38 lines
1.0 KiB
GLSL
38 lines
1.0 KiB
GLSL
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// Generates an irradiance cube from an environment map using convolution
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#version 450
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layout (location = 0) in vec3 inPos;
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layout (location = 0) out vec4 outColor;
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layout (binding = 0) uniform samplerCube samplerEnv;
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layout(push_constant) uniform PushConsts {
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layout (offset = 64) float deltaPhi;
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layout (offset = 68) float deltaTheta;
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} consts;
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#define PI 3.1415926535897932384626433832795
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void main()
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{
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vec3 N = normalize(inPos);
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vec3 up = vec3(0.0, 1.0, 0.0);
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vec3 right = normalize(cross(up, N));
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up = cross(N, right);
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const float TWO_PI = PI * 2.0;
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const float HALF_PI = PI * 0.5;
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vec3 color = vec3(0.0);
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uint sampleCount = 0u;
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for (float phi = 0.0; phi < TWO_PI; phi += consts.deltaPhi) {
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for (float theta = 0.0; theta < HALF_PI; theta += consts.deltaTheta) {
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vec3 tempVec = cos(phi) * right + sin(phi) * up;
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vec3 sampleVector = cos(theta) * N + sin(theta) * tempVec;
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color += texture(samplerEnv, sampleVector).rgb * cos(theta) * sin(theta);
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sampleCount++;
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}
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}
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outColor = vec4(PI * color / float(sampleCount), 1.0);
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}
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