cocos2d for iPhone

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

1. 

   smooth
   Member

   Hi!

   As far as i understand memory management all alloc/copy/new set retain counter to 1 and are not auto-released by default and you should be careful to release them when not needed anymore, but if you create an object via any other method like [Sprite spriteWithFile:...], we assume this objects are autoreleased. (Please let me know if i got it wrong)

   So, my question is very general: how does cocos2d manages AutoRelease Pools or who is responsible to creating/draining them. If you have only one (default in main) NSAutoRelase pool does this mean, that all those sprites you create during game play go to that pool and are not released/deallocated until your app exits? How could we than create autorelease pools if our game is mainly created in one Scene (without destroying bunch of other, still used objects?). Does this mean that although this objects are autoreleased we should still release them manually when not needed anymore?

   btw. I HATE all those books on Amazon about iphone/objective-C development, they are all the same - for beginners. But it is really hard to find some advanced topics, that matter when working on real project...like memory management on real project.

   Yesterday i was really frustrated trying to find why two classes you define can not be referenced in each other (A using B and B using A). And the solution was NOT find in any of books but with google on some general programming site... (using @class directive instead of #include/#import)

   I would be really happy if you know any good, advanced sources for working a real project...

   thank you!

   Posted 2 years ago #
2. 

   riq
   Key Master

   cocos2d uses the same technique used by any other Cocoa application.

   Documantation:
   http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSAutoreleasePool_Class/Reference/Reference.html

   If you are using the FastDirector, another autorelease pool will be created on the Director and it will be drained after each step of the main loop.

   For more info see: Director.m

   Posted 2 years ago #
3. 

   smooth
   Member

   thanks!

   i have one more question:
   Check the code output. When target is created is it autoreleased and retain counter is on 1. When added, retain counter is 2. But when timer fires a moment later retain counter is 1?!?. What happened? Who released my target? I didnt find any pools being released. I know that if i need "target" for future use, i need to retain it after creation and then release it. But i want to understand how this cocos work. (no fast director used)

   Output:
   

   Init 1 , 1
   Init 2 , 2
   TX1: , 1
   and than it fails...

   Code:
   

   - (id) initWithType:(CarModel) carModel {
   	self = [super init];
   	if (self != nil) {
   		target = [Sprite spriteWithFile:@"blocks.png"];
   		NSLog(@"Init 1 , %d",[target retainCount]);
   		[self addChild:target];
   		NSLog(@"Init 2 , %d",[target retainCount]);
   		[[Scheduler sharedScheduler] scheduleTimer:[Timer timerWithTarget:self selector:@selector(tx) interval:1]];
   	}
   	return self;
   }
   -(void) tx{
   	NSLog(@"TX1: , %d",[target retainCount]);
   	[self removeChild:target cleanup:false];
   	NSLog(@"TX2: , %d",[target retainCount]); //FAIL
   }

   Posted 2 years ago #
4. 

   Codemattic
   Moderator

   please use the backticks but *without* using html like:
   

   <p>
   <br />

   Just paste the raw code inbetween backticks.
   

   //target is a member variable
   target = [Sprite spriteWithFile:@"blocks.png"];
   //we want target to stay around
   //but right now spriteWithFile created a Sprite that has only been *autoreleased*
   //that means it will stay around only for this code block
   //so we retain it
   [target retain];
   //and we should also remember to release it in -dealloc

   Posted 2 years ago #
5. 

   smooth
   Member

   sorry for html, i edited my post and i don't know how they got there...

   ok i think i found what i was looking for in one of the books: that pools are created and destroyed automatically on regular basis. Like beginning and ending some event..
   So i guess the pool that accepts this target is not created manually. Seems logical now since otherwise these objects would be around for a looong time. In case of pool in main.c until you close your app and in that case it would be like having no memory management at all, pool would just grow and grow.

   thank you

   Posted 2 years ago #
6. 

   Codemattic
   Moderator

   Yeah, dont worry too much about pools, cocos and Cocoa will handle that for you. You only have to use pools directly in very specific circumstances.

   Posted 2 years ago #

RSS feed for this topic

Reply

You must log in to post.