forked from BilalY/Rasagar
388 lines
19 KiB
HLSL
388 lines
19 KiB
HLSL
#include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/PathTracing/Shaders/PathTracingPayload.hlsl"
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#include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/PathTracing/Shaders/PathTracingMaterial.hlsl"
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#include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/PathTracing/Shaders/PathTracingBSDF.hlsl"
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#include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/PathTracing/Shaders/PathTracingAOV.hlsl"
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// StackLit Material Data:
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//
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// bsdfWeight0 Diffuse BRDF
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// bsdfWeight1 Coat GGX BRDF
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// bsdfWeight2 SpecA GGX BRDF
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// bsdfWeight3 SpecB GGX BRDF
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float3 GetCoatNormal(MaterialData mtlData)
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{
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return mtlData.bsdfData.coatNormalWS;
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}
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float3 GetSpecularCompensationA(MaterialData mtlData)
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{
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return 1.0 + mtlData.bsdfData.specularOcclusionCustomInput * mtlData.bsdfData.fresnel0;
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}
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float3 GetSpecularCompensationB(MaterialData mtlData)
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{
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return 1.0 + mtlData.bsdfData.soFixupStrengthFactor * mtlData.bsdfData.fresnel0;
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}
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void ProcessBSDFData(PathPayload payload, BuiltinData builtinData, MaterialData mtlData, inout BSDFData bsdfData)
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{
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// Adjust roughness to reduce fireflies
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bsdfData.roughnessAT = max(payload.maxRoughness, bsdfData.roughnessAT);
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bsdfData.roughnessAB = max(payload.maxRoughness, bsdfData.roughnessAB);
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bsdfData.roughnessBT = max(payload.maxRoughness, bsdfData.roughnessBT);
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bsdfData.roughnessBB = max(payload.maxRoughness, bsdfData.roughnessBB);
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float NdotV = abs(dot(GetSpecularNormal(mtlData), mtlData.V));
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// Modify fresnel0 value to take iridescence into account
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if (HasFlag(bsdfData.materialFeatures, MATERIALFEATUREFLAGS_STACK_LIT_IRIDESCENCE) && bsdfData.iridescenceMask > 0.0)
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bsdfData.fresnel0 = lerp(bsdfData.fresnel0, EvalIridescence(1.0, NdotV, bsdfData.iridescenceThickness, bsdfData.fresnel0), bsdfData.iridescenceMask);
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// We store energy compensation coefficients for GGX into the specular occlusion and strength factor
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#ifdef STACK_LIT_USE_GGX_ENERGY_COMPENSATION
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float sqrtNdotV = sqrt(NdotV);
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if (bsdfData.lobeMix < 1.0)
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bsdfData.specularOcclusionCustomInput = BRDF::GetGGXMultipleScatteringEnergy(0.5 * (bsdfData.roughnessAT + bsdfData.roughnessAB), sqrtNdotV);
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if (bsdfData.lobeMix > 0.0)
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bsdfData.soFixupStrengthFactor = BRDF::GetGGXMultipleScatteringEnergy(0.5 * (bsdfData.roughnessBT + bsdfData.roughnessBB), sqrtNdotV);
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#else
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bsdfData.specularOcclusionCustomInput = 0.0;
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bsdfData.soFixupStrengthFactor = 0.0;
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#endif
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// We restore the original coatIor by reverting the premultiplication, when possible (see StackLit.hlsl, l471)
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if (bsdfData.coatMask > 0.001)
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bsdfData.coatIor = (bsdfData.coatIor + bsdfData.coatMask - 1.0) / bsdfData.coatMask;
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// Override exctinction, that we won't need, with the transmission value for the incoming segment
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float sinThetaI = sqrt(1.0 - Sq(NdotV));
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float cosThetaO = sqrt(1.0 - Sq(sinThetaI / bsdfData.coatIor));
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bsdfData.coatExtinction = exp(-bsdfData.coatThickness * bsdfData.coatExtinction / cosThetaO);
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// Make sure we can get valid coat normal reflection directions
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bsdfData.coatNormalWS = IsCoatNormalMapEnabled(bsdfData) ?
