From 230ada7ba1ff09e30bc8a6713eb220bc5af5981a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois=20Mockers?= <mockersf@gmail.com>
Date: Mon, 7 Dec 2020 03:38:19 +0100
Subject: [PATCH] add list of primitive per mesh, and their associated material

---
 crates/bevy_gltf/src/lib.rs    | 15 ++++++++++++++-
 crates/bevy_gltf/src/loader.rs | 13 +++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_gltf/src/lib.rs b/crates/bevy_gltf/src/lib.rs
index 636c0925233d10..2e7702b436575f 100644
--- a/crates/bevy_gltf/src/lib.rs
+++ b/crates/bevy_gltf/src/lib.rs
@@ -11,7 +11,8 @@ pub struct GltfPlugin;
 impl Plugin for GltfPlugin {
     fn build(&self, app: &mut AppBuilder) {
         app.init_asset_loader::<GltfLoader>()
-            .add_asset::<GltfNode>();
+            .add_asset::<GltfNode>()
+            .add_asset::<GltfMesh>();
     }
 }
 
@@ -22,3 +23,15 @@ pub struct GltfNode {
     pub mesh: Option<usize>,
     pub transform: bevy_transform::prelude::Transform,
 }
+
+#[derive(Debug, Clone, bevy_reflect::TypeUuid)]
+#[uuid = "8ceaec9a-926a-4f29-8ee3-578a69f42315"]
+pub struct GltfMesh {
+    pub primitives: Vec<GltfPrimitive>,
+}
+
+#[derive(Debug, Clone)]
+pub struct GltfPrimitive {
+    index: usize,
+    material: Option<usize>,
+}
diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index c881d192ec2fc5..4a371bd972d3f5 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -106,7 +106,12 @@ async fn load_gltf<'a, 'b>(
     }
 
     for mesh in gltf.meshes() {
+        let mut primitives = vec![];
         for primitive in mesh.primitives() {
+            primitives.push(super::GltfPrimitive {
+                index: primitive.index(),
+                material: primitive.material().index(),
+            });
             let primitive_label = primitive_label(&mesh, &primitive);
             if !load_context.has_labeled_asset(&primitive_label) {
                 let reader = primitive.reader(|buffer| Some(&buffer_data[buffer.index()]));
@@ -142,6 +147,10 @@ async fn load_gltf<'a, 'b>(
                 load_context.set_labeled_asset(&primitive_label, LoadedAsset::new(mesh));
             };
         }
+        load_context.set_labeled_asset(
+            &mesh_label(&mesh),
+            LoadedAsset::new(super::GltfMesh { primitives }),
+        );
     }
 
     for texture in gltf.textures() {
@@ -326,6 +335,10 @@ fn load_node(
     }
 }
 
+fn mesh_label(mesh: &gltf::Mesh) -> String {
+    format!("Mesh{}", mesh.index())
+}
+
 fn primitive_label(mesh: &gltf::Mesh, primitive: &Primitive) -> String {
     format!("Mesh{}/Primitive{}", mesh.index(), primitive.index())
 }