Render process

之前看代码都是纠结于widget的创建，以为只要看懂widget创建的问题，就基本上看懂MyGui

但是当看到widget的渲染就没从着手。下面的博客给了很大的提示。

http://blog.csdn.net/liigo/article/details/7089832

void DirectXRenderManager::drawOneFrame()
{
	static Timer timer;
	//static variable first initialized
	//it will keep his value during next change!
	static unsigned long last_time = timer.getMilliseconds();
	unsigned long now_time = timer.getMilliseconds();
	unsigned long time = now_time - last_time;

	Gui* gui = Gui::getInstancePtr();
	if (gui != nullptr)
		gui->_injectFrameEntered((float)((double)(time) / (double)1000));

	last_time = now_time;

	begin();
	LayerManager::getInstance().renderToTarget(this, mUpdate);
	end();

	mUpdate = false;
}

render 从LayerManager上把render的渲染结构理清。