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ComputeConsistentShadingNormal(mtlData.V, bsdfData.geomNormalWS, bsdfData.coatNormalWS) : GetSpecularNormal(mtlData);
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}
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bool CreateMaterialData(PathPayload payload, BuiltinData builtinData, BSDFData bsdfData, inout float3 shadingPosition, inout float theSample, out MaterialData mtlData)
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{
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// Alter values in the material's bsdfData struct, to better suit path tracing
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mtlData.V = -WorldRayDirection();
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mtlData.Nv = ComputeConsistentShadingNormal(mtlData.V, bsdfData.geomNormalWS, bsdfData.normalWS);
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mtlData.bsdfData = bsdfData;
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ProcessBSDFData(payload, builtinData, mtlData, mtlData.bsdfData);
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mtlData.bsdfWeight = 0.0;
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// Assume no coating by default
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float3 coatingTransmission = 1.0;
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// First determine if our incoming direction V is above (exterior) or below (interior) the surface
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if (IsAbove(mtlData))
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{
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float NcoatdotV = dot(GetCoatNormal(mtlData), mtlData.V);
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float NspecdotV = dot(GetSpecularNormal(mtlData), mtlData.V);
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float Fcoat = F_Schlick(IorToFresnel0(bsdfData.coatIor), NcoatdotV);
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float Fspec = Luminance(F_Schlick(mtlData.bsdfData.fresnel0, NspecdotV));
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mtlData.bsdfWeight[1] = Fcoat * mtlData.bsdfData.coatMask;
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coatingTransmission = (1.0 - mtlData.bsdfWeight[1]) * mtlData.bsdfData.coatExtinction;
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float coatingTransmissionWeight = Luminance(coatingTransmission);
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mtlData.bsdfWeight[2] = coatingTransmissionWeight * (1.0 - mtlData.bsdfData.lobeMix) * lerp(Fspec, 0.5, 0.5 * (mtlData.bsdfData.roughnessAT + mtlData.bsdfData.roughnessAB)) * GetSpecularCompensationA(mtlData).x; // consider spec as float as it is dieltric
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mtlData.bsdfWeight[3] = coatingTransmissionWeight * mtlData.bsdfData.lobeMix * lerp(Fspec, 0.5, 0.5 * (mtlData.bsdfData.roughnessBT + mtlData.bsdfData.roughnessBB)) * GetSpecularCompensationB(mtlData).x;
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mtlData.bsdfWeight[0] = coatingTransmissionWeight * Luminance(mtlData.bsdfData.diffuseColor) * max(mtlData.bsdfData.ambientOcclusion, 0.001);
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}
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// Normalize the weights
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float wSum = mtlData.bsdfWeight[0] + mtlData.bsdfWeight[1] + mtlData.bsdfWeight[2] + mtlData.bsdfWeight[3];
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if (wSum < BSDF_WEIGHT_EPSILON)
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return false;
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mtlData.bsdfWeight /= wSum;
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#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
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float subsurfaceWeight = mtlData.bsdfWeight[0] * mtlData.bsdfData.subsurfaceMask * (1.0 - payload.maxRoughness);
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mtlData.isSubsurface = theSample < subsurfaceWeight;
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if (mtlData.isSubsurface)
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{
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// We do a full, ray-traced subsurface scattering computation here:
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// Let's try and change shading position and normal, and replace the diffuse color by the subsurface throughput
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mtlData.subsurfaceWeightFactor = subsurfaceWeight;
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SSS::Result subsurfaceResult;
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float3 meanFreePath = 0.001 / (_ShapeParamsAndMaxScatterDists[mtlData.bsdfData.diffusionProfileIndex].rgb * _WorldScalesAndFilterRadiiAndThicknessRemaps[mtlData.bsdfData.diffusionProfileIndex].x);
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#ifdef _MATERIAL_FEATURE_TRANSMISSION
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bool isThin = true;
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#else
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bool isThin = false;
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#endif
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if (!SSS::RandomWalk(shadingPosition, GetDiffuseNormal(mtlData), mtlData.bsdfData.diffuseColor, meanFreePath, payload.pixelCoord, subsurfaceResult, isThin))
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return false;
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shadingPosition = subsurfaceResult.exitPosition;
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mtlData.bsdfData.normalWS = subsurfaceResult.exitNormal;
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mtlData.bsdfData.geomNormalWS = subsurfaceResult.exitNormal;
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mtlData.bsdfData.diffuseColor = subsurfaceResult.throughput * coatingTransmission;
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}
