Smarter way to spawn meshes?

[AaronKanaron]

Hello!

Currently I have setup a function that spawns a circle using this:

pub fn spawn_body( mass: f32, position: Vec2, mut commands: Commands, mut meshes: ResMut<Assets<Mesh>>, mut materials: ResMut<Assets<ColorMaterial>> ) {
    commands.spawn((
        Ball {
            mass,
            position,
            velocity: Vec2::new(0.,0.),
        },
        MaterialMesh2dBundle {
            mesh: meshes.add(shape::Circle::new(2.).into()).into(),
            material: materials.add(Color::rgb(0.5, 0.5, 1.0).into()),
            ..Default::default()
        },
    ));
}

The problem begins when using the function. In my main script I have the setup function,

fn setup( mut commands: Commands, ) {
    commands.spawn(Camera2dBundle::default());
    
    spawn_body(50., Vec2::new(0.,0.), commands, meshes, materials)
}

Is there any way for me to not have to specify commands, meshes and materials and only use the parameters that actually changes anything?

[nicopap]

Do you want to avoid passing the Assets to the spawn_body function?

Do you have control over the Ball type? If so I would suggest defining the mesh and material as methods on Ball.

impl Ball {
    fn new(mass: f32, position: Vec2) -> Self { Ball { mass, position, velocity: Vec2::ZERO } }
    fn mesh(&self) -> Mesh { /* .... */ }
    fn matieral(&self) -> ColorMaterial { /* .... */ }
}
fn setup(mut cmds: Commands, mut meshes: ResMut<Assets<Mesh>>, mut mats: ResMut<Assets<ColorMaterial>>) {
    commands.spawn(Camera2dBundle::default());
    
    let ball = Ball::new(50., Vec2::ZERO);
    let mesh = meshes.add(ball.mesh());
    let material = mats.add(ball.material());
    let bundle = MaterialMesh2dBundle { mesh, material, ..default() };

    cmds.spawn((ball, bundle));
}