该例子演示的是使用OPENGL标准框架在游戏中建立菜单的方法，包括菜单的建立、鼠标指针的创建、菜单对鼠标的响应事件以及对贴图的处理和在菜单中对光线的应用。-demonstrated by the example of the use of OpenGL standard fr a mework for the game to establish the menu, including the establishment of the menu, the mouse pointer's f