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else
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{
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// Otherwise, we just compute BSDFs as usual
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mtlData.subsurfaceWeightFactor = 1.0 - subsurfaceWeight;
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mtlData.bsdfWeight[0] = max(mtlData.bsdfWeight[0] - subsurfaceWeight, BSDF_WEIGHT_EPSILON);
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mtlData.bsdfWeight /= mtlData.subsurfaceWeightFactor;
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theSample -= subsurfaceWeight;
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}
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// Rescale the sample we used for the SSS selection test
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theSample /= mtlData.subsurfaceWeightFactor;
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#endif
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return true;
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}
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bool SampleMaterial(MaterialData mtlData, float3 inputSample, out float3 sampleDir, out MaterialResult result)
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{
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Init(result);
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#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
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if (mtlData.isSubsurface)
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{
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if (!BRDF::SampleLambert(mtlData, GetDiffuseNormal(mtlData), inputSample, sampleDir, result.diffValue, result.diffPdf))
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return false;
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result.diffValue *= mtlData.bsdfData.ambientOcclusion;
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return true;
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}
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#endif
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if (IsAbove(mtlData))
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{
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float3 value;
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float pdf;
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float f0ClearCoat = IorToFresnel0(mtlData.bsdfData.coatIor);
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float3 fresnelClearCoat, coatingTransmission = 1.0;
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if (inputSample.z < mtlData.bsdfWeight[0]) // Diffuse BRDF
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{
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if (!BRDF::SampleLambert(mtlData, GetDiffuseNormal(mtlData), inputSample, sampleDir, result.diffValue, result.diffPdf))
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return false;
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result.diffPdf *= mtlData.bsdfWeight[0];
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if (mtlData.bsdfWeight[1] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateGGX(mtlData, GetCoatNormal(mtlData), mtlData.bsdfData.coatRoughness, f0ClearCoat, sampleDir, value, pdf, fresnelClearCoat);
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coatingTransmission = (1.0 - fresnelClearCoat * mtlData.bsdfData.coatMask) * mtlData.bsdfData.coatExtinction;
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result.specValue += value * mtlData.bsdfData.coatMask;
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result.specPdf += mtlData.bsdfWeight[1] * pdf;
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}
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result.diffValue *= mtlData.bsdfData.ambientOcclusion * coatingTransmission;
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if (mtlData.bsdfWeight[2] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * (1.0 - mtlData.bsdfData.lobeMix) * GetSpecularCompensationA(mtlData);
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result.specPdf += mtlData.bsdfWeight[2] * pdf;
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}
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if (mtlData.bsdfWeight[3] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * mtlData.bsdfData.lobeMix * GetSpecularCompensationB(mtlData);
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result.specPdf += mtlData.bsdfWeight[3] * pdf;
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}
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}
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else if (inputSample.z < mtlData.bsdfWeight[0] + mtlData.bsdfWeight[1]) // Clear coat BRDF
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{
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if (!BRDF::SampleGGX(mtlData, GetCoatNormal(mtlData), mtlData.bsdfData.coatRoughness, f0ClearCoat, inputSample, sampleDir, result.specValue, result.specPdf, fresnelClearCoat))
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return false;
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coatingTransmission = (1.0 - fresnelClearCoat * mtlData.bsdfData.coatMask) * mtlData.bsdfData.coatExtinction;
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result.specValue *= mtlData.bsdfData.coatMask;
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result.specPdf *= mtlData.bsdfWeight[1];
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if (mtlData.bsdfWeight[0] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateLambert(mtlData, GetDiffuseNormal(mtlData), sampleDir, result.diffValue, result.diffPdf);
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result.diffValue *= mtlData.bsdfData.ambientOcclusion * coatingTransmission;
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result.diffPdf *= mtlData.bsdfWeight[0];
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}
