Bundles

Many of the built in systems require a certain set of components to be present in order to avoid many Option in query and branches.

For example, rendering requires Position, Rotation, Scale, Mesh, Visible, Color, Pass. Remembering to add all these when spawning entities is a chore, and makes it easy to forget some and not having the entity show up.

To fix this several bundles are provided, which has the added benefit of providing sane defaults.

The following snippet shows how to create a new entity which will be moving in the world with an initial velocity.

Note: The entity won't be rendered, since no rendergraph has been setup, and the entity does not have the ObjectBundle bundle. It is recommended to use a custom layer and creating the entities in new or a setup function. However, the raw usage of App is used for brevity.

#![allow(unused)]
fn main() {
fn bundles() {
    let mut app = App::builder().build();

    let world = app.world_mut();

    let entity = Entity::builder()
        .mount(RbBundle {
            vel: vec3(1.0, 0.0, 0.0),
            mass: 5.0,
            ang_mass: 2.0,
            ..Default::default()
        })
        .set(name(), "My Entity".into())
        .spawn(world);

    // Get the `Resitution` component
    assert_eq!(*world.get(entity, restitution()).unwrap(), 0.0,);
}
}

Bundles

The following bundles are provided:

• ObjectBundle - Renderable objects with position and mesh
• RbBundle - Rigidbody obejct
• RbColliderBundle - Rigidbody object with a collider
• WidgetBundle - Base UI element, similar to html div
• TextBundle - UI text element
• ImageBundle - UI image element
• ConnectionBundle - Declare physical relationships between entities
• TransformBundle - Position an object with Position, Rotation, and Scale. A matching TransformQuery and .into_matrix() are provided as well.
• ConstraintBundle - UI constraints bundle, part of WidgetBundle