Its possible to use CRT shaders on DOSBOX of late thanks to Dosbox ECE and X supporting it, also reshade got a boost with more CRT shaders from retroarch being backported like royale, and i think crosire is working on making its support better for the next major update.
seeing them ported to it and even working on DBGL if it gets a shader update for it, would be the perfect mix.

Also
https://github.com/tyrells/dosbox-svn-shaders and https://krystof.io/dosbox-shaders-comparison- … s-retro-gaming/

I wish someone would start a DOSBOX for with these shaders.. I want to use this but I am too lazy to get ECE and set this up myself 🤣

appiah4 wrote on 2021-10-12, 06:25:

I wish someone would start a DOSBOX for with these shaders.. I want to use this but I am too lazy to get ECE and set this up myself 🤣

And I wished someone would integrate cool-retro-term into DOSBox.
Would definitely improve the visuals of Hercules emulation.
- And monochrome CGA, too. Some XTs had on-board CGAs with an RCA connector installed at the back that carried Luma only.

Source: https://steemit.com/technology/@crypticwyrm/c … macos-and-linux

Proper early monochrome CGA/Hercules requires ghosting, too. Those displays sometimes had a minor but noticeable delay of the phosphors.

That retro term is nice but is missing emulation of the individual pixels and phosphors within, which would create a grainy grid-like effect.

Mr_Blastman wrote on 2021-10-18, 19:16:

Proper early monochrome CGA/Hercules requires ghosting, too. Those displays sometimes had a minor but noticeable delay of the phosphors.

That retro term is nice but is missing emulation of the individual pixels and phosphors within, which would create a grainy grid-like effect.

Hm, okay. I do have a few green/amber monitors stored in the attic (bas and mda/ttl) ..
From what I remember, in the default config, coolretroterm is a bit too excessive with the effects by comparison, even:
The physical devices are much more crisp (very tiny, grainy pixels visible) and the afterglow more subtle, as you said.
And there are no moving scan lines and wobble effects, as seen in coolretroterm.
The backgrounds are not glowing, either, unless brightness is turned up way too much.

Edit: I have no time for testing at the moment, sadly, but these monitors can be seen in some of my older videos:
https://www.youtube.com/channel/UCM_rzw6WcXib … y=green%2Bamber

That being said, what cool-retro-term does fine is that "bloom" and glow effect.
I think that's one of the features that provide that mono CRT feel.

Edit: Vids must be watched in 1080p, unfortunately. Those monitors were meant for professional use and draw very fine structures.

Mono monitors don't have a pixel grid like a color monitor, just the entire back of the glass is phosphor and it lights where the beams hit. The pixels are a spot of diminishing brightness from the center so in a block are evenly lit. You'll only see signs of pixellation in single lines (As most non bold characters are) and along edges, and then it will be indistinct.

BitWrangler wrote on 2021-10-18, 20:50:

Mono monitors don't have a pixel grid like a color monitor, just the entire back of the glass is phosphor and it lights where the beams hit. The pixels are a spot of diminishing brightness from the center so in a block are evenly lit. You'll only see signs of pixellation in single lines (As most non bold characters are) and along edges, and then it will be indistinct.

Yes, that matches what I learned - mono CRTs have no mask.
It makes sense, because it's just one tube that does its magic.
That's why I love old b/w tv sets, too, btw. They are more blurry for several reasons (focus etc), but equally "pure".
The Composite signal (CVBS) we all have a love/hate relationship with is based on the VBS signal, for example, which is just luma (brightness), sync and blanking combined.
Which in turn can natively be processed by a single mono CRT tube. Or a classic two oscilloscope.
- It kinda makes me sad that people forget that the human eye also has rods for gray information, besides the green (4), blue (2), red (2) related cones.

Btw, there's a special use case: Slow Scan TV (SSTV).
It was based on radar screens based on P7 (?) which has an afterglow of 7-8 secs.
Some people used old oscilloscope for that, they simply swapped the CRT for a 7 sec model.
That's essentially what cool-retro-term without knowing tries to emulate in default configuration. 😁

https://www.taswegian.com/NBTV/forum/viewtopi … t=2832&start=15

Getting that organic glow is hard, but you're right, is far more subtle on real tubes vs. your screenshot.

