bevy/examples/window/custom_user_event.rs
Mike cfcb56f5b9
Remove need for EventLoopProxy to be NonSend (#14198)
# Objective

- Continue to pare down the uses on NonSend resources in the engine. In
this case, EventLoopProxy used to be `!Sync`, but is now `Sync` in the
latest version of winit.

## Solution

- New type `EventLoopProxy` as `EventLoopProxyWrapper` to make it into a
normal resource.
- Update the `custom_user_event` example as it no longer needs to
indirectly access the `EventLoopProxy` through a static variable
anymore.

## Testing

- Ran the example. The resource exists just for users to use, so there
aren't any in engine uses for it currently.

---

## Changelog

- make EventLoopProxy into a regular resource. 

## Migration Guide

`EventLoopProxy` has been renamed to `EventLoopProxyWrapper` and is now
`Send`, making it an ordinary resource.

Before:
```rust
event_loop_system(event_loop: NonSend<EventLoopProxy<MyEvent>>) {
    event_loop.send_event(MyEvent);
}
```

After:
```rust
event_loop_system(event_loop: Res<EventLoopProxy<MyEvent>>) {
    event_loop.send_event(MyEvent);
}
```
2024-07-16 06:59:01 +00:00

112 lines
3.3 KiB
Rust

//! Shows how to create a custom event that can be handled by `winit`'s event loop.
use bevy::prelude::*;
use bevy::winit::{EventLoopProxyWrapper, WakeUp, WinitPlugin};
use std::fmt::Formatter;
#[derive(Default, Debug, Event)]
enum CustomEvent {
#[default]
WakeUp,
Key(char),
}
impl std::fmt::Display for CustomEvent {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
match self {
Self::WakeUp => write!(f, "Wake up"),
Self::Key(ch) => write!(f, "Key: {ch}"),
}
}
}
fn main() {
let winit_plugin = WinitPlugin::<CustomEvent>::default();
App::new()
.add_plugins(
DefaultPlugins
.build()
// Only one event type can be handled at once
// so we must disable the default event type
.disable::<WinitPlugin<WakeUp>>()
.add(winit_plugin),
)
.add_systems(
Startup,
(
setup,
#[cfg(target_arch = "wasm32")]
wasm::setup_js_closure,
),
)
.add_systems(Update, (send_event, handle_event))
.run();
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2dBundle::default());
}
fn send_event(
input: Res<ButtonInput<KeyCode>>,
event_loop_proxy: Res<EventLoopProxyWrapper<CustomEvent>>,
) {
if input.just_pressed(KeyCode::Space) {
let _ = event_loop_proxy.send_event(CustomEvent::WakeUp);
}
// This simulates sending a custom event through an external thread.
#[cfg(not(target_arch = "wasm32"))]
if input.just_pressed(KeyCode::KeyE) {
let event_loop_proxy = event_loop_proxy.clone();
let handler = std::thread::spawn(move || {
let _ = event_loop_proxy.clone().send_event(CustomEvent::Key('e'));
});
handler.join().unwrap();
}
}
fn handle_event(mut events: EventReader<CustomEvent>) {
for evt in events.read() {
info!("Received event: {evt:?}");
}
}
/// Since the [`EventLoopProxy`] can be exposed to the javascript environment, it can
/// be used to send events inside the loop, to be handled by a system or simply to wake up
/// the loop if that's currently waiting for a timeout or a user event.
#[cfg(target_arch = "wasm32")]
pub(crate) mod wasm {
use super::*;
use bevy::winit::EventLoopProxy;
use wasm_bindgen::prelude::*;
use wasm_bindgen::JsCast;
use web_sys::KeyboardEvent;
pub(crate) fn setup_js_closure(event_loop: Res<EventLoopProxyWrapper<CustomEvent>>) {
let window = web_sys::window().unwrap();
let document = window.document().unwrap();
let event_loop = event_loop.clone();
let closure = Closure::wrap(Box::new(move |event: KeyboardEvent| {
let key = event.key();
if key == "e" {
send_custom_event('e', &event_loop).unwrap();
}
}) as Box<dyn FnMut(KeyboardEvent)>);
document
.add_event_listener_with_callback("keydown", closure.as_ref().unchecked_ref())
.unwrap();
closure.forget();
}
fn send_custom_event(ch: char, proxy: &EventLoopProxy<CustomEvent>) -> Result<(), String> {
proxy
.send_event(CustomEvent::Key(ch))
.map_err(|_| "Failed to send event".to_string())
}
}