mirror of
https://github.com/bevyengine/bevy
synced 2024-11-30 08:30:24 +00:00
dcc03724a5
# Objective NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267. "Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365). ## Solution This adds "base sets" as a variant of `SystemSet`: A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive: ```rust #[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)] #[system_set(base)] enum MyBaseSet { A, B, } ``` **Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. **Base sets cannot belong to other sets**: this is where the word "base" comes from Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set. ```rust app.add_system(foo.in_base_set(MyBaseSet::A)) // X must be a normal set ... base sets cannot be added to base sets .configure_set(X.in_base_set(MyBaseSet::A)) ``` Base sets can still be configured like normal sets: ```rust app.add_system(MyBaseSet::B.after(MyBaseSet::Ap)) ``` The primary use case for base sets is enabling a "default base set": ```rust schedule.set_default_base_set(CoreSet::Update) // this will belong to CoreSet::Update by default .add_system(foo) // this will override the default base set with PostUpdate .add_system(bar.in_base_set(CoreSet::PostUpdate)) ``` This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides. --- ## Changelog - Added "base sets" and ported CoreSet to use them. ## Migration Guide TODO
74 lines
2.2 KiB
Rust
74 lines
2.2 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_startup_system(setup)
|
|
.add_system(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((
|
|
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),
|
|
));
|
|
|
|
// Spawn a camera looking at the entities to show what's happening in this example.
|
|
commands.spawn(Camera3dBundle {
|
|
transform: Transform::from_xyz(0.0, 10.0, 20.0).looking_at(entity_spawn, Vec3::Y),
|
|
..default()
|
|
});
|
|
|
|
// Add a light source for better 3d visibility.
|
|
commands.spawn(PointLightBundle {
|
|
transform: Transform::from_translation(Vec3::ONE * 3.0),
|
|
..default()
|
|
});
|
|
}
|
|
|
|
// 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_seconds();
|
|
}
|
|
}
|