I need to draw some specific 3d object, which don't zoom with camera(such as coordinate system).
For now, I would like to implement this by adopting two different project matrix, which meant that I draw these 3d object in specific project matrx(which don't zoom at all).
here is problem, while drawing coordinates system, a 3d location and vector direction are provided, I transform 3d point onto screen coordinates by gluProject(spt, using project matrix1), then I translate screen spt onto another 3d coordinates(using project matrix2), then I setup the second camera to draw the coordinates system.
It seems work, but location is not right. anybody can give me suggestion?