VGA 320x200 mode w glshaders seems scale incorrectly Dosbox-X/Staging others, using 640x480@60 hz downscaling helps \ VOGONS

VGA 320x200 mode w glshaders seems scale incorrectly Dosbox-X/Staging others, using 640x480@60 hz downscaling helps

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First post, by rico001

Posted on 2026-02-07, 02:48

rico001 Offline

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Rank: Newbie
Posts: 47
Joined: 2019-11-13, 19:17

I think DOSbox glshaders/scalers do not look good /work right. They upscale for some reason... Example from log on World Rally Championship fever... Auto-switched to shader 'crt/vga-1080p'
2026-02-06 20:34:15.338 | SDL: Using standard SDI (auto) display refresh rate of 60 Hz Windows 11 oled tv.
2026-02-06 20:34:15.351 | DISPLAY: VGA 720x400 16-colour text mode 03h at 70.087 Hz throttled VFR, scaled to 1067x800 pixels with 1:1.35 (20:27) pixel aspect ratio

need to go to 640x400(double-scan) and maybe use standard of 640x480 emulated... will try to explain better and post more info...

The glscaler scaler standard may be the issue... On Windows 95/98 with crt monitor it had an option to use double-scan in a compatibilty mode (I think I remember from command and conquer red alert) So am trying to say upscale differently for 320x200 games. EDIT:
Learned about Pixel Aspect Ratio and DisplayPixel Aspect Ratio... PAR of 1:1.22 instead of 1:1 changes demensions of each pixel and is differant process than simply upscaling the on-screen image by an integer.

Last edited by rico001 on 2026-02-11, 01:54. Edited 2 times in total.

Reply 1 of 4, by rico001

Posted on 2026-02-09, 20:31

rico001 Offline

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Rank: Newbie
Posts: 47
Joined: 2019-11-13, 19:17

Found a ton of cool info, ideas failed couldn't get a game working in .82.2 might try regular dosbox, am able to use both monitor and tv -2000+(date) years... Found out 320x200 (might be mode 12h) might be considered 16:10, and might not work on tv's 1280x800... Still learning... hopefully ok to post here, learning alot remembering fun things ...

Reply 2 of 4, by theelf

Posted on 2026-02-10, 14:51

theelf Offline

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Posts: 1198
Joined: 2011-09-25, 19:39

Cant understand anything

Reply 3 of 4, by rico001

Posted on 2026-02-11, 01:36

rico001 Offline

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Rank: Newbie
Posts: 47
Joined: 2019-11-13, 19:17

theelf wrote on 2026-02-10, 14:51:

Cant understand anything

Still learning too. will try to posts pics or a video...

Reply 4 of 4, by rico001

Posted on Today, 00:23

rico001 Offline

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Rank: Newbie
Posts: 47
Joined: 2019-11-13, 19:17

Don't legally know about posting pic/videos for commercial games, but FOSS games software to compare without licensing issues: fractint (fractal generator by stone soup), sopwith2, scumm vm games... One or 2 comercial examples that are dramatically differant with proper scaling and aspect ratio was Lemmings, another was Earthworm Jim 2. Perhaps someone can make a program to match color in game screenshots to your computer monitor or tv. An app that helps to control aspect ratio and control scan line or shader settings is shaderglass(available on github), for Windows or linux and can be used externally to Dosbox. An app that people used to use to change settings such as gamma and brightness was Powerstrip by Entech (2001)... Some of these scaling changes can be viewed in DOSBOX_Staging image gallery..

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