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

shaders/Lib/PathTracing/Voxelizer/VoxelProfile.glsl

@@ -0,0 +1,139 @@
+#include "/Lib/Settings.glsl"
+#include "/Lib/Utilities.glsl"
+// MinecraftPT — Voxel Profile
+// Voxel grid parameters derived from settings.
+//
+// The shadow framebuffer (shadowcolor0/1) is square, size S x S, and holds:
+//   - the VOXEL ATLAS in the bottom-left region: texels [0, W) x [0, H)
+//     where W = voxelWidth and H = ceil(N / W), N = Rx*Ry*Rz voxels.
+//     Each voxel is one texel; linear packing: n = x + y*Rx + z*Rx*Ry.
+//   - the SHADOW MAP in the right square region: texels [W, 2W) x [0, W).
+//     The shadow camera NDC is shifted into this region (square -> square,
+//     no aspect distortion). Effective shadow resolution = W.
+
+#ifndef VOXEL_PROFILE_GLSL
+#define VOXEL_PROFILE_GLSL
+
+// Shadow render distance -> shadow coverage
+#if SHADOW_RENDER_DISTANCE == 4
+	const float shadowDistance = 64.1;
+#elif SHADOW_RENDER_DISTANCE == 6
+	const float shadowDistance = 96.1;
+#elif SHADOW_RENDER_DISTANCE == 8
+	const float shadowDistance = 128.1;
+#elif SHADOW_RENDER_DISTANCE == 12
+	const float shadowDistance = 192.1;
+#elif SHADOW_RENDER_DISTANCE == 16
+	const float shadowDistance = 256.1;
+#elif SHADOW_RENDER_DISTANCE == 24
+	const float shadowDistance = 384.1;
+#elif SHADOW_RENDER_DISTANCE == 32
+	const float shadowDistance = 512.1;
+#elif SHADOW_RENDER_DISTANCE == 48
+	const float shadowDistance = 768.1;
+#elif SHADOW_RENDER_DISTANCE == 64
+	const float shadowDistance = 1024.1;
+#elif SHADOW_RENDER_DISTANCE == 96
+	const float shadowDistance = 1536.1;
+#elif SHADOW_RENDER_DISTANCE == 128
+	const float shadowDistance = 2048.1;
+#else
+	const float shadowDistance = 256.1;
+#endif
+
+// Voxel grid resolution and coverage (blocks)
+#if   PT_VOXEL_RESOLUTION == 4004
+	const ivec3 voxelResolutionInt = ivec3(128);
+	const float voxelDistance = 64.0;
+	const int voxelWidth = 2048;
+#elif PT_VOXEL_RESOLUTION == 6004
+	const ivec3 voxelResolutionInt = ivec3(192, 128, 192);
+	const float voxelDistance = 96.0;
+	const int voxelWidth = 2048;
+#elif PT_VOXEL_RESOLUTION == 8004
+	const ivec3 voxelResolutionInt = ivec3(256, 128, 256);
+	const float voxelDistance = 128.0;
+	const int voxelWidth = 2048;
+#elif PT_VOXEL_RESOLUTION == 8006
+	const ivec3 voxelResolutionInt = ivec3(256, 192, 256);
+	const float voxelDistance = 128.0;
+	const int voxelWidth = 4096;
+#elif PT_VOXEL_RESOLUTION == 8008
+	const ivec3 voxelResolutionInt = ivec3(256);
+	const float voxelDistance = 128.0;
+	const int voxelWidth = 4096;
+#elif PT_VOXEL_RESOLUTION == 12004
+	const ivec3 voxelResolutionInt = ivec3(384, 128, 384);
+	const float voxelDistance = 192.0;
+	const int voxelWidth = 4096;
+#elif PT_VOXEL_RESOLUTION == 12006
+	const ivec3 voxelResolutionInt = ivec3(384, 192, 384);
+	const float voxelDistance = 192.0;
+	const int voxelWidth = 4096;
+#elif PT_VOXEL_RESOLUTION == 12008
+	const ivec3 voxelResolutionInt = ivec3(384, 256, 384);
+	const float voxelDistance = 192.0;
+	const int voxelWidth = 6144;
+#elif PT_VOXEL_RESOLUTION == 16004
+	const ivec3 voxelResolutionInt = ivec3(512, 128, 512);
+	const float voxelDistance = 256.0;
+	const int voxelWidth = 6144;
+#elif PT_VOXEL_RESOLUTION == 16008
+	const ivec3 voxelResolutionInt = ivec3(512, 256, 512);
+	const float voxelDistance = 256.0;
+	const int voxelWidth = 6144;
+#elif PT_VOXEL_RESOLUTION == 16016
+	const ivec3 voxelResolutionInt = ivec3(512);
+	const float voxelDistance = 256.0;
+	const int voxelWidth = 8192;
+#else
+	const ivec3 voxelResolutionInt = ivec3(256, 192, 256);
+	const float voxelDistance = 128.0;
+	const int voxelWidth = 4096;
+#endif
+
+const vec3 voxelResolution = vec3(voxelResolutionInt);
+
+// Irradiance cache resolution (clamped to voxel grid)
+const int ircResolution = min(PT_IRC_RESOLUTION, voxelResolutionInt.x);
+
+// Shadow framebuffer size (square)
+const int shadowMapResolution = voxelWidth * 2;
+const float shadowSize = float(shadowMapResolution);
+const float shadowPixelSize = 1.0 / shadowSize;
+const float shadowRatio = 0.5; // W / S
+
+// Map 3D voxel coordinate to 2D atlas texel (linear packing)
+vec2 VoxelTexel_From_VoxelCoord(vec3 voxelCoord){
+	float n = voxelCoord.x + voxelCoord.y * voxelResolution.x + voxelCoord.z * voxelResolution.x * voxelResolution.y;
+	return vec2(mod(n, float(voxelWidth)), floor(n / float(voxelWidth)));
+}
+
+// Shift shadow map NDC into the right square region [W, 2W] x [0, W]
+void ShiftShadowNdcPos(inout vec2 coord){
+	coord = coord * shadowRatio + vec2(1.0 - shadowRatio, shadowRatio - 1.0);
+}
+
+// Shift shadow map screen uv into the right square region
+void ShiftShadowScreenPos(inout vec2 coord){
+	coord = coord * shadowRatio + vec2(1.0 - shadowRatio, 0.0);
+}
+
+// Shift back from shadow region uv to standard shadow uv
+vec2 UnshiftShadowScreenPos(vec2 coord){
+	return (coord - vec2(1.0 - shadowRatio, 0.0)) / shadowRatio;
+}
+
+// Block ID encoding (16-bit range)
+// Full block: voxelID + 1000
+// Cutout shape: 1000 - voxelID
+// Empty markers: 0.91 (8^3), 0.71 (4^3), 0.61 (2^3)
+float EncodeVoxelID(float voxelID){
+	return saturate((voxelID + 1000.0) / 65535.0);
+}
+
+float DecodeVoxelID(float encoded){
+	return abs(floor(encoded * 65535.0 - 999.9));
+}
+
+#endif