bevy-scenes

name	bevy-scenes
description	Reference for Bevy scenes — saving and loading entity/component snapshots via reflection, DynamicWorld, WorldInstanceSpawner, and DynamicWorldRoot.
metadata	{"crate":"bevy_scene","bevy":"0.19"}

Scene types

• DynamicWorld — serializable representation (no own world), stores Vec<Box<dyn PartialReflect>> resources + Vec<DynamicEntity> entities

Saving a scene

fn save_scene(world: &mut World) {
  let scene = DynamicWorld::from_world(world);
  let type_registry = world.resource::<AppTypeRegistry>();
  let reg = type_registry.read();
  let serialized = scene.serialize(&reg).unwrap();
  // write serialized to file (e.g., "scene.scn.ron")
}

Loading a scene

Three ways:

// 1. DynamicWorldRoot component
fn load(asset_server: Res<AssetServer>, mut commands: Commands) {
  commands.spawn(DynamicWorldRoot(asset_server.load("scene.scn.ron")));
}

// 2. WorldInstanceSpawner::spawn_dynamic
// 3. DynamicWorldBuilder

Scene events

WorldInstanceReady fires when the scene is fully loaded. SceneInstance component is added to the root entity:

fn on_loaded(mut spawner: ResMut<WorldInstanceSpawner>, query: Query<&SceneInstance>) {
  for instance in &query {
    spawner.despawn_instance_sync(world, instance);
  }
}

Serialization format (RON)

(
  resources: { "my::Resource": (score: 1) },
  entities: {
    4294967297: (
      components: {
        "bevy_transform::components::transform::Transform": (
          translation: (0.0, 0.0, 0.0),
          rotation: (0.0, 0.0, 0.0, 1.0),
          scale: (1.0, 1.0, 1.0),
        ),
      },
    ),
  },
)

Required setup

• Components must #[derive(Reflect)] for auto-registration
• FromWorld on a component customizes initialization during load
• #[reflect(skip_serializing)] excludes fields from serialization