Hitting the wall

Author: marcusbuffett

src/main.rs

@@ -34,6 +34,7 @@ struct SnakeHead {
     direction: Direction,
 }
 
+struct GameOverEvent;
 struct GrowthEvent;
 
 #[derive(Default)]
@@ -109,6 +110,7 @@ fn spawn_segment(mut commands: Commands, position: Position) -> Entity {
 
 fn snake_movement(
     mut last_tail_position: ResMut<LastTailPosition>,
+    mut game_over_writer: EventWriter<GameOverEvent>,
     segments: ResMut<SnakeSegments>,
     mut heads: Query<(Entity, &SnakeHead)>,
     mut positions: Query<&mut Position>,
@@ -133,6 +135,16 @@ fn snake_movement(
                 head_pos.y -= 1;
             }
         };
+        if head_pos.x < 0
+            || head_pos.y < 0
+            || head_pos.x as u32 >= ARENA_WIDTH
+            || head_pos.y as u32 >= ARENA_HEIGHT
+        {
+            game_over_writer.send(GameOverEvent);
+        }
+        if segment_positions.contains(&head_pos) {
+            game_over_writer.send(GameOverEvent);
+        }
         segment_positions
             .iter()
             .zip(segments.iter().skip(1))
@@ -161,6 +173,22 @@ fn snake_movement_input(keyboard_input: Res<Input<KeyCode>>, mut heads: Query<&m
         }
     }
 }
+
+fn game_over(
+    mut commands: Commands,
+    mut reader: EventReader<GameOverEvent>,
+    segments_res: ResMut<SnakeSegments>,
+    food: Query<Entity, With<Food>>,
+    segments: Query<Entity, With<SnakeSegment>>,
+) {
+    if reader.iter().next().is_some() {
+        for ent in food.iter().chain(segments.iter()) {
+            commands.entity(ent).despawn();
+        }
+        spawn_snake(commands, segments_res);
+    }
+}
+
 fn snake_eating(
     mut commands: Commands,
     mut growth_writer: EventWriter<GrowthEvent>,
@@ -246,13 +274,15 @@ fn main() {
         .insert_resource(LastTailPosition::default())
         .add_event::<GrowthEvent>()
         .add_system(snake_movement_input.before(snake_movement))
+        .add_event::<GameOverEvent>()
         .add_system_set(
             SystemSet::new()
                 .with_run_criteria(FixedTimestep::step(0.150))
                 .with_system(snake_movement)
                 .with_system(snake_eating.after(snake_movement))
                 .with_system(snake_growth.after(snake_eating)),
         )
+        .add_system(game_over.after(snake_movement))
         .add_system_set(
             SystemSet::new()
                 .with_run_criteria(FixedTimestep::step(1.0))