"Extra" VESA resolutions

[alanrothenbush]

Does DOSBox-X support VESA mode 11Ch or 166h? (1600x1200 or 1920 x 1080)

I have an older DOS program that I love, that I paid for, and that works so well I cannot imagine changing to something "modern. I've been running it in DOSBox at 1280x1024 and it works perfectly well. Then I upgraded to a higher res monitor and now everything is way too small. It's still usable, but a VESA mode with more dots sure would be nice.

It seems like DOSBox-x might be an answer, but before burning up hours of time experimenting, I thought maybe I'd ask the question.

[joncampbell123]

Yes: https://github.com/joncampbell123/dosbox-x/blob/master/src/ints/int10_modes.cpp#L297

And yes: https://github.com/joncampbell123/dosbox-x/blob/master/src/ints/int10_modes.cpp#L311

But you have to enable them in dosbox.conf. See the reference dosbox.conf file for details.

The video modes numbers though are not necessarily the same.

They're not enabled by default because too many DOS games crash if the VESA BIOS extensions enumerate too many modes. Lazy programmers with fixed sized arrays, typically, though some games like Quake actually have serious memory leak issues for every VBE mode they enumerate that is not a 256-color mode.

[joncampbell123]

If you're wondering, I even tried to implement a 4K UHD VBE mode, however the S3 emulation can't go that high, and even if it could, the rendering system behind the the scaler render system cannot.

[joncampbell123]

If your DOS program properly enumerates video modes, it should find the 1600x1200 and 1920x1080 modes just fine no matter what the video mode number is.

[alanrothenbush]

Thanks for this! I now have a variety of VESA modes working .. after a fashion. What I mean is, the application runs at about 1/4 to 1/10 the speed, compared to DosBox .74, at least in terms of video. The app is Traxedit, an old PCB creation program. PgUp is the Zoom In key, and a PgUp under DosBos is darn near instantaneous. Under DosBox-X, it takes between a second and 2 seconds, making it pretty much unusable. (This test is performed using the identical Traxedit configuration in both emulators.) I guess I now try to speed things up. Thanks again! Alan

…

On 9/2/2025 12:57 PM, Jonathan Campbell wrote: Yes: https://github.com/joncampbell123/dosbox-x/blob/master/src/ints/ int10_modes.cpp#L297 <https://github.com/joncampbell123/dosbox-x/blob/ master/src/ints/int10_modes.cpp#L297> And yes: https://github.com/joncampbell123/dosbox-x/blob/master/src/ ints/int10_modes.cpp#L311 <https://github.com/joncampbell123/dosbox-x/ blob/master/src/ints/int10_modes.cpp#L311> But you have to enable them in dosbox.conf. See the reference dosbox.conf file for details. The video modes numbers though are not necessarily the same. They're not enabled by default because too many DOS games crash if the VESA BIOS extensions enumerate too many modes. Lazy programmers with fixed sized arrays, typically, though some games like Quake actually have serious memory leak issues for every VBE mode they enumerate that / is not/ a 256-color mode. — Reply to this email directly, view it on GitHub <https://github.com/ joncampbell123/dosbox-x#5816#discussioncomment-14289276>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ AUOHSJTQD7Q3XPIP65KWTRT3QXZBXAVCNFSM6AAAAACFOCNIIOVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTIMRYHEZDONQ>. You are receiving this because you authored the thread.Message ID: ***@***.***>

-- There’s nothing - absolutely nothing - half so much worth doing as simply messing about in boats. Water Rat to Mole, from The Wind in the Willows

[alanrothenbush]

OK, I've got everything mostly working pretty well, using a resolution of 1600 x 1200, with speeds comparable to DosBox at 1280x1024. In fact, it's a bit slower at the higher res, , but I guess that makes sense because it's drawing more dots. I could not get any 1920 x #### modes working , and there were a number to try. (I actually have the source code for the graphics driver, so I can easily try a number of options.) If you remember old fashioned TVs, it was like the horizontal hold was off.) My program DID run .. 30 years of muscle memory makes it easy for me to type the correct startup and exit keys to return to a DOS prompt. But it was unusable. It was almost as if the "line buffer" was the wrong size, like the first 1800 pixels of the first 1920 pixel line were displayed, but the last 120 were displayed on the beginning of line 2. Line 2 then displayed just 1680 of line 2's pixels, with the remaining 240 being displayed on the beginning of line 3, and so forth. Oh well, it's better, and that's a plus. Thanks for this.

[joncampbell123]

Please try setting the vmemsize option to a larger value, such as vmemsize=8, to get higher resolution modes.

[alanrothenbush]

Sadly, no change. See attached pics of splash screen for working 1600x1200 and non-working 1920x1080.

vmemsize set to 8.

Also tried vmemsize set to 8, vmemsizekb set to 8192. These settings appeared to have no change.

Tried with machine=vesa_nolfb and machine=svga_s3; no change. Didn't know if there were any other machine types to try.