fix: sheen layer

galacean · Dec 10, 2024 · f550f37 · f550f37
1 parent 99a6d8e
commit f550f37
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Showing 7 changed files with 54 additions and 48 deletions.
diff --git a/packages/shaderlab/src/shaders/PBR.gs b/packages/shaderlab/src/shaders/PBR.gs
@@ -48,8 +48,8 @@ Shader "PBR.gs" {
       }
 
       Header("Sheen"){
-        material_Sheen("Sheen", Range(0, 1, 0.01)) = 0;
-        material_SheenColor("SheenColor", Color ) = (0, 0, 0, 1);
+        material_Sheen("SheenIntensity", Range(0, 1, 0.01)) = 0;
+        material_SheenColor("SheenColor", Color ) = (0, 0, 0, 0);
         material_SheenRoughness("SheenRoughness", Range(0, 1, 0.01)) = 0;
         material_SheenTexture("SheenTexture", Texture2D);
         material_SheenRoughnessTexture("SheenRoughnessTexture", Texture2D);

diff --git a/packages/shaderlab/src/shaders/shadingPBR/BRDF.glsl b/packages/shaderlab/src/shaders/shadingPBR/BRDF.glsl
@@ -80,8 +80,7 @@ struct BRDFData{
 
     #ifdef MATERIAL_ENABLE_SHEEN
         float sheenRoughness;
-        float sheenScaling;
-        float sheenDFG;
+        float sheenEnergy;
     #endif
 
 };
@@ -331,27 +330,15 @@ vec3 BRDF_Diffuse_Lambert(vec3 diffuseColor) {
         return saturate(1.0 / (4.0 * (NoL + NoV - NoL * NoV)));
     }
 
-    vec3 BRDF_Sheen(vec3 incidentDirection, SurfaceData surfaceData, vec3 sheenColor, float sheenRoughness) {
+    vec3 sheenBRDF(vec3 incidentDirection, SurfaceData surfaceData, vec3 sheenColor, float sheenRoughness) {
         vec3 halfDir = normalize(incidentDirection + surfaceData.viewDir);
         float dotNL = saturate(dot(surfaceData.normal, incidentDirection));
         float dotNH = saturate(dot(surfaceData.normal, halfDir));
         float D = D_Charlie(sheenRoughness, dotNH);
         float V = V_Neubelt(surfaceData.dotNV, dotNL);
-        vec3 F = sheenColor;
+        vec3 F = sheenColor.rgb;
         return  D * V * F;
     }
-
-    // This is a curve-fit approxmation to the "Charlie sheen" BRDF integrated over the hemisphere from
-    // Estevez and Kulla 2017, "Production Friendly Microfacet Sheen BRDF". The analysis can be found
-    // in the Sheen section of https://drive.google.com/file/d/1T0D1VSyR4AllqIJTQAraEIzjlb5h4FKH/view?usp=sharing
-    float IBLSheenBRDF(SurfaceData surfaceData, float roughness) {
-        float dotNV = surfaceData.dotNV;
-        float r2 = roughness * roughness;
-        float a = roughness < 0.25 ? -339.2 * r2 + 161.4 * roughness - 25.9 : -8.48 * r2 + 14.3 * roughness - 9.95;
-        float b = roughness < 0.25 ? 44.0 * r2 - 23.7 * roughness + 3.26 : 1.97 * r2 - 3.27 * roughness + 0.72;
-        float DG = exp( a * dotNV + b ) + ( roughness < 0.25 ? 0.0 : 0.1 * ( roughness - 0.25 ) );
-        return saturate( DG * RECIPROCAL_PI );
-    }
 #endif
 
 void initBRDFData(SurfaceData surfaceData, out BRDFData brdfData){
@@ -384,10 +371,9 @@ void initBRDFData(SurfaceData surfaceData, out BRDFData brdfData){
 
     #ifdef MATERIAL_ENABLE_SHEEN
         brdfData.sheenRoughness = max(MIN_PERCEPTUAL_ROUGHNESS, min(surfaceData.sheenRoughness + getAARoughnessFactor(surfaceData.normal), 1.0));
-        brdfData.sheenDFG = IBLSheenBRDF(surfaceData, brdfData.sheenRoughness);
         // sheen energy compensation approximation calculation in ‘Sheen DFG LUT integrated over diffuse IBL’
         // https://drive.google.com/file/d/1T0D1VSyR4AllqIJTQAraEIzjlb5h4FKH/view?usp=sharing
-        brdfData.sheenScaling = 1.0 - 0.157 * max(max(surfaceData.sheenColor.r, surfaceData.sheenColor.g), surfaceData.sheenColor.b);
+        brdfData.sheenEnergy = 1.0 - 0.157 * max(max(surfaceData.sheenColor.r, surfaceData.sheenColor.g), surfaceData.sheenColor.b);
     #endif
 }
 

diff --git a/packages/shaderlab/src/shaders/shadingPBR/FragmentPBR.glsl b/packages/shaderlab/src/shaders/shadingPBR/FragmentPBR.glsl
@@ -51,9 +51,8 @@ float material_OcclusionTextureCoord;
 #endif
 
