public void update(){
  if (lastTime != -1L) {
    long delta=System.nanoTime() - lastTime;
    rollingAverage.addValue(delta);
  }
  lastTime=System.nanoTime();
}

public void update ( ) { if ( lastTime != - 1L ) { long delta = System . nanoTime ( ) - lastTime ; rollingAverage . addValue ( delta ) ; } lastTime = System . nanoTime ( ) ; }
update the fps counter . < p / > call this method every frame !
