说明：  Ogre消息机制，详细介绍了ogre内部的消息传递，对了解ogre内部的管理很有帮助，对大型程序的消息管理也有借鉴作用
(Ogre message mechanism, details of the ogre internal messaging, and helpful to understand the ogre internal management, message management of large programs also serve as a reference)