Merge pull request #552 from jyb125/YibingProject

fixed the black dots on screen bug

ScriptableRenderPipeline/HDRenderPipeline/Material/Fabric/Fabric.hlsl

 	bsdfData.tangentWS = tangentWS;
 	bsdfData.bitangentWS = cross(normalWS, tangentWS);
 	ConvertAnisotropyToRoughness(roughness, anisotropy, bsdfData.roughnessT, bsdfData.roughnessB);
-	bsdfData.anisotropy = 1;
+	bsdfData.anisotropy = 0.75;
 }
 
 //-----------------------------------------------------------------------------
 	float3 F = F_Schlick(0.2, LdotH);
 
 	float Vis;
-	float D;
+	float D_Velvet;//Ready at dawn cloth
-	float roughnessSq = bsdfData.roughness*bsdfData.roughness;
-	float cnorm = 1.0 / (PI * (4.0 * roughnessSq + 1.0));
+	float roughnessSq = bsdfData.roughness*bsdfData.roughness;  
+	float N = 1.0 / (PI * (4.0 * roughnessSq + 1.0));  
-	float cot2 = NdotH2 / (1.0 - NdotH2);
-	float sin2 = 1.0 - NdotH2;
-	float sin4 = sin2 * sin2;
-	float amp = 4.0;
-	D = cnorm * (1.0 + (amp * exp(-cot2 / roughnessSq) / sin4));
+	float cotNdotH2 = NdotH2 / (1.000001 - NdotH2);  
+	float sinNdotH2 = 1.0 - NdotH2;
+	D_Velvet = N * (1.0 + (4.0 * exp(-cotNdotH2 / roughnessSq) / max(sinNdotH2*sinNdotH2,1e-5)));
 
 	#ifdef LIT_USE_BSDF_PRE_LAMBDAV
 		Vis = V_SmithJointGGX(NdotL, NdotV, bsdfData.roughness, preLightData.ggxLambdaV);
 
 	float NdotLwrap = sqrt(NdotL);
 
-	specularLighting = NdotLwrap*F *(Vis * D)*_FuzzTint;
+	specularLighting = NdotLwrap* F *Vis * D_Velvet *_FuzzTint;
 
 #ifdef LIT_DIFFUSE_LAMBERT_BRDF
     float  diffuseTerm = Lambert();

ScriptableRenderPipeline/HDRenderPipeline/Material/Fabric/FabricDataInternal.hlsl

 #endif
     surfaceData.perceptualSmoothness *= ADD_IDX(lerp(0.1,0.6,_Smoothness));
 #ifdef _DETAIL_MAP_IDX
-    surfaceData.perceptualSmoothness *= 2.0 * saturate(detailSmoothness * ADD_IDX(_DetailSmoothnessScale));
+    // Use overlay blend mode for detail abledo: (base < 0.5 ? (2.0 * base * blend) : (1.0 - 2.0 * (1.0 - base) * (1.0 - blend)))
+    float smoothnessOverlay = (detailSmoothness < 0.5) ?
+                                surfaceData.perceptualSmoothness * PositivePow(2.0 * detailSmoothness, ADD_IDX(_DetailSmoothnessScale)) :
+                                1.0 - (1.0 - surfaceData.perceptualSmoothness) * PositivePow(2.0 * (1.0 - detailSmoothness), ADD_IDX(_DetailSmoothnessScale));
+    surfaceData.perceptualSmoothness = saturate(smoothnessOverlay);
-
     // MaskMap is RGBA: Metallic, Ambient Occlusion (Optional), emissive Mask (Optional), Smoothness
 #ifdef _MASKMAP_IDX
     surfaceData.ambientOcclusion = SAMPLE_UVMAPPING_TEXTURE2D(ADD_IDX(_MaskMap), SAMPLER_MASKMAP_IDX, ADD_IDX(layerTexCoord.base)).g;
     surfaceData.tangentWS = normalize(input.worldToTangent[0].xyz); // The tangent is not normalize in worldToTangent for mikkt. TODO: Check if it expected that we normalize with Morten. Tag: SURFACE_GRADIENT
 #endif
 
-    surfaceData.anisotropy = 1.0;
+    surfaceData.anisotropy = 0.8;
-    surfaceData.specular = 0.04;
+    surfaceData.specular = 1;
 
     surfaceData.subsurfaceProfile = _SubsurfaceProfile;
     surfaceData.subsurfaceRadius  = _SubsurfaceRadius;

ScriptableRenderPipeline/HDRenderPipeline/Material/Hair/Hair.hlsl

     bsdfData.normalWS = surfaceData.normalWS;
 
     //NOTE: On Hair UI side, we use slider for roughness. So not necesarry to invert.
-    bsdfData.perceptualRoughness = lerp(0.4,1.5,surfaceData.perceptualSmoothness);//PerceptualSmoothnessToPerceptualRoughness(surfaceData.perceptualSmoothness);
-    bsdfData.roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
+    bsdfData.perceptualRoughness = surfaceData.ambientOcclusion;//PerceptualSmoothnessToPerceptualRoughness(surfaceData.perceptualSmoothness);
+    bsdfData.roughness = PerceptualRoughnessToRoughness(lerp(0.4,1.5,surfaceData.perceptualSmoothness));
 
     bsdfData.fresnel0 = 0.04;
 
     float invLenLV = rsqrt(abs(2 + 2 * LdotV));    // invLenLV = rcp(length(L + V))
     float NdotH    = saturate((NdotL + NdotV) * invLenLV);
     float LdotH    = saturate(invLenLV + invLenLV * LdotV);
+    float invVdotL = saturate(dot(V,-L));
 
     //float3 F = F_Schlick(bsdfData.fresnel0, LdotH);
 
     // For anisotropy we must not saturate these values
 
 
-    float3 transL=L+bsdfData.normalWS*0.3;
-	  // TODO: Do comparison between this correct version and the one from isotropic and see if there is any visual difference
+    // TODO: Do comparison between this correct version and the one from isotropic and see if there is any visual difference
-    specularLighting = 0.15*bsdfData.specularOcclusion*(hairSpec1 + hairSpec2);
+    specularLighting = 0.15*bsdfData.perceptualRoughness*(hairSpec1 + hairSpec2);
-	float scatterFresnel = 3*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*dot(V,-transL)*(1.0 - NdotV)*(1.0 - NdotL)+ 0.5*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV)*(1-NdotV);
-	float transAmount = _Scatter*scatterFresnel;
-	float3 transColor = 2*saturate(transAmount * float3(1, 0.6, 0.26)*bsdfData.specularOcclusion*bsdfData.specularOcclusion);
+	float scatterFresnel = 30*pow(invVdotL,9)*(1.0 - NdotV)*(1.0 - NdotL)+ 5*pow((1-NdotV),9);
+    float scatterAmount = _Scatter*scatterFresnel;
+	float3 transColor = 2*saturate(scatterAmount * float3(1, 0.6, 0.26)*bsdfData.specularOcclusion*bsdfData.specularOcclusion);
     float  diffuseTerm = Lambert();
     diffuseLighting = bsdfData.diffuseColor * diffuseTerm+transColor;
 }