As this page is outdated, please refer to Bevy's official migration guides while reading, to cover the differences: 0.9 to 0.10, 0.10 to 0.11, 0.11 to 0.12, 0.12 to 0.13.

I apologize for the inconvenience. I will update the page as soon as I find the time.

Track Loading Progress

There are good community plugins that can help with this. Otherwise, this page shows you how to do it yourself.

If you want to check the status of various asset files, you can poll it from the AssetServer. It will tell you whether the asset(s) are loaded, still loading, not loaded, or encountered an error.

To check an individual asset, you can use asset_server.get_load_state(…) with a handle or path to refer to the asset.

To check a group of many assets, you can add them to a single collection (such as a Vec<HandleUntyped>; untyped handles are very useful for this) and use asset_server.get_group_load_state(…).

Here is a more complete code example:

#[derive(Resource)]
struct AssetsLoading(Vec<HandleUntyped>);

fn setup(server: Res<AssetServer>, mut loading: ResMut<AssetsLoading>) {
    // we can have different asset types
    let font: Handle<Font> = server.load("my_font.ttf");
    let menu_bg: Handle<Image> = server.load("menu.png");
    let scene: Handle<Scene> = server.load("level01.gltf#Scene0");

    // add them all to our collection for tracking
    loading.0.push(font.clone_untyped());
    loading.0.push(menu_bg.clone_untyped());
    loading.0.push(scene.clone_untyped());
}

fn check_assets_ready(
    mut commands: Commands,
    server: Res<AssetServer>,
    loading: Res<AssetsLoading>
) {
    use bevy::asset::LoadState;

    match server.get_group_load_state(loading.0.iter().map(|h| h.id)) {
        LoadState::Failed => {
            // one of our assets had an error
        }
        LoadState::Loaded => {
            // all assets are now ready

            // this might be a good place to transition into your in-game state

            // remove the resource to drop the tracking handles
            commands.remove_resource::<AssetsLoading>();
            // (note: if you don't have any other handles to the assets
            // elsewhere, they will get unloaded after this)
        }
        _ => {
            // NotLoaded/Loading: not fully ready yet
        }
    }
}