32 lines
No EOL
1.3 KiB
HLSL
32 lines
No EOL
1.3 KiB
HLSL
/*
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contributors: Patricio Gonzalez Vivo
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description: Calculate diffuse contribution using Oren and Nayar equation https://en.wikipedia.org/wiki/Oren%E2%80%93Nayar_reflectance_model
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use:
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- <float> diffuseOrenNayar(<float3> light, <float3> normal, <float3> view, <float> roughness )
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- <float> diffuseOrenNayar(<float3> L, <float3> N, <float3> V, <float> NoV, <float> NoL, <float> roughness)
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license:
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- Copyright (c) 2021 Patricio Gonzalez Vivo under Prosperity License - https://prosperitylicense.com/versions/3.0.0
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- Copyright (c) 2021 Patricio Gonzalez Vivo under Patron License - https://lygia.xyz/license
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*/
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#ifndef FNC_DIFFUSE_ORENNAYAR
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#define FNC_DIFFUSE_ORENNAYAR
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float diffuseOrenNayar(float3 L, float3 N, float3 V, float NoV, float NoL, float roughness) {
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float LoV = dot(L, V);
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float s = LoV - NoL * NoV;
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float t = lerp(1.0, max(NoL, NoV), step(0.0, s));
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float sigma2 = roughness * roughness;
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float A = 1.0 + sigma2 * (1.0 / (sigma2 + 0.13) + 0.5 / (sigma2 + 0.33));
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float B = 0.45 * sigma2 / (sigma2 + 0.09);
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return max(0.0, NoL) * (A + B * s / t);
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}
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float diffuseOrenNayar(ShadingData shadingData) {
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return diffuseOrenNayar(shadingData.L, shadingData.N, shadingData.V, shadingData.NoV, shadingData.NoL, shadingData.roughness);
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}
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#endif |