bevy/examples/3d/parenting.rs
Carter Anderson b6a647cc01 default() shorthand (#4071)
Adds a `default()` shorthand for `Default::default()` ... because life is too short to constantly type `Default::default()`.

```rust
use bevy::prelude::*;

#[derive(Default)]
struct Foo {
  bar: usize,
  baz: usize,
}

// Normally you would do this:
let foo = Foo {
  bar: 10,
  ..Default::default()
};

// But now you can do this:
let foo = Foo {
  bar: 10,
  ..default()
};
```

The examples have been adapted to use `..default()`. I've left internal crates as-is for now because they don't pull in the bevy prelude, and the ergonomics of each case should be considered individually.
2022-03-01 20:52:09 +00:00

65 lines
2 KiB
Rust

use bevy::prelude::*;
/// This example illustrates how to create parent->child relationships between entities how parent
/// transforms are propagated to their descendants
fn main() {
App::new()
.insert_resource(Msaa { samples: 4 })
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(rotator_system)
.run();
}
/// this component indicates what entities should rotate
#[derive(Component)]
struct Rotator;
/// rotates the parent, which will result in the child also rotating
fn rotator_system(time: Res<Time>, mut query: Query<&mut Transform, With<Rotator>>) {
for mut transform in query.iter_mut() {
transform.rotation *= Quat::from_rotation_x(3.0 * time.delta_seconds());
}
}
/// set up a simple scene with a "parent" cube and a "child" cube
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
let cube_handle = meshes.add(Mesh::from(shape::Cube { size: 2.0 }));
let cube_material_handle = materials.add(StandardMaterial {
base_color: Color::rgb(0.8, 0.7, 0.6),
..default()
});
// parent cube
commands
.spawn_bundle(PbrBundle {
mesh: cube_handle.clone(),
material: cube_material_handle.clone(),
transform: Transform::from_xyz(0.0, 0.0, 1.0),
..default()
})
.insert(Rotator)
.with_children(|parent| {
// child cube
parent.spawn_bundle(PbrBundle {
mesh: cube_handle,
material: cube_material_handle,
transform: Transform::from_xyz(0.0, 0.0, 3.0),
..default()
});
});
// light
commands.spawn_bundle(PointLightBundle {
transform: Transform::from_xyz(4.0, 5.0, -4.0),
..default()
});
// camera
commands.spawn_bundle(PerspectiveCameraBundle {
transform: Transform::from_xyz(5.0, 10.0, 10.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
}