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