Question

I have a cocos2d powered game that uses UIKit menues, so I only use the framework for one viewcontroller, which is the game itself. Also, it only has one scene. Since cocos2d 2.0 the director itself is a UIViewController subclass, so I just push it in my MenuViewController when the user taps a start button:

-(void)startGameButtonPressed {

    CCDirectorIOS* director = (CCDirectorIOS *) [CCDirector sharedDirector];


    // Create an CCGLView with a RGB565 color buffer, and a depth buffer of 0-bits
    self.glView = [CCGLView viewWithFrame:CGRectMake(0, 0, 480, 320)
                              pixelFormat:kEAGLColorFormatRGB565    //kEAGLColorFormatRGBA8
                              depthFormat:0 //GL_DEPTH_COMPONENT24_OES
                       preserveBackbuffer:NO
                               sharegroup:nil
                            multiSampling:NO
                          numberOfSamples:0];

    // attach the openglView to the director
    [director setView:glView];
    [director runWithScene:[GameLayer scene]];
    [director setDelegate:(id <CCDirectorDelegate>) [[UIApplication sharedApplication] delegate]];
    [self.navigationController pushViewController:director animated:YES];
}

This works fine for the first time the method is called, when the user starts the first game. When the game is over, I call [[CCDirector sharedDirector] end].

Most of the director setup is done in the appDelegate (it’s taken unchanged from the default Cocos2d template). I only put the CCGLView as a retained property into my MenuViewController, because otherwise the app crashes when [[CCDirector sharedDirector] end] is called and the CCGLView is not retained. I think that might be a cocos2d bug. In [[CCDirector sharedDirector] end] the framework calls [self setView:nil], but it still tries to access the view later on (probably on another thread).

The problem now is that on the second call of my method above (when the user wants to start another game from the menu), startGameButtonPressed, the director gets pushed but the screen remains black. The game is running and responding, I just don’t see anything. Can someone please help me out with that?

Answer 1

OK, I had the same problem and I was able to “fix it”.

When you set the CCGLView and [director setView:], even if you pop the controller the scene still exists. the only thing that happens is that the scene gets stopped.

So in order to have the “restart” working, you have to check if there is already a running scene (even if it’s stopped, and instead of runWithScene: you use replaceScene:.

Here is my code so you can see:

- (void)setupCocos2D {
    CCGLView *glView = [CCGLView viewWithFrame:CGRectMake(0, 0, 320, 480)
                               pixelFormat:kEAGLColorFormatRGB565   //kEAGLColorFormatRGBA8
                               depthFormat:0    //GL_DEPTH_COMPONENT24_OES
                        preserveBackbuffer:NO
                                sharegroup:nil
                             multiSampling:NO
                           numberOfSamples:0];

// HERE YOU CHECK TO SEE IF THERE IS A SCENE RUNNING IN THE DIRECTOR ALREADY    
if(![director_ runningScene]){
    [director_ setView:glView]; // SET THE DIRECTOR VIEW
    if( ! [director_ enableRetinaDisplay:YES] ) // ENABLE RETINA
        CCLOG(@"Retina Display Not supported");

    [director_ runWithScene:[HelloWorldLayer scene]]; // RUN THE SCENE

} else {
    // THERE IS A SCENE, START SINCE IT WAS STOPPED AND REPLACE TO RESTART
    [director_ startAnimation];
    [director_ replaceScene:[HelloWorldLayer scene]];
}      


[director_ setDelegate:(id <CCDirectorDelegate>) [[UIApplication sharedApplication] delegate]];

// I DO NOT PUSH BECAUSE I ALREADY PUSHED TO THIS CONTROLLER, SO I ADD THE COCOS2D VIEW AS A SUBVIEW
[self.view addSubview:[director_ view]];

}

Hope this code will help you, because I spent a whole day trying to figure this out.
It may not be the correct way or even the prettiest way, but it’s working 🙂

EDIT:
Also, please not that if you POP the COCOS2D scene, you don’t have to [[CCDirector sharedDirector] end] as the animation will be stopped when the view is dealloc/removed.