Add KHR_materials_clearcoat support

Cargo.toml

@@ -36,3 +36,7 @@ gltf = "1.3"
 egui = "0.27"
 egui-winit = "0.27"
 egui-ash-renderer = { version = "0.3.0", features = ["dynamic-rendering"]}
+
+[patch.crates-io.gltf]
+git = "https://github.com/adrien-ben/gltf"
+branch = "missing_extensions"

crates/libs/model/Cargo.toml

@@ -18,5 +18,6 @@ features = [
     "KHR_lights_punctual", 
     "KHR_materials_unlit", 
     "KHR_materials_pbrSpecularGlossiness",
-    "KHR_materials_emissive_strength"
+    "KHR_materials_emissive_strength",
+    "KHR_materials_clearcoat",
 ]

crates/libs/model/src/material.rs

@@ -21,6 +21,7 @@ pub struct Material {
     alpha_cutoff: f32,
     double_sided: bool,
     is_unlit: bool,
+    clearcoat: Option<Clearcoat>,
 }
 
 #[derive(Clone, Copy, Debug)]
@@ -85,6 +86,49 @@ impl SpecularGlossinessWorkflow {
     }
 }
 
+#[derive(Clone, Copy, Debug, Default)]
+pub struct Clearcoat {
+    factor: f32,
+    roughness: f32,
+    factor_texture: Option<TextureInfo>,
+    roughness_texture: Option<TextureInfo>,
+    normal_texture: Option<TextureInfo>,
+}
+
+impl Clearcoat {
+    pub fn factor(&self) -> f32 {
+        self.factor
+    }
+
+    pub fn roughness(&self) -> f32 {
+        self.roughness
+    }
+
+    pub fn factor_texture(&self) -> Option<TextureInfo> {
+        self.factor_texture
+    }
+
+    pub fn factor_texture_index(&self) -> Option<usize> {
+        self.factor_texture.map(|info| info.index)
+    }
+
+    pub fn roughness_texture(&self) -> Option<TextureInfo> {
+        self.roughness_texture
+    }
+
+    pub fn roughness_texture_index(&self) -> Option<usize> {
+        self.roughness_texture.map(|info| info.index)
+    }
+
+    pub fn normal_texture(&self) -> Option<TextureInfo> {
+        self.normal_texture
+    }
+
+    pub fn normal_texture_index(&self) -> Option<usize> {
+        self.normal_texture.map(|info| info.index)
+    }
+}
+
 impl Material {
     pub fn get_color(&self) -> [f32; 4] {
         self.color
@@ -150,6 +194,10 @@ impl Material {
         self.is_unlit
     }
 
+    pub fn get_clearcoat(&self) -> Option<Clearcoat> {
+        self.clearcoat
+    }
+
     pub fn get_workflow(&self) -> Workflow {
         self.workflow
     }
@@ -212,6 +260,14 @@ impl<'a> From<GltfMaterial<'a>> for Material {
 
         let is_unlit = material.unlit();
 
+        let clearcoat = material.clearcoat().map(|m| Clearcoat {
+            factor: m.clearcoat_factor(),
+            roughness: m.clearcoat_roughness_factor(),
+            factor_texture: get_texture(m.clearcoat_texture()),
+            roughness_texture: get_texture(m.clearcoat_roughness_texture()),
+            normal_texture: get_texture(m.clearcoat_normal_texture()),
+        });
+
         Material {
             color,
             emissive,
@@ -225,6 +281,7 @@ impl<'a> From<GltfMaterial<'a>> for Material {
             alpha_cutoff,
             double_sided,
             is_unlit,
+            clearcoat,
         }
     }
 }