103 lines
3.4 KiB
Plaintext
103 lines
3.4 KiB
Plaintext
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layout(local_size_x = 16, local_size_y = 16) in;
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uniform sampler2D inputTexture;
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layout(std430, binding = 1) buffer SHCoefficients {
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vec3 sh[9];
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};
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layout(std430, binding = 2) buffer WorkGroupResults {
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vec3 wg_results[];
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};
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uniform float skyIntensity;
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uniform ivec2 textureSize;
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uniform int faceIndex;
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uniform int pass;
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shared vec3 sh_local[9];
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const float PI = 3.14159265359;
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const vec3 skyDir[6] = vec3[6](
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vec3( 1, 0, 0), vec3(-1, 0, 0),
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vec3( 0, 1, 0), vec3( 0,-1, 0),
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vec3( 0, 0, 1), vec3( 0, 0,-1)
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);
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const vec3 skyX[6] = vec3[6](
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vec3( 0, 0,-1), vec3( 0, 0, 1),
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vec3( 1, 0, 0), vec3( 1, 0, 0),
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vec3( 1, 0, 0), vec3(-1, 0, 0)
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);
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const vec3 skyY[6] = vec3[6](
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vec3( 0, 1, 0), vec3( 0, 1, 0),
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vec3( 0, 0,-1), vec3( 0, 0, 1),
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vec3( 0, 1, 0), vec3( 0, 1, 0)
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);
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void main() {
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if (pass == 0) {
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// First pass: process texels and accumulate in work groups
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if (gl_LocalInvocationIndex == 0) {
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for (int i = 0; i < 9; ++i) {
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sh_local[i] = vec3(0.0);
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}
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}
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barrier();
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ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
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if (any(greaterThanEqual(texel, textureSize))) return;
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vec2 uv = (vec2(texel) + 0.5) / vec2(textureSize);
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vec3 n = normalize(skyDir[faceIndex] +
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skyX[faceIndex] * (2.0 * uv.x - 1.0) +
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skyY[faceIndex] * (1.0 - 2.0 * uv.y));
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vec3 color = textureLod(inputTexture, uv, 0).rgb;
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float l = length(n);
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vec3 light = color * (1.0 / (l * l * l)) * skyIntensity;
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// Accumulate SH coefficients
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vec3 sh_[9];
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sh_[0] = light * 0.282095f;
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sh_[1] = light * (-0.488603f * n.y * 2.0 / 3.0);
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sh_[2] = light * (0.488603f * n.z * 2.0 / 3.0);
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sh_[3] = light * (-0.488603f * n.x * 2.0 / 3.0);
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sh_[4] = light * (1.092548f * n.x * n.y / 4.0);
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sh_[5] = light * (-1.092548f * n.y * n.z / 4.0);
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sh_[6] = light * (0.315392f * (3.0f * n.z * n.z - 1.0f) / 4.0);
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sh_[7] = light * (-1.092548f * n.x * n.z / 4.0);
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sh_[8] = light * (0.546274f * (n.x * n.x - n.y * n.y) / 4.0);
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// Add to local SH coefficients
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for (int i = 0; i < 9; ++i) {
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sh_local[i] += sh_[i];
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}
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barrier();
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// Store work group results
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if (gl_LocalInvocationIndex == 0) {
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uint wg_index = gl_WorkGroupID.y * gl_NumWorkGroups.x + gl_WorkGroupID.x;
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for (int i = 0; i < 9; ++i) {
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wg_results[wg_index * 9 + i] = sh_local[i];
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}
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}
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} else {
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// Second pass: combine work group results
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if (gl_WorkGroupID.x == 0 && gl_WorkGroupID.y == 0) {
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vec3 total_sh[9] = vec3[9](vec3(0), vec3(0), vec3(0), vec3(0), vec3(0), vec3(0), vec3(0), vec3(0), vec3(0));
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uint num_work_groups = gl_NumWorkGroups.x * gl_NumWorkGroups.y;
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for (uint i = gl_LocalInvocationIndex; i < num_work_groups; i += gl_WorkGroupSize.x * gl_WorkGroupSize.y) {
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for (int j = 0; j < 9; ++j) {
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total_sh[j] += wg_results[i * 9 + j];
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}
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}
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barrier();
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if (gl_LocalInvocationIndex < 9) {
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sh[gl_LocalInvocationIndex] += total_sh[gl_LocalInvocationIndex];
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}
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}
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}
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}
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