Sparrow Forum

1. 

   Thegeek
   Member

   For the game I am writing, I have a several screens at the beginning where the user makes selection of difficulty, type of game, etc. I transition from screen to screen by creating the screen outside of the viewing area, then tweening it onscreen, while tweening the old one offscreen. I really like the effect, however, I was getting some lag at the very beginning as I create the new screen, and load in the background graphic. This causes an initial 'pop' as the transition begins.
   My solution to this was to create another juggler in my class, and then only call advanceTime if the event.passedTime was less than 0.1 sec.

       double passedTime = event.passedTime;
       if (passedTime < 0.1){
           [mSmoothJuggler advanceTime:passedTime];
       }

   I'm kind of torn between feeling clever, and like I'm doing it wrong. While the exact amount of time that the scene transition takes isn't critical to me, having it appear smooth makes it look a LOT better. Is this a reasonable solution, or is there a better way? Thanks!

   Posted 11 months ago #
2. 

   Ron
   Moderator

   That sounds like a reasonable hack to me.

   Another approach might be to initialize the new scene, and then start the tween only after the new scene (and all its graphics) are ready.

   Posted 11 months ago #
3. 

   baike
   Moderator

   You can do it your way, but I think it's cleaner to do it Ron's way. You would load your background graphic, then set a flag. Then in advanceTime of the next frame, if the flag is set, you unset it and start the tween. That way the large event.passedTime will be ignored even if it is 0.099 (which is still a slow frame), but doesn't exacerbate other valid situations for having a long delay between frames (like maybe if the iPhone was performing a heavy operating system job that you have no control over). In the worst case, with intermittent interruptions (which is probably never going to realistically happen), your game could theoretically pause forever with your solution.

   Better than a flag would be a state variable that lets you start the right tween based on the menu state. After processing a tween for a state, reset the state to StateNull, which would mean don't start any tweens (the norm). This could just be an enum.

   Posted 11 months ago #
4. 

   Thegeek
   Member

   I totally agree. I was so set on doing something similar to the old hacks similar to Sleep(0) so that you get the message pump to do something that I completely forgot that I could flip off a bool the next time through the onEnterFrame method. I am facepalming right now. So, I guess to answer my own question, Yup, I was doing it poorly. Much better to set a one-shot to delay the start of the ween by one frame. Thanks guys!

   Posted 11 months ago #

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