Behavior lifecycle

Back to JavaScript.

let speed = 4; // private to this behavior instance

globalThis.behavior = {
  Start() {
    rustic.log("info", `started ${rustic.entity_id()}`);
  },
  OnEnable() {},
  FixedUpdate(dt) {
    const move = rustic.key("KeyW");
    if (move.held) {
      const [x, y, z] = rustic.get_translation();
      rustic.set_translation(x, y, z + speed * dt);
    }
  },
  Update(dt) {},
  OnDisable() {},
  OnDestroy() {},
};

Every method is optional. Canonical names are Start, FixedUpdate, Update, OnEnable, OnDisable, and OnDestroy; legacy on_start, fixed_update, update, on_enable, on_disable, and on_destroy remain compatible. Canonical wins when both exist. on_create and on_stop remain recognized legacy internal hooks. Collision names exist in the common scheduler contract, but the current JavaScript adapter does not bind them yet.

Global scripts start before scene scripts, which start before object components. Within a scope, execution order, entity ID, script Asset ID, and attachment order are the stable tie-breakers. Disabling an object stops its component updates; destruction invokes teardown and unregisters the instance.