シングルトン

cocos2dは以下のようにシングルトンがよく使われている

CCActionManager* sharedManager = [CCActionManager sharedManager];
CCDirector* sharedDirector = [CCDirector sharedDirector];
CCSpriteFrameCache* sharedCache = [CCSpriteFrameCache sharedSpriteFrameCache];
CCTextureCache* sharedTexCache = [CCTextureCache sharedTextureCache];
CCTouchDispatcher* sharedDispatcher = [CCTouchDispatcher sharedDispatcher];
CDAudioManager* sharedManager = [CDAudioManager sharedManager];
SimpleAudioEngine* sharedEngine = [SimpleAudioEngine sharedEngine];

シングルトン実装例

static MyManager *sharedManager = nil;

+ (MyManager*) sharedManager {
    if (sharedManager == nil) {
        sharedManager = [[MyManager alloc] init];
    }
    return sharedManager;
}