use bevy::prelude::*;
#[derive(Component)]
struct Movable {
spawn: Vec3,
max_distance: f32,
speed: f32,
}
impl Movable {
fn new(spawn: Vec3) -> Self {
Movable {
spawn,
max_distance: 5.0,
speed: 2.0,
}
}
}
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, move_cube)
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
let entity_spawn = Vec3::ZERO;
commands.spawn((
PbrBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(Color::WHITE.into()),
transform: Transform::from_translation(entity_spawn),
..default()
},
Movable::new(entity_spawn),
));
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(0.0, 10.0, 20.0).looking_at(entity_spawn, Vec3::Y),
..default()
});
commands.spawn(PointLightBundle {
transform: Transform::from_translation(Vec3::ONE * 3.0),
..default()
});
}
fn move_cube(mut cubes: Query<(&mut Transform, &mut Movable)>, timer: Res<Time>) {
for (mut transform, mut cube) in &mut cubes {
if (cube.spawn - transform.translation).length() > cube.max_distance {
cube.speed *= -1.0;
}
let direction = transform.local_x();
transform.translation += direction * cube.speed * timer.delta_seconds();
}
}