DOSBox Feature Request Thread

General information and assistance with DOSBox.

Re: DOSBox Feature Request Thread

Postby Ant_222 » 2019-2-22 @ 13:18

junglemontana wrote:Not sure if anyone else is interested, but bicubic and/or Sinc/Lanczos based scaling would be interesting too.
Is the blurring that you get with the overlay, ddraw, and opengl outputs not enough for you? What is the reason for blurring sharp images?
Ant_222
Member
 
Posts: 448
Joined: 2010-7-24 @ 21:29

Re: DOSBox Feature Request Thread

Postby junglemontana » 2019-2-23 @ 15:42

Ant_222 wrote:
junglemontana wrote:Not sure if anyone else is interested, but bicubic and/or Sinc/Lanczos based scaling would be interesting too.
Is the blurring that you get with the overlay, ddraw, and opengl outputs not enough for you? What is the reason for blurring sharp images?


Aren't those based on bilinear interpolation? Bicubic or Sinc should provide somewhat better results.

I undestand that many people like the blocky appearance of nearest-neighbor upscaling but I often prefer something smoother. :P The scalers used by Dosbox (e.g. hq, supersai) are very nice but it seems that they only support certain resolutions.
junglemontana
Newbie
 
Posts: 14
Joined: 2019-2-16 @ 17:37

Re: DOSBox Feature Request Thread

Postby Ant_222 » 2019-2-23 @ 19:36

junglemontana wrote:Aren't those based on bilinear interpolation? Bicubic or Sinc should provide somewhat better results.
Yes, and bicubic is indeed vastly better for photographic interpolation, whereas for pixel art I consider both methods equally useless. Bicubic interpolation is much slower and it may be difficult to implement with sufficient efficiency.
junglemontana wrote:I undestand that many people like the blocky appearance of nearest-neighbor upscaling but I often prefer something smoother. :P
Anything except pixel-perfect integer scaling distorts the original image, the sort of the distortion depending on the interpolation technique used. The distortion of nearest-neighbor interpolation is irregular pixel sizes. But large, sharp pixels, are part of MS-DOS aesthetics. Remember also that monitors used to be smaller, so you may want to sit further back from your large display to make the image appear smaller.
junglemontana wrote:The scalers used by Dosbox (e.g. hq, supersai) are very nice but it seems that they only support certain resolutions.
When don't they work for you?
Ant_222
Member
 
Posts: 448
Joined: 2010-7-24 @ 21:29

Re: DOSBox Feature Request Thread

Postby junglemontana » 2019-2-23 @ 20:55

Ant_222 wrote:
junglemontana wrote:Aren't those based on bilinear interpolation? Bicubic or Sinc should provide somewhat better results.
Yes, and bicubic is indeed vastly better for photographic interpolation, whereas for pixel art I consider both methods equally useless. Bicubic interpolation is much slower and it may be difficult to implement with sufficient efficiency.


Performance may become a problem, though I'm not familiar with that. Some video renderers support real-time bicubic and Lanczos upscaling but I'm not sure if they are hardware accelerated or pure software implementations.

junglemontana wrote:The scalers used by Dosbox (e.g. hq, supersai) are very nice but it seems that they only support certain resolutions.
When don't they work for you?


For example, when hq2x is used (even with the forced option), selecting video mode 800x600x16 in the original GTA causes Dosbox to print a message "Scaler can't handle this resolution, going back to normal" and the game is not scaled.

I posted a question about this here:
viewtopic.php?f=31&t=65372
junglemontana
Newbie
 
Posts: 14
Joined: 2019-2-16 @ 17:37

Re: DOSBox Feature Request Thread

Postby Ant_222 » 2019-2-23 @ 21:24

junglemontana wrote:For example, when hq2x is used (even with the forced option), selecting video mode 800x600x16 in the original GTA causes Dosbox to print a message "Scaler can't handle this resolution, going back to normal" and the game is not scaled.
Looks like an arbitrary constraint to me. The relevant constants can be redefined in
Code: Select all
src/gui/render_scalers.h
.
junglemontana wrote:I posted a question about this here:
viewtopic.php?f=31&t=65372
Sadly, no replies.
Ant_222
Member
 
Posts: 448
Joined: 2010-7-24 @ 21:29

Re: DOSBox Feature Request Thread

Postby Gatekeeper » 2019-3-04 @ 13:42

Suggestion: DOSBox should have the option to preserve files' original date/time modified.

