boid mesh setup

src/main.rs

@@ -11,33 +11,45 @@ use std::f32::consts::FRAC_PI_2;
 
 fn main() {
     App::new()
+        .init_resource::<BoidMesh>()
         .add_plugins(DefaultPlugins)
-        .add_systems(Startup, setup)
+        .add_systems(Startup, (build_boid_mesh, setup).chain())
         .run();
 }
 
+#[derive(Resource, Default)]
+struct BoidMesh(Mesh2dHandle);
+
 #[derive(Component)]
 struct Boid;
 
+#[derive(Component)]
+struct Velocity(Vec2);
+
+#[derive(Bundle)]
 struct BoidBundle {
     mesh: MaterialMesh2dBundle<ColorMaterial>,
-    position: TransformBundle,
+    velocity: Velocity,
-    velocity: Vec2,
+    boid: Boid,
+}
+
+fn build_boid_mesh(mut meshes: ResMut<Assets<Mesh>>, mut boid_mesh: ResMut<BoidMesh>) {
+    let mesh = Mesh2dHandle(meshes.add(make_boid_mesh()));
+    boid_mesh.0 = mesh;
 }
 
 fn setup(
     mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<ColorMaterial>>,
+    boid_mesh: Res<BoidMesh>,
 ) {
     commands.spawn(Camera2dBundle::default());
 
-    let boid_mesh = make_boid_mesh();
+    let boid_color = materials.add(Color::from(tailwind::NEUTRAL_50));
 
-    let boid_color = Color::from(tailwind::NEUTRAL_50);
     commands.spawn(MaterialMesh2dBundle {
-        mesh: Mesh2dHandle(meshes.add(boid_mesh)),
+        mesh: boid_mesh.0.clone(),
-        material: materials.add(boid_color),
+        material: boid_color,
         transform: Transform::from_scale(Vec3::splat(2.5)),
         ..default()
     });