Support ior for PBRMaterial and glTF plugin

packages/core/src/material/PBRMaterial.ts

@@ -11,8 +11,23 @@ export class PBRMaterial extends PBRBaseMaterial {
   private static _roughnessProp = Shader.getPropertyByName("u_roughness");
   private static _roughnessMetallicTextureProp = Shader.getPropertyByName("u_roughnessMetallicTexture");
 
+  private static _iorProp = Shader.getPropertyByName("material_IOR");
+
+  /**
+   * Index Of Refraction.
+   * @defaultValue `1.5`
+   */
+  get ior(): number {
+    return this.shaderData.getFloat(PBRMaterial._iorProp);
+  }
+
+  set ior(v: number) {
+    this.shaderData.setFloat(PBRMaterial._iorProp, Math.max(v, 0));
+  }
+
   /**
-   * Metallic, default 1.0.
+   * Metallic.
+   * @defaultValue `1.0`
    */
   get metallic(): number {
     return this.shaderData.getFloat(PBRMaterial._metallicProp);
@@ -23,7 +38,8 @@ export class PBRMaterial extends PBRBaseMaterial {
   }
 
   /**
-   * Roughness, default 1.0.
+   * Roughness. default 1.0.
+   * @defaultValue `1.0`
    */
   get roughness(): number {
     return this.shaderData.getFloat(PBRMaterial._roughnessProp);
@@ -58,6 +74,7 @@ export class PBRMaterial extends PBRBaseMaterial {
     super(engine, Shader.find("pbr"));
     this.shaderData.setFloat(PBRMaterial._metallicProp, 1);
     this.shaderData.setFloat(PBRMaterial._roughnessProp, 1);
+    this.shaderData.setFloat(PBRMaterial._iorProp, 1.5);
   }
 
   /**

packages/core/src/shaderlib/pbr/pbr_frag_define.glsl

@@ -87,3 +87,5 @@ struct Material {
     #endif
 
 };
+
+uniform float material_IOR;

packages/core/src/shaderlib/pbr/pbr_helper.glsl

@@ -52,6 +52,8 @@ void initMaterial(out Material material, const in Geometry geometry){
         vec3 specularColor = u_PBRSpecularColor;
         float glossiness = u_glossiness;
         float alphaCutoff = u_alphaCutoff;
+        float F0 = pow2( (material_IOR - 1.0) / (material_IOR + 1.0) )
+
 
         #ifdef BASETEXTURE
             vec4 baseTextureColor = texture2D(u_baseTexture, v_uv);
@@ -90,7 +92,7 @@ void initMaterial(out Material material, const in Geometry geometry){
 
         #ifdef IS_METALLIC_WORKFLOW
             material.diffuseColor = baseColor.rgb * ( 1.0 - metal );
-            material.specularColor = mix( vec3( 0.04), baseColor.rgb, metal );
+            material.specularColor = mix( vec3(F0), baseColor.rgb, metal );
             material.roughness = roughness;
         #else
             float specularStrength = max( max( specularColor.r, specularColor.g ), specularColor.b );

packages/loader/src/gltf/extensions/KHR_materials_ior.ts

@@ -0,0 +1,15 @@
+import { PBRMaterial } from "@galacean/engine-core";
+import { IKHRMaterialsIor } from "./Schema";
+
+import { registerExtension } from "../parser/Parser";
+import { ParserContext } from "../parser/ParserContext";
+import { ExtensionParser } from "./ExtensionParser";
+
+@registerExtension("KHR_materials_ior")
+class KHR_materials_ior extends ExtensionParser {
+  parseEngineResource(schema: IKHRMaterialsIor, material: PBRMaterial, context: ParserContext): void {
+    const { ior = 1.5 } = schema;
+
+    material.ior = ior;
+  }
+}

packages/loader/src/gltf/extensions/index.ts

@@ -12,3 +12,4 @@ import "./KHR_mesh_quantization";
 import "./KHR_texture_basisu";
 import "./KHR_texture_transform";
 import "./GALACEAN_materials_remap";
+import "./KHR_materials_ior";

packages/loader/src/gltf/parser/MaterialParser.ts

@@ -49,6 +49,7 @@ export class MaterialParser extends Parser {
         KHR_materials_unlit,
         KHR_materials_pbrSpecularGlossiness,
         KHR_materials_clearcoat,
+        KHR_materials_ior,
         OASIS_materials_remap
       } = extensions;
 
@@ -74,6 +75,10 @@ export class MaterialParser extends Parser {
         Parser.parseEngineResource("KHR_materials_clearcoat", KHR_materials_clearcoat, material, context);
       }
 
+      if (KHR_materials_ior) {
+        Parser.parseEngineResource("KHR_materials_ior", KHR_materials_ior, material, context);
+      }
+
       if (pbrMetallicRoughness) {
         const { baseColorFactor, baseColorTexture, metallicFactor, roughnessFactor, metallicRoughnessTexture } =
           pbrMetallicRoughness;