Achieving period-correct graphics in personal computer emulators

[deama]

This looks good, but man, I can't think of a single game I'd replay that would benefit from this, if this was done back 15 years ago...
Well, there is one, super metroid, but that's it, sadly.

Anyone know if these filters exist on the super nintendo emulator? I got a 4k screen.

 

[ind33d]

i'm curious how 3D games like Morrowind look on a CRT with anti-aliasing. I vaguely remember playing Oblivion on a CRT, and it must have been quite impressive considering the high refresh rate. obviously Quake 3 looks good at like 240 FPS on a CRT, but even other genres must be significantly smoother

 

[deama]

i'm curious how 3D games like Morrowind look on a CRT with anti-aliasing. I vaguely remember playing Oblivion on a CRT, and it must have been quite impressive considering the high refresh rate. obviously Quake 3 looks good at like 240 FPS on a CRT, but even other genres must be significantly smoother

That's an interesting idea, if you added these black horizontal lines, and somehow programmed them into the graphics API, would it result in a decent fps boost? E.g. downscaling from an 8k to 4k resolution due to the black lines? I wonder how'd that work.

 

[Rincewind]

Anyone know if these filters exist on the super nintendo emulator? I got a 4k screen.

They're my custom-tweaked version of Hyllian's single-pass CRT shader. But for NES you need some TV shader, not these. It gets complicated, but these are really tweaked for the characteristics and resolutions of PC CRT monitors.

That's an interesting idea, if you added these black horizontal lines, and somehow programmed them into the graphics API, would it result in a decent fps boost? E.g. downscaling from an 8k to 4k resolution due to the black lines? I wonder how'd that work.

I'm not sure I'm following what you're saying, but all these scaling processes are fixed-cost. Input and output resolution matter only, and that's it. Scaling random noise or a completely black screen will take the exact same amount of processing effort for a given scaling algorithm or CRT shader. They work at a per-pixel level; only the total pixel count matters.

i'm curious how 3D games like Morrowind look on a CRT with anti-aliasing.

They're glorious—that's how I play pre 2010 games these days. I just fired up Gothic and Morrowind on my Win XP + 17" CRT box the other day to do some shader tweaking. 800x600 with forced 8x antialiasing is as good as it gets. But even 640x480 with no antialiasing whatsoever has a certain *feel* that I very much like. Those jagged edges are softened, they aren't as sharp as with integer upscaling on modern flat-screens. Then with proper GPU antialiasing, from 800x600 onwards things look butter smooth.

I never understood in the CRT monitor era why people wanted to play 3D games above 1024x768 at all. 1024x768 or even 800x600 with antialiasing is way better and usually less demanding. More FPS and better visuals.

 

[deama]

They're glorious—that's how I play pre 2010 games these days. I just fired up Gothic and Morrowind on my Win XP + 17" CRT box the other day to do some shader tweaking. 800x600 with forced 8x antialiasing is as good as it gets. But even 640x480 with no antialiasing whatsoever has a certain *feel* that I very much like. Those jagged edges are softened, they aren't as sharp as with integer upscaling on modern flat-screens. Then with proper GPU antialiasing, from 800x600 onwards things look butter smooth.

Is there a way to apply the filter without dosbox? Like some sort of overlay you can place ontop of everything? Maybe some application that hooks onto games or something.

 

[Rincewind]

They're glorious—that's how I play pre 2010 games these days. I just fired up Gothic and Morrowind on my Win XP + 17" CRT box the other day to do some shader tweaking. 800x600 with forced 8x antialiasing is as good as it gets. But even 640x480 with no antialiasing whatsoever has a certain *feel* that I very much like. Those jagged edges are softened, they aren't as sharp as with integer upscaling on modern flat-screens. Then with proper GPU antialiasing, from 800x600 onwards things look butter smooth.

Is there a way to apply the filter without dosbox? Like some sort of overlay you can place ontop of everything? Maybe some application that hooks onto games or something.

