Alien cake addict: Allow holding movement keys (bevyengine#2072)

I wanted to try one of the new examples but it felt so clunky that I wanted to improve it.

It did make me feel like maybe some input axes abstraction like Unity has might be useful.

Also, eating cake should probably be a separate system from movement.

examples/game/alien_cake_addict.rs

@@ -46,6 +46,7 @@ struct Player {
     entity: Option<Entity>,
     i: usize,
     j: usize,
+    move_cooldown: Timer,
 }
 
 #[derive(Default)]
@@ -97,6 +98,7 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>, mut game: ResMu
     game.score = 0;
     game.player.i = BOARD_SIZE_I / 2;
     game.player.j = BOARD_SIZE_J / 2;
+    game.player.move_cooldown = Timer::from_seconds(0.3, false);
 
     commands.spawn_bundle(PointLightBundle {
         transform: Transform::from_xyz(4.0, 10.0, 4.0),
@@ -189,49 +191,54 @@ fn move_player(
     keyboard_input: Res<Input<KeyCode>>,
     mut game: ResMut<Game>,
     mut transforms: Query<&mut Transform>,
+    time: Res<Time>,
 ) {
-    let mut moved = false;
-    let mut rotation = 0.0;
-    if keyboard_input.just_pressed(KeyCode::Up) {
-        if game.player.i < BOARD_SIZE_I - 1 {
-            game.player.i += 1;
+    if game.player.move_cooldown.tick(time.delta()).finished() {
+        let mut moved = false;
+        let mut rotation = 0.0;
+
+        if keyboard_input.pressed(KeyCode::Up) {
+            if game.player.i < BOARD_SIZE_I - 1 {
+                game.player.i += 1;
+            }
+            rotation = -std::f32::consts::FRAC_PI_2;
+            moved = true;
         }
-        rotation = -std::f32::consts::FRAC_PI_2;
-        moved = true;
-    }
-    if keyboard_input.just_pressed(KeyCode::Down) {
-        if game.player.i > 0 {
-            game.player.i -= 1;
+        if keyboard_input.pressed(KeyCode::Down) {
+            if game.player.i > 0 {
+                game.player.i -= 1;
+            }
+            rotation = std::f32::consts::FRAC_PI_2;
+            moved = true;
         }
-        rotation = std::f32::consts::FRAC_PI_2;
-        moved = true;
-    }
-    if keyboard_input.just_pressed(KeyCode::Right) {
-        if game.player.j < BOARD_SIZE_J - 1 {
-            game.player.j += 1;
+        if keyboard_input.pressed(KeyCode::Right) {
+            if game.player.j < BOARD_SIZE_J - 1 {
+                game.player.j += 1;
+            }
+            rotation = std::f32::consts::PI;
+            moved = true;
         }
-        rotation = std::f32::consts::PI;
-        moved = true;
-    }
-    if keyboard_input.just_pressed(KeyCode::Left) {
-        if game.player.j > 0 {
-            game.player.j -= 1;
+        if keyboard_input.pressed(KeyCode::Left) {
+            if game.player.j > 0 {
+                game.player.j -= 1;
+            }
+            rotation = 0.0;
+            moved = true;
         }
-        rotation = 0.0;
-        moved = true;
-    }
 
-    // move on the board
-    if moved {
-        *transforms.get_mut(game.player.entity.unwrap()).unwrap() = Transform {
-            translation: Vec3::new(
-                game.player.i as f32,
-                game.board[game.player.j][game.player.i].height,
-                game.player.j as f32,
-            ),
-            rotation: Quat::from_rotation_y(rotation),
-            ..Default::default()
-        };
+        // move on the board
+        if moved {
+            game.player.move_cooldown.reset();
+            *transforms.get_mut(game.player.entity.unwrap()).unwrap() = Transform {
+                translation: Vec3::new(
+                    game.player.i as f32,
+                    game.board[game.player.j][game.player.i].height,
+                    game.player.j as f32,
+                ),
+                rotation: Quat::from_rotation_y(rotation),
+                ..Default::default()
+            };
+        }
     }
 
     // eat the cake!