I am new to OpenGL and I am trying to code un optic flow with dots appearing from the background and moving towards the viewer. As a consequence of a perspective projection, the dots are faster and bigger when they move towards the viewer, but they are smaller and slower when they are farther away from the viewer.
As a result of OpenGL perspective projection, I got the dots moving faster when approaching the viewer, but their size does not change with the distance. Isn't the change of size a consequence of the projection -- just as the change of speed? If not, shall I compute it separately?
Thanks in advance for your help]1