DOOM 3 - Screen Resolution Fix (Widescreen)
The following method should let you change the screen resolution for the game to whichever you want. The main menu offers quite a few resolutions, but sometimes you may want a more specific resolution. You can change it this way.Set Custom Resolution Using Console
1. Open Console
Open the game and press CTRL, ALT and ~ keys together (in some countries you will have to press CTRL, ALT and the key directly beneath the ESC key if ~ doesn't work)2. Console Commands
Write following commands to Console and press ENTER after each command.
r_Mode -1 //press ENTER
r_AspectRatio VALUE //press ENTER
r_CustomHeight XXXX //replace XXXX with your Screen Height and press ENTER
r_CustomWidth XXXX //replace XXXX with your Screen Width and press ENTER
vid_Restart //press ENTER
r_AspectRatio VALUE //press ENTER
r_CustomHeight XXXX //replace XXXX with your Screen Height and press ENTER
r_CustomWidth XXXX //replace XXXX with your Screen Width and press ENTER
vid_Restart //press ENTER
And there you go, the game might crash for some computers after using vid_restart so try re-launching it if this happens, the changes should be applied next time you start the game. I don't know why this happens but I'm guessing it's because the game hasn't been updated to work properly on modern operating systems.