Nothing that works really well and reliably that I'm aware of. I'd very much like to be able to do that too.

Well, there's ReShade, of course, but it's fiddly and not really well-suited for adding CRT shader on top of something (complicated...)
https://reshade.me/

 

[schru]

Rincewind, do you have Quake and Quake II on Steam? Night Dive included C.R.T. shaders for the Quake 64 add-on in the former and one for the main game in the latter.

Could you take a look at them and tell us how faithful they are to what they're supposed to emulate? In case of Quake 64 it would be a television set with whatever resolution Nintendo 64 used. And was the default resolution for the first Voodoo card 512x384? Do you have a computer with it?

As for Heretic tracks, I apologize for not coming up with anything so far, but I haven't been feeling well enough to focus on it.

 

[Incognito]

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

Looks amazing! As someone who keeps a CRT connected and a few spares in the attic, I'm looking forward to this. I've used your shader for WinUAE and it's really good (awesome blog post that one).

 

[Rincewind]

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

Looks amazing! As someone who keeps a CRT connected and a few spares in the attic, I'm looking forward to this. I've used your shader for WinUAE and it's really good (awesome blog post that one).

I'm glad you like the WinUAE shaders, man.

Yeah, I have 9 VGA CRTs in the house at the moment, plus one small early 90s TV for the C64 A man gotta have some spares; hopefully, these and my closet full of retro PCs will last me a few more decades until we can fully emulate 1024x768 Windows games from the 1997-2010 era on 8K 1000Hz HDR OLED screens on our 256-core hydrogen-cooled quantum processors... Yeah, using the original hardware is still the superior option for the Windows 98+ / CRT era...

 

[Rincewind]

Rincewind, do you have Quake and Quake II on Steam? Night Dive included C.R.T. shaders for the Quake 64 add-on in the former and one for the main game in the latter.

I had a look at these two videos; yeah, they've done a good job, overall. They're a bit on the caricature side (scanlines are too strong for an SVGA monitor, even at 640x480, and bloom is just *way* over the top, even for a TV), but I think they knew exactly what they were doing. They most likely optimised it for the average gamer and wanted them to go "wow, scanlines!"

https://www.youtube.com/watch?v=l0b7EIEsAxI
https://www.youtube.com/watch?v=s0xurR2exI0

It's a cool effect, but intentionally overdone—real SVGA monitors are a lot subtler. It's still not completely off the mark like many wild CRT shader attempts you can run into on the Internet, just a caricature of the authentic thing.

Could you take a look at them and tell us how faithful they are to what they're supposed to emulate? In case of Quake 64 it would be a television set with whatever resolution Nintendo 64 used. And was the default resolution for the first Voodoo card 512x384? Do you have a computer with it?

Yeah, that's closer to an actual TV.

https://www.youtube.com/watch?v=h0e_0B5Rzgo

Pretty much everybody used 640x480 at 60Hz (yes) with the first-generation of Voodoo cards under DOS. Some variants that had more on-board RAM could do 800x600 too, but at lower FPS, and 640x480 was all you needed anyway on 14-17" CRTs. Then later Voodoo cards people used on Windows 95/98+ supported higher refresh rates and resolutions. I don't have one, btw—I don't care much for those late-90s Voodoo DOS games, I'm an old-school 2D adventure/RPG/strategy gamer.

Oh, by the way, DOSBox Staging has now Voodoo emulation for DOS games in our latest dev build. It will be part of the next official release along with the adaptive CRT shaders.

This is how Quake looks with my shaders in a few different resolutions. I just ran Quake bench quickly (that's what our team uses as the ultimate stress test and to catch performance regressions). The results are definitely subtler and closer to the actual CRT look. At 1024x768 you can't really see the effects of the shaders anymore, unless you zoom in, but they help with some "natural antialiasing". That's how it's in real life; it's really hard to see scanlines and "pixels" from 800x600 upwards even on a 17" CRT. For personal enjoyment, I like to play games at 640x480 with forced anti-aliasing for that reason; it's more fun for me to see those subtle scanlines (unless the UI is too large on 640x480, then I go to 800x600 like in Morrowind and Gothic).


