2
0
Fork 0
mirror of https://github.com/bevyengine/bevy synced 2024-12-23 11:33:06 +00:00
bevy/examples/async_tasks/external_source_external_thread.rs
andristarr 7482a0d26d
aligning public apis of Time,Timer and Stopwatch ()
Fixes 

## 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

77 lines
2.5 KiB
Rust

//! How to use an external thread to run an infinite task and communicate with a channel.
use bevy::prelude::*;
// Using crossbeam_channel instead of std as std `Receiver` is `!Sync`
use crossbeam_channel::{bounded, Receiver};
use rand::{Rng, SeedableRng};
use rand_chacha::ChaCha8Rng;
use std::time::{Duration, Instant};
fn main() {
App::new()
.add_event::<StreamEvent>()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, (read_stream, spawn_text, move_text))
.run();
}
#[derive(Resource, Deref)]
struct StreamReceiver(Receiver<u32>);
#[derive(Event)]
struct StreamEvent(u32);
fn setup(mut commands: Commands) {
commands.spawn(Camera2d);
let (tx, rx) = bounded::<u32>(10);
std::thread::spawn(move || {
// We're seeding the PRNG here to make this example deterministic for testing purposes.
// This isn't strictly required in practical use unless you need your app to be deterministic.
let mut rng = ChaCha8Rng::seed_from_u64(19878367467713);
loop {
// Everything here happens in another thread
// This is where you could connect to an external data source
let start_time = Instant::now();
let duration = Duration::from_secs_f32(rng.gen_range(0.0..0.2));
while start_time.elapsed() < duration {
// Spinning for 'duration', simulating doing hard work!
}
tx.send(rng.gen_range(0..2000)).unwrap();
}
});
commands.insert_resource(StreamReceiver(rx));
}
// This system reads from the receiver and sends events to Bevy
fn read_stream(receiver: Res<StreamReceiver>, mut events: EventWriter<StreamEvent>) {
for from_stream in receiver.try_iter() {
events.send(StreamEvent(from_stream));
}
}
fn spawn_text(mut commands: Commands, mut reader: EventReader<StreamEvent>) {
for (per_frame, event) in reader.read().enumerate() {
commands.spawn((
Text2d::new(event.0.to_string()),
TextLayout::new_with_justify(JustifyText::Center),
Transform::from_xyz(per_frame as f32 * 100.0, 300.0, 0.0),
));
}
}
fn move_text(
mut commands: Commands,
mut texts: Query<(Entity, &mut Transform), With<Text2d>>,
time: Res<Time>,
) {
for (entity, mut position) in &mut texts {
position.translation -= Vec3::new(0.0, 100.0 * time.delta_secs(), 0.0);
if position.translation.y < -300.0 {
commands.entity(entity).despawn();
}
}
}