temporal smoothing), ping-pong by frame parity
+	bool evenFrame = (frameCounter % 2) == 0;
+	vec3 prev = evenFrame
+		? texelFetch(img_irradianceCache3D_Alt, texel, 0).rgb
+		: texelFetch(img_irradianceCache3D, texel, 0).rgb;
+	irradiance = mix(prev, irradiance, PT_IRC_BLENDWEIGHT);
+
+	if (evenFrame){
+		imageStore(img_irradianceCache3D, texel, vec4(irradiance, 1.0));
+	}else{
+		imageStore(img_irradianceCache3D_Alt, texel, vec4(irradiance, 1.0));
+	}
+}
+
+#endif