What aspect ratio was Doom originally?

[Graf Zahl]

Out of curiosity, why on earth did they ever use that bizarre resolution for that?

Back then it was the highest you can get with plain VGA cards and 256 colors. Although the mode was undocumented it was available on all VGA cards.

[LogicDeLuxe]

Back then it was the highest you can get with plain VGA cards and 256 colors.

Actually, you can go up to 400x540. However Notebooks usually could not display such unusual resolutions. 320x480 would have worked, though.

[Graf Zahl]

We are talking regular VGA cards here. 320x400 was the absolute maximum you could get with the minimum memory installed back then.

[LogicDeLuxe]

Exactly, we talking regular VGA cards. Take a build engine game (DOS executable), Duke Nukem 3D for instance, and edit the duke3d.cfg. In the graphic mode section use this:

Code: Select all

ScreenMode = 0
ScreenWidth = 400
ScreenHeight = 540

Should work with any VGA compatible screen which can handle 53 Hz. Some LCD or TFT might have problems with it, though. And 400x480 should work on any VGA screen.

VGA standard is 256 kB video RAM. No more, no less.
400 x 540 = 216000 byte, ie. still below the limit.
Though, 320 x 400 is the highest which can be done with page flipping, which was not a requirement for the Windows boot screen. It's merely "animated" with a palette rotation.

The speed difference in Duke 3D, start position after the plain crashed, small HUD. Measured on my old DOS PC, Pentium 200 mmx, Winner 2000 AVI, General MIDI music, highest quality Soundblaster Pro sfx enabled, nothing overclocked:
Chained 320x200: 72 fps
Buffered 320x200: 80 fps
VESA 320x200: 102 fps
Chained 320x400: 34 fps
VESA 320x400: 69 fps
Chained 400x540: 24 fps
VESA 640x400: 41 fps

I remember playing Doom 95 on that machine, which was much slower on 640x400 than this. Hence I got always the impression that the Build engine is highly optimzed. Although, build slows down noticable when slopes take much of the screen, while I never noticed a slowdown in ZDoom with them.

[Graf Zahl]

Should work with any VGA compatible screen which can handle 53 Hz.

Clearly something that could not be taken for granted. 320x400 was safe, though.