add more gltf extensions

4 files changed, 68 insertions, 29 deletions

diff --git a/doc/resources.md b/doc/resources.md
index a6b885b..4931f51 100644
--- a/doc/resources.md
+++ b/doc/resources.md
@@ -27,38 +27,62 @@
 
 ## MeshPart
 
-Combinations of g__, va__ and tex_* are multiplied except normal which is added.
-Defaults should be the identity for that operation, so default is 1 / white
-except normals are zero.
+Combinations of g_\*, va_\* and tex_\* are multiplied except normal which is
+added. Defaults should be the identity for that operation, so default is 1 /
+white except normals are zero.
 
-| Key              | Value Type    |                    |
-| ---------------- | ------------- | ------------------ |
-| index            | Resource      |                    |
-| g_metallic       | f32           |                    |
-| g_roughness      | f32           |                    |
-| g_albedo         | Vec3          |                    |
-| g_transmission   | f32           |                    |
-| g_emission       | Vec3          |                    |
-| va_position      | [Resource; 3] |                    |
-| va_normal        | [Resource; 3] |                    |
-| va_texcoord      | [Resource; 2] |                    |
-| va_roughness     | Resource      |                    |
-| va_metallic      | Resource      |                    |
-| va_albedo        | [Resource; 3] |                    |
-| va_transmission  | Resource      |                    |
-| va_emission      | Resource      |                    |
-| tex_normal       | Resource      | Use color channels |
-| tex_roughness    | Resource      | Use green channel  |
-| tex_metallic     | Resource      | Use blue channel   |
-| tex_albedo       | Resource      | Use color channels |
-| tex_transmission | Resource      | Use alpha channel  |
-| tex_emission     | Resource      | Use color channels |
+| Key                | Value Type    |   |                    |
+| ------------------ | ------------- | - | ------------------ |
+| index              | Resource      |   |                    |
+| g_metallic         | Float         |   |                    |
+| g_roughness        | Float         |   |                    |
+| g_albedo           | Vec3          |   |                    |
+| g_alpha            | Float         |   |                    |
+| g_transmission     | Float         |   |                    |
+| g_emission         | Vec3          |   |                    |
+| g_refractive_index | Float         |   |                    |
+| g_attenuation      | Vec3          |   |                    |
+| g_dispersion       | Float         |   |                    |
+| g_thickness        | Float         |   |                    |
+| va_position        | [Resource; 3] |   |                    |
+| va_normal          | [Resource; 3] |   |                    |
+| va_texcoord        | [Resource; 2] |   |                    |
+| va_roughness       | Resource      |   |                    |
+| va_metallic        | Resource      |   |                    |
+| va_albedo          | [Resource; 3] |   |                    |
+| va_alpha           | Resource      |   |                    |
+| va_transmission    | Resource      |   |                    |
+| va_emission        | Resource      |   |                    |
+| tex_normal         | Resource      |   | Use color channels |
+| tex_roughness      | Resource      |   | Use green channel  |
+| tex_metallic       | Resource      |   | Use blue channel   |
+| tex_albedo         | Resource      |   | Use color channels |
+| tex_alpha          | Resource      |   | Use alpha channel  |
+| tex_transmission   | Resource      |   | Use red channel    |
+| tex_emission       | Resource      |   | Use color channels |
+| tex_thickness      | Resource      |   | Use green channels |
+
+- **Attenuation**: Attenuation coefficient for each color channel due to
+  scattering within the material volume expressed as e-folding distance (m^-1).
+  See [KHR_materials_volume].
+- **Transmission**: Equivalent to `transmissionFactor` and `transmissionTexture`
+  of [KHR_materials_transmission].
+- **Refractive Index**: Equivalent to `ior` of [KHR_materials_ior]
+- **Thickness**: Equivalent to `thicknessFactor` and `thicknessTexture` of
+  [KHR_materials_volume].
+- **Dispersion**: 20 / Abbe Number. Equivalent to `dispersion` of
+  [KHR_materials_dispersion].
+
+[KHR_materials_transmission]: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_transmission
+[KHR_materials_ior]: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_ior
+[KHR_materials_volume]: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_volume
+[KHR_materials_dispersion]: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_dispersion
 
 ## LightPart
 
 | Key      | Value Type |
 | -------- | ---------- |
-| radius   | f32        |
+| radius   | Float      |
 | emission | Vec3       |
 
 ## EnvironmentPart
diff --git a/shared/src/resources.rs b/shared/src/resources.rs
index 628fa1e..08fb6f5 100644
--- a/shared/src/resources.rs
+++ b/shared/src/resources.rs
@@ -51,6 +51,10 @@ pub struct MeshPart {
     pub g_transmission: Option<f32>,
     pub g_alpha: Option<f32>,
     pub g_emission: Option<Vec3A>,
+    pub g_thickness: Option<f32>,
+    pub g_refractive_index: Option<f32>,
+    pub g_attenuation: Option<Vec3A>,
+    pub g_dispersion: Option<f32>,
     pub va_position: Option<[Resource<AttributeArray>; 3]>,
     pub va_normal: Option<[Resource<AttributeArray>; 3]>,
     pub va_texcoord: Option<[Resource<AttributeArray>; 2]>,
@@ -67,6 +71,7 @@ pub struct MeshPart {
     pub tex_transmission: Option<Resource<Image>>,
     pub tex_alpha: Option<Resource<Image>>,
     pub tex_emission: Option<Resource<Image>>,
+    pub tex_thickness: Option<Resource<Image>>,
 }
 
 #[derive(Debug, Default, Clone)]
diff --git a/world/Cargo.toml b/world/Cargo.toml
index 11272ed..51437d5 100644
--- a/world/Cargo.toml
+++ b/world/Cargo.toml
@@ -12,6 +12,9 @@ gltf = { version = "1.4.1", features = [
     "names",
     "KHR_lights_punctual",
     "KHR_materials_transmission",
+    "KHR_materials_ior",
+    "KHR_materials_volume",
+    "KHR_materials_emissive_strength",
 ] }
 log = "0.4.22"
 weareshared = { path = "../shared" }
diff --git a/world/src/mesh.rs b/world/src/mesh.rs
index 3190c28..216f8f3 100644
--- a/world/src/mesh.rs
+++ b/world/src/mesh.rs
@@ -283,10 +283,17 @@ pub fn import_mesh(
             tex_emission,
             tex_transmission,
             index,
+            // not yet implemented
+            g_attenuation: None,
+            g_dispersion: None,
+            g_refractive_index: None,
+            g_thickness: None,
+            tex_thickness: None,
+            // not supported by gltf
             va_transmission: None,
-            va_emission: None,  // not supported by gltf
-            va_metallic: None,  // not supported by gltf
-            va_roughness: None, // not supported by gltf
+            va_emission: None,
+            va_metallic: None,
+            va_roughness: None,
         })?;
         let mat = node.transform().matrix();
         let aff = Affine3A::from_cols_array_2d(&[