 #ifdef MATERIAL_ENABLE_SHEEN
-    float material_Sheen;
     float material_SheenRoughness;
-    vec3 material_SheenColor;
+    vec4 material_SheenColor;
     #ifdef MATERIAL_HAS_SHEEN_TEXTURE
        sampler2D material_SheenTexture;
     #endif
@@ -277,7 +276,8 @@ SurfaceData getSurfaceData(Varyings v, vec2 aoUV, bool isFrontFacing){
     #endif
 
     #ifdef MATERIAL_ENABLE_SHEEN
-        vec3 sheencolor = material_SheenColor * material_Sheen;
+        float sheen = material_SheenColor.a;
+        vec3 sheencolor = material_SheenColor.rgb * sheen;
         #ifdef MATERIAL_HAS_SHEEN_TEXTURE
             vec4 sheenTexturecolor = texture2D(material_SheenTexture, uv);
             #ifndef ENGINE_IS_COLORSPACE_GAMMA
@@ -287,12 +287,11 @@ SurfaceData getSurfaceData(Varyings v, vec2 aoUV, bool isFrontFacing){
         #endif
         surfaceData.sheenColor = sheencolor;
 
-        float sheenRoughness = clamp(material_SheenRoughness, 0.01, 1.0);
+        surfaceData.sheenRoughness = material_SheenRoughness;
         #ifdef MATERIAL_HAS_SHEEN_ROUGHNESS_TEXTURE
-            vec4 sheenRoughnessTexture = (texture2D(material_SheenRoughnessTexture, uv));
-            sheenRoughness *= sheenRoughnessTexture.a;
+            vec4 sheenRoughnessTexture = texture2D(material_SheenRoughnessTexture, uv);
+            surfaceData.sheenRoughness *= sheenRoughnessTexture.a;
         #endif
-        surfaceData.sheenRoughness = sheenRoughness;
     #endif
 
     // AO

diff --git a/packages/shaderlab/src/shaders/shadingPBR/LightDirectPBR.glsl b/packages/shaderlab/src/shaders/shadingPBR/LightDirectPBR.glsl
@@ -14,6 +14,9 @@
 #ifndef FUNCTION_CLEAR_COAT_LOBE
     #define FUNCTION_CLEAR_COAT_LOBE clearCoatLobe
 #endif
+#ifndef FUNCTION_SHEEN_LOBE
+    #define FUNCTION_SHEEN_LOBE SheenLobe
+#endif
 
 #include "BRDF.glsl"
 #include "Light.glsl"
@@ -34,6 +37,8 @@ void surfaceShading(Varyings varyings, SurfaceData surfaceData, BRDFData brdfDat
     FUNCTION_DIFFUSE_LOBE(varyings, surfaceData, brdfData, attenuationIrradiance, diffuseColor);
     // Specular Lobe
     FUNCTION_SPECULAR_LOBE(varyings, surfaceData, brdfData, incidentDirection, attenuationIrradiance, specularColor);
+    // Sheen Lobe
+    FUNCTION_SHEEN_LOBE(varyings, surfaceData, brdfData, incidentDirection, diffuseColor, specularColor);
 
     color += diffuseColor + specularColor;
 

diff --git a/packages/shaderlab/src/shaders/shadingPBR/LightIndirectPBR.glsl b/packages/shaderlab/src/shaders/shadingPBR/LightIndirectPBR.glsl
@@ -11,7 +11,9 @@
 #ifndef FUNCTION_CLEAR_COAT_IBL
     #define FUNCTION_CLEAR_COAT_IBL evaluateClearCoatIBL
 #endif
-
+#ifndef FUNCTION_SHEEN_IBL
+    #define FUNCTION_SHEEN_IBL evaluateSheenIBL
+#endif
 #include "BRDF.glsl"
 #include "Light.glsl"
 #include "LightProbe.glsl"
@@ -50,10 +52,6 @@ void evaluateDiffuseIBL(Varyings varyings, SurfaceData surfaceData, BRDFData brd
        irradiance *= PI;
     #endif
 
-    #ifdef MATERIAL_ENABLE_SHEEN
-    diffuseColor *= brdfData.sheenScaling;
-    #endif
-
     diffuseColor += surfaceData.diffuseAO * irradiance * BRDF_Diffuse_Lambert( brdfData.diffuseColor );
 }
 
@@ -78,17 +76,19 @@ void evaluateSpecularIBL(Varyings varyings, SurfaceData surfaceData, BRDFData br
         vec3 speculaColor = brdfData.specularColor;
     #endif
 
