Achieving period-correct graphics in personal computer emulators

[A horse of course]

What a depressing thread.

 

[Machocruz]

This guy keeps churning out screenshots with 100% sharp pixels and no aspect ratio correction whatsoever on anything like there's no tomorrow. I'm gonna send him a link to my upcoming article about PC/DOS games, and I fully expect he'll tell me to fuck off :shrug:

I checked out that link. Calls himself the King of Grabs, grabs look as shitty and he's as clueless as anyone else. Hail to da kang baby

 

[A horse of course]

Rincewind did you end up writing an article for DOS emulation? I couldn't find it on your site.

 

[Rincewind]

Rincewind did you end up writing an article for DOS emulation? I couldn't find it on your site.

Not yet. ETA is end of January / early February. I need to research it thoroughly because there's far greater interest in DOS/PC gaming than in the Amiga.

Hmm, maybe it would be best to split it into two parts: DOS, and then late 90s/early 2000s Windows gaming. Writing the DOS (and Win3.11) part is easy, but the Win95/98 stuff needs further research. Of course, we know what the best current solution is (build a retro Win98 box and use a real CRT), but this series is about emulation. I'll need to screw around with PCem / 86box and shaders on my 1080p monitor and on my Mac laptop which is effectively 4k (you really need 4k for proper CRT shaders from 640x480 upwards).

 

[Norfleet]

I am pretty sure all of these "graphics emulators" are NOT, in fact, accurate, because I actually have real screenshots taken from those days, and can physically compare the screenshots, and these screenshots do not match. They aren't merely embiggened versions of old screenshots, either. They're just straight up wrong.

 

[Narushima]

Not on DOS, but this video gives a few nice examples of the difference between real composite and RGB displays.

 

[Rincewind]

Not on DOS, but this video gives a few nice examples of the difference between real composite and RGB displays.

Games developed for composite should be played on composite.
That stands for TVs, Amiga monitors, and so on.

 

[Bester]

Someone made a fork of Dosbox called Dosbox-Pure as a Retroarch core, so the CRT shaders are now very accessible for dos games and even some win95/98 games. (haven't tried the latter yet)

TLDR:
- all standard .conf options are tweakable in retroarch UI under "Core Options", and save/load is integrated with retroarch
- conf files aren't loaded by default, but you can change that
- when you run an exe/conf, Dosbox-Pure will mount the directory as C:, so unmount it in the conf file first thing if you want a different setup
- by default it'll use scummve's Roland SC-55 soundfont for midi
- if you set it to use Frontend Midi device, you need to go to RetroArch's settings -> Audio -> Midi -> set Output to the full name of the device, e.g. "MT-32 Synth Emulator" if you're using Munt (names can be found in dosbox's mixer /listmidi, but not in dosbox-pure, you'll have to launch a normal one)

I'm mostly happy with it, but I wonder if using soundfont is inferior to using yamaha syxg50 vsti for games? Rincewind any idea? I know you prefer the yamaha, but putting it aside for a moment, does vsti implement more functionality than a simple soundfont?
And if so, I'm not sure how to make it work on Win11 right now. The way it was used to be done with midimapper seems to be broken https://www.vogons.org/viewtopic.php?t=59471
They apparently have some workaround involving a complicated setup of multiple programs, but I haven't figured out how they do it yet.

 

[Rincewind]

I'm mostly happy with it, but I wonder if using soundfont is inferior to using yamaha syxg50 vsti for games? @Rincewind any idea? I know you prefer the yamaha, but putting it aside for a moment, does vsti implement more functionality than a simple soundfont?

Well, you can download a huge set of comparison recordings from here:
https://blog.johnnovak.net/2023/03/05/grand-ms-dos-gaming-general-midi-showdown/

They sound quite different on some soundtracks, almost the same on others. That's between the SC-55/SoundCanvas hardware and the S-YXG50/MU80 hardware though.

