Tells you to perform any app specific logic to update your scene.
- iOS 8.0+
- macOS 10.10+
- tvOS 9.0+
- watchOS 3.0+
The current system time.
The scene that is being animated.
Do not call this method directly; it is called by the system exactly once per frame, so long as the scene is presented in a view and is not paused. This is the first method called when animating the scene, before any actions are evaluated and before any physics are simulated.