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WebGLRenderer/WebGPURenderer: Improve Physical Accuracy #32330

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Merged
mrdoob merged 1 commit into from
Nov 22, 2025
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WebGLRenderer/WebGPURenderer: Improve Physical Accuracy #32330

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2 changes: 1 addition & 1 deletion src/nodes/functions/BSDF/V_GGX_SmithCorrelated_Anisotropic.js
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ const V_GGX_SmithCorrelated_Anisotropic = /*@__PURE__*/ Fn( ( { alphaT, alphaB,
const gl = dotNV.mul( vec3( alphaT.mul( dotTL ), alphaB.mul( dotBL ), dotNL ).length() );
const v = div( 0.5, gv.add( gl ) );

return v.saturate();
return v;

} ).setLayout( {
name: 'V_GGX_SmithCorrelated_Anisotropic',
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2 changes: 1 addition & 1 deletion src/nodes/functions/PhysicalLightingModel.js
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Expand Up @@ -751,7 +751,7 @@ class PhysicalLightingModel extends LightingModel {
// Diffuse energy conservation uses dielectric path
const totalScatteringDielectric = singleScatteringDielectric.add( multiScatteringDielectric );

const diffuse = diffuseContribution.mul( totalScatteringDielectric.r.max( totalScatteringDielectric.g ).max( totalScatteringDielectric.b ).oneMinus() );
const diffuse = diffuseContribution.mul( totalScatteringDielectric.oneMinus() );

const cosineWeightedIrradiance = iblIrradiance.mul( 1 / Math.PI );

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10 changes: 4 additions & 6 deletions src/renderers/shaders/ShaderChunk/lights_physical_pars_fragment.glsl.js
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Expand Up @@ -71,12 +71,10 @@ vec3 Schlick_to_F0( const in vec3 f, const in float f90, const in float dotVH )
return ( f - vec3( f90 ) * x5 ) / ( 1.0 - x5 );
}

// Moving Frostbite to Physically Based Rendering 3.0 - page 12, listing 2
// https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf
// Heitz 2014, "Understanding the Masking-Shadowing Function in Microfacet-Based BRDFs"
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@donmccurdy donmccurdy Nov 24, 2025

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It doesn't seem like this function's implementation has changed, and the previous link gave a specific location in the paper, where the new link is a 60-page document. Perhaps the old link could be kept, or a more specific section of the new paper referenced?

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@mrdoob mrdoob Nov 25, 2025

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Done! 53e7451

float V_GGX_SmithCorrelated( const in float alpha, const in float dotNL, const in float dotNV ) {

float a2 = pow2( alpha );

float gv = dotNL * sqrt( a2 + ( 1.0 - a2 ) * pow2( dotNV ) );
float gl = dotNV * sqrt( a2 + ( 1.0 - a2 ) * pow2( dotNL ) );

Expand Down Expand Up @@ -106,7 +104,7 @@ float D_GGX( const in float alpha, const in float dotNH ) {
float gl = dotNV * length( vec3( alphaT * dotTL, alphaB * dotBL, dotNL ) );
float v = 0.5 / ( gv + gl );

return saturate(v);
return v;

}

Expand Down Expand Up @@ -463,7 +461,7 @@ vec3 BRDF_GGX_Multiscatter( const in vec3 lightDir, const in vec3 viewDir, const
vec3 Favg = material.specularColorBlended + ( 1.0 - material.specularColorBlended ) * 0.047619; // 1/21

// Multiple scattering contribution
vec3 Fms = FssEss_V * FssEss_L * Favg / ( 1.0 - Ems_V * Ems_L * Favg * Favg + EPSILON );
vec3 Fms = FssEss_V * FssEss_L * Favg / ( 1.0 - Ems_V * Ems_L * Favg + EPSILON );

// Energy compensation factor
float compensationFactor = Ems_V * Ems_L;
Expand Down Expand Up @@ -590,7 +588,7 @@ void RE_IndirectSpecular_Physical( const in vec3 radiance, const in vec3 irradia

// Diffuse energy conservation uses dielectric path
vec3 totalScatteringDielectric = singleScatteringDielectric + multiScatteringDielectric;
vec3 diffuse = material.diffuseContribution * ( 1.0 - max( max( totalScatteringDielectric.r, totalScatteringDielectric.g ), totalScatteringDielectric.b ) );
vec3 diffuse = material.diffuseContribution * ( 1.0 - totalScatteringDielectric );

vec3 cosineWeightedIrradiance = irradiance * RECIPROCAL_PI;

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