一个Demo（演示MD2调用、影子做法、gluUnProject用法，含源码）, 影子的实现算法还不是很完美。应用只局限于在平面上而不能在曲面上。-a Demo (demo MD2 called shadow, gluUnProject usage, including source code), the shadow of the algorithm is not perfect. Application confined to the flat surface and not on the

用opengl自带的glReadPixels(以及gluUnProject(）函数和点落在三角形内的矢量判断IntersectTriangle然后转成三维坐标的两种方式获取屏幕点选的场景坐标，通过对比发现其值是一样。-Use opengl own glReadPixels (as well as gluUnProject () function and the points fall within the vector triangle to determine IntersectTriangl

OpenGL逆变换 opengl可以实现从窗口坐标到实际物体三维坐标的变换-OpenGL inverse transformation opengl can transform coordinates from the window to the actual three-dimensional coordinates of the object