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fix(pbr): fix improper kD terms #1971

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Merged
doodlum merged 3 commits into from
Mar 13, 2026
Merged

fix(pbr): fix improper kD terms #1971

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4c5c89e
fix: pbr fixes
doodlum Mar 13, 2026
73c91ec
style: 🎨 apply pre-commit.ci formatting
pre-commit-ci[bot] Mar 13, 2026
3b38b90
refactor: idk
doodlum Mar 13, 2026
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31 changes: 15 additions & 16 deletions package/Shaders/Common/PBR.hlsli
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Original file line number Diff line number Diff line change
Expand Up @@ -152,21 +152,22 @@ namespace PBR
else
#endif
{
lightingOutput.diffuse += detailedLightColor * satNdotL * BRDF::Diffuse_Lambert();

float3 F;
#if defined(GLINT)
lightingOutput.specular += GetSpecularDirectLightMultiplierMicrofacetWithGlint(material.Noise, material.Roughness, material.F0, satNdotL, satNdotV, satNdotH, satVdotH, mul(tbnTr, H).x,
material.GlintLogMicrofacetDensity, material.GlintMicrofacetRoughness, material.GlintDensityRandomization, material.GlintCache, F) *
detailedLightColor * satNdotL;
float3 specular = GetSpecularDirectLightMultiplierMicrofacetWithGlint(material.Noise, material.Roughness, material.F0, satNdotL, satNdotV, satNdotH, satVdotH, mul(tbnTr, H).x,
material.GlintLogMicrofacetDensity, material.GlintMicrofacetRoughness, material.GlintDensityRandomization, material.GlintCache, F);
#else
lightingOutput.specular += GetSpecularDirectLightMultiplierMicrofacet(material.Roughness, material.F0, satNdotL, satNdotV, satNdotH, satVdotH, F) * detailedLightColor * satNdotL;
float3 specular = GetSpecularDirectLightMultiplierMicrofacet(material.Roughness, material.F0, satNdotL, satNdotV, satNdotH, satVdotH, F);
#endif
float3 kD = 1 - F;

lightingOutput.diffuse += detailedLightColor * satNdotL * BRDF::Diffuse_Lambert() * kD;
lightingOutput.specular += specular * detailedLightColor * satNdotL;

#if !defined(LANDSCAPE) && !defined(LODLANDSCAPE)
[branch] if ((PBRFlags & Flags::Fuzz) != 0)
{
float3 fuzzSpecular = GetSpecularDirectLightMultiplierMicroflakes(material.Roughness, material.FuzzColor, satNdotL, satNdotV, satNdotH, satVdotH) * context.lightColor * satNdotL;
float3 fuzzSpecular = GetSpecularDirectLightMultiplierMicroflakes(material.Roughness, material.FuzzColor, satNdotL, satNdotV, satNdotH, satVdotH) * detailedLightColor * satNdotL;
lightingOutput.specular = lerp(lightingOutput.specular, fuzzSpecular, material.FuzzWeight);
}

Expand All @@ -176,7 +177,7 @@ namespace PBR
float forwardScatter = exp2(saturate(-VdotL) * subsurfacePower - subsurfacePower);
float backScatter = saturate(satNdotL * material.Thickness + (1.0 - material.Thickness)) * 0.5;
float subsurface = lerp(backScatter, 1, forwardScatter) * (1.0 - material.Thickness);
lightingOutput.transmission += material.SubsurfaceColor * subsurface * softLightColor * BRDF::Diffuse_Lambert();
lightingOutput.transmission += material.SubsurfaceColor * subsurface * softLightColor * BRDF::Diffuse_Lambert() * kD;
}
else if ((PBRFlags & Flags::TwoLayer) != 0)
{
Expand Down Expand Up @@ -241,27 +242,25 @@ namespace PBR
float2 specularBRDF = BRDF::EnvBRDF(material.Roughness, NdotV);
lobeWeights.specular = material.F0 * specularBRDF.x + specularBRDF.y;

float3 F = BRDF::F_Schlick(material.F0, NdotV);
lobeWeights.diffuse *= 1 - F;
float3 kD = 1 - lobeWeights.specular;
lobeWeights.diffuse *= kD;

#if !defined(LANDSCAPE) && !defined(LODLANDSCAPE)
[branch] if ((PBRFlags & Flags::TwoLayer) != 0)
{
float2 coatSpecularBRDF = BRDF::EnvBRDF(material.CoatRoughness, NdotV);
float3 coatSpecularLobeWeight = material.CoatF0 * coatSpecularBRDF.x + coatSpecularBRDF.y;
float3 coatSpecularLobeSpecular = material.CoatF0 * coatSpecularBRDF.x + coatSpecularBRDF.y;

float3 coatF = BRDF::F_Schlick(material.CoatF0, NdotV);

float3 layerAttenuation = 1 - coatF * material.CoatStrength;
float3 layerAttenuation = 1 - coatSpecularLobeSpecular * material.CoatStrength;
lobeWeights.diffuse *= layerAttenuation;
lobeWeights.specular *= layerAttenuation;

[branch] if ((PBRFlags & Flags::ColoredCoat) != 0)
{
float3 coatDiffuseLobeWeight = material.CoatColor * (1 - coatSpecularLobeWeight);
float3 coatDiffuseLobeWeight = material.CoatColor * (1 - coatSpecularLobeSpecular);
lobeWeights.diffuse += coatDiffuseLobeWeight * material.CoatStrength;
}
lobeWeights.specular += coatSpecularLobeWeight * material.CoatStrength;
lobeWeights.specular += coatSpecularLobeSpecular * material.CoatStrength;
}
#endif
}
Expand Down
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