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https://github.com/bevyengine/bevy
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370eed05e5
# Objective The documentation for the `print_when_completed` system stated that this system would tick the `Timer` component on every entity in the scene. This was incorrect as this system only ticks the `Timer` on entities with the `PrintOnCompletionTimer` component. ## Solution We suggest a modification to the documentation of this system to make it more clear.
77 lines
2.4 KiB
Rust
77 lines
2.4 KiB
Rust
//! Illustrates how `Timer`s can be used both as resources and components.
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use bevy::{log::info, prelude::*};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.init_resource::<Countdown>()
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.add_systems(Startup, setup)
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.add_systems(Update, (countdown, print_when_completed))
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.run();
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}
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#[derive(Component, Deref, DerefMut)]
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pub struct PrintOnCompletionTimer(Timer);
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#[derive(Resource)]
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pub struct Countdown {
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pub percent_trigger: Timer,
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pub main_timer: Timer,
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}
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impl Countdown {
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pub fn new() -> Self {
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Self {
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percent_trigger: Timer::from_seconds(4.0, TimerMode::Repeating),
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main_timer: Timer::from_seconds(20.0, TimerMode::Once),
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}
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}
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}
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impl Default for Countdown {
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fn default() -> Self {
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Self::new()
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}
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}
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fn setup(mut commands: Commands) {
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// Add an entity to the world with a timer
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commands.spawn(PrintOnCompletionTimer(Timer::from_seconds(
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5.0,
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TimerMode::Once,
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)));
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}
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/// This system ticks the `Timer` on the entity with the `PrintOnCompletionTimer`
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/// component using bevy's `Time` resource to get the delta between each update.
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fn print_when_completed(time: Res<Time>, mut query: Query<&mut PrintOnCompletionTimer>) {
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for mut timer in &mut query {
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if timer.tick(time.delta()).just_finished() {
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info!("Entity timer just finished");
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}
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}
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}
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/// This system controls ticking the timer within the countdown resource and
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/// handling its state.
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fn countdown(time: Res<Time>, mut countdown: ResMut<Countdown>) {
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countdown.main_timer.tick(time.delta());
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// The API encourages this kind of timer state checking (if you're only checking for one value)
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// Additionally, `finished()` would accomplish the same thing as `just_finished` due to the
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// timer being repeating, however this makes more sense visually.
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if countdown.percent_trigger.tick(time.delta()).just_finished() {
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if !countdown.main_timer.finished() {
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// Print the percent complete the main timer is.
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info!(
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"Timer is {:0.0}% complete!",
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countdown.main_timer.percent() * 100.0
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);
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} else {
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// The timer has finished so we pause the percent output timer
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countdown.percent_trigger.pause();
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info!("Paused percent trigger timer");
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}
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}
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}
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