64 lines
2.0 KiB
GLSL
64 lines
2.0 KiB
GLSL
// MinecraftPT — SH_Tracing_CS
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// Low-order spherical-harmonics sky tracing: evaluates sky radiance on a small
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// SH basis and stores it for ambient light estimation (used by IRC seeding).
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#include "/Lib/Settings.glsl"
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#include "/Lib/Utilities.glsl"
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#include "/Lib/BasicFunctions/LightingConstants.glsl"
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#include "/Lib/BasicFunctions/PrecomputedAtmosphere.glsl"
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#include "/Lib/PathTracing/Tracer/ShadowTracing.glsl"
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#include "/Lib/PathTracing/Voxelizer/VoxelProfile.glsl"
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#ifdef PT_IRC
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const ivec3 workGroups = ivec3(int(ceil(float(ircResolution) / 4.0)));
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layout (local_size_x = 4, local_size_y = 4, local_size_z = 4) in;
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layout (rgba16f) uniform writeonly image3D img_irradianceCache3D;
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layout (rgba16f) uniform readonly image3D img_irradianceCache3D_Alt;
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uniform sampler3D voxelData3D;
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// SH basis Y1 (linear, 3 components) coefficients for sky radiance at a cell
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void main(){
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ivec3 texel = ivec3(gl_GlobalInvocationID.xyz);
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if (any(greaterThanEqual(texel, ivec3(ircResolution)))){
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return;
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}
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vec3 cellPos = (vec3(texel) + 0.5) / float(ircResolution);
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vec3 worldPos = (cellPos - 0.5) * voxelDistance + cameraPosition;
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vec3 voxelCoord = cellPos * voxelResolution;
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vec4 voxelData = texelFetch(voxelData3D, ivec3(clamp(voxelCoord, vec3(0.0), vec3(voxelResolution - 1.0))), 0);
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float voxelID = DecodeVoxelID(voxelData.z);
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if (voxelID > 1.0 && voxelID < 999.0){
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return;
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}
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// Trace N directions, accumulate SH coefficients
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vec3 sh = vec3(0.0);
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for (int i = 0; i < 6; i++){
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float phi = 6.28318 * hash1(vec3(texel) * 1.3 + float(i) * 0.7);
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float cosTheta = hash1(vec3(texel) * 0.7 + float(i) * 1.9);
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float sinTheta = sqrt(1.0 - cosTheta * cosTheta);
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vec3 dir = vec3(cos(phi) * sinTheta, cosTheta, sin(phi) * sinTheta);
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float visibility = SimpleShadowTracing(WorldToVoxel(worldPos) + dir * 0.5, dir);
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vec3 radiance = GetSkyRadiance(dir, GetSunDirWorld());
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sh += radiance * visibility * cosTheta; // cos-weighted
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}
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sh /= 6.0;
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imageStore(img_irradianceCache3D, texel, vec4(sh, 1.0));
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}
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#endif |