SoundFonts are a different story... I've made a small comparison here, *-sc55-v1.21 is the original hardware. Personally, I'd just use GeneralUser GS if I had to use FluidSynth.
https://archive.org/details/FluidSynth-MIDI-Comparison

I put them up on our wiki with some explanatory text, might wanna check it out:
https://github.com/dosbox-staging/dosbox-staging/wiki/MIDI#comparison-recordings

I will write a guide on how to set it up VSTi plugins as external MIDI devices for DOSBox on Windows... someday
This should help you in the meantime:

https://www.youtube.com/watch?v=WumRboSfn90

 

[schru]

Bester, I'm not sure about typical General MIDI cases, but DOS games often have separate settings for specific music cards or synthesizers, in which cases I think special instructions are involved. And at any rate, I'm pretty certain that hardware synthesizers are much more complex than the free software ones.

The video which Rincewind included at the end of his post is a very good solution. Sound Canvas VA is quite close to SC-55, which was the standard for very many games at the time.


As for using an additional MIDI device in Windows 11, CoolSoft's MIDIMapper isn't necessary. As long as the VSTi plug-in can be linked to some piece of software which Windows can see as a MIDI device, it will be assigned a number, 1 or greater (0 is for Windows's built-in synthesizer). This number can be used in DOSBox's configuration file to tell it which MIDI device it should use. The setting in question is in the [midi] section, but note that some versions of the regular DOSBox have this setting as config=, while all the more advanced custom builds have it as midiconfig=.

Perhaps the Yamaha VSTi plug-in can be embedded in SAVIHost in the same way that Sound Canvas VA can. If so, all you need to do is follow the instructions in that video above. The program which serves as a virtual MIDI device which Windows can recognize is loopMIDI.

 

[Rincewind]

Perhaps the Yamaha VSTi plug-in can be embedded in SAVIHost in the same way that Sound Canvas VA can. If so, all you need to do is follow the instructions in that video above. The program which serves as a virtual MIDI device which Windows can recognize is loopMIDI.

It can, and I've done it.

 

[Bester]

I followed the video's instructions and have successfully tested SC-55 VSTi through Sound Canvas VA + loopMIDI + SAVIHost, but I can't launch SAVIHost with syxg50.dll to give Yamaha a try, it just doesn't want to load it. Any recommendations?

 

[Rincewind]

I followed the video's instructions and have successfully tested SC-55 VSTi through Sound Canvas VA + loopMIDI + SAVIHost, but I can't launch SAVIHost with syxg50.dll to give Yamaha a try, it just doesn't want to load it. Any recommendations?

Use the 64-bit plugin with the 64-bit version of SAVIHost, or the 32-bit plugin with the 32-bit version of SAVIHost. This is the most common mistake. They can't be mixed.

 

[LarryTyphoid]

I never used shaders on DOS games before, but I've been trying them out recently.

Not quite sure how I feel about it. I don't know how accurate it is to original displays, either.

 

[Rincewind]

I never used shaders on DOS games before, but I've been trying them out recently.

Not quite sure how I feel about it. I don't know how accurate it is to original displays, either.

There's a lot of moire going on in these screenshots. On 1080p, you can't do much to improve things or to make it more "CRT like". You really need 4k monitors for that. Just use the DOSBox Staging defaults, that's my best suggestion.

Otherwise, wait for my PC / DOS shader article. There *are* some tricks to improve things even on 1080p, especially for 640x480. But for low-res 320x200 gaming, the stock settings are about as good as it gets on 1080p.

 

[Rincewind]

Quick preview for the impatient. "Ravenloft – Stone Prophet" with a period-accurate VGA CRT shader.

The game uses a so-called tweaked VGA mode (non-standard mode) of 320x400 resolution popularised by demoscene coders. That's taking advantage of the full 400 lines of vertical resolution of the low-res VGA mode, as opposed to letting the VGA hardware simply scan-double 320x200 to 640x400 (as is the default standard behaviour).

This is on 4K; you really need 4K for proper VGA emulation (zoom in).

 

[Derringer]

The only shader I remember really liking was gtuv50, past that I just used the gaussian blur shader from gshade in reshade to blur the pixels in games.

 

[soulburner]

Too bad about the 4K requirement (I'm on 1440p). I guess you can't cheat pure path here. That screenshot above looks so good.

 

[Rincewind]

The only shader I remember really liking was gtuv50, past that I just used the gaussian blur shader from gshade in reshade to blur the pixels in games.

