The problem with that is the mouse cursor still hits the edge of the screen, and what I need is unlimited mouse movement. Warping the cursor to the centre of the screen every frame - or every time the mouse changes position - will let me have unlimited mouse movement like in a first person shooter.
In an FPS, you can keep rotating left or right as much as you want, but I can't make that happen without getting the mouse to warp the the screen centre, while still getting accurate mouse mickeys from ev.mouse.dx
I'm running the program in fullscreen of course, and once I get the mouse code working well, I can, for the game menu, draw a custom cursor with primitives that keeps on the screen while the (hidden) real cursor is constantly being warped to the centre of the screen.
I've attached what I've done so far on the Allegro 5 program code as well as the Allegro 4.2 code and executable that I'm trying to port to fullscreen Allegro 5.