cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   bitfool
   Member

   I installed cocos2d 0.8.1 beta, and the first thing I compiled was the Box2dTest app, the one that just says "Tap screen" and a square with a letter (A,B,C,D) appears and gravity brings it down. Ok, great. I like it!

   Problem is that if you compile it to your device (1st gen iPhone for me), there seems to be a memory leak. Behavior: FPS slows down more and more as you add more boxes... even if those boxes move offscreen and "disappear" from the system. FPS dropped down to the low single digits. Just now I recompiled it for the Simulator, and it behaves similarly, and the app crashed when it got down to 30 FPS.

   I'm new to both cocos2d and Box2d, so I don't know where to begin finding this problem. I would just like to play around a bit. Anybody else seen this behavior? Anyone know their code enough to know if it's in Box2d code, or in cocos2d itself? Thanks.

   Posted 2 years ago #
2. 

   LongJohnnyE
   Member

   I haven't actually tested this, but possibly when the boxes go off screen they aren't really being removed from the Box2D world, so eventually you'll end up with a massive amount of shapes in your system that is causing the lag you see.

   To make objects 'disappear' and stop using CPU and memory you need to remove them from the Box2D world using the built-in box2d destructor methods.

   Posted 2 years ago #
3. 

   crmagicxxx
   Member

   Johnny is right.
   Look this game http://www.4iphone4.me/AirportMadness/ Suitcases are falling all the time. Top player on high score list made about 1600 suitcases. If I didn't free and destroy all those unneeded objects there would be big mess...
   

   Posted 2 years ago #
4. 

   bitfool
   Member

   Right... so, if this is the case, either someone in the Box2d world should fix their code so it doesn't leak, or there is a memory leak bug in the cocos2d implementation of this example that should be fixed for the 0.8.1 final release. Again, I'm not yet really competent in either world to find the leaks or suggest fixes... just wanted to bring it to someone's attention who might care enough to make sure this project has solid test and sample code out there, not buggy/leaky test/sample code.

   Posted 2 years ago #
5. 

   Steve Oldmeadow
   Administrator

   @bitfool - it is not a memory leak, it is perfectly normal that when more boxes get added the frame rate drops. Also, Riq has set up the demo so that the boxes are confined to the screen so I don't understand why you are seeing boxes leave the screen. Did you change any of the compiler settings, for example using -O2 optimization without the -fnoregmove flag can lead to strange Box2D behavior. Also, you need to realize that the version of Box2D we are working with is a work in progress so you have to expect there will be some issues. If you want a stable version of Box2D then use version 2.0.2.

   Posted 2 years ago #

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