Yeah that's a good one. My no.1 favourite is "Guest Advanced" (it was also known as "Guest & Dr.Venom"), but that requires a multi-pass setup we don't currently have in DOSBox Staging (but it's coming). I'm using the original incarnation of Guest's shader in WinUAE, btw.

That above screenshot is a tweaked version of the good old Hyllian CRT shader, plus I hacked a few extra features in from other shaders (different pixel masks, white balance, and black levels). Hyllian is a very nice one, fast *and* high-quality (as it takes no shortcuts).

Too bad about the 4K requirement (I'm on 1440p). I guess you can't cheat pure path here. That screenshot above looks so good.

1440p is fine if you're happy with playing games fullscreen or near-fullscreen. With 3 native pixels per emulated scanline, you can do a rather good emulation:

400 * 3 = 1200
480 * 3 = 1440

That's good news because 640x480 content perfectly fits with a 3x scaling factor!

But that would require a slightly tweaked shader. This is how 320x400 content looks like at 1600x1200 with the exact same shader. The phosphor/pixel grid is a bit busy and too strong, it would require some tweaking for 1440p. But not bad!

 

[soulburner]

That above screenshot is a tweaked version of the good old Hyllian CRT shader, plus I hacked a few extra features in from other shaders (different pixel masks, white balance, and black levels). Hyllian is a very nice one, fast *and* high-quality (as it takes no shortcuts).

Would you like to share the modified shader? I'll try to tweak it on my own to maybe suit 1440p a bit better.

 

[Rincewind]

That above screenshot is a tweaked version of the good old Hyllian CRT shader, plus I hacked a few extra features in from other shaders (different pixel masks, white balance, and black levels). Hyllian is a very nice one, fast *and* high-quality (as it takes no shortcuts).

Would you like to share the modified shader? I'll try to tweak it on my own to maybe suit 1440p a bit better.

Sure thing.

https://pastebin.com/X2wUUF3g

It works in DOSBox Staging, I have no idea if it works with anything else (probably not).

Show me if you come up with something cool.

 

[Jack Of Owls]

Will be rereading this topic for suggestions because so far on the libretro forums I found nothing that particularly pleases me as much as CRT-EasyMode did. There's one maniac there who has an entire huge thread to himself of nothing but self-aggrandizing comments and continuous, spergy and spastic posting of his massive collection of 4K shader creations. I tried some of his "Best Of" shader compilations based on CRT-Royale and, man, do they all look like cold garbage. Rincewind's screenshots are a thousand times better in this topic yet I'm still looking for that more subtle pixel shader look with perhaps just a hint of scanlines to bring out details and to offset the horrible raw pixel look of 16-bit/32-bit era console emulators ie Retroarch on my modern 65" 4K OLED TV (complicated by the fact that I sit only about 10' from it).

 

[caffeine]

my modern 65" 4K OLED TV (complicated by the fact that I sit only about 10' from it).

IMO crt shaders on big TVs look like ass, specially as you don't get to sit far away from the TV. But the one I've found it looks alright on my TV (50" 4K LCD) is Lottes, try messing with it.

I guess the 4K meme only applies to computer monitors because on TVs the result is disappointing.

 

[Jack Of Owls]

Update on my RA issue with not getting the

my modern 65" 4K OLED TV (complicated by the fact that I sit only about 10' from it).

IMO crt shaders on big TVs look like ass, specially as you don't get to sit far away from the TV. But the one I've found it looks alright on my TV (50" 4K LCD) is Lottes, try messing with it.

I guess the 4K meme only applies to computer monitors because on TVs the result is disappointing.

Yeah, just checked it out and it doesn't look too bad. It reminds me of CRT-easymode but without the terrible artifacts on gray backgrounds in 16-bit console games. I'll have to remove that screen curvature though. Hate that shit. Another alternative is use a border or something and make the viewport smaller but I like my extra large on-screen real estate. This is the game I use to test those gray backgrounds for artifacts and they look okay here. Enabling HDR within Retroarch causes it to look washed out in screenshots but it's a lot more vibrant in-game.

 

[Rincewind]

Authentic, zero-configuration, fully automatic CRT emulation from Hercules to SVGA, supporting 720p to 4k, is coming to DOSBox Staging... by yours truly.

Some teaser screenies: