mirror of
https://github.com/bevyengine/bevy
synced 2024-11-23 05:03:47 +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
76 lines
2.6 KiB
Rust
76 lines
2.6 KiB
Rust
//! Illustrates parallel queries with `ParallelIterator`.
|
|
|
|
use bevy::ecs::query::BatchingStrategy;
|
|
use bevy::prelude::*;
|
|
use rand::random;
|
|
|
|
#[derive(Component, Deref)]
|
|
struct Velocity(Vec2);
|
|
|
|
fn spawn_system(mut commands: Commands, asset_server: Res<AssetServer>) {
|
|
commands.spawn(Camera2dBundle::default());
|
|
let texture = asset_server.load("branding/icon.png");
|
|
for _ in 0..128 {
|
|
commands.spawn((
|
|
SpriteBundle {
|
|
texture: texture.clone(),
|
|
transform: Transform::from_scale(Vec3::splat(0.1)),
|
|
..default()
|
|
},
|
|
Velocity(20.0 * Vec2::new(random::<f32>() - 0.5, random::<f32>() - 0.5)),
|
|
));
|
|
}
|
|
}
|
|
|
|
// Move sprites according to their velocity
|
|
fn move_system(mut sprites: Query<(&mut Transform, &Velocity)>) {
|
|
// Compute the new location of each sprite in parallel on the
|
|
// ComputeTaskPool
|
|
//
|
|
// This example is only for demonstrative purposes. Using a
|
|
// ParallelIterator for an inexpensive operation like addition on only 128
|
|
// elements will not typically be faster than just using a normal Iterator.
|
|
// See the ParallelIterator documentation for more information on when
|
|
// to use or not use ParallelIterator over a normal Iterator.
|
|
sprites
|
|
.par_iter_mut()
|
|
.for_each_mut(|(mut transform, velocity)| {
|
|
transform.translation += velocity.extend(0.0);
|
|
});
|
|
}
|
|
|
|
// Bounce sprites outside the window
|
|
fn bounce_system(windows: Query<&Window>, mut sprites: Query<(&Transform, &mut Velocity)>) {
|
|
let window = windows.single();
|
|
let width = window.width();
|
|
let height = window.height();
|
|
let left = width / -2.0;
|
|
let right = width / 2.0;
|
|
let bottom = height / -2.0;
|
|
let top = height / 2.0;
|
|
// The default batch size can also be overridden.
|
|
// In this case a batch size of 32 is chosen to limit the overhead of
|
|
// ParallelIterator, since negating a vector is very inexpensive.
|
|
sprites
|
|
.par_iter_mut()
|
|
.batching_strategy(BatchingStrategy::fixed(32))
|
|
.for_each_mut(|(transform, mut v)| {
|
|
if !(left < transform.translation.x
|
|
&& transform.translation.x < right
|
|
&& bottom < transform.translation.y
|
|
&& transform.translation.y < top)
|
|
{
|
|
// For simplicity, just reverse the velocity; don't use realistic bounces
|
|
v.0 = -v.0;
|
|
}
|
|
});
|
|
}
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.add_startup_system(spawn_system)
|
|
.add_system(move_system)
|
|
.add_system(bounce_system)
|
|
.run();
|
|
}
|