How to mutable access meshes/materials in loaded Gltf scene ?

[sergio-ivanuzzo]

Hi everyone !

I loaded the scene from .glb file and I want to change the color of the model. So, I do the next for solving this:

#[derive(Resource)]
struct MaterialResource(Handle<StandardMaterial>);

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    asset_server: Res<AssetServer>,
) {
    // ...

    let material_handle = materials.add(Color::srgb(0.5, 0.3, 0.9));
    commands.insert_resource(MaterialResource(material_handle.clone()));

    // ...

    let scene_handle: Handle<Scene> = asset_server.load("models/asteroid.glb#Scene0");

    commands.spawn((Name::new("asteroid"), SceneBundle {
        scene: scene_handle.clone(),
        transform: Transform {
            scale: Vec3::splat(0.3),
            translation: Vec3::new(1., 1., 1.),
            ..default()
        },
        ..default()
    }));
}

fn customize_asteroid(
    material_handle: Res<MaterialResource>,
    mut query: Query<(Entity, &Handle<Scene>, &Name)>,
    mut material_query: Query<(&mut Handle<StandardMaterial>)>,
) {
    for (entity, handle, name) in query.iter_mut() {
        if name == &Name::new("asteroid") {
            for (mut material) in material_query.iter_mut() {
                if let Some(path) = material.path() {
                    if path.to_string() == "models/asteroid.glb#Material0" {
                        *material = material_handle.0.clone();
                    }
                }
            }
        }
    }
}

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, customize_asteroid)
        .run();
}

But this solutions looks a bit hardcoded. Does it exist the way to get all meshes/materials for related scene, so I will not need to check each path manually ?