我在cocos2dx 3.x版本，一般会根据自己的图片去设置屏幕尺寸大小，那么如何去设置呢，下面给出具体代码

	auto glView = Director::getInstance()->getOpenGLView();
 
	if (! glView)
	{
		glView = GLViewImpl::create("star");
		glView->setFrameSize(640,960);
		Director::getInstance()->setOpenGLView(glView);
	}
	glView->setDesignResolutionSize(640,960,ResolutionPolicy::FIXED_HEIGHT); //1
	glView->setFrameSize(640,960);  //2