Overview
In this guide I will help you change your resolution for Doom 3 and Doom 3 ROE. This guide also tells you how to get around the really annoying and fustrating Cannot write to doom 3 cfg message.
How to do it. XD
Now, I’m sure you have already tried going into the console and typing in the codes which allow you to change your resolution.
The problem I faced was only with Doom 3 ROE. When I tried to enter the lines which had previously worked for Doom 3, it came up with an error. “Cannot write to doom config”. This was strange because I had no problems with getting the widescreen resolution to work with Doom 3.
I did a bit of searching online and found this helpful forum thread: [link]
I decided to write this guide in case the thread is ever removed, and so people can more easily find the solution if they visit the steam guides. That is what the steam guides are for after all!
So what you need to do is create a cfg file in your doom 3 directory. To do this, go to programfiles86/steam/steamapps/common/doom 3/base/. There, just create a notepad file and place this code in to it.
r_mode “-1”
r_aspectratio “2” (If your aspect ratio is 16:9 change this value to 1, if it is 16:10, change the value to 2.)
r_customwidth “YOURWIDTH”
r_customheight “YOURHEIGHT”
seta r_multiSamples “16” (I only recommend this line because many people are having trouble setting the antialiasing. To be honest, since we are now running much higher resolutions than when the game was made, it looks fine without it.)
vid_restart
Right, now save this file as res.cfg.
When you load into either Doom 3 or Doom 3 ROE, open the console by clicking ctrl, alt and the button next to 1 on the keyboard. (This key is usually ~, but it might be different for some people.)
Then, type into the console, exec res.cfg.
Your screen may go black for a few seconds, but when it loads in your game will have changed resolution. (yay)
*Please note that the resolution will not change for the main menu. When you load into a level, the res should change.*