Fix clearcoat F0 that should not be remapped for gltf files

inspector/src/components/actionTabs/tabs/propertyGrids/materials/pbrMaterialPropertyGridComponent.tsx

@@ -176,6 +176,7 @@ export class PBRMaterialPropertyGridComponent extends React.Component<IPBRMateri
                             <SliderLineComponent label="Intensity" target={material.clearCoat} propertyName="intensity" minimum={0} maximum={1} step={0.01} onPropertyChangedObservable={this.props.onPropertyChangedObservable} />
                             <SliderLineComponent label="Roughness" target={material.clearCoat} propertyName="roughness" minimum={0} maximum={1} step={0.01} onPropertyChangedObservable={this.props.onPropertyChangedObservable} />
                             <SliderLineComponent label="IOR" target={material.clearCoat} propertyName="indexOfRefraction" minimum={1.0} maximum={3} step={0.01} onPropertyChangedObservable={this.props.onPropertyChangedObservable} />
+                            <CheckBoxLineComponent label="Remap F0" target={material.clearCoat} propertyName="remapF0OnInterfaceChange" onPropertyChangedObservable={this.props.onPropertyChangedObservable} />
                             <TextureLinkLineComponent label="Clear coat" texture={material.clearCoat.texture} onTextureCreated={(texture) => material.clearCoat.texture = texture} onTextureRemoved={() => material.clearCoat.texture = null} material={material} onSelectionChangedObservable={this.props.onSelectionChangedObservable} onDebugSelectionChangeObservable={this._onDebugSelectionChangeObservable} />
                             <TextureLinkLineComponent label="Bump" texture={material.clearCoat.bumpTexture} onTextureCreated={(texture) => material.clearCoat.bumpTexture = texture} onTextureRemoved={() => material.clearCoat.bumpTexture = null} material={material} onSelectionChangedObservable={this.props.onSelectionChangedObservable} onDebugSelectionChangeObservable={this._onDebugSelectionChangeObservable} />
                             {

loaders/src/glTF/2.0/Extensions/KHR_materials_clearcoat.ts

@@ -61,6 +61,7 @@ export class KHR_materials_clearcoat implements IGLTFLoaderExtension {
         const promises = new Array<Promise<any>>();
 
         babylonMaterial.clearCoat.isEnabled = true;
+        babylonMaterial.clearCoat.remapF0OnInterfaceChange = false;
 
         if (properties.clearcoatFactor != undefined) {
             babylonMaterial.clearCoat.intensity = properties.clearcoatFactor;

src/Materials/PBR/pbrBaseMaterial.ts

@@ -224,6 +224,7 @@ export class PBRMaterialDefines extends MaterialDefines
     public CLEARCOAT_TEXTUREDIRECTUV = 0;
     public CLEARCOAT_BUMP = false;
     public CLEARCOAT_BUMPDIRECTUV = 0;
+    public CLEARCOAT_REMAPP_F0 = true;
     public CLEARCOAT_TINT = false;
     public CLEARCOAT_TINT_TEXTURE = false;
     public CLEARCOAT_TINT_TEXTUREDIRECTUV = 0;

src/Materials/PBR/pbrClearCoatConfiguration.ts

@@ -21,6 +21,7 @@ export interface IMaterialClearCoatDefines {
     CLEARCOAT_TEXTUREDIRECTUV: number;
     CLEARCOAT_BUMP: boolean;
     CLEARCOAT_BUMPDIRECTUV: number;
+    CLEARCOAT_REMAPP_F0: boolean;
 
     CLEARCOAT_TINT: boolean;
     CLEARCOAT_TINT_TEXTURE: boolean;
@@ -79,6 +80,14 @@ export class PBRClearCoatConfiguration {
     @expandToProperty("_markAllSubMeshesAsTexturesDirty")
     public texture: Nullable<BaseTexture> = null;
 
+    private _remapF0OnInterfaceChange = true;
+    /**
+     * Defines if the F0 value should be remapped to account for the interface change in the material.
+     */
+    @serialize()
+    @expandToProperty("_markAllSubMeshesAsTexturesDirty")
+    public remapF0OnInterfaceChange = true;
+
     private _bumpTexture: Nullable<BaseTexture> = null;
     /**
      * Define the clear coat specific bump texture.
@@ -186,6 +195,7 @@ export class PBRClearCoatConfiguration {
     public prepareDefines(defines: IMaterialClearCoatDefines, scene: Scene): void {
         if (this._isEnabled) {
             defines.CLEARCOAT = true;
+            defines.CLEARCOAT_REMAPP_F0 = this._remapF0OnInterfaceChange;
 
             if (defines._areTexturesDirty) {
                 if (scene.texturesEnabled) {

src/Shaders/ShadersInclude/pbrBlockClearcoat.fx

@@ -128,7 +128,11 @@ struct clearcoatOutParams
         // clearCoatRoughness = mix(0.089, 0.6, clearCoatRoughness);
 
         // Remap F0 to account for the change of interface within the material.
-        vec3 specularEnvironmentR0Updated = getR0RemappedForClearCoat(specularEnvironmentR0);
+        #ifdef CLEARCOAT_REMAPP_F0
+            vec3 specularEnvironmentR0Updated = getR0RemappedForClearCoat(specularEnvironmentR0);
+        #else
+            vec3 specularEnvironmentR0Updated = specularEnvironmentR0;
+        #endif
         outParams.specularEnvironmentR0 = mix(specularEnvironmentR0, specularEnvironmentR0Updated, clearCoatIntensity);
 
         // Needs to use the geometric normal before bump for this.