Question

I don’t know if this is possible, but I would like to create one big texture atlas and use it on all classes of the application.

Can one CCSpriteBatchNode be used for multiple classes?

Suppose I create this on the main class

[[CCSpriteFrameCache sharedSpriteFrameCache] addSpriteFramesWithFile:@"atlasGeral.plist"];
self.batchNodeGeneral = [CCSpriteBatchNode batchNodeWithFile:@"atlasGeral.png"];
[self addChild:self.batchNodeGeneral];

and I have another class creating CCLayers on the main class, that is initialized, before using CCSpriteBatchNode, like this:

-(id) init 
{

   if( (self=[super init])) {

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

        self.dr = [CCSprite spriteWithFile: @"cCircularDR.png"];
        [self addChild:self.dr];      
  }
  return self;  // self is a CCLayer
}

can this be optimized using the self.batchNodeGeneral from the main class? My idea is to replace these two sprites and others with something like [CCSprite spriteWithSpriteFrameName:…

thanks

Answer 1

I’m not entirely sure I follow, but I’m pretty sure the answer is yes.

CCSpriteBatchNode doesn’t have anything to do with classes, it has to do with assets. The important restriction on the use of batch nodes is that every sprite in the batch needs to reference the same texture atlas. So it is perfectly fine to have one batch node for your entire application and have every gameplay class add its own sprites to that batch. This can turn into a practical issue if your texture atlas becomes larger than the maximum texture size on your target hardware (see iOS device specs for details), but if you still want to have global batches and lots of assets it’s not too hard to create a batch pool indexed by texture ID, create one batch node per atlas, and whenever you create a new sprite add it to the appropriate batch.

Honestly, I feel like the whole batch node thing is a terrible kludge on Cocos2D’s part that could be made almost completely transparent to developers while still retaining its efficiency, but maybe this opinion is not entirely fair since I haven’t dug around in the rendering code to understand their motivations. I guess it would mess with expectations of how depth sorting works, etc., but still I don’t understand why batching objects for render is made the programmer’s responsibility, it should be done by the engine.

Edit to add possible solution:

-(id) initWithMainClass:(MainClass*)mc
{

   if( (self=[super init])) {

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

        self.dr = [CCSprite spriteWithSpriteFrameName: @"cCircularDR.png"];
        [mc.batchNodeGeneral addChild:self.dr];      
  }
  return self;  // self is a CCLayer
}
`

So when you initialize one of the other classes, you pass the main class instance as a parameter so you can access its fields. Or make the main/manager class a singleton or find another architecture suitable to your needs.