71 lines
2.6 KiB
HLSL
71 lines
2.6 KiB
HLSL
#ifndef UNITY_SIX_WAY_COMMON_INCLUDED
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#define UNITY_SIX_WAY_COMMON_INCLUDED
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#define ABSORPTION_EPSILON max(REAL_MIN, 1e-5)
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real3 ComputeDensityScales(real3 absorptionColor)
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{
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absorptionColor.rgb = max(ABSORPTION_EPSILON, absorptionColor.rgb);
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// Empirical value used to parametrize absorption from color
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const real absorptionStrength = 0.2f;
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return 1.0f + log2(absorptionColor.rgb) / log2(absorptionStrength);
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}
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real3 GetTransmissionWithAbsorption(real transmission, real3 densityScales, real absorptionRange)
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{
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// Recompute transmission based on density scaling
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return pow(saturate(transmission / absorptionRange), densityScales);
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}
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real3 GetTransmissionWithAbsorption(real transmission, real4 absorptionColor, real absorptionRange, bool alphaPremultiplied)
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{
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#if defined(_SIX_WAY_COLOR_ABSORPTION)
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real3 densityScales = ComputeDensityScales(absorptionColor.rgb);
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if(alphaPremultiplied)
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absorptionRange *= (absorptionColor.a > 0) ? absorptionColor.a : 1.0f;
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real3 outTransmission = GetTransmissionWithAbsorption(transmission, densityScales, absorptionRange);
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outTransmission *= absorptionRange;
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return outTransmission;
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#else
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return transmission.xxx * absorptionColor.rgb; // simple multiply
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#endif
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}
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real3 GetSixWayDiffuseContributions(real3 rightTopBack, real3 leftBottomFront, real4 baseColor, real3 L0, real3 diffuseGIData[3], real absorptionRange, bool alphaPremultiplied)
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{
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real3 giColor = real3(0,0,0);
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// Scale to be energy conserving: Total energy = 4*pi; divided by 6 directions
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real scale = 4.0f * PI / 6.0f;
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#if defined(_SIX_WAY_COLOR_ABSORPTION)
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real3 densityScales = ComputeDensityScales(baseColor.rgb);
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if(alphaPremultiplied)
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absorptionRange *= (baseColor.a > 0) ? baseColor.a : 1.0f;
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for(int i = 0; i < 3; i++)
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{
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real3 bakeDiffuseLighting = L0 + diffuseGIData[i];
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giColor += GetTransmissionWithAbsorption(rightTopBack[i], densityScales, absorptionRange) * bakeDiffuseLighting;
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bakeDiffuseLighting = L0 - diffuseGIData[i];
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giColor += GetTransmissionWithAbsorption(leftBottomFront[i], densityScales, absorptionRange) * bakeDiffuseLighting;
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}
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giColor *= absorptionRange;
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#else
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for(int i = 0; i < 3; i++)
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{
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real3 bakeDiffuseLighting = L0 + diffuseGIData[i];
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giColor += rightTopBack[i] * bakeDiffuseLighting;
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bakeDiffuseLighting = L0 - diffuseGIData[i];
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giColor += leftBottomFront[i] * bakeDiffuseLighting;
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}
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giColor *= baseColor.rgb;
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#endif
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return giColor * scale;
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}
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#endif // UNITY_SIX_WAY_COMMON_INCLUDED
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