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if (mtlData.bsdfWeight[2] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * (1.0 - mtlData.bsdfData.lobeMix) * GetSpecularCompensationA(mtlData);
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result.specPdf += mtlData.bsdfWeight[2] * pdf;
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}
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if (mtlData.bsdfWeight[3] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * mtlData.bsdfData.lobeMix * GetSpecularCompensationB(mtlData);
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result.specPdf += mtlData.bsdfWeight[3] * pdf;
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}
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}
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else if (inputSample.z < mtlData.bsdfWeight[0] + mtlData.bsdfWeight[1] + mtlData.bsdfWeight[2]) // Specular A BRDF
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{
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if (!BRDF::SampleAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB, mtlData.bsdfData.fresnel0, inputSample, sampleDir, result.specValue, result.specPdf))
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return false;
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result.specValue *= (1.0 - mtlData.bsdfData.lobeMix) * GetSpecularCompensationA(mtlData);
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result.specPdf *= mtlData.bsdfWeight[2];
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if (mtlData.bsdfWeight[3] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * mtlData.bsdfData.lobeMix * GetSpecularCompensationB(mtlData);
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result.specPdf += mtlData.bsdfWeight[3] * pdf;
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}
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if (mtlData.bsdfWeight[1] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateGGX(mtlData, GetCoatNormal(mtlData), mtlData.bsdfData.coatRoughness, f0ClearCoat, sampleDir, value, pdf, fresnelClearCoat);
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coatingTransmission = (1.0 - fresnelClearCoat * mtlData.bsdfData.coatMask) * mtlData.bsdfData.coatExtinction;
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result.specValue = result.specValue * coatingTransmission + value * mtlData.bsdfData.coatMask;
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result.specPdf += mtlData.bsdfWeight[1] * pdf;
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}
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if (mtlData.bsdfWeight[0] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateLambert(mtlData, GetDiffuseNormal(mtlData), sampleDir, result.diffValue, result.diffPdf);
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result.diffValue *= mtlData.bsdfData.ambientOcclusion * coatingTransmission;
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result.diffPdf *= mtlData.bsdfWeight[0];
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}
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}
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else // Specular B BRDF
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{
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if (!BRDF::SampleAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB, mtlData.bsdfData.fresnel0, inputSample, sampleDir, result.specValue, result.specPdf))
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return false;
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result.specValue *= mtlData.bsdfData.lobeMix * GetSpecularCompensationB(mtlData);
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result.specPdf *= mtlData.bsdfWeight[3];
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if (mtlData.bsdfWeight[2] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * (1.0 - mtlData.bsdfData.lobeMix) * GetSpecularCompensationA(mtlData);
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result.specPdf += mtlData.bsdfWeight[2] * pdf;
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}
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if (mtlData.bsdfWeight[1] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateGGX(mtlData, GetCoatNormal(mtlData), mtlData.bsdfData.coatRoughness, f0ClearCoat, sampleDir, value, pdf, fresnelClearCoat);
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coatingTransmission = (1.0 - fresnelClearCoat * mtlData.bsdfData.coatMask) * mtlData.bsdfData.coatExtinction;
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result.specValue = result.specValue * coatingTransmission + value * mtlData.bsdfData.coatMask;
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result.specPdf += mtlData.bsdfWeight[1] * pdf;
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}
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if (mtlData.bsdfWeight[0] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateLambert(mtlData, GetDiffuseNormal(mtlData), sampleDir, result.diffValue, result.diffPdf);
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result.diffValue *= mtlData.bsdfData.ambientOcclusion * coatingTransmission;
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result.diffPdf *= mtlData.bsdfWeight[0];
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}
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}
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#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
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// We compensate for the fact that there is no spec when computing SSS
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result.specValue /= mtlData.subsurfaceWeightFactor;
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#endif
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}
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return result.diffPdf + result.specPdf > 0.0;
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}
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void EvaluateMaterial(MaterialData mtlData, float3 sampleDir, out MaterialResult result)
