feat: print sprite names every 2 seconds

src/main.rs

@@ -2,16 +2,11 @@ use bevy::prelude::*;
 
 fn main() {
     App::new()
-        .add_startup_system(add_default_sprites)
-        .add_system(hello_world)
-        .add_system(print_sprite_names)
+        .add_plugins(DefaultPlugins)
+        .add_plugin(HelloPlugin)
         .run();
 }
 
-fn hello_world() {
-    println!("hello, world!");
-}
-
 #[derive(Component)]
 struct Sprite;
 
@@ -23,8 +18,23 @@ fn add_default_sprites(mut commands: Commands) {
     commands.spawn().insert(Sprite).insert(Name("Sprite 2".to_string()));
 }
 
-fn print_sprite_names(query: Query<&Name, With<Sprite>>) {
-    for name in query.iter() {
-        println!("found a sprite named {}", name.0);
+fn print_sprite_names(time: Res<Time>, mut timer: ResMut<SpriteNameTimer>, query: Query<&Name, With<Sprite>>) {
+    if timer.0.tick(time.delta()).just_finished() {
+        for name in query.iter() {
+            println!("found a sprite named {}", name.0);
+        }
+    }
+}
+
+pub struct HelloPlugin;
+
+struct SpriteNameTimer(Timer);
+
+impl Plugin for HelloPlugin {
+    fn build(&self, app: &mut App) {
+        app
+            .insert_resource(SpriteNameTimer(Timer::from_seconds(2.0, true)))
+            .add_startup_system(add_default_sprites)
+            .add_system(print_sprite_names);
     }
 }