bevy/examples/ecs/event.rs
Chris Janaqi ab407aa697 ♻️ Timer refactor to duration. Add Stopwatch struct. (#1151)
This pull request is following the discussion on the issue #1127. Additionally, it integrates the change proposed by #1112.

The list of change of this pull request:

*  Add `Timer::times_finished` method that counts the number of wraps for repeating timers.
* ♻️ Refactored `Timer`
* 🐛 Fix a bug where 2 successive calls to `Timer::tick` which makes a repeating timer to finish makes `Timer::just_finished` to return `false` where it should return `true`. Minimal failing example:
```rust
use bevy::prelude::*;
let mut timer: Timer<()> = Timer::from_seconds(1.0, true);
timer.tick(1.5);
assert!(timer.finished());
assert!(timer.just_finished());
timer.tick(1.5);
assert!(timer.finished());
assert!(timer.just_finished()); // <- This fails where it should not
```
* 📚 Add extensive documentation for Timer with doc examples.
*  Add a `Stopwatch` struct similar to `Timer` with extensive doc and tests.

Even if the type specialization is not retained for bevy, the doc, bugfix and added method are worth salvaging 😅.
This is my first PR for bevy, please be kind to me ❤️ .

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2021-03-05 19:59:14 +00:00

49 lines
1.2 KiB
Rust

use bevy::prelude::*;
/// This example creates a new event, a system that triggers the event once per second,
/// and a system that prints a message whenever the event is received.
fn main() {
App::build()
.add_plugins(DefaultPlugins)
.add_event::<MyEvent>()
.init_resource::<EventTriggerState>()
.add_system(event_trigger_system.system())
.add_system(event_listener_system.system())
.run();
}
struct MyEvent {
pub message: String,
}
struct EventTriggerState {
event_timer: Timer,
}
impl Default for EventTriggerState {
fn default() -> Self {
EventTriggerState {
event_timer: Timer::from_seconds(1.0, true),
}
}
}
// sends MyEvent every second
fn event_trigger_system(
time: Res<Time>,
mut state: ResMut<EventTriggerState>,
mut my_events: ResMut<Events<MyEvent>>,
) {
if state.event_timer.tick(time.delta()).finished() {
my_events.send(MyEvent {
message: "MyEvent just happened!".to_string(),
});
}
}
// prints events as they come in
fn event_listener_system(mut events: EventReader<MyEvent>) {
for my_event in events.iter() {
println!("{}", my_event.message);
}
}