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No CRT Emulation? Why!?

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Reply 140 of 162, by Mr_Blastman

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CM-5 RGB emulation is getting closer. I'm working on tweaking little nuances:

ZRKHTpi.jpg

Unfortunately my monitor is not high enough resolution(1920x1080) to use curvature without severe moire patterns, which detract from 16 color scenes.

I have achieved proper excessive brightness, but cannot refine the pinpoint brightness of each individual pixel without more resolution. The pixels on the real CM-5 resemble a sun behind black construction paper with a pinhole poked through. They are quite striking.

Also, it is funny to play VGA games using this setting. They absolutely do not look right! As they would on the real thing, too, the monitor simply wasn't made for more than 16 simultaneous colors.

Speaking of VGA, here is another picture of my latest VGA tweaks:

vfhERoE.jpg

The whole purpose was to move from the older system of overlays to the newer, active bezel system that the MEGA Bezel shader packages provide.

Reply 143 of 162, by rucuk0kt

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Mr_Blastman wrote on 2023-03-17, 03:37:
I continue to tweak for further clarity and proper graininess. […]
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I continue to tweak for further clarity and proper graininess.

zHrgeRW.jpg

I think the results are getting closer to a real CM-5, despite the inadequate resolution for proper justice.

It looks great.
Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-)

  • Black is not black in a lit room
  • The shadow mask is slightly visible in black areas
  • The CRT and the frame alignment isn't so perfect (slightly angled and much larger border)
  • The CRT isn't flat

Reply 144 of 162, by Jo22

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rucuk0kt wrote on 2023-03-18, 18:04:
It looks great. Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-) […]
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Mr_Blastman wrote on 2023-03-17, 03:37:
I continue to tweak for further clarity and proper graininess. […]
Show full quote

I continue to tweak for further clarity and proper graininess.

zHrgeRW.jpg

I think the results are getting closer to a real CM-5, despite the inadequate resolution for proper justice.

It looks great.
Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-)

  • Black is not black in a lit room
  • The shadow mask is slightly visible in black areas
  • The CRT and the frame alignment isn't so perfect (slightly angled and much larger border)
  • The CRT isn't flat

Just asking because of curiosity: Is it a bright black, as seen in those screenshots by any chance?

https://www.vintagecomputer.net/tandy/cm-5/

I'm not very familiar with this monitor model, hence I looked for photos online. 😅

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 145 of 162, by rucuk0kt

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Jo22 wrote on 2023-03-18, 21:00:
Just asking because of curiosity: Is it a bright black, as seen in those screenshots by any chance? […]
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rucuk0kt wrote on 2023-03-18, 18:04:
It looks great. Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-) […]
Show full quote
Mr_Blastman wrote on 2023-03-17, 03:37:
I continue to tweak for further clarity and proper graininess. […]
Show full quote

I continue to tweak for further clarity and proper graininess.

zHrgeRW.jpg

I think the results are getting closer to a real CM-5, despite the inadequate resolution for proper justice.

It looks great.
Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-)

  • Black is not black in a lit room
  • The shadow mask is slightly visible in black areas
  • The CRT and the frame alignment isn't so perfect (slightly angled and much larger border)
  • The CRT isn't flat

Just asking because of curiosity: Is it a bright black, as seen in those screenshots by any chance?

https://www.vintagecomputer.net/tandy/cm-5/

I'm not very familiar with this monitor model, hence I looked for photos online. 😅

Yes, my CM-5 looks about the same if the room lighting is on.
The CM-5 in those images is a 25-1043A from may 1988. Mine is a 25-1043B from august 1990, which has just the text 'TANDY CM-5' on the front.
I tried to take some pictures, but failed at creating good ones. I found some nice ones on twitter by Pinot W. Ichwandardi: https://twitter.com/pinot/status/1425872343457533959
The first photo is of a CM-5 like mine. It shows the problem with black. I've attached a small section from the photo:

cm-5.png
Filename
cm-5.png
File size
76.17 KiB
Views
924 views
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Example from https://twitter.com/pinot/status/1425872343457533959/photo/1
File license
Fair use/fair dealing exception

After examining the photo, I believe my previous statement 'The shadow mask is slightly visible in black areas' is wrong. The dark areas are showing vertical lines and the lighter lines might be the areas with phosphor.
The image also has an area with black and white checkerboard pattern. The black pixels are much less visible that the white pixels and some pixels are discolored.

Edit: I used a different camera and was able to take a picture of the vertical r/g/b lines. The colours in that picture are off, but that's a camera issue:

cm5-1.jpg
Filename
cm5-1.jpg
File size
560.75 KiB
Views
865 views
File comment
Vertical phosphor lines
File license
Public domain

I've added another picture that has more accurate colours but no vertical lines:

cm5-2.jpg
Filename
cm5-2.jpg
File size
714.05 KiB
Views
865 views
File comment
More accurate colours
File license
Public domain

My CM-5 is even worse than I remembered. I counted only 19 phosphor groups per cm in horizontal and vertical direction, so that's about 0.52 mm dot pitch.

Last edited by rucuk0kt on 2023-03-24, 17:46. Edited 1 time in total.

Reply 146 of 162, by Mr_Blastman

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rucuk0kt wrote on 2023-03-18, 18:04:
It looks great. Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-) […]
Show full quote
Mr_Blastman wrote on 2023-03-17, 03:37:
I continue to tweak for further clarity and proper graininess. […]
Show full quote

I continue to tweak for further clarity and proper graininess.

zHrgeRW.jpg

I think the results are getting closer to a real CM-5, despite the inadequate resolution for proper justice.

