Listing 2

1 long fractions = 0L;

2 long overSleepTime = 0L;

3 int noDelays = 0;

4 animating = true;

5 StopWatch stopWatch

= StopWatchSource.getStopWatch();

6 stopWatch.start();

7

8 while(animating) {

9

10 // Update the game state

11 listener.updateModel();

12

13 // Obtain a graphics context to the

14 // back buffer and render the frame

15 Graphics g = bufferStrategy

.getDrawGraphics();

16

17 if (bufferStrategy.contentsLost())

18 clearCount = (isPageFlipping)

? 2 : 1;

19 else {

20 boolean isBufferCleared = false;

21 if (clearCount > 0) {

22 clearCount--;

23 isBufferCleared = true;

24 }

25 listener.render(g,

isBufferCleared, bufferIndex);

26 bufferStrategy.show();

27 if (isPageFlipping)

28 bufferIndex =

(bufferIndex == 0) ? 1 : 0;

29 }

30 g.dispose();

31

32 // Compute the time remaining in

33 // the frame period

33 long sleepTime = PERIOD

- stopWatch.stop()-overSleepTime;

34

35 // If there is time remaining,

36 // sleep it away

37 stopWatch.start();

38 if (sleepTime >= 0L) {

39 Thread.sleep(

sleepTime / 1000000L);

40 overSleepTime = stopWatch.stop()

- sleepTime;

41 stopWatch.start();

42 } else {

43

44 // Otherwise aggregate the excess

45 fractions -= sleepTime;

46 overSleepTime = 0L;

47

48 if (++noDelays

>= NO_DELAYS_PER_YIELD) {

49 Thread.yield();

50 noDelays = 0;

51 }

52 }

53

54 // While excess aggregate exceeds

55 // frame period, update the model

56 int skips = 0;

57 while(fractions > PERIOD

&& ++skips < maxFrameSkips) {

58 fractions -= PERIOD;

59 listener.updateModel();

60 }

61 while(fractions > PERIOD)

62 fractions -= PERIOD;

63 }

64 }