bevy/examples/ecs/timers.rs
Daniel McNab 6f111136b9 Cleanup some things which shouldn't be components (#2982)
# Objective

- Using `Stopwatch` and `Timer` as raw components is a footgun.

## Solution

- Stop them from being components
2022-02-03 23:56:57 +00:00

74 lines
2.2 KiB
Rust

use bevy::{log::info, prelude::*};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.init_resource::<Countdown>()
.add_startup_system(setup)
.add_system(countdown)
.add_system(print_when_completed)
.run();
}
#[derive(Component)]
pub struct PrintOnCompletionTimer(Timer);
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(mut commands: Commands) {
// Add an entity to the world with a timer
commands
.spawn()
.insert(PrintOnCompletionTimer(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 print_when_completed(time: Res<Time>, mut query: Query<&mut PrintOnCompletionTimer>) {
for mut timer in query.iter_mut() {
if timer.0.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(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")
}
}
}