[Merged by Bors] - Slight perf improvements and tidy for contributors example

examples/2d/contributors.rs

@@ -1,11 +1,13 @@
-use bevy::{prelude::*, utils::HashSet};
-use rand::{prelude::SliceRandom, Rng};
 use std::{
     env::VarError,
     io::{self, BufRead, BufReader},
     process::Stdio,
 };
 
+use rand::{prelude::SliceRandom, Rng};
+
+use bevy::{prelude::*, utils::HashSet};
+
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
@@ -26,8 +28,10 @@ struct ContributorSelection {
     idx: usize,
 }
 
-#[derive(Component)]
-struct SelectTimer;
+struct SelectTimerState {
+    timer: Timer,
+    has_triggered: bool,
+}
 
 #[derive(Component)]
 struct ContributorDisplay;
@@ -69,7 +73,7 @@ fn setup_contributor_selection(mut commands: Commands, asset_server: Res<AssetSe
     let texture_handle = asset_server.load("branding/icon.png");
 
     let mut contributor_selection = ContributorSelection {
-        order: vec![],
+        order: Vec::with_capacity(contribs.len()),
         idx: 0,
     };
 
@@ -120,7 +124,10 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
     commands.spawn_bundle(OrthographicCameraBundle::new_2d());
     commands.spawn_bundle(UiCameraBundle::default());
 
-    commands.spawn_bundle((SelectTimer, Timer::from_seconds(SHOWCASE_TIMER_SECS, true)));
+    commands.insert_resource(SelectTimerState {
+        timer: Timer::from_seconds(SHOWCASE_TIMER_SECS, true),
+        has_triggered: false,
+    });
 
     commands
         .spawn()
@@ -159,44 +166,39 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
 fn select_system(
     mut contributor_selection: ResMut<ContributorSelection>,
     mut text_query: Query<&mut Text, With<ContributorDisplay>>,
-    mut timer_query: Query<&mut Timer, With<SelectTimer>>,
     mut query: Query<(&Contributor, &mut Sprite, &mut Transform)>,
+    mut timer_state: ResMut<SelectTimerState>,
     time: Res<Time>,
 ) {
-    let mut timer_fired = false;
-    for mut timer in timer_query.iter_mut() {
-        if !timer.tick(time.delta()).just_finished() {
-            continue;
-        }
-        timer.reset();
-        timer_fired = true;
-    }
-
-    if !timer_fired {
+    if !timer_state.timer.tick(time.delta()).just_finished() {
         return;
     }
+    if !timer_state.has_triggered {
+        let mut text = text_query.single_mut();
+        text.sections[0].value.clear();
+        text.sections[0].value.push_str("Contributor: ");
 
-    let prev = contributor_selection.idx;
-
-    if (contributor_selection.idx + 1) < contributor_selection.order.len() {
-        contributor_selection.idx += 1;
-    } else {
-        contributor_selection.idx = 0;
+        timer_state.has_triggered = true;
     }
 
     {
-        let (_, entity) = &contributor_selection.order[prev];
+        let (_, entity) = &contributor_selection.order[contributor_selection.idx];
         if let Ok((contributor, mut sprite, mut transform)) = query.get_mut(*entity) {
             deselect(&mut sprite, contributor, &mut *transform);
         }
     }
 
+    if (contributor_selection.idx + 1) < contributor_selection.order.len() {
+        contributor_selection.idx += 1;
+    } else {
+        contributor_selection.idx = 0;
+    }
+
     let (name, entity) = &contributor_selection.order[contributor_selection.idx];
 
     if let Ok((contributor, mut sprite, mut transform)) = query.get_mut(*entity) {
-        if let Some(mut text) = text_query.iter_mut().next() {
-            select(&mut sprite, contributor, &mut *transform, &mut *text, name);
-        }
+        let mut text = text_query.single_mut();
+        select(&mut sprite, contributor, &mut *transform, &mut *text, name);
     }
 }
 
@@ -207,7 +209,7 @@ fn select(
     contributor: &Contributor,
     transform: &mut Transform,
     text: &mut Text,
-    name: &str,
+    #[allow(clippy::ptr_arg)] name: &String,
 ) {
     sprite.color = Color::hsla(
         contributor.hue,
@@ -218,8 +220,7 @@ fn select(
 
     transform.translation.z = 100.0;
 
-    text.sections[0].value = "Contributor: ".to_string();
-    text.sections[1].value = name.to_string();
+    text.sections[1].value.clone_from(name);
     text.sections[1].style.color = sprite.color;
 }