All these are at 4k; open in new window, use 100% magnification:

360x240

640x480

1024x768

As for Heretic tracks, I apologize for not coming up with anything so far, but I haven't been feeling well enough to focus on it.

No problem, I'm busy with a million other things. Once the video-related changes are out of the way, I will tackle adding Sound Blaster AWE32 emulation next. Hopefully, I'll be able to start on that this year.

 

[Rincewind]

For the record, my zero-config PC CRT shaders will be part of the upcoming eXoDOS v6 DOS game mega-collection. eXo, the man himself, gives a nice non-technical rundown on them in his video:

 

[Rincewind]

Very nice and succinct rundown by PhilsComputerLabs on my adaptive CRT shaders that will be part of the next DOSBox Staging release.

Release candidate will come out around December or so, then final release early next year. But you can try the current dev snapshot builds right now (generally, they're pretty stable; it's rare we break something and it stays so for long):

https://dosbox-staging.github.io/downloads/development-builds/

 

[Great Deceiver]

Very nice and succinct rundown by PhilsComputerLabs on my adaptive CRT shaders that will be part of the next DOSBox Staging release.

Release candidate will come out around December or so, then final release early next year. But you can try the current dev snapshot builds right now (generally, they're pretty stable; it's rare we break something and it stays so for long):

https://dosbox-staging.github.io/downloads/development-builds/

Great work, congratulations!

 

[jimster]

What if you're using a lower res screen, like 1080p or even lower like Steam Deck's 800p? Which shaders should you use? Or would they all look crappy and shouldn't bother.

Was thinking you could probably make a good set of CRT filters on something like linux's wayland compositor, it should be easy to create a hook, or probably there's already 3rd party tools that allow you to customize the output of wayland.

Gamescope has Reshade support I guess some would work with that

 

[Rincewind]

What if you're using a lower res screen, like 1080p or even lower like Steam Deck's 800p? Which shaders should you use? Or would they all look crappy and shouldn't bother.

Emulating a single-scanned look on 1080p is perfectly doable and looks very good (so CGA/EGA, home computers and consoles that have 200 to 256 lines of vertical resolution).

Emulating *double scanned* 320x200 VGA, which in reality is 640x400, is not possible on 1080p. You can fudge it and get something acceptable but not great with tricks, though. I'm doing such fakery in my shaders for VGA on 1080p. Naturally, 640x480 or higher is a no-go too (without tricks).

For standard CRT shaders, you need 3 host pixels per emulated scanline at minimum. So for 320x200 VGA double-scanned to 640x400, you need 1200 pixels of vertical resolution at minimum.

 

[Incognito]

Very nice and succinct rundown by PhilsComputerLabs on my adaptive CRT shaders that will be part of the next DOSBox Staging release.

Release candidate will come out around December or so, then final release early next year. But you can try the current dev snapshot builds right now (generally, they're pretty stable; it's rare we break something and it stays so for long):

https://dosbox-staging.github.io/downloads/development-builds/

Tested a couple of Sierra and Lucasart games, also CGA oldies like Sokoban, on a 1440p display. It just works and looks gorgeous. More time playing, less time worrying about configs. Some day when all CRTs are dead, we'll still have this.

 

[tritosine2k]

when all CRTs are dead,

Not a plausible scenario bc. by that time "necking" CRT will be the new craft beer eg. hipsterism. Both thermionic emitter and phosphor faceplate are suitably low tech.

 

[Rincewind]

when all CRTs are dead,

Not a plausible scenario bc. by that time "necking" CRT will be the new craft beer eg. hipsterism. Both thermionic emitter and phosphor faceplate are suitably low tech.

I don't even know what that means, but if CRTs will ever make a comeback, I'm 100% in the target market.

