Objective

Bevy 0.15 got support for required components! We can replace a lot of our custom-made automatic component insertion with them, reducing the number of archetype moves and making startup more efficient.

Solution

Use required components for most component initialization logic.

I have also made CollidingEntities optional, as adding it automatically for every collider wastes memory unnecessarily. It must now be added manually.

Follow-ups

• Make Position and Rotation required and rework init_transforms (ran into some ordering issues, so left it to a follow-up)
• Make force and impulse components optional
• Make friction and restitution components optional, and default to globally defined default material properties

Migration Guide

The CollidingEntities component is no longer added automatically. To read entities that are colliding with a given entity, you must now add the CollidingEntities component for it manually.

To revert to the old behavior, you can also make CollidingEntities a required component for colliders:

app.register_required_components::<Collider, CollidingEntities>();