+    outSpecularColor += surfaceData.specularAO * radianceAttenuation * radiance * envBRDFApprox(speculaColor, brdfData.roughness, surfaceData.dotNV);
+}
+
+void evaluateSheenIBL(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData, inout vec3 diffuseColor, inout vec3 SpecularColor){
     #ifdef MATERIAL_ENABLE_SHEEN
-    outSpecularColor *= brdfData.sheenScaling;
-    vec3 environmentBRDF = brdfData.sheenDFG * surfaceData.sheenColor;
-    #else
-    vec3 environmentBRDF = envBRDFApprox(speculaColor, brdfData.roughness, surfaceData.dotNV);
+    diffuseColor *= brdfData.sheenEnergy;
+    SpecularColor *= brdfData.sheenEnergy;
+
+    vec3 reflectance = IBLSheenDFG(surfaceData, brdfData.sheenRoughness) * surfaceData.sheenColor;
+    SpecularColor += reflectance;
     #endif
-
-    outSpecularColor += surfaceData.specularAO * radianceAttenuation * radiance * environmentBRDF;
 }
 
-
 void evaluateIBL(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData, inout vec3 color){
     vec3 diffuseColor = vec3(0);
     vec3 specularColor = vec3(0);
@@ -101,8 +101,12 @@ void evaluateIBL(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData,
 
     // IBL specular
     FUNCTION_SPECULAR_IBL(varyings, surfaceData, brdfData, radianceAttenuation, specularColor);
-
+
+    // IBL sheen
+    FUNCTION_SHEEN_IBL(varyings, surfaceData, brdfData, diffuseColor, specularColor);
+
     color += diffuseColor + specularColor;
+
 }
 
 

diff --git a/packages/shaderlab/src/shaders/shadingPBR/LightProbe.glsl b/packages/shaderlab/src/shaders/shadingPBR/LightProbe.glsl
@@ -68,4 +68,16 @@ vec3 getLightProbeRadiance(SurfaceData surfaceData, vec3 normal, float roughness
     #endif
 }
 
+// This is a curve-fit approxmation to the "Charlie sheen" BRDF integrated over the hemisphere from
+// Estevez and Kulla 2017, "Production Friendly Microfacet Sheen BRDF". The analysis can be found
+// in the Sheen section of https://drive.google.com/file/d/1T0D1VSyR4AllqIJTQAraEIzjlb5h4FKH/view?usp=sharing
+float IBLSheenDFG(SurfaceData surfaceData, float roughness) {
+    float dotNV = surfaceData.dotNV;
+    float r2 = roughness * roughness;
+    float a = roughness < 0.25 ? -339.2 * r2 + 161.4 * roughness - 25.9 : -8.48 * r2 + 14.3 * roughness - 9.95;
+    float b = roughness < 0.25 ? 44.0 * r2 - 23.7 * roughness + 3.26 : 1.97 * r2 - 3.27 * roughness + 0.72;
+    float DG = exp( a * dotNV + b ) + ( roughness < 0.25 ? 0.0 : 0.1 * ( roughness - 0.25 ) );
+    return saturate( DG * RECIPROCAL_PI );
+}
+
 #endif
diff --git a/packages/shaderlab/src/shaders/shadingPBR/ReflectionLobe.glsl b/packages/shaderlab/src/shaders/shadingPBR/ReflectionLobe.glsl
@@ -2,19 +2,19 @@
 #define REFLECTION_LOBE_INCLUDED
 
 void diffuseLobe(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData, vec3 attenuationIrradiance, inout vec3 diffuseColor){
-    #ifdef MATERIAL_ENABLE_SHEEN
-    diffuseColor *= brdfData.sheenScaling;
-    #endif
     diffuseColor += attenuationIrradiance * BRDF_Diffuse_Lambert( brdfData.diffuseColor );
 }
 
 void specularLobe(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData, vec3 incidentDirection, vec3 attenuationIrradiance, inout vec3 specularColor){
-    #ifdef MATERIAL_ENABLE_SHEEN
-        specularColor *= brdfData.sheenScaling;
-        vec3 BRDF_sheen = BRDF_Sheen(incidentDirection, surfaceData, surfaceData.sheenColor, brdfData.sheenRoughness);
-        specularColor += attenuationIrradiance * BRDF_sheen;
-    #else
         specularColor += attenuationIrradiance *  BRDF_Specular_GGX( incidentDirection, surfaceData, brdfData, surfaceData.normal, brdfData.specularColor, brdfData.roughness);
+}
+
+void SheenLobe(Varyings varyings, SurfaceData surfaceData, BRDFData brdfData, vec3 incidentDirection, inout vec3 diffuseColor, inout vec3 specularColor){
+    #ifdef MATERIAL_ENABLE_SHEEN
+        diffuseColor *= brdfData.sheenEnergy;
+        diffuseColor += sheenBRDF(incidentDirection, surfaceData, surfaceData.sheenColor, brdfData.sheenRoughness);
+        specularColor *= brdfData.sheenEnergy;
+        specularColor += sheenBRDF(incidentDirection, surfaceData, surfaceData.sheenColor, brdfData.sheenRoughness);
     #endif
 }