mirror of
https://github.com/bevyengine/bevy
synced 2025-02-18 15:08:36 +00:00
37893a3f9e
Per title. Note the "improve this page" link on the [site](https://bevyengine.org/learn/errors/b0004/) gives a 404.
112 lines
3.5 KiB
Markdown
112 lines
3.5 KiB
Markdown
# B0004
|
|
|
|
A runtime warning.
|
|
|
|
An [`Entity`] with a hierarchy-inherited component has a [`ChildOf`]
|
|
without the hierarchy-inherited component in question.
|
|
|
|
The hierarchy-inherited components defined in bevy include:
|
|
|
|
- [`InheritedVisibility`]
|
|
- [`GlobalTransform`]
|
|
|
|
Third party plugins may also define their own hierarchy components, so
|
|
read the warning message carefully and pay attention to the exact type
|
|
of the missing component.
|
|
|
|
To fix this warning, add the missing hierarchy component to all ancestors
|
|
of entities with the hierarchy component you wish to use.
|
|
|
|
The following code will cause a warning to be emitted:
|
|
|
|
```rust,no_run
|
|
use bevy::prelude::*;
|
|
|
|
// WARNING: this code is buggy
|
|
fn setup_cube(
|
|
mut commands: Commands,
|
|
mut meshes: ResMut<Assets<Mesh>>,
|
|
mut materials: ResMut<Assets<StandardMaterial>>,
|
|
) {
|
|
commands
|
|
.spawn(Transform::default())
|
|
.with_children(|parent| {
|
|
// cube
|
|
parent.spawn((
|
|
Mesh3d(meshes.add(Cuboid::default())),
|
|
MeshMaterial3d(materials.add(Color::srgb(0.8, 0.7, 0.6))),
|
|
Transform::from_xyz(0.0, 0.5, 0.0),
|
|
));
|
|
});
|
|
|
|
// camera
|
|
commands.spawn((
|
|
Camera3d::default(),
|
|
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
|
|
));
|
|
}
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.add_systems(Startup, setup_cube)
|
|
.run();
|
|
}
|
|
```
|
|
|
|
This code **will not** show a cube on screen.
|
|
This is because the entity spawned with `commands.spawn(…)`
|
|
doesn't have a [`ViewVisibility`] or [`InheritedVisibility`] component.
|
|
Since the cube is spawned as a child of an entity without the
|
|
visibility components, it will not be visible at all.
|
|
|
|
To fix this, you must also add a [`Visibility`] component.
|
|
It automatically adds the other relevant visibility components for you:
|
|
|
|
```rust,no_run
|
|
use bevy::prelude::*;
|
|
|
|
fn setup_cube(
|
|
mut commands: Commands,
|
|
mut meshes: ResMut<Assets<Mesh>>,
|
|
mut materials: ResMut<Assets<StandardMaterial>>,
|
|
) {
|
|
commands
|
|
.spawn((Transform::default(), Visibility::default()))
|
|
.with_children(|parent| {
|
|
// cube
|
|
parent.spawn((
|
|
Mesh3d(meshes.add(Cuboid::default())),
|
|
MeshMaterial3d(materials.add(Color::srgb(0.8, 0.7, 0.6))),
|
|
Transform::from_xyz(0.0, 0.5, 0.0),
|
|
));
|
|
});
|
|
|
|
// camera
|
|
commands.spawn((
|
|
Camera3d::default(),
|
|
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
|
|
));
|
|
}
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.add_systems(Startup, setup_cube)
|
|
.run();
|
|
}
|
|
```
|
|
|
|
A similar problem occurs when the [`GlobalTransform`] component is missing.
|
|
However, it will be automatically inserted whenever `Transform` is
|
|
inserted, as it is a required component.
|
|
|
|
You will most likely encounter this warning when loading a scene
|
|
as a child of a pre-existing [`Entity`] that does not have the proper components.
|
|
|
|
[`InheritedVisibility`]: https://docs.rs/bevy/*/bevy/render/view/struct.InheritedVisibility.html
|
|
[`ViewVisibility`]: https://docs.rs/bevy/*/bevy/render/view/struct.ViewVisibility.html
|
|
[`Visibility`]: https://docs.rs/bevy/*/bevy/render/view/enum.Visibility.html
|
|
[`GlobalTransform`]: https://docs.rs/bevy/*/bevy/transform/components/struct.GlobalTransform.html
|
|
[`ChildOf`]: https://docs.rs/bevy/*/bevy/ecs/hierarchy/struct.ChildOf.html
|
|
[`Entity`]: https://docs.rs/bevy/*/bevy/ecs/entity/struct.Entity.html
|