Skip to main content

Physics

note

Physics entities do not render to the scene by default.

You can enable the physics debug overlay in the editor to show wireframe representations of colliders and rigidbodies.

Physics Debug Button

Physics entities in Dreamlab are simulated on at most one client (including the server) at a time, with the position and rotation being synced to all other connected clients. Entities in the world root default to being simulated on the server. When a client takes authority of an Entity, it will then be responsible for simulating its physics.

Colliders​

Colliders are static shapes that other physics entities will interact with. Colliders can be either rectangular or circular in shape, and do not move on their own. They are ideal for walls, floors, obstacles, etc.

Rigidbodies​

Rigidbody entities by themselves don't do anything, you must add one or more Collider entities as children to define the shape of the rigidbody. This is where the mass value of a collider is used.

Character Controller​

The character controller is a special kind of physics entity. Despite having "character" in the name it can be used for any kinematic (moving) object. These entities are not simulated by the physics engine and must be controlled by scripts. After setting the position of a character controller, the physics engine will compute and handle collisions and prevent the character controller from intersecting colliders.

Collision Events​

The physics system will emit EntityCollision events when two colliders (including rigidbody colliders and character controllers) start and stop colliding. The events are fired on both entities involved in the collision and report information about the collision.

import { Behavior, EntityCollision } from "@dreamlab/engine";

export default class MyBehavior extends Behavior {
  onInitialize(): void {
    this.listen(this.entity, EntityCollision, ({ started, other, contactPoint, normal }) => {
      // react to collision event
    });
  }
}