I would pay thousands for mint condition Commodore style 15kHz monitord with ongoing maintenance and parts support.

 

[tritosine2k]

https://www.earlytelevision.org/crt_color_champion.html

...saw on twitter "craft beer drinkers" found out about CRTs during lockdown. Also something something retrotink4k bro

I find it kinda sad because "CRT picture" could be a thing instead as a performance metric.

 

[Incognito]

when all CRTs are dead,

Not a plausible scenario bc. by that time "necking" CRT will be the new craft beer eg. hipsterism. Both thermionic emitter and phosphor faceplate are suitably low tech.

I don't even know what that means, but if CRTs will ever make a comeback, I'm 100% in the target market.

I would pay thousands for mint condition Commodore style 15kHz monitord with ongoing maintenance and parts support.

This. I keep collecting old TVs because even with a scan doubler and a VGA monitor the Amiga doesn't look right. Sharp pixels belong to PCs.

But I'm not counting on a CRT revival anytime soon. Just the logistic nightmare of moving those things around is enough to deter any potential investor/manufacturer.

 

[Hellraiser]

when all CRTs are dead,

Not a plausible scenario bc. by that time "necking" CRT will be the new craft beer eg. hipsterism. Both thermionic emitter and phosphor faceplate are suitably low tech.

Ehh, it's not that simple (copied relevant post to the spoiler below).

tl;dr version is that rebuilding/building a new tube requires a too costly specialist setup, which is probably why even small companies selling "new" CRTs are using old stock tubes from some warehouse for their products.

some guy's long post about how a shadowmask CRT TV was manufactured

The shadow mask and color phosphors are placed with precision equipment. I doubt it will be practical to open the crt to straighten the shadow mask and an impact that either dislodged or deformed the shadow mask would worry me about the safety of the glass.

The phosphor and shadow mask are placed in the front glass tray ( the part of the crt that forms the screen. The bell is attached to the front glass tray with a glass frit. The glass frit and the crt glass has a high lead content to suppress X-Rays that are generated when the electrons impact the shadow mask. The sets made in the last 50 years used a high voltage anode source of 30,000 Volts DC. Once the bell is attached to the tray and the frit is cured, the electron gun assembly is inserted. This again is a precision placement to help insure the scanning of the screen is uniform. Once the gun is inserted the crt is baked in a gas fired oven to boil off residual gases left in the glass, phosphor, and metal parts in the shadow mask and gun.

After a given time, a vacuum is pulled to evacuate the air in the crt down to a pressure of about 1 X 10^-9 Torr. While the vacuum is still being pulled the tube continues to be bakes in an effort to evacuate the remaining few air molecules left inside the crt. Again at a set time, the tube is tipped (sealed) and then allowed to cool down. Once the tube is cooled the neck is inserted into an induction heater which boils a combination of barium, aluminum and other metals which are reactive with differing atmospheric gases. The process is called Gettering as the process 'gets' the residual gas. It will typically pull the pressure inside he crt down to around 1 X 10^-10 torr to 10^-12 torr.

The other part of the process in handling the crt is the aquadag. Look at the outside of the crt bell. Notice the flat grey colored paint. That is a conductive coating that is sprayed on the inside of the bell as well as the outside. The two layers of aquadag form a capacitor which is used to filer the applied high voltage to remove the rectifier ripple. Damage to inside or outside aquadag has to be repaired else you have to use a very expensive capacitor called a "Door Knob" capacitor to filtered the rectified high voltage. A single cap designed to handle 50 KV will run you about $100.00 if you can find one.
When opening the CRT you first have to allow the interior pressure in the crt to rise to standard room air pressure. This has to be controlled. A crack in the glass or breaking off the crt glass were it was tipped usually results in rapid pressurization that disturbs the phosphors on the faceplate and drafts in contaminants that make it almost impossible to rebuild the crt without complete disassembly and through washing of everything.

