47 lines
1.6 KiB
GLSL
47 lines
1.6 KiB
GLSL
//This shader file is part of FLAR - Advanced Renderer for Freelancer by Schmackbolzen
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//If you use the supplied shader files you may not modify them unless you state in them what you changed
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//and also mention the source or who the author is.
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//Code based on https://learnopengl.com/PBR/IBL/Specular-IBL
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#version 330
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#include "ColorConversion.inc"
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in vec3 WorldPos;
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uniform samplerCube environmentMap;
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uniform bool convertToLinear;
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const float PI = 3.14159265359;
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void main()
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{
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vec3 N = normalize(WorldPos);
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vec3 irradiance = vec3(0.0);
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// tangent space calculation from origin point
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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 = normalize(cross(N, right));
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float sampleDelta = 0.025;
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float nrSamples = 0.0f;
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for(float phi = 0.0; phi < 2.0 * PI; phi += sampleDelta)
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{
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for(float theta = 0.0; theta < 0.5 * PI; theta += sampleDelta)
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{
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// spherical to cartesian (in tangent space)
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vec3 tangentSample = vec3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
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// tangent space to world
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vec3 sampleVec = tangentSample.x * right + tangentSample.y * up + tangentSample.z * N;
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vec3 texColor=texture(environmentMap, sampleVec).rgb;
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if(convertToLinear)
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texColor=ToLinear(texColor);
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irradiance += texColor * cos(theta) * sin(theta);
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nrSamples++;
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}
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}
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irradiance = PI * irradiance * (1.0 / float(nrSamples));
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gl_FragColor = vec4(ToGammaCorrected(irradiance), 1.0);
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} |