bevy-assets

Bevy 0.19 — Assets

When to use this skill

• Loading a model, texture, audio file, or scene.
• Reading the loaded data back from Assets<T> once it's ready.
• Reacting to load progress (AssetEvent::Added / Modified).
• Spawning glTF scenes, waiting for WorldInstanceReady, reading names/extras, or owning/despawning an instance cleanly.
• Enabling hot-reload during development.
• Writing your own loader → see bevy-custom-assets.

Canonical pattern

use bevy::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins.set(AssetPlugin {
            // Hot-reload on file change — dev-only.
            watch_for_changes_override: Some(true),
            ..default()
        }))
        .init_resource::<MyHandles>()
        .add_systems(Startup, load_handles)
        .add_systems(Update, react_to_loads)
        .run();
}

#[derive(Resource, Default)]
struct MyHandles {
    hero: Handle<WorldAsset>,
    bricks: Handle<Image>,
}

fn load_handles(asset_server: Res<AssetServer>, mut handles: ResMut<MyHandles>) {
    // GLTF scenes are addressed by sub-asset label.
    handles.hero = asset_server.load("models/hero.glb#Scene0");
    handles.bricks = asset_server.load("textures/bricks.png");
}

fn react_to_loads(
    mut ev: MessageReader<AssetEvent<Image>>,
    images: Res<Assets<Image>>,
) {
    for event in ev.read() {
        if let AssetEvent::LoadedWithDependencies { id } = event {
            if let Some(img) = images.get(*id) {
                info!("image loaded: {}x{}", img.width(), img.height());
            }
        }
    }
}

Asset paths

use bevy::asset::AssetPath;

// `LoadContext::path()` returns `AssetPath`, not `&Path`.
// Build paths explicitly when generating handles inside a custom loader:
let path = AssetPath::from("textures/bricks.png");
let path_with_label = AssetPath::from("models/hero.glb").with_label("Scene0");
let _ = path;
let _ = path_with_label;

Asset readiness check

use bevy::prelude::*;

# fn _check(
asset_server: Res<AssetServer>,
handles: Res<MyHandles>,
# ) {
use bevy::asset::LoadState;

if asset_server.load_state(&handles.hero) == LoadState::Loaded {
    // Safe to spawn WorldAssetRoot(handles.hero.clone()).
}
# }
# #[derive(Resource)] struct MyHandles { hero: Handle<WorldAsset> }