34 lines
956 B
GLSL
34 lines
956 B
GLSL
uniform samplerCube tex;
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uniform samplerBuffer samples;
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uniform float ViewportSize;
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uniform mat4 PermutationMatrix;
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out vec4 FragColor;
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void main(void)
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{
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vec2 uv = gl_FragCoord.xy / ViewportSize;
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vec3 RayDir = 2. * vec3(uv, 1.) - 1.;
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RayDir = normalize((PermutationMatrix * vec4(RayDir, 0.)).xyz);
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vec4 FinalColor = vec4(0.);
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vec3 up = (RayDir.y < .99) ? vec3(0., 1., 0.) : vec3(0., 0., 1.);
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vec3 Tangent = normalize(cross(up, RayDir));
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vec3 Bitangent = cross(RayDir, Tangent);
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float weight = 0.;
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for (int i = 0; i < 1024; i++)
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{
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float Theta = texelFetch(samples, i).r;
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float Phi = texelFetch(samples, i).g;
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vec3 L = cos(Theta) * RayDir + sin(Theta) * cos(Phi) * Tangent + sin(Theta) * sin(Phi) * Bitangent;
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float NdotL = clamp(dot(RayDir, L), 0., 1.);
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FinalColor += textureLod(tex, L, 0.) * NdotL;
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weight += NdotL;
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}
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FragColor = FinalColor / weight;
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}
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