Bevy version

v0.12

What you did

Bevy panics when you spawn a Mesh from a GLTF asset that has an attached armature. The GLTF file I'm working with contains a single cube, with a single bone inside it. When I spawn it as #Scene0 it works fine, but when I only want to spawn the #Mesh0/Primitive0 it panics.

When I spawn it, the application crashes with:

2023-11-29T22:44:06.310929Z ERROR log: Handling wgpu errors as fatal by default thread '<unnamed>' panicked at /Users/dmlary/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-0.17.2/src/backend/direct.rs:3056:5: wgpu error: Validation Error

Caused by:
    In a RenderPass
      note: encoder = `<CommandBuffer-(0, 2, Metal)>`
    In a draw command, indexed:true indirect:false
      note: render pipeline = `pbr_opaque_mesh_pipeline`
    The pipeline layout, associated with the current render pipeline, contains a bind group layout at index 2 which is incompatible with the bind group layout associated with the bind group at 2

Source code used to load the asset.

use bevy::prelude::*;

fn main() {
    let mut app = App::new();

    app.add_plugins((DefaultPlugins,))
        .add_systems(Startup, setup)
        .run();
}

fn setup(
    mut commands: Commands,
    mut materials: ResMut<Assets<StandardMaterial>>,
    asset_server: Res<AssetServer>,
) {
    // XXX works fine
    // let scene = asset_server.load("cube-with-bone.glb#Scene0");
    // commands.spawn(SceneBundle { scene, ..default() });

    // XXX panics during render
    let mesh_handle: Handle<Mesh> = asset_server.load("cube-with-bone.glb#Mesh0/Primitive0");
    commands.spawn(MaterialMeshBundle {
        mesh: mesh_handle,
        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
        ..default()
    });

    // camera
    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(10.0, 12.0, 16.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });
}

Questions

• Is there a way to spawn a Mesh from a GLTF without its Armature?
• How would we spawn the Mesh with its Armature?
  • Example: How is a GltfNode connected to the Armature?
  • Is there an AssetServer::load() path that encompasses Mesh and Armature?
• Is there any way to get a better error message when this happens?

Additional information

Zip file of both .blender and .glb files (thanks for the idea @alice-i-cecile): cube-with-bone.zip

blender file screenshot (because github no support gltf/blender files):

gltf file loaded in gltf viewer:

full-panic-output.txt

Another person brought up this issue in the discord recently: https://discord.com/channels/691052431525675048/1179374309882462239

Further background

The wider context for this is I'm working on a scene-less blender workflow for spawning objects, characters, etc from a GLTF file. I'm able to spawn the hierarchy from GltfNode¹, but it panics if any Mesh had bones attached. Unless I'm missing something obvious, the Armature have been removed from the GltfNode, so I don't know that it should be spawned.