The contamination problem is so finicky that the ovens have to be electric or natural gas fired as gases such as propane have to much carbon and contaminate the tube during the bakeout. Contaminated tubes often exhibit a symptom of internally arcing rather loudly which consumers did not like.

Just to give you an idea of how critical the glass used in vacuum tubes is, when Sylvania was producing tube by the tend of thousands a day, they bought sand by the hundreds of rail cars on each order. Then lab techs descended on the stored sand, taking samples for lab tests. That data was used by scientists to determine if the sand was suitable for making the glass needed at a cost that did not increase the routine production expenses.

Another issue in making the crts was making a seal around the pins used in the crt. The expansion of the wire was different than the glass. So Dumet wire was developed. Dumet wire has a copper coating around the steel wire. The combined expansion coefficient of the steel and copper in the laminated wire matched the glass close enough the glass seal around the tube pins remained patent and prevent air seeping into the tube for decades.

So can you rebuild that tube? Well yeah, sort of, but you will need to have a good grip on multiple disciplines (mechanical engineering, glass science, metallurgy, chemistry, etc) as well as some very deep pockets to succeed.

My hopium for preserving accurate CRT picture experience is that consumer LPD displays become widespread and amateurs will be able to macgyver mod them to be CRT like*, with custom phosphor masks and replacement control boards for the laser-mirror array, which would accept proper analogue signals.

*similar to how phone and camcorder displays are modded as replacement screens for gameboys, but more involved than that due to the custom phosphor mask.

 

[tritosine2k]

"LPD displays"

That was kind of a swindle because phosphor backscatter is addressed in a CRT with a thin layer of aluminium behind phosphors. And you can't do that without e-beam (penetrates AL). In any case this phosphor stuff is much less important than timing aspect and emulating projection CRT complete with viewing distance. That's why I think it's hipsterism.

Saw the link in my post? This was done with projection CRTs up to 2010 in US.

Oh and projection CRT tubes have colorfilters like LCD, I'm not into that 15khz stuff...

 

[Rincewind]

This. I keep collecting old TVs because even with a scan doubler and a VGA monitor the Amiga doesn't look right. Sharp pixels belong to PCs.

Same here. Amiga + scan doubler looks totally wrong; that's making a double-scanning VGA adapter out of your Amiga, serious decline.

I don't even care for that stuff; my WinUAE shader setup that emulates a C= monitor is superior to any scan doubler + real CRT, or these Amiga HDMI solutions which are terrible, IMO.

 

[Jarpie]

This. I keep collecting old TVs because even with a scan doubler and a VGA monitor the Amiga doesn't look right. Sharp pixels belong to PCs.

Same here. Amiga + scan doubler looks totally wrong; that's making a double-scanning VGA adapter out of your Amiga, serious decline.

I don't even care for that stuff; my WinUAE shader setup that emulates a C= monitor is superior to any scan doubler + real CRT, or these Amiga HDMI solutions which are terrible, IMO.

I used 1084s monitor with RGB on my Amiga for a long time. That monitor is great 14" crt video monitor, superior to any TV I've seen of similar size.

 

[Rincewind]

This. I keep collecting old TVs because even with a scan doubler and a VGA monitor the Amiga doesn't look right. Sharp pixels belong to PCs.

Same here. Amiga + scan doubler looks totally wrong; that's making a double-scanning VGA adapter out of your Amiga, serious decline.

I don't even care for that stuff; my WinUAE shader setup that emulates a C= monitor is superior to any scan doubler + real CRT, or these Amiga HDMI solutions which are terrible, IMO.

I used 1084s monitor with RGB on my Amiga for a long time. That monitor is great 14" crt video monitor, superior to any TV I've seen of similar size.

Yep, I used to have the Philips CM8833 and used it via RGB with my Amiga. That's effectively the same monitor with slightly different controls; Philips was one of the manufacturers who produced the 1084. I even hooked up a VHS then a TV tuner to it, it was a *really* high quality small TV, effectively, but without the tuner.