main game loop version

- (void) applicationDidFinishLaunching:(UIApplication*)application
{
	// create our rendering timer
	[self performSelectorOnMainThread:@selector(mainGameLoop) withObject:nil waitUntilDone:NO];
}

- (void) mainGameLoop
{
	while (gameRunning)
	{
		// Yield to system calls (touches, etc.)
		while(CFRunLoopRunInMode(kCFRunLoopDefaultMode, kGameSystemCallYield, FALSE) == kCFRunLoopRunHandledSource);
		
		// Update the game logic.
		shell->UpdateScene();
		
		// Draw the game.
		shell->RenderScene();
        
        [_glView swapBuffers];
	}
    
    NSLog(@"game no longer running");
}

ns timer version

- (void) applicationDidFinishLaunching:(UIApplication*)application
{
	// create our rendering timer
	[NSTimer scheduledTimerWithTimeInterval:(1.0 / kFPS) target:self selector:@selector(update) userInfo:nil repeats:YES];
}

- (void) update
{
    if (!gameRunning) {
        NSLog(@"game no longer running");
        return;
    }
    
	if(!shell->UpdateScene())
		printf("UpdateScene error\n");
	
    if(!shell->RenderScene())
		printf("RenderScene error\n");
	
	[_glView swapBuffers];
}