bevy/examples/ecs/timers.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

69 lines
2.2 KiB
Rust

use bevy::{log::info, prelude::*};
fn main() {
App::build()
.add_plugins(DefaultPlugins)
.insert_resource(Countdown::default())
.add_startup_system(setup_system.system())
.add_system(countdown_system.system())
.add_system(timer_system.system())
.run();
}
pub struct Countdown {
pub percent_trigger: Timer,
pub main_timer: Timer,
}
impl Countdown {
pub fn new() -> Self {
Self {
percent_trigger: Timer::from_seconds(4.0, true),
main_timer: Timer::from_seconds(20.0, false),
}
}
}
impl Default for Countdown {
fn default() -> Self {
Self::new()
}
}
fn setup_system(mut commands: Commands) {
// Add an entity to the world with a timer
commands.spawn((Timer::from_seconds(5.0, false),));
}
/// This system ticks all the `Timer` components on entities within the scene
/// using bevy's `Time` resource to get the delta between each update.
fn timer_system(time: Res<Time>, mut query: Query<&mut Timer>) {
for mut timer in query.iter_mut() {
if timer.tick(time.delta()).just_finished() {
info!("Entity timer just finished")
}
}
}
/// This system controls ticking the timer within the countdown resource and
/// handling its state.
fn countdown_system(time: Res<Time>, mut countdown: ResMut<Countdown>) {
countdown.main_timer.tick(time.delta());
// The API encourages this kind of timer state checking (if you're only checking for one value)
// Additionally, `finished()` would accomplish the same thing as `just_finished` due to the timer
// being repeating, however this makes more sense visually.
if countdown.percent_trigger.tick(time.delta()).just_finished() {
if !countdown.main_timer.finished() {
// Print the percent complete the main timer is.
info!(
"Timer is {:0.0}% complete!",
countdown.main_timer.percent() * 100.0
);
} else {
// The timer has finished so we pause the percent output timer
countdown.percent_trigger.pause();
info!("Paused percent trigger timer")
}
}
}