cocos2d for iPhone

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

1. 

   mojo86
   Member

   If I have a background:

   CCSprite bg = [CCSprite spriteWithSpriteFrameName:@"bg.png"];
   [self addChild:bg]

   And then I assign the bg to a new image

   bg = [CCSprite spriteWithSpriteFrameName:@"bg2.png"];

   Just wondering if I have the right idea about this: My bg is pointed to an image in the cache. So when I'm adding bg as a child I'm not making a copy of bg.png, I'm just referencing it. So it's perfectly ok to change my background this way and I can reference my bg pointer to other images in my cache how many times I want to (lets say 100 tmes) and it won't cause memory problems.

   Is that right?

   But I was also wondering, what happens to bg.png when I'm not referencing it anymore? For how long will it stay in the cache and do I have to manually release the image files when I'm done with it?

   Posted 4 months ago #
2. 

   Dani
   Member

   Maybe it's a better way to change the displayed frame of the sprite:

   CCSprite *bg = [CCSprite spriteWithSpriteFRameName:@"bg.png"];
   [self addChild:bg];
   
   [bg setDisplayFrame:[[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:@"bg2.png"];

   That way there is no memory problems at all. With your shown code, you're allocating memory for another sprite again. And I'm not 100% sure, but I think that you have to manually release the sprite frames that you no longer need.

   Posted 4 months ago #
3. 

   Karl
   Member

   bg.png and bg2.png are both in memory, and will remain so until all CCSprites that use them are gone, AND the cache is cleared.

   Posted 4 months ago #
4. 

   Birkemose
   Moderator

   I think of the texture cache as a big pool you can toss textures into, and them use them freely ( at the expense of memory of course )
   The clue is to add and remove the right ones. The better you control this manually, the better performance you will get.

   On older devices the texture memory was fixed, so when you started to get memory warnings, there really wasn't much you could do about it, other than reducing memory usage.

   On never devices, the texture cache and memory is shared, so you can allocate away. The penalty is, that if you use to much memory, you might not be able to load ex a sound clip, because some unused textures are holding memory. So managing your texture cache gets more important, if you run into memory warnings.

   Posted 4 months ago #

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