// Attach this to a GUIText to make a frames/second indicator.
  //
  // It calculates frames/second over each updateInterval,
  // so the display does not keep changing wildly.
  //
  // It is also fairly accurate at very low FPS counts (<10).
  // We do this not by simply counting frames per interval, but
  // by accumulating FPS for each frame. This way we end up with
  // correct overall FPS even if the interval renders something like
  // 5.5 frames.
   
  var updateInterval = 0.5;
   
  private var accum = 0.0; // FPS accumulated over the interval
  private var frames = 0; // Frames drawn over the interval
  private var timeleft : float; // Left time for current interval
   
  function Start()
  {
      if( !guiText )
      {
          print ("FramesPerSecond needs a GUIText component!");
          enabled = false;
          return;
      }
      timeleft = updateInterval;  
  }
   
  function Update()
  {
      timeleft -= Time.deltaTime;
      accum += Time.timeScale/Time.deltaTime;
      ++frames;
      
      // Interval ended - update GUI text and start new interval
      if( timeleft <= 0.0 )
      {
          // display two fractional digits (f2 format)
          guiText.text = "" + (accum/frames).ToString("f2");
          timeleft = updateInterval;
          accum = 0.0;
          frames = 0;
      }
  }