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{
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Init(result);
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#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
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if (mtlData.isSubsurface)
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{
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BRDF::EvaluateLambert(mtlData, GetDiffuseNormal(mtlData), sampleDir, result.diffValue, result.diffPdf);
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result.diffValue *= mtlData.bsdfData.ambientOcclusion; // Take into account AO the same way as in SampleMaterial
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return;
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}
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#endif
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if (IsAbove(mtlData))
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{
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float3 value;
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float pdf;
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float3 fresnelClearCoat, coatingTransmission = 1.0;
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if (mtlData.bsdfWeight[1] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateGGX(mtlData, GetCoatNormal(mtlData), mtlData.bsdfData.coatRoughness, IorToFresnel0(mtlData.bsdfData.coatIor), sampleDir, result.specValue, result.specPdf, fresnelClearCoat);
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coatingTransmission = (1.0 - fresnelClearCoat * mtlData.bsdfData.coatMask) * mtlData.bsdfData.coatExtinction;
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result.specValue *= mtlData.bsdfData.coatMask;
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result.specPdf *= mtlData.bsdfWeight[1];
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}
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if (mtlData.bsdfWeight[0] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateLambert(mtlData, GetDiffuseNormal(mtlData), sampleDir, result.diffValue, result.diffPdf);
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result.diffValue *= coatingTransmission;
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result.diffValue *= mtlData.bsdfData.ambientOcclusion; // Take into account AO the same way as in SampleMaterial
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result.diffPdf *= mtlData.bsdfWeight[0];
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}
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if (mtlData.bsdfWeight[2] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * (1.0 - mtlData.bsdfData.lobeMix) * GetSpecularCompensationA(mtlData);
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result.specPdf += mtlData.bsdfWeight[2] * pdf;
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}
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if (mtlData.bsdfWeight[3] > BSDF_WEIGHT_EPSILON)
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{
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BRDF::EvaluateAnisoGGX(mtlData, GetSpecularNormal(mtlData), mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB, mtlData.bsdfData.fresnel0, sampleDir, value, pdf);
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result.specValue += value * coatingTransmission * mtlData.bsdfData.lobeMix * GetSpecularCompensationB(mtlData);
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result.specPdf += mtlData.bsdfWeight[3] * pdf;
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}
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#ifdef _MATERIAL_FEATURE_SUBSURFACE_SCATTERING
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// We compensate for the fact that there is no spec when computing SSS
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result.specValue /= mtlData.subsurfaceWeightFactor;
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#endif
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}
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}
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|
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float3 GetLightNormal(MaterialData mtlData)
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{
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// If diffuse, specular and coating normals are quasi-indentical, return one of them, otherwise return a null vector
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const float dotThreshold = 0.99;
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return dot(GetDiffuseNormal(mtlData), GetSpecularNormal(mtlData)) > dotThreshold && dot(GetDiffuseNormal(mtlData), GetCoatNormal(mtlData)) > dotThreshold ?
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GetDiffuseNormal(mtlData) : float3(0.0, 0.0, 0.0);
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}
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|
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|
float AdjustPathRoughness(MaterialData mtlData, MaterialResult mtlResult, bool isSampleBelow, float pathRoughness)
|
|
{
|
|
// Adjust the max roughness, based on the estimated diff/spec ratio
|
|
float maxSpecRoughness = lerp(max(mtlData.bsdfData.roughnessAT, mtlData.bsdfData.roughnessAB), max(mtlData.bsdfData.roughnessBT, mtlData.bsdfData.roughnessBB), mtlData.bsdfData.lobeMix);
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float adjustedPathRoughness = (mtlResult.specPdf * maxSpecRoughness + mtlResult.diffPdf) / (mtlResult.diffPdf + mtlResult.specPdf);
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|
|
|
return adjustedPathRoughness;
|
|
}
|
|
|
|
float3 GetMaterialAbsorption(MaterialData mtlData, SurfaceData surfaceData, float dist, bool isSampleBelow)
|
|
{
|
|
// No absorption here
|
|
return 1.0;
|
|
}
|
|
|
|
void GetAOVData(BSDFData bsdfData, out AOVData aovData)
|
|
{
|
|
aovData.albedo = bsdfData.diffuseColor;
|
|
aovData.normal = bsdfData.normalWS;
|
|
}
|