说明：  提出并实现一种用于三维坐标拣选的RIP（Ray-Intersection-Penetration）方法。介绍了如何在已经渲染至窗口的三维场景中，使用鼠标或者相关设备拣选特定三维对象的方法。此方法对于正交投影或透视投影均有效，相对于OpenGL自带的选择与反馈机制，本方法无论是拣选精度还是算法实现效率均高出许多，是一种比较通用的解决方案。
(Proposed and implemented for three-dimensional coordinates of a selected RIP (Ray-Intersection-Penetration) method. Introduce how to have a window of three-dimensional rendering to scene, using the mouse or related devices to choose a particular method of three-dimensional object. This method is orthogonal projection or perspective projection are effective, as opposed to OpenGL)