I came closest I think in Reshade using the multipass adjustments and stacking shaders:

https://www.youtube.com/watch?v=HIkB7lapnTg&t=28s

But that is television tube simulation. Youtube and video compression makes it impossible to record properly--the real picture on my screen is no where near as "dotty" and grainy and very convincing.

Maybe you guys could get a few ideas from my non-realtime (video processing only, no shaders) attempts at color/mono CRT simulations.

https://www.youtube.com/watch?v=oMibMBPSO-o (various color CRTs)
https://www.youtube.com/watch?v=DGAt3Y6Pxn4 (various mono CRTs)
https://www.youtube.com/watch?v=sZdc655YefA (bonus: oldschool flat panels)

The actual script has been improved since those videos, especially the first one, so what you see there are not the 'best' possible results but all parameters are tweakable (phosphor decay time, brightness, curvature, shadow mask type/size etc.)

VileR wrote on 2021-10-22, 09:59:

Maybe you guys could get a few ideas from my non-realtime (video processing only, no shaders) attempts at color/mono CRT simulat […]
Show full quote

Maybe you guys could get a few ideas from my non-realtime (video processing only, no shaders) attempts at color/mono CRT simulations.

https://www.youtube.com/watch?v=oMibMBPSO-o (various color CRTs)
https://www.youtube.com/watch?v=DGAt3Y6Pxn4 (various mono CRTs)
https://www.youtube.com/watch?v=sZdc655YefA (bonus: oldschool flat panels)

The actual script has been improved since those videos, especially the first one, so what you see there are not the 'best' possible results but all parameters are tweakable (phosphor decay time, brightness, curvature, shadow mask type/size etc.)

For my part, I've pointed cgwg, the MAME contributor who created a few of MAME's shaders, at your Github. Hopefully that will be enough to prod him into seeing if there's anything more he can do with his shader "crt-geom-deluxe", but he is pretty inactive these days, so we'll see. He did tell me that he would love to have the time to do a write-up just like you did, though!

probably the worst part of crt emulation with regards to PCs is:

- the moral dilemma of recreating any out-of-sync effects as it's technically flashing and can be extremely inconsiderate. Modern CRTs would politely blank the screen.
- the loud revisionism of no Trinitron and other 'trons (there were quite a few available by the mid-90s and I had one then)
- with the mask and/or scanlines, the moire you'll get at higher resolutions (i.e. 1024+) vs. common 1080p screens (I tried to do hack a temporal jiggle about that, I know royale does something else with a box filter)
- the lack of overscan emulation (left out due to old OS/video driver/API limitation reasons) means your text modes get cut off and some games can't color in borders. (however, there are some real old monitors like that)
- you'd also need to shader the vga output before that, color pollution, and maybe a simple lighten-blended motion blur pass prior to CRT in order to fake phosphors.
- CRT TVs are also still relevant to the experience 😀 Gateway Destination comes to mind. It's not a crime to throw a NTSC shader in the mix for that (but also have a blur/filter shader before that, as many video cards sporting TV out tried their best to reduce flickering)

leileilol wrote on 2021-10-29, 08:08:

- the moral dilemma of recreating any out-of-sync effects as it's technically flashing and can be extremely inconsiderate. Modern CRTs would politely blank the screen.

Sounds like a very made up 'moral' dilemma... an out-of-sync signal doesn't cause flashing in itself, and it's not like displays are trying to do any sort of flashing-mitigation otherwise. Blanking the screen when sync is bad is necessary either to protect sensitive components that might be damaged, or (with digital video signals) because sync timing becomes necessary to determine positioning, scaling etc. I don't believe that has anything to do with politeness.

- with the mask and/or scanlines, the moire you'll get at higher resolutions (i.e. 1024+) vs. common 1080p screens (I tried to do hack a temporal jiggle about that, I know royale does something else with a box filter)

Yep, that's a problem, but it can also be mitigated by oversampling by say 4x or 8x before applying mask/scanlines/curvature. Major speed hit of course, but maybe not a problem with recent GPUs?

