Cocos2d. Load and store images correctly?

Question

There are a lot of answers for this question. But all of them are incorrect!

For example if I have created a CCLayer object with one CCSprite object. I have 3 textures and I want to switch between them on every touch.

For example I will use something similar to this:

link

I run this application in Simulator. Then I call a memory warning. Then I try to switch between images (textures). And I see that 2 of 3 images are deleted (except of the image was shown at the same time memory warning appeared).

I tried to use retain/release commands for CCSprite and ССTexture2D but they cause a situation when dealloc method of released object is never called.

So how to store them correctly? I want to store them at memory warning and release/remove them when the current layer is destroyed.

Answer 1

Store them in one texture atlas, created with Texture Packer. Then it's as simple as calling [Sprite setDisplayFrame:frameName] to switch the displayed texture.

Answer 2

By default on memory warning cocos2d will remove unused textures. The whole point of memory warning is that OS tells your app "hey, that's not okay, cut down your memory appetite or I'll shut you down", and your app should be like "oops, sorry, freeing memory now".

Answer 3

If you receive a memory warning when preloading textures, cocos2d's default behavior of removing unused textures will shoot you in the foot. More about this issue here.

My advice: remove the call to purge cocos2d's caches in the memory warning method in AppDelegate. Of course you want to be extra careful with your memory usage. Alternatively you could simply disable the behavior while you're preloading images, but this might simply move the problem to a later point.