97 lines
3.3 KiB
HLSL
97 lines
3.3 KiB
HLSL
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#ifndef __AMBIENTPROBE_HLSL__
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#define __AMBIENTPROBE_HLSL__
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/SphericalHarmonics.hlsl"
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// Ambient Probe is preconvolved with clamped cosinus
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// In case we use a diffuse power, we have to edit the coefficients to change the convolution
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// This is currently not used because visual difference is really minor
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void ReconvolveAmbientProbeWithPower(float diffusePower, inout float4 SHCoefficients[7])
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{
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if (diffusePower == 0.0f)
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return;
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// convolution coefs
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float w = diffusePower + 1;
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float kModifiedLambertian0 = 1.0f;
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float kModifiedLambertian1 = (w + 1.0f) / (w + 2.0f);
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float kModifiedLambertian2 = w / (w + 3.0f);
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// ambient probe is pre-convolved by clamped cosine - we have to undo pre-convolution and
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// convolve again with coefs for modified lambertian
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float wrapScaling0 = kModifiedLambertian0 / kClampedCosine0;
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float wrapScaling1 = kModifiedLambertian1 / kClampedCosine1;
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float wrapScaling2 = kModifiedLambertian2 / kClampedCosine2;
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// handle coeficient packing - see AmbientProbeConvolution.compute : PackSHFromScratchBuffer
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float3 ambient6 = float3(SHCoefficients[3].z, SHCoefficients[4].z, SHCoefficients[5].z) / 3.0f;
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float3 ambient0 = float3(SHCoefficients[0].a, SHCoefficients[1].a, SHCoefficients[2].a) + ambient6;
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SHCoefficients[0].xyz *= wrapScaling1;
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SHCoefficients[1].xyz *= wrapScaling1;
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SHCoefficients[2].xyz *= wrapScaling1;
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SHCoefficients[3] *= wrapScaling2;
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SHCoefficients[4] *= wrapScaling2;
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SHCoefficients[5] *= wrapScaling2;
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SHCoefficients[6] *= wrapScaling2;
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SHCoefficients[0].a = ambient0.r * wrapScaling0 - ambient6.r * wrapScaling2;
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SHCoefficients[1].a = ambient0.g * wrapScaling0 - ambient6.g * wrapScaling2;
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SHCoefficients[2].a = ambient0.b * wrapScaling0 - ambient6.b * wrapScaling2;
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}
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// We need to define this before including ProbeVolume.hlsl as that file expects this function to be defined.
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// AmbientProbe Data is fetch directly from a compute buffer to remain on GPU and is preconvolved with clamped cosinus
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real3 EvaluateAmbientProbe(real3 normalWS)
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{
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#if AMBIENT_PROBE_BUFFER
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return SampleSH9(_AmbientProbeData, normalWS);
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#else
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// Linear + constant polynomial terms
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real3 res = SHEvalLinearL0L1(normalWS, unity_SHAr, unity_SHAg, unity_SHAb);
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// Quadratic polynomials
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res += SHEvalLinearL2(normalWS, unity_SHBr, unity_SHBg, unity_SHBb, unity_SHC);
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return res;
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#endif
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}
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real3 EvaluateAmbientProbeSRGB(real3 normalWS)
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{
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real3 res = EvaluateAmbientProbe(normalWS);
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#ifdef UNITY_COLORSPACE_GAMMA
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res = LinearToSRGB(res);
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#endif
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return res;
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}
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real3 SampleSH(real3 normalWS)
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{
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return EvaluateAmbientProbeSRGB(normalWS);
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}
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real3 EvaluateAmbientProbeL1(real3 normalWS)
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{
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#if AMBIENT_PROBE_BUFFER
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real4 SHCoefficients[3];
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SHCoefficients[0] = _AmbientProbeData[0];
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SHCoefficients[1] = _AmbientProbeData[1];
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SHCoefficients[2] = _AmbientProbeData[2];
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return SampleSH4_L1(SHCoefficients, normalWS);
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#else
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return real3(0.0, 0.0, 0.0);
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#endif
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}
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real3 EvaluateAmbientProbeL0()
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{
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#if AMBIENT_PROBE_BUFFER
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return real3(_AmbientProbeData[0].w, _AmbientProbeData[1].w, _AmbientProbeData[2].w);
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#else
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return real3(0.0, 0.0, 0.0);
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#endif
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}
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#endif
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