Adding "Go!" button to start/un-pause the game

src/bin/flappy/main.rs

@@ -12,7 +12,9 @@ fn main() {
         .init_state::<PlayerState>()
         .add_systems(Startup, (init_bird, init_obstacles, init_ui, tweak_camera.after(setup_camera)))
         .add_systems(OnEnter(PlayerState::Alive), alive_bird)
-        .add_systems(OnExit(PlayerState::Alive), kill_bird)
+        .add_systems(OnEnter(PlayerState::Pause), pause_bird)
+        .add_systems(OnEnter(PlayerState::Stasis), pause_bird)
+        .add_systems(OnEnter(PlayerState::Rewind), pause_bird)
         .add_systems(
             Update,
             (
@@ -42,6 +44,8 @@ fn main() {
                 rewind.run_if(in_state(PlayerState::Rewind)),
                 // Camera follows when bird moves regardless of player state
                 camera_follow_bird.run_if(any_component_changed::<Transform>),
+                // Pause when the player presses Escape
+                pause_game.run_if(input_just_pressed(KeyCode::Escape)),
             ),
         )
         .run();
@@ -63,10 +67,11 @@ struct Bird;
 
 #[derive(States, Clone, Eq, PartialEq, Debug, Hash, Default, Component)]
 enum PlayerState {
-    #[default]
     Alive,
     Rewind,
-    Dead,
+    Stasis,
+    #[default]
+    Pause
 }
 
 // A tape tracking the bird's state every frame
@@ -96,7 +101,7 @@ fn init_bird(
     let t = Transform::from_xyz(0.0, 0.0, 0.0).with_rotation(Quat::from_rotation_x(PI / 2.0));
 
     let physics = (
-        RigidBody::Dynamic,
+        RigidBody::Static,
         Collider::capsule(1.0, 1.0), Mass(1.0),
         ExternalForce::new(Vec3::X * 1.0).with_persistence(true),
         ExternalImpulse::default().with_persistence(false),
@@ -150,7 +155,7 @@ fn init_obstacles(
     // screens and then "move" them around.
     // This is considerably more complexity so can be implemented later, but would keep memory
     // overhead fairly static.
-    (1..50).for_each(|i| {
+    (1..99).for_each(|i| {
         // TODO: Jitter up/down/close/far of pipes for challenge
         let above = Transform::from_xyz(5.0 * i as f32, 4.0, 0.0);
         let below = Transform::from_xyz(5.0 * i as f32, -4.0, 0.0);
@@ -173,12 +178,38 @@ fn init_ui(
             flex_direction: FlexDirection::Column,
             ..default()
         },
-        PlayerState::Dead,
+        PlayerState::Stasis,
         children![
             Text::new("You Died"),
             Text::new("Press R to Rewind"),
         ],
     ));
+
+    fn start_game(_trigger: Trigger<Pointer<Click>>, mut next: ResMut<NextState<PlayerState>>) {
+        next.set(PlayerState::Alive);
+    }
+
+    commands.spawn((
+        Node {
+            align_self: AlignSelf::Center,
+            justify_self: JustifySelf::Center,
+            flex_direction: FlexDirection::Column,
+            ..default()
+        },
+        Button,
+        // TODO: Add Pause (basically Stasis) state
+        PlayerState::Pause,
+        children![
+            Text::new("Go!"),
+        ],
+    )).observe(start_game);
+}
+
+/// Pause the game when the player presses "Escape"
+fn pause_game(
+    mut next: ResMut<NextState<PlayerState>>,
+) {
+    next.set(PlayerState::Pause);
 }
 
 // TODO: Create floor (and ceiling?)
@@ -268,7 +299,7 @@ fn detect_dead(
     if obstacles.iter().any(|obstacle| {
         bird.intersects(obstacle)
     }) {
-        next.set(PlayerState::Dead);
+        next.set(PlayerState::Stasis);
     }
 }
 
@@ -276,17 +307,17 @@ fn alive_bird(
     #[cfg(debug_assertions)] state: Res<State<PlayerState>>,
     mut bird: Single<&mut RigidBody, With<Bird>>,
 ) {
-    debug_assert!(!matches!(state.get(), PlayerState::Dead));
+    debug_assert!(matches!(state.get(), PlayerState::Alive));
-    debug!("Aliving bird");
+    debug!("Setting bird to Dynamic");
     **bird = RigidBody::Dynamic;
 }
 
-fn kill_bird(
+fn pause_bird(
     #[cfg(debug_assertions)] state: Res<State<PlayerState>>,
     mut bird: Single<&mut RigidBody, With<Bird>>,
 ) {
     debug_assert!(!matches!(state.get(), PlayerState::Alive));
-    debug!("Killing bird");
+    debug!("Setting bird to Static");
     **bird = RigidBody::Static;
 }