collider_active_events

Event handlers are user-defined callbacks used to be notified when two colliders start/stop touching. By default no collision event is generated by the narrow-phase. In order to enable a collision event for a pair of colliders, at least one of the involved colliders must have the corresponding event set as active. An event is activated for a collider by setting its corresponding active events bit to 1:

• Setting the ActiveEvents::COLLISION_EVENTS bit to 1 enables the collision events involving the collider.

The active events of a collider can be set when the collider is created or after its creation:

/* Set the active events when the collider is created. */
commands
    .spawn(Collider::ball(0.5))
    .insert(ActiveEvents::COLLISION_EVENTS);

/* Set the active events inside of a system. */
fn modify_collider_active_events(mut active_events: Query<&mut ActiveEvents>) {
    for mut active_events in active_events.iter_mut() {
        *active_events = ActiveEvents::COLLISION_EVENTS;
    }
}