registering our update call as a listener to our worldController

main.dart

Duration lastUpdateCall = Duration();
 
@override
void initState() {
  super.initState();
  worldController =
      AnimationController(vsync: this, duration: Duration(days: 99));
 
  worldController.addListener(_update);
}
 
void _update() {
  dino.update(lastUpdateCall, worldController.lastElapsedDuration)
 
  lastUpdateCall = worldController.lastElapsedDuration
}