Added clear coat energy conservation (#9238)

src/renderers/shaders/ShaderChunk/lights_physical_pars_fragment.glsl

@@ -14,6 +14,13 @@ struct PhysicalMaterial {
 #define MAXIMUM_SPECULAR_COEFFICIENT 0.16
 #define DEFAULT_SPECULAR_COEFFICIENT 0.04
 
+// Clear coat directional hemishperical reflectance (this approximation should be improved)
+float clearCoatDHRApprox( const in float roughness, const in float dotNL ) {
+
+	return DEFAULT_SPECULAR_COEFFICIENT + ( 1.0 - DEFAULT_SPECULAR_COEFFICIENT ) * ( pow( 1.0 - dotNL, 5.0 ) * pow( 1.0 - roughness, 2.0 ) );
+
+}
+
 void RE_Direct_Physical( const in IncidentLight directLight, const in GeometricContext geometry, const in PhysicalMaterial material, inout ReflectedLight reflectedLight ) {
 
 	float dotNL = saturate( dot( geometry.normal, directLight.direction ) );
@@ -26,8 +33,14 @@ void RE_Direct_Physical( const in IncidentLight directLight, const in GeometricC
 
 	#endif
 
-	reflectedLight.directSpecular += irradiance * BRDF_Specular_GGX( directLight, geometry, material.specularColor, material.specularRoughness );
-	reflectedLight.directDiffuse += irradiance * BRDF_Diffuse_Lambert( material.diffuseColor );
+	#ifndef STANDARD
+		float clearCoatDHR = material.clearCoat * clearCoatDHRApprox( material.clearCoatRoughness, dotNL );
+	#else
+		float clearCoatDHR = 0.0;
+	#endif
+
+	reflectedLight.directSpecular += ( 1.0 - clearCoatDHR ) * irradiance * BRDF_Specular_GGX( directLight, geometry, material.specularColor, material.specularRoughness );
+	reflectedLight.directDiffuse += ( 1.0 - clearCoatDHR ) * irradiance * BRDF_Diffuse_Lambert( material.diffuseColor );
 
 	#ifndef STANDARD
 
@@ -45,7 +58,15 @@ void RE_IndirectDiffuse_Physical( const in vec3 irradiance, const in GeometricCo
 
 void RE_IndirectSpecular_Physical( const in vec3 radiance, const in vec3 clearCoatRadiance, const in GeometricContext geometry, const in PhysicalMaterial material, inout ReflectedLight reflectedLight ) {
 
-	reflectedLight.indirectSpecular += radiance * BRDF_Specular_GGX_Environment( geometry, material.specularColor, material.specularRoughness );
+	#ifndef STANDARD
+		float dotNV = saturate( dot( geometry.normal, geometry.viewDir ) );
+		float dotNL = dotNV;
+		float clearCoatDHR = material.clearCoat * clearCoatDHRApprox( material.clearCoatRoughness, dotNL );
+	#else
+		float clearCoatDHR = 0.0;
+	#endif
+
+	reflectedLight.indirectSpecular += ( 1.0 - clearCoatDHR ) * radiance * BRDF_Specular_GGX_Environment( geometry, material.specularColor, material.specularRoughness );
 
 	#ifndef STANDARD