Cocos2dx报OpenGL error 0x0506错误

近期做第三方sdk接入时，发现iOS8系统下，进行银联充值后，返回游戏有很大几率会报 
OpenGL error 0x0506............ 
之类的绘制问题，游戏卡死，花了很长时间，一直没有头绪 

最终找到这篇文章： 
http://blog.lessfun.com/blog/2014/09/24/ios8-issue-keyboard-orientation-and-idletimerdisabled-not-working/ 

原来后台运行的app，是不允许进行openGL绘制的，而且iOS8要求更严格 

好吧，切换到RootViewController.mm，加上这两个方法： 

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    cocos2d::CCApplication::sharedApplication()->applicationDidEnterBackground();
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    cocos2d::CCApplication::sharedApplication()->applicationWillEnterForeground();
}

applicationDidEnterBackground主要是在切到后台时做这些： 

CCDirector::sharedDirector()->stopAnimation();
SimpleAudioEngine::sharedEngine()->pauseBackgroundMusic();
SimpleAudioEngine::sharedEngine()->pauseAllEffects();

applicationWillEnterForeground是切回前台，做这些： 

CCDirector::sharedDirector()->startAnimation();
SimpleAudioEngine::sharedEngine()->resumeBackgroundMusic();
SimpleAudioEngine::sharedEngine()->resumeAllEffects();