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：

1. - (void)viewWillDisappear:(BOOL)animated
2. {
3. [super viewWillDisappear:animated];
4. cocos2d::CCApplication::sharedApplication()->applicationDidEnterBackground();
5. }
6. - (void)viewWillAppear:(BOOL)animated
7. {
8. [super viewWillAppear:animated];
9. cocos2d::CCApplication::sharedApplication()->applicationWillEnterForeground();
10. }

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

1. CCDirector::sharedDirector()->stopAnimation();
2. SimpleAudioEngine::sharedEngine()->pauseBackgroundMusic();
3. SimpleAudioEngine::sharedEngine()->pauseAllEffects();

applicationWillEnterForeground是切回前台，做这些：

1. CCDirector::sharedDirector()->startAnimation();
2. SimpleAudioEngine::sharedEngine()->resumeBackgroundMusic();
3. SimpleAudioEngine::sharedEngine()->resumeAllEffects();