I want to draw a disk with a fixed radius (in screen pixels) so that it always looks the same size no matter how you zoom-in/zoom-out or change the window size. Unfortunately I don’t know how the 3rd party software zoom-in/zoom-out (either change scaling factor or viewport??). I tried the following but the disk size does change while zooming. Can anyone give me a hint? Thanks.
gluDisk(qobj, 0.0, .01, 10, 1); // radius .01