Adding a tail

src/main.rs

@@ -30,11 +30,17 @@ struct SnakeHead {
 }
 struct Materials {
     head_material: Handle<ColorMaterial>,
+    segment_material: Handle<ColorMaterial>,
     food_material: Handle<ColorMaterial>,
 }
 
 struct SnakeMoveTimer(Timer);
 
+struct SnakeSegment;
+
+#[derive(Default)]
+struct SnakeSegments(Vec<Entity>);
+
 struct Food;
 
 struct FoodSpawnTimer(Timer);
@@ -66,22 +72,54 @@ fn setup(commands: &mut Commands, mut materials: ResMut<Assets<ColorMaterial>>)
     commands.spawn(Camera2dBundle::default());
     commands.insert_resource(Materials {
         head_material: materials.add(Color::rgb(0.7, 0.7, 0.7).into()),
+        segment_material: materials.add(Color::rgb(0.3, 0.3, 0.3).into()),
         food_material: materials.add(Color::rgb(1.0, 0.0, 1.0).into()),
     });
 }
 
-fn spawn_snake(commands: &mut Commands, materials: Res<Materials>) {
+fn spawn_snake(
+    commands: &mut Commands,
+    materials: Res<Materials>,
+    mut segments: ResMut<SnakeSegments>,
+) {
+    segments.0 = vec![
+        commands
+            .spawn(SpriteBundle {
+                material: materials.head_material.clone(),
+                sprite: Sprite::new(Vec2::new(10.0, 10.0)),
+                ..Default::default()
+            })
+            .with(SnakeHead {
+                direction: Direction::Up,
+            })
+            .with(SnakeSegment)
+            .with(Position { x: 3, y: 3 })
+            .with(Size::square(0.8))
+            .current_entity()
+            .unwrap(),
+        spawn_segment(
+            commands,
+            &materials.segment_material,
+            Position { x: 3, y: 2 },
+        ),
+    ];
+}
+
+fn spawn_segment(
+    commands: &mut Commands,
+    material: &Handle<ColorMaterial>,
+    position: Position,
+) -> Entity {
     commands
         .spawn(SpriteBundle {
-            material: materials.head_material.clone(),
-            sprite: Sprite::new(Vec2::new(10.0, 10.0)),
+            material: material.clone(),
             ..Default::default()
         })
-        .with(SnakeHead {
-            direction: Direction::Up,
-        })
-        .with(Position { x: 3, y: 3 })
-        .with(Size::square(0.8));
+        .with(SnakeSegment)
+        .with(position)
+        .with(Size::square(0.65))
+        .current_entity()
+        .unwrap()
 }
 
 fn snake_movement(
@@ -186,10 +224,8 @@ fn main() {
             height: 500.0,
             ..Default::default()
         })
-        .add_resource(SnakeMoveTimer(Timer::new(
-            Duration::from_millis(150),
-            true,
-        )))
+        .add_resource(SnakeMoveTimer(Timer::new(Duration::from_millis(150), true)))
+        .add_resource(SnakeSegments::default())
         .add_startup_system(setup.system())
         .add_startup_stage("game_setup", SystemStage::single(spawn_snake.system()))
         .add_system(snake_movement.system())