Allow timers to be paused

crates/bevy_core/src/lib.rs

@@ -40,7 +40,6 @@ impl Plugin for CorePlugin {
             .register_property::<Quat>()
             .register_property::<Option<String>>()
             .add_system_to_stage(stage::FIRST, time_system)
-            .add_system_to_stage(stage::FIRST, timer_system)
             .add_system_to_stage(stage::PRE_UPDATE, entity_labels_system);
     }
 }

crates/bevy_core/src/time/timer.rs

@@ -1,23 +1,21 @@
-use crate::time::Time;
-use bevy_ecs::prelude::*;
 use bevy_property::Properties;
 use bevy_utils::Duration;
 
 /// Tracks elapsed time. Enters the finished state once `duration` is reached.
 ///
 /// Non repeating timers will stop tracking and stay in the finished state until reset.
 /// Repeating timers will only be in the finished state on each tick `duration` is reached or exceeded, and can still be reset at any given point.
+///
+/// Paused timers will not have elapsed time increased.
 #[derive(Clone, Debug, Default, Properties)]
 pub struct Timer {
-    /// Time elapsed on the timer. Guaranteed to be between 0.0 and `duration`, inclusive.
-    pub elapsed: f32,
-    pub duration: f32,
-    /// Non repeating timers will stop tracking and stay in the finished state until reset.
-    /// Repeating timers will only be in the finished state on each tick `duration` is reached or exceeded, and can still be reset at any given point.
-    pub finished: bool,
+    elapsed: f32,
+    duration: f32,
+    finished: bool,
     /// Will only be true on the tick `duration` is reached or exceeded.
-    pub just_finished: bool,
-    pub repeating: bool,
+    just_finished: bool,
+    paused: bool,
+    repeating: bool,
 }
 
 impl Timer {
@@ -37,6 +35,67 @@ impl Timer {
         }
     }
 
+    #[inline]
+    pub fn pause(&mut self) {
+        self.paused = true
+    }
+
+    #[inline]
+    pub fn resume(&mut self) {
+        self.paused = false
+    }
+
+    #[inline]
+    pub fn is_paused(&self) -> bool {
+        self.paused
+    }
+
+    /// Returns the time elapsed on the timer. Guaranteed to be between 0.0 and `duration`, inclusive.
+    #[inline]
+    pub fn elapsed(&self) -> f32 {
+        self.elapsed
+    }
+
+    #[inline]
+    pub fn set_elapsed(&mut self, elapsed: f32) {
+        self.elapsed = elapsed
+    }
+
+    #[inline]
+    pub fn duration(&self) -> f32 {
+        self.duration
+    }
+
+    #[inline]
+    pub fn set_duration(&mut self, duration: f32) {
+        self.duration = duration
+    }
+
+    /// Returns the finished state of the timer.
+    ///
+    /// Non repeating timers will stop tracking and stay in the finished state until reset.
+    /// Repeating timers will only be in the finished state on each tick `duration` is reached or exceeded, and can still be reset at any given point.
+    #[inline]
+    pub fn is_finished(&self) -> bool {
+        self.finished
+    }
+
+    /// Will only be true on the tick the timer's duration is reached or exceeded.
+    #[inline]
+    pub fn just_finished(&self) -> bool {
+        self.just_finished
+    }
+
+    #[inline]
+    pub fn is_repeating(&self) -> bool {
+        self.repeating
+    }
+
+    #[inline]
+    pub fn set_repeating(&mut self, repeating: bool) {
+        self.repeating = repeating
+    }
+
     /// Advances the timer by `delta` seconds.
     pub fn tick(&mut self, delta: f32) -> &Self {
         let prev_finished = self.finished;
@@ -56,6 +115,7 @@ impl Timer {
         self
     }
 
+    #[inline]
     pub fn reset(&mut self) {
         self.finished = false;
         self.just_finished = false;
@@ -73,12 +133,6 @@ impl Timer {
     }
 }
 
-pub(crate) fn timer_system(time: Res<Time>, mut query: Query<&mut Timer>) {
-    for mut timer in query.iter_mut() {
-        timer.tick(time.delta_seconds);
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::Timer;

crates/bevy_diagnostic/src/print_diagnostics_plugin.rs

@@ -66,7 +66,7 @@ impl PrintDiagnosticsPlugin {
         time: Res<Time>,
         diagnostics: Res<Diagnostics>,
     ) {
-        if state.timer.tick(time.delta_seconds).finished {
+        if state.timer.tick(time.delta_seconds).is_finished() {
             println!("Diagnostics:");
             println!("{}", "-".repeat(93));
             if let Some(ref filter) = state.filter {
@@ -86,7 +86,7 @@ impl PrintDiagnosticsPlugin {
         time: Res<Time>,
         diagnostics: Res<Diagnostics>,
     ) {
-        if state.timer.tick(time.delta_seconds).finished {
+        if state.timer.tick(time.delta_seconds).is_finished() {
             println!("Diagnostics (Debug):");
             println!("{}", "-".repeat(93));
             if let Some(ref filter) = state.filter {

examples/2d/contributors.rs

@@ -137,7 +137,7 @@ fn select_system(
 ) {
     let mut timer_fired = false;
     for mut t in tq.iter_mut() {
-        if !t.just_finished {
+        if !t.just_finished() {
             continue;
         }
         t.reset();

examples/2d/sprite_sheet.rs

@@ -13,7 +13,7 @@ fn animate_sprite_system(
     mut query: Query<(&mut Timer, &mut TextureAtlasSprite, &Handle<TextureAtlas>)>,
 ) {
     for (timer, mut sprite, texture_atlas_handle) in query.iter_mut() {
-        if timer.finished {
+        if timer.is_finished() {
             let texture_atlas = texture_atlases.get(texture_atlas_handle).unwrap();
             sprite.index = ((sprite.index as usize + 1) % texture_atlas.textures.len()) as u32;
         }

examples/app/plugin.rs

@@ -38,7 +38,7 @@ struct PrintMessageState {
 }
 
 fn print_message_system(mut state: ResMut<PrintMessageState>, time: Res<Time>) {
-    if state.timer.tick(time.delta_seconds).finished {
+    if state.timer.tick(time.delta_seconds).is_finished() {
         println!("{}", state.message);
     }
 }

examples/ecs/event.rs

@@ -34,7 +34,7 @@ fn event_trigger_system(
     mut state: ResMut<EventTriggerState>,
     mut my_events: ResMut<Events<MyEvent>>,
 ) {
-    if state.event_timer.tick(time.delta_seconds).finished {
+    if state.event_timer.tick(time.delta_seconds).is_finished() {
         my_events.send(MyEvent {
             message: "MyEvent just happened!".to_string(),
         });

examples/ui/font_atlas_debug.rs

@@ -62,7 +62,7 @@ fn atlas_render_system(
 }
 
 fn text_update_system(mut state: ResMut<State>, time: Res<Time>, mut query: Query<&mut Text>) {
-    if state.timer.tick(time.delta_seconds).finished {
+    if state.timer.tick(time.delta_seconds).is_finished() {
         for mut text in query.iter_mut() {
             let c = rand::random::<u8>() as char;
             if !text.value.contains(c) {