make more information available from loaded GLTF model (#1020)

make more information available from loaded GLTF model 
* make gltf nodes available as assets
* add list of primitive per mesh, and their associated material
* complete gltf structure
* get names of gltf assets
* only load materials once
* add labels with node names

crates/bevy_asset/src/loader.rs

@@ -89,9 +89,10 @@ impl<'a> LoadContext<'a> {
         self.labeled_assets.insert(None, asset);
     }
 
-    pub fn set_labeled_asset(&mut self, label: &str, asset: LoadedAsset) {
+    pub fn set_labeled_asset<T: Asset>(&mut self, label: &str, asset: LoadedAsset) -> Handle<T> {
         assert!(!label.is_empty());
         self.labeled_assets.insert(Some(label.to_string()), asset);
+        self.get_handle(AssetPath::new_ref(self.path(), Some(label)))
     }
 
     pub fn get_handle<I: Into<HandleId>, T: Asset>(&self, id: I) -> Handle<T> {

crates/bevy_gltf/Cargo.toml

@@ -16,6 +16,7 @@ keywords = ["bevy"]
 # bevy
 bevy_app = { path = "../bevy_app", version = "0.4.0" }
 bevy_asset = { path = "../bevy_asset", version = "0.4.0" }
+bevy_core = { path = "../bevy_core", version = "0.4.0" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.4.0" }
 bevy_pbr = { path = "../bevy_pbr", version = "0.4.0" }
 bevy_reflect = { path = "../bevy_reflect", version = "0.4.0", features = ["bevy"] }
@@ -25,7 +26,7 @@ bevy_math = { path = "../bevy_math", version = "0.4.0" }
 bevy_scene = { path = "../bevy_scene", version = "0.4.0" }
 
 # other
-gltf = { version = "0.15.2", default-features = false, features = ["utils"] }
+gltf = { version = "0.15.2", default-features = false, features = ["utils", "names"] }
 image = { version = "0.23.12", default-features = false }
 thiserror = "1.0"
 anyhow = "1.0"

crates/bevy_gltf/src/lib.rs

@@ -1,15 +1,60 @@
+use std::collections::HashMap;
+
 mod loader;
 pub use loader::*;
 
 use bevy_app::prelude::*;
-use bevy_asset::AddAsset;
+use bevy_asset::{AddAsset, Handle};
+use bevy_pbr::prelude::StandardMaterial;
+use bevy_reflect::TypeUuid;
+use bevy_render::mesh::Mesh;
+use bevy_scene::Scene;
 
 /// Adds support for GLTF file loading to Apps
 #[derive(Default)]
 pub struct GltfPlugin;
 
 impl Plugin for GltfPlugin {
     fn build(&self, app: &mut AppBuilder) {
-        app.init_asset_loader::<GltfLoader>();
+        app.init_asset_loader::<GltfLoader>()
+            .add_asset::<Gltf>()
+            .add_asset::<GltfNode>()
+            .add_asset::<GltfPrimitive>()
+            .add_asset::<GltfMesh>();
     }
 }
+
+#[derive(Debug, TypeUuid)]
+#[uuid = "5c7d5f8a-f7b0-4e45-a09e-406c0372fea2"]
+pub struct Gltf {
+    pub scenes: Vec<Handle<Scene>>,
+    pub named_scenes: HashMap<String, Handle<Scene>>,
+    pub meshes: Vec<Handle<GltfMesh>>,
+    pub named_meshes: HashMap<String, Handle<GltfMesh>>,
+    pub materials: Vec<Handle<StandardMaterial>>,
+    pub named_materials: HashMap<String, Handle<StandardMaterial>>,
+    pub nodes: Vec<Handle<GltfNode>>,
+    pub named_nodes: HashMap<String, Handle<GltfNode>>,
+    pub default_scene: Option<Handle<Scene>>,
+}
+
+#[derive(Debug, Clone, TypeUuid)]
+#[uuid = "dad74750-1fd6-460f-ac51-0a7937563865"]
+pub struct GltfNode {
+    pub children: Vec<GltfNode>,
+    pub mesh: Option<Handle<GltfMesh>>,
+    pub transform: bevy_transform::prelude::Transform,
+}
+
+#[derive(Debug, Clone, TypeUuid)]
+#[uuid = "8ceaec9a-926a-4f29-8ee3-578a69f42315"]
+pub struct GltfMesh {
+    pub primitives: Vec<GltfPrimitive>,
+}
+
+#[derive(Debug, Clone, TypeUuid)]
+#[uuid = "cbfca302-82fd-41cb-af77-cab6b3d50af1"]
+pub struct GltfPrimitive {
+    pub mesh: Handle<Mesh>,
+    pub material: Option<Handle<StandardMaterial>>,
+}