Hello everyone.
I hope you don't mind for "resurrecting" this topic/thread in 2022.
I just want to say that you're awesome and that it's nice discussing these things here! 😎👍

PS: I came across another interesting type of CRT device. The Tektronix 4010 series.
https://en.wikipedia.org/wiki/Tektronix_4010

While these don't have any relevance in gaming (DOS, arcade etc),
especially since they are terminal devices based on vector graphics,
they do partially kind of have a relationship with CRT emulation..
https://www.youtube.com/watch?v=IztxeoHhoyM

(Thing is, such early professional monochrome monitors did tend to be razor sharp - almost LCD or VFD like, but more organic..
So not quite Fallout style. More lika a traditional oscilloscope.)

There's an emulator called "Tek4010", which does simulate ghosting/the bright glowing spot of such a radar screen.
Maybe it can also be used at some point to enhance emulation of, say, the IBM 5151, not sure.
https://github.com/rricharz/Tek4010

Similar screens (ppi scope; radar display tubes) had been used with the DEC PDP-1 (Space War game).
https://en.wikipedia.org/wiki/PDP-1
https://www.youtube.com/watch?v=MvGzAvNLcew

Edit: I'm looking forward Sony Trinitron emulation, too.
My father had one of such TVs in the late 80s/ early 90s, I think.
Unfortunately, I didn't have one myself, though.
I used to be an owner of a Commodore 1702, however.
The screen wasn't great, but above the average TV set of the time.

Btw. Recently, I found this article, also.
Apparently, RCA monitors had quite good picture tubes, as well.
It's amazing, I think, how much "new" things we can still learn about CRTs.. 😀
https://lowendmac.com/2019/rca-mm36100-amazin … er-crt-display/

The journey continues...

Ghosting is important for proper 80s era RGB CRTs, particularly the Tandy CM-5 color monitor. They were unrefined beasts, but produced beautiful images for 16 color games.

And of course, there's 80s VGA monitors, too, for those of us fortunate enough to have one at the time...

I may tone down the glow slightly, but the 80s era ones had some quirks that even the early 90s VGA monitors managed to overcome.

The above require MegaBezel shaders for the Vulkan enabled version of libretro DOSBox-core within Retroarch, available on Steam. Once you have the up to date shaders, you must then install TheNamec's Commodore pack. A few presets are attached to this post, one for Tandy, the others for VGA. Enjoy. 😀

Megabezel shader thread:
https://forums.libretro.com/t/mega-bezel-refl … d-updates/25512

TheNamec's pack:
https://github.com/TheNamec/megabezel-commodore-pack

I still have a lot of work refining the VGA preset--doesn't quite match my 1.7.3 preset I have been using for the past couple of years.

Yah in pondering a Wing Commander setup, I was thinking about digging out and dusting off a late 80s "fishbowl" just because it softens up those scenes nice. Seeing every pixel as a clear distinct square kind of ruins the art. Kinda like viewing a perfectly done stop motion animation scene through a dirty window, "clean the window, clean the window!" everyone yells, but that destroys the illusion completely. I particularly notice it in things like Lemmings or The Settlers, where on CRT they could be little lego people far away, but LCD makes it abundantly clear that a face or foot etc is but a single square block. Then you're watching a square block flash from side to side, and not a tiny being far off.

^I couldn't have put it better myself.

That's exactly what I experienced in the 90s with my old IBM PS/2 monitor.
Unfortunately, I didn't realize at the time what I had.

Often when thinking about the times gone by, I really miss that ugly little VGA monitor.. 😢

Edit: And I played both Lemmings and Wing Commander on that monitor.
The blurriness really made things look more real, as said.
Simultaneously, VGA in 640x480 looked smooth, however.
I can't remember having had headaches or eye strain from my Windows 3.1 sessions.
The Windows fonts didn't look pixelated, either. Just "normal".

Edit: Judging by the size, it could have been an IBM Model 8513 or 8514..
Edit: Here's a picture of a similar looking IBM monitor, showing OS/2 desktop and a chess game ..
Edit: Fun fact: The IBM PGC's monitor was the precursor to the VGA monitor as we know it. PGC was what VGA should have been, IMHO.