This isn't usually a problem, however I've had numerous cases of patches or even game expansion installers failing due to incorrect date/time modified. Example: Duke Nukem Plutonium PAK - it won't install under DOSBox (says the original game files are missing or corrupted), but works just fine in PCem, running DOS 5.00a.

The really NASTY example, though, is Star Wars: X-Wing & TIE Fighter games. Their expansions also fail to install correctly due to mismatched date/time modified. But the installer doesn't tell you that. Oh no, it makes it look like everything installed correctly... and then the game is messed-up and has severe graphical glitches or just crashes randomly. It took me nearly 10 (ten) years to figure this out, and I only realized what was going on after comparing the MD5 checksums of the files. Old fiels were simply not replaced with the new ones, even though the installer allegedly did that (and never gave me any error messages).

An experiment with files, whose original date/time modified was restored to original with a third-party program, showed that these same expansions install successfully under DOSBox... proving that it was the date/time modified that caused this whole confusion. Other things (mostly patches) that fail to install in DOSBox also work correctly in PCem (or an old laptop that I borrowed for experimental purposes).

Yes, I can always use PCem to install stuff and it is fairly convenient to use... but I hope we can all agree that being able to do everything within DOSBox, without resorting to third-party programs, would be better. I've been using DOSBox for over 12 years now and it's one of the best applications I've ever discovered :happy:
Don't waste your time, or time will waste you...
User avatar
Gatekeeper
Newbie
 
Posts: 23
Joined: 2006-4-14 @ 22:50
Location: Sofia, Bulgaria

Re: DOSBox Feature Request Thread

Postby DosFreak » 2019-3-04 @ 15:48

DOSBox can already do this if you use a HD image.

Without an image DOSBox would have to do that across all host filesystems unless it's determine to only do that for specific ones which would be annoying.

Would likely be better to print a message to console when that functionality is used or when specific hashes are detected.

Another concern although slight is security since a modified file would reflect an earlier date but obviously dates on files are easy to change anyway.
User avatar
DosFreak
l33t++
 
Posts: 10134
Joined: 2002-6-30 @ 16:35
Location: Your Head

Re: DOSBox Feature Request Thread

Postby Gatekeeper » 2019-3-05 @ 09:35

HD image - I'll look into it. Thanks!
Don't waste your time, or time will waste you...
User avatar
Gatekeeper
Newbie
 
Posts: 23
Joined: 2006-4-14 @ 22:50
Location: Sofia, Bulgaria

Re: DOSBox Feature Request Thread

Postby junglemontana » 2019-3-09 @ 18:23

Ant_222 wrote:
junglemontana wrote:For example, when hq2x is used (even with the forced option), selecting video mode 800x600x16 in the original GTA causes Dosbox to print a message "Scaler can't handle this resolution, going back to normal" and the game is not scaled.
Looks like an arbitrary constraint to me. The relevant constants can be redefined in
Code: Select all
src/gui/render_scalers.h
.
junglemontana wrote:I posted a question about this here:
viewtopic.php?f=31&t=65372
Sadly, no replies.


Hm, thanks for the tip. I edited that file and changed the SCALER_MAXWIDTH/MAXHEIGHT and SCALER_COMPLEXWIDTH/COMPLEXHEIGHT macros to 1280/1024 instead of the default 800/600, then compiled Dosbox, and now the scalers work as I wanted. Performance of the hq scaler is just a bit slow, as one might expect. I'll try others as well.

Were those limits originally set for performance reasons? I think a warning would be enough when someone uses heavy scalers for high resolutions...


Just for general curiosity, would these scalers benefit from multithreading? Or even some sort of OpenCL/CUDA acceleration?
junglemontana
Newbie
 
Posts: 14
Joined: 2019-2-16 @ 17:37

Previous

Return to DOSBox General

Who is online

Users browsing this forum: No registered users and 1 guest