It looks great.
Not suggesting that you should change it, but my crappy CM-5 has some flaws that your image does not have;-)

  • Black is not black in a lit room
  • The shadow mask is slightly visible in black areas
  • The CRT and the frame alignment isn't so perfect (slightly angled and much larger border)
  • The CRT isn't flat

All great observations and suggestions! Thank you.

The flat part bothers me the most because at the moment I cannot use curvature or there will be severe artifacting of the image. I need a higher end monitor to get more resolution for this. I'd love to improve here.

The phosphors distinct on the CM-5. Mine has vertical grey lines that are definitely visible when off, and midly so when on. That will be more difficult to produce.

Thanks for the photos, they are excellent and very helpful. 😀

At the moment my Tandy 1000's 20 megabyte hard drive has decided to stop working, so the only thing I can do with the machine is boot up into Deskmate. I can't even play games. 🙁

I'm wondering if there's a way to hook up a USB stick through a port in the back, similar to what folks do on Amigas and C64s.

Reply 147 of 162, by rucuk0kt

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Mr_Blastman wrote on 2023-03-21, 02:24:

The phosphors distinct on the CM-5. Mine has vertical grey lines that are definitely visible when off, and midly so when on. That will be more difficult to produce.

On my picture the r/g/b line colours are visible, but they look grey to me with the naked eye.

Mr_Blastman wrote on 2023-03-21, 02:24:

At the moment my Tandy 1000's 20 megabyte hard drive has decided to stop working, so the only thing I can do with the machine is boot up into Deskmate. I can't even play games. 🙁

I'm wondering if there's a way to hook up a USB stick through a port in the back, similar to what folks do on Amigas and C64s.

Maybe use a GoTek USB Floppy Emulator if you only use programs that fit on floppy. Should work on a Tandy, but may require some modifications for some models / floppy cable types, because those have different wiring (e.g. dangerous 12V power). Note that I've not tried it myself.

Reply 148 of 162, by Mr_Blastman

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rucuk0kt wrote on 2023-03-24, 18:11:
On my picture the r/g/b line colours are visible, but they look grey to me with the naked eye. […]
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Mr_Blastman wrote on 2023-03-21, 02:24:

The phosphors distinct on the CM-5. Mine has vertical grey lines that are definitely visible when off, and midly so when on. That will be more difficult to produce.

On my picture the r/g/b line colours are visible, but they look grey to me with the naked eye.

Mr_Blastman wrote on 2023-03-21, 02:24:

At the moment my Tandy 1000's 20 megabyte hard drive has decided to stop working, so the only thing I can do with the machine is boot up into Deskmate. I can't even play games. 🙁

I'm wondering if there's a way to hook up a USB stick through a port in the back, similar to what folks do on Amigas and C64s.

Maybe use a GoTek USB Floppy Emulator if you only use programs that fit on floppy. Should work on a Tandy, but may require some modifications for some models / floppy cable types, because those have different wiring (e.g. dangerous 12V power). Note that I've not tried it myself.

Somehow I removed some artifacts and now we have the gap between the bezel and the image, as is on the real monitor. I also am working on scaling the size to match the actual monitor 1:1 on my 27 inch display(which should look the same on a 32:9 as well if centered and not stretched).

sDw76uF.jpg

Reply 149 of 162, by sliderider

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So if someone does emulate it, will we get glare from sunlight through the windows behind us, or lamps and light fixtures around the room, like we did with CRT's? That is so distracting, and I say no. Good riddance to CRT's.

Reply 150 of 162, by dormcat

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sliderider wrote on 2023-04-01, 01:14:

So if someone does emulate it, will we get glare from sunlight through the windows behind us, or lamps and light fixtures around the room, like we did with CRT's? That is so distracting, and I say no. Good riddance to CRT's.

It's like the CRT filter function of NES / SNES Classic: it was actually a defect caused by RF signal degradation (develepers, professional reviewers, and really rich kids bought Sharp C1 / SF1 to avoid this defect) but it became an nostalgic, emotional element so it had to be recreated on those Classic remakes via emulation.

Reply 151 of 162, by leileilol

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FWIW the SNES classic doesn't have the signal effect, just the NES classic. Likewise either Genesis Mini don't have a proper composite blur effect either to deal with the designed jailbar dithering it's known for, and I should remind that NTSC signal artifacts defects are not CRT effects (you can also get these on capture cards, TFTs, etc)

Actual NTSC NES however is a huge YMMV due to color encoding vs various TVs. NES emulators have varying palettes because of it.

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Reply 152 of 162, by xcomcmdr

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sliderider wrote on 2023-04-01, 01:14:

So if someone does emulate it, will we get glare from sunlight through the windows behind us, or lamps and light fixtures around the room, like we did with CRT's? That is so distracting, and I say no. Good riddance to CRT's.

But, a CRT for DOS games is so much better than a TFT screen... It looks like it should, especially (some) pixel art.

Reply 153 of 162, by Jo22

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sliderider wrote on 2023-04-01, 01:14:

So if someone does emulate it, will we get glare from sunlight through the windows behind us, or lamps and light fixtures around the room, like we did with CRT's? That is so distracting, and I say no. Good riddance to CRT's.

Some CRTs had anti-glare coating, I belive to remember. They've been used in professional/commercial sector.
Optional, attachable filters also were available. Their main purpose was to filter x-ray radiation, I believe.

Glossy LCD/TFT panels also exist. Most consumer types belong into that category, I believe.
They have the same problem with sun light. Not only reflections, but also dim brightness issues.

Like with CRTs, professional/commercial LCD/TFT panels are anti-reflective.
But for some reasons, they're apparently not as popular as the glossy type. Not sure why. 