68 lines
2.0 KiB
Rust
68 lines
2.0 KiB
Rust
//! Illustrates how to create parent-child relationships between entities and how parent transforms
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//! are propagated to their descendants.
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use bevy::prelude::*;
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_systems(Startup, setup)
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.add_systems(Update, rotator_system)
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.run();
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}
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/// this component indicates what entities should rotate
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#[derive(Component)]
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struct Rotator;
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/// rotates the parent, which will result in the child also rotating
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fn rotator_system(time: Res<Time>, mut query: Query<&mut Transform, With<Rotator>>) {
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for mut transform in &mut query {
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transform.rotate_x(3.0 * time.delta_seconds());
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}
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}
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/// set up a simple scene with a "parent" cube and a "child" cube
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fn setup(
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mut commands: Commands,
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mut meshes: ResMut<Assets<Mesh>>,
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mut materials: ResMut<Assets<StandardMaterial>>,
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) {
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let cube_handle = meshes.add(Mesh::from(shape::Cube { size: 2.0 }));
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let cube_material_handle = materials.add(StandardMaterial {
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base_color: Color::rgb(0.8, 0.7, 0.6),
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..default()
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});
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// parent cube
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commands
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.spawn((
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PbrBundle {
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mesh: cube_handle.clone(),
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material: cube_material_handle.clone(),
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transform: Transform::from_xyz(0.0, 0.0, 1.0),
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..default()
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},
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Rotator,
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))
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.with_children(|parent| {
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// child cube
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parent.spawn(PbrBundle {
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mesh: cube_handle,
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material: cube_material_handle,
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transform: Transform::from_xyz(0.0, 0.0, 3.0),
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..default()
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});
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});
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// light
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commands.spawn(PointLightBundle {
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transform: Transform::from_xyz(4.0, 5.0, -4.0),
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..default()
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});
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// camera
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commands.spawn(Camera3dBundle {
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transform: Transform::from_xyz(5.0, 10.0, 10.0).looking_at(Vec3::ZERO, Vec3::Y),
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..default()
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});
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}
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