bevy/examples/transforms/scale.rs
ira 4847f7e3ad Update codebase to use IntoIterator where possible. (#5269)
Remove unnecessary calls to `iter()`/`iter_mut()`.
Mainly updates the use of queries in our code, docs, and examples.

```rust
// From
for _ in list.iter() {
for _ in list.iter_mut() {

// To
for _ in &list {
for _ in &mut list {
```

We already enable the pedantic lint [clippy::explicit_iter_loop](https://rust-lang.github.io/rust-clippy/stable/) inside of Bevy. However, this only warns for a few known types from the standard library.

## Note for reviewers
As you can see the additions and deletions are exactly equal.
Maybe give it a quick skim to check I didn't sneak in a crypto miner, but you don't have to torture yourself by reading every line.
I already experienced enough pain making this PR :) 


Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-07-11 15:28:50 +00:00

98 lines
3.5 KiB
Rust

//! Illustrates how to scale an object in each direction.
use bevy::math::Vec3Swizzles;
use bevy::prelude::*;
use std::f32::consts::PI;
// Define a component to keep information for the scaled object.
#[derive(Component)]
struct Scaling {
scale_direction: Vec3,
scale_speed: f32,
max_element_size: f32,
min_element_size: f32,
}
// Implement a simple initialisation.
impl Scaling {
fn new() -> Self {
Scaling {
scale_direction: Vec3::X,
scale_speed: 2.0,
max_element_size: 5.0,
min_element_size: 1.0,
}
}
}
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(change_scale_direction)
.add_system(scale_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>>,
) {
// Spawn a cube to scale.
commands
.spawn_bundle(PbrBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(Color::WHITE.into()),
transform: Transform::from_rotation(Quat::from_rotation_y(PI / 4.0)),
..default()
})
.insert(Scaling::new());
// Spawn a camera looking at the entities to show what's happening in this example.
commands.spawn_bundle(Camera3dBundle {
transform: Transform::from_xyz(0.0, 10.0, 20.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
// Add a light source for better 3d visibility.
commands.spawn_bundle(PointLightBundle {
transform: Transform::from_translation(Vec3::ONE * 3.0),
..default()
});
}
// This system will check if a scaled entity went above or below the entities scaling bounds
// and change the direction of the scaling vector.
fn change_scale_direction(mut cubes: Query<(&mut Transform, &mut Scaling)>) {
for (mut transform, mut cube) in &mut cubes {
// If an entity scaled beyond the maximum of its size in any dimension
// the scaling vector is flipped so the scaling is gradually reverted.
// Additionally, to ensure the condition does not trigger again we floor the elements to
// their next full value, which should be max_element_size at max.
if transform.scale.max_element() > cube.max_element_size {
cube.scale_direction *= -1.0;
transform.scale = transform.scale.floor();
}
// If an entity scaled beyond the minimum of its size in any dimension
// the scaling vector is also flipped.
// Additionally the Values are ceiled to be min_element_size at least
// and the scale direction is flipped.
// This way the entity will change the dimension in which it is scaled any time it
// reaches its min_element_size.
if transform.scale.min_element() < cube.min_element_size {
cube.scale_direction *= -1.0;
transform.scale = transform.scale.ceil();
cube.scale_direction = cube.scale_direction.zxy();
}
}
}
// This system will scale any entity with assigned Scaling in each direction
// by cycling through the directions to scale.
fn scale_cube(mut cubes: Query<(&mut Transform, &Scaling)>, timer: Res<Time>) {
for (mut transform, cube) in &mut cubes {
transform.scale += cube.scale_direction * cube.scale_speed * timer.delta_seconds();
}
}