# Objective
Make documentation of a component's required components more visible by
moving it to the type's docs
## Solution
Change `#[require]` from a derive macro helper to an attribute macro.
Disadvantages:
- this silences any unused code warnings on the component, as it is used
by the macro!
- need to import `require` if not using the ecs prelude (I have not
included this in the migration guilde as Rust tooling already suggests
the fix)
---
## Showcase
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
# Objective
A step in the migration to required components: scenes!
## Solution
As per the [selected
proposal](https://hackmd.io/@bevy/required_components/%2FPJtNGVMMQhyM0zIvCJSkbA):
- Deprecate `SceneBundle` and `DynamicSceneBundle`.
- Add `SceneRoot` and `DynamicSceneRoot` components, which wrap a
`Handle<Scene>` and `Handle<DynamicScene>` respectively.
## Migration Guide
Asset handles for scenes and dynamic scenes must now be wrapped in the
`SceneRoot` and `DynamicSceneRoot` components. Raw handles as components
no longer spawn scenes.
Additionally, `SceneBundle` and `DynamicSceneBundle` have been
deprecated. Instead, use the scene components directly.
Previously:
```rust
let model_scene = asset_server.load(GltfAssetLabel::Scene(0).from_asset("model.gltf"));
commands.spawn(SceneBundle {
scene: model_scene,
transform: Transform::from_xyz(-4.0, 0.0, -3.0),
..default()
});
```
Now:
```rust
let model_scene = asset_server.load(GltfAssetLabel::Scene(0).from_asset("model.gltf"));
commands.spawn((
SceneRoot(model_scene),
Transform::from_xyz(-4.0, 0.0, -3.0),
));
```
