desktop: add coin despawning

Author: georgik

desktop/src/desktop_systems/player_input.rs

@@ -1,6 +1,6 @@
 use bevy::input::keyboard::KeyboardInput;
 use bevy::prelude::*;
-use spooky_core::events::player_events::PlayerInputEvent;
+use spooky_core::events::player::PlayerInputEvent;
 
 /// Reads keyboard input (arrow keys) and sends a PlayerInputEvent.
 /// A positive dx moves right; a positive dy moves up.

desktop/src/main.rs

@@ -2,7 +2,7 @@ mod desktop_systems;
 
 use bevy::prelude::*;
 use spooky_core::systems;
-use spooky_core::events::player_events::PlayerInputEvent;
+use spooky_core::events::player::PlayerInputEvent;
 
 fn main() {
     let mut app = App::new();
@@ -11,8 +11,11 @@ fn main() {
     ))
     .add_systems(Startup, systems::setup::setup)
     .add_event::<PlayerInputEvent>()
+    .add_event::<spooky_core::events::coin::CoinCollisionEvent>()
     .add_systems(Update, crate::desktop_systems::player_input::dispatch_keyboard_input)
     .add_systems(Update, systems::process_player_input::process_player_input)
+    .add_systems(Update, spooky_core::systems::coin_collision::detect_coin_collision)
+    .add_systems(Update, spooky_core::systems::coin_collision::remove_coin_on_collision)
     .add_systems(Update, systems::game_logic::update_game)
     .run();
 }

spooky-core/src/components.rs

@@ -13,4 +13,10 @@ pub struct Wall;
 pub struct Ghost;
 
 #[derive(Component)]
-pub struct MainCamera;
+pub struct MainCamera;
+
+#[derive(Component)]
+pub struct CoinComponent {
+    pub x: i32,
+    pub y: i32,
+}

spooky-core/src/events/coin.rs

@@ -0,0 +1,9 @@
+use bevy::prelude::Event;
+
+/// This event is fired when the player collides with a coin.
+/// The event carries the coin's pixel coordinates.
+#[derive(Debug, Event)]
+pub struct CoinCollisionEvent {
+    pub coin_x: i32,
+    pub coin_y: i32,
+}

spooky-core/src/events/mod.rs

@@ -1 +1,2 @@
-pub mod player_events;
+pub mod player;
+pub mod coin;

spooky-core/src/events/player_events.rs renamed to spooky-core/src/events/player.rs

@@ -0,0 +1,45 @@
+use bevy::prelude::*;
+use crate::components::CoinComponent;
+use crate::events::coin::CoinCollisionEvent;
+use crate::resources::{PlayerPosition, MazeResource};
+use crate::maze::Coin;
+
+/// This system checks the player's current position against all coin positions in the maze.
+/// If the player is on the same tile as a coin, it dispatches a `CoinCollisionEvent`.
+pub fn detect_coin_collision(
+    player_pos: Res<PlayerPosition>,
+    maze_res: Res<MazeResource>,
+    mut event_writer: EventWriter<CoinCollisionEvent>,
+) {
+    // Assuming the player moves in tile increments, cast the logical position to i32.
+    let player_tile_x = player_pos.x as i32;
+    let player_tile_y = player_pos.y as i32;
+
+    for coin in maze_res.maze.coins.iter() {
+        if coin.x == player_tile_x && coin.y == player_tile_y {
+            event_writer.send(CoinCollisionEvent {
+                coin_x: coin.x,
+                coin_y: coin.y,
+            });
+        }
+    }
+}
+
+/// This system listens for `CoinCollisionEvent` and removes the collided coin from the maze.
+pub fn remove_coin_on_collision(
+    mut events: EventReader<CoinCollisionEvent>,
+    mut maze_res: ResMut<MazeResource>,
+    mut commands: Commands,
+    query: Query<(Entity, &CoinComponent)>,
+) {
+    for event in events.read() {
+        // Remove the coin at the collision coordinates.
+        maze_res.maze.remove_coin(Coin { x: event.coin_x, y: event.coin_y });
+        // Despawn coin entity with matching coordinates.
+        for (entity, coin_comp) in query.iter() {
+            if coin_comp.x == event.coin_x && coin_comp.y == event.coin_y {
+                commands.entity(entity).despawn_recursive();
+            }
+        }
+    }
+}

spooky-core/src/systems/coin_collision.rs

@@ -1,3 +1,4 @@
 pub mod setup;
 pub mod process_player_input;
-pub mod game_logic;
+pub mod game_logic;
+pub mod coin_collision;

spooky-core/src/systems/mod.rs

@@ -1,7 +1,7 @@
 use bevy::prelude::*;
 use crate::components::{Player, MainCamera};
 use crate::resources::{PlayerPosition, MazeResource};
-use crate::events::player_events::PlayerInputEvent;
+use crate::events::player::PlayerInputEvent;
 
 // Use our unified transform type alias.
 use crate::transform::SpookyTransform;

spooky-core/src/systems/process_player_input.rs

@@ -6,7 +6,7 @@ use bevy_math::Vec3;
 use bevy_transform::prelude::{Transform, GlobalTransform};
 use crate::maze::Maze;
 use crate::resources::{MazeResource, PlayerPosition};
-use crate::components::Player;
+use crate::components::{CoinComponent, Player};
 
 // When compiling for desktop (std enabled), use Bevy's AssetServer and its Image type.
 #[cfg(feature = "std")]
@@ -157,6 +157,7 @@ pub fn setup(mut commands: Commands, #[cfg(feature = "std")] asset_server: Res<A
                 commands.spawn((
                     Sprite::from_image(textures.coin.clone()),
                     Transform::from_translation(Vec3::new(coin.x as f32, coin.y as f32, 2.0)),
+                    CoinComponent { x: coin.x, y: coin.y },
                 ));
             }
             #[cfg(not(feature = "std"))]