Struct OnCollisionStart

pub struct OnCollisionStart {
    pub collider: Entity,
    pub body: Option<Entity>,
}

A collision event that is triggered for observers when two colliders start touching.

The event is only triggered if the target entity has the CollisionEventsEnabled component.

Unlike CollisionStarted, this event can not be read using an EventReader. Instead, you must use an observer. This makes it good for entity-specific collision listeners.

Example

use avian3d::prelude::*;
use bevy::prelude::*;

#[derive(Component)]
struct Player;

#[derive(Component)]
struct PressurePlate;

fn setup_pressure_plates(mut commands: Commands) {
    commands.spawn((
        PressurePlate,
        Collider::cuboid(1.0, 0.1, 1.0),
        Sensor,
        // Enable collision events for this entity.
        CollisionEventsEnabled,
    ))
    .observe(|trigger: Trigger<OnCollisionStart>, player_query: Query<&Player>| {
        let pressure_plate = trigger.target();
        let other_entity = trigger.collider;
        if player_query.contains(other_entity) {
            println!("Player {other_entity} stepped on pressure plate {pressure_plate}");
        }
    });
}

Scheduling

The OnCollisionStart event is triggered after the physics step in the CollisionEventSystems system set. At this point, the solver has already run and contact impulses have been updated.

Fields

collider: Entity

The entity of the collider that started colliding with the Trigger::target.

body: Option<Entity>

The entity of the rigid body that started colliding with the Trigger::target.

If the collider is not attached to a rigid body, this will be None.

Trait Implementations

impl Clone for OnCollisionStart

fn clone(&self) -> OnCollisionStart

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for OnCollisionStart

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Event for OnCollisionStart

where Self: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

When true, this event will always attempt to propagate when triggered, without requiring a call to Trigger::propagate.

type Traversal = ()

The component that describes which Entity to propagate this event to next, when propagation is enabled.

fn register_component_id(world: &mut World) -> ComponentId

Generates the ComponentId for this event type.

fn component_id(world: &World) -> Option<ComponentId>

Fetches the ComponentId for this event type, if it has already been generated.

impl PartialEq for OnCollisionStart

fn eq(&self, other: &OnCollisionStart) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for OnCollisionStart

impl StructuralPartialEq for OnCollisionStart