PS: @Mr_Blastman Thank you, too, for the pictures, of course! They're awesome (U2)! 😎 👍

Those PS/1 and PS/2 monitors were sublime. They had a "sparkly" sheen to them that only IBM color monitors had. Hard to describe unless you saw one, but the sparkle was real. They had a softness to the image, particularly the prompt text, that was quite pleasing. Wing Commander and even MCGA games such as Silpheed looked great on them.

Mr_Blastman wrote on 2023-02-23, 20:40:

Those PS/1 and PS/2 monitors were sublime. They had a "sparkly" sheen to them that only IBM color monitors had. Hard to describe unless you saw one, but the sparkle was real. They had a softness to the image, particularly the prompt text, that was quite pleasing. Wing Commander and even MCGA games such as Silpheed looked great on them.

I fully agree! 😃

Essentially, these early IBM VGA monitors had the same status/value as a Commodore 1702/1902 or Atari SM124.

The picture quality was as you said, I remember that the characters of the C:\> prompt looked absolutely clean.
Same goes for Norton Commander, it looked nicely readable - soft, but not smeary by any means.

Edit: Here are some photos that give an idea.
http://trelohra.blogspot.com/2015/07/ibm-ps2-77i.html
(They're not taken by me.)

Windows 3.1 and 2.03 looked fine, too. Same goes for PC booter games, I recall.
Though they used the CGA simulation of my ATI VGA Wonder.
Commander Keen IV looked absolutely beautiful on this monitor, by the way.
Almost like a Super NES game, if I may let my younger self speak about the matter.

All in all, I really hope there will be a filter/shader some time that resembles an IBM PS/1 or PS/2 monitor.

It's not perfect by any means, but it provides an alternate view on the games we love so much.
Maybe the game designers even had these old monitors in use at some point, who knows.

Together with a Raspberry Pi, maybe in tandem with that other project over here, it would be possible to simulate such an IBM monitor on an PC flat-screen or any other monitor.
That way, physical PC systems of that era could get their VGA monitor back.

Maybe the resulting image will be even cleaner than the real thing,
because the RF noise on the VGA cable would be missing.

Akin to an idealistic version of a Composite signal versus an a real, physical version.
Anyway, making an image worse isn't difficult, so that noise could be simulated at one point.

Edit: @Mr_Blastman That being said, your work already comes quite close to the IBM monitor! And playing Wing Commander that way is in no way less fun than with the IBM monitor! 😃👍

It's just.. that the CRT mask of the IBM series was different, somehow. Lower end, maybe.
Don't know how to explain.. It's been so long. If I only had my old monitor for comparison, still. Anyway, I'm just thinking out loud, essentially. Sorry for talking/thinking so much. 😅

There was just enough phosphor dwell on those PS/2 monitors to take the sting out of interlace flicker at 1024x768 too. There used to be so many of them around that they were the cheapest VGA to get hold of refurbished through mid-late 90s.

BitWrangler wrote on 2023-02-24, 02:47:

There was just enough phosphor dwell on those PS/2 monitors to take the sting out of interlace flicker at 1024x768 too.
There used to be so many of them around that they were the cheapest VGA to get hold of refurbished through mid-late 90s.

That makes sense. I got both that 286 and the monitor second hand from a company liquidation, afaik.
The 286 was stripped from all hardware except floppy/mainboard+cpu and power supply.
I still remember how my father and me stood in the building's stairwell, with all that scrap pile in front of us.
Back then, I had to choose from two monitors. A pretty rounded one and the ugly duck (guess which one's that).
Luckily, my father told me that the pretty one might be monochrome model (maybe he saw it because of missing pins on the connector, not sure).

Anyway, so we got the IBM and the rest was history. The monitor was more reliable that the PC, even, perhaps.
At least in 640x480 Standard VGA. Haven't tried Super VGA, I believe. Not sure if it was multi-sync, at all.
Maybe just dual sync, which required manual calibration after mode switch.
Both IBM monitor's flyback transformer and its PSU worked flawlessly all the years, unlike the weak ~120w model of the 286.

Personally, I could tell so many stories about such things.. 😁
But that belongs in another thread. I don't mean to get on all your nerves any longer.
My apologies for those long postings of mine.
I try my best to keep them short, but somehow they end up always being so long. 😅