ZDoom

Can someone explain to me how these variables work? I don't really understand what they do at all, and there appears to be no documentation on what they do anywhere.
I'm mostly asking this to help write my documentation, so please be aware your answers will be used for a public domain work!

They contain the closest full integer scaling factor from 320x200 to the actual screen size. Their purpose is to allow HUD graphics to be scaled so that all pixels are evenly scaled. I guess with HD screens or even larger most of their reason for existence no longer applies. When this code was written, screen sizes of 800x600 or 1024x768 were commonplace on which uneven scaling with the software renderer looked exceedinly bad.

Graf Zahl wrote:They contain the closest full integer scaling factor from 320x200 to the actual screen size. Their purpose is to allow HUD graphics to be scaled so that all pixels are evenly scaled. I guess with HD screens or even larger most of their reason for existence no longer applies. When this code was written, screen sizes of 800x600 or 1024x768 were commonplace on which uneven scaling with the software renderer looked exceedinly bad.

I see, so then:
CleanXFac would be the closest integer scaling for a `x` parameter from 320x200 to the virtual screen resolution, CleanYFac would be the closest integer scaling for a `y` parameter, and CleanWidth/CleanHeight are the screen width/height scaled to those.
What are the `_1` variables in that case?

// if the width is between 800 and 960 the ratio between the screensize and CleanXFac-1 becomes too large.

That's all the info that is available. For any other screen sizes they are the same.