What is the difference between `Subclass of CCScene` and `Subclass of CCNode` in cocos2d-iphone?

Question

What is the difference between Subclass of CCScene and Subclass of CCNode when adding new cocos2d CCNode class? I used CCScene when I was following cocos2d-tutorials, but in the cocos2d + SpriteBuilder project default MainScene class is subclass of node, so can somebody explain it to me?

Answer 1

Very little. Open CCScene's header file and you see it subclasses CCNode. If you open CCScene's implementation file you'll essentially see this (assuming we are talking about cocos2d v3):

@implementation CCScene

// -----------------------------------------------------------------

// Private method used by the CCNode.scene property.
-(BOOL)isScene {return YES;}

-(id)init
{
    if((self = [ super init ]))
    {
        CGSize s = [CCDirector sharedDirector].designSize;
        _anchorPoint = ccp(0.0f, 0.0f);
        [self setContentSize:s];

        self.colorRGBA = [CCColor blackColor];
    }

    return( self );
}

// -----------------------------------------------------------------

- (void)onEnter
{
    [super onEnter];

    // mark starting scene as dirty, to make sure responder manager is updated
    [[[CCDirector sharedDirector] responderManager] markAsDirty];
}

// -----------------------------------------------------------------

- (void)onEnterTransitionDidFinish
{
    [super onEnterTransitionDidFinish];

    // mark starting scene as dirty, to make sure responder manager is updated
    [[[CCDirector sharedDirector] responderManager] markAsDirty];
}

// -----------------------------------------------------------------

@end

What you see above is the scene's implementation. It is essentially a node with the content size set to the design size (view size if it is not set), an anchor point of (0,0), a flag that marks it as a scene (which is privately used by CCNode), and a black color for its RGBA. A CCNode does not assume this stuff (for example content size of a node is 0,0 whereas the scene has a a content size of the view/design).

Nodes are the base class for many cocos2d classes. A scene, as you see, is just a node with a meaningful name, a set content size the size of the view (unless you specify a design size), and a black color. On the other hand a sprite is also a node but with other properties related to sprites.

I haven't bothered to use Sprite Builder, but I'd assume by what you've wrote that everything is added to a CCNode, which is ultimately added to a CCScene. Since there is no CCLayer, I'd assume it is simply just using a CCNode to act as the default layer. Someone else can confirm since I've never had a reason to use Sprite Builder but that sounds like it would be the case.