bevy/examples/transforms/translation.rs
andristarr 7482a0d26d
aligning public apis of Time,Timer and Stopwatch (#15962)
Fixes #15834

## Migration Guide

The APIs of `Time`, `Timer` and `Stopwatch` have been cleaned up for
consistency with each other and the standard library's `Duration` type.
The following methods have been renamed:

- `Stowatch::paused` -> `Stopwatch::is_paused`
- `Time::elapsed_seconds` -> `Time::elasped_secs` (including `_f64` and
`_wrapped` variants)
2024-10-16 21:09:32 +00:00

71 lines
2.1 KiB
Rust

//! Illustrates how to move an object along an axis.
use bevy::prelude::*;
// Define a struct to keep some information about our entity.
// Here it's an arbitrary movement speed, the spawn location, and a maximum distance from it.
#[derive(Component)]
struct Movable {
spawn: Vec3,
max_distance: f32,
speed: f32,
}
// Implement a utility function for easier Movable struct creation.
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();
}
// Startup system to setup the scene and spawn all relevant entities.
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
// Add a cube to visualize translation.
let entity_spawn = Vec3::ZERO;
commands.spawn((
Mesh3d(meshes.add(Cuboid::default())),
MeshMaterial3d(materials.add(Color::WHITE)),
Transform::from_translation(entity_spawn),
Movable::new(entity_spawn),
));
// Spawn a camera looking at the entities to show what's happening in this example.
commands.spawn((
Camera3d::default(),
Transform::from_xyz(0.0, 10.0, 20.0).looking_at(entity_spawn, Vec3::Y),
));
// Add a light source for better 3d visibility.
commands.spawn((
DirectionalLight::default(),
Transform::from_xyz(3.0, 3.0, 3.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}
// This system will move all Movable entities with a Transform
fn move_cube(mut cubes: Query<(&mut Transform, &mut Movable)>, timer: Res<Time>) {
for (mut transform, mut cube) in &mut cubes {
// Check if the entity moved too far from its spawn, if so invert the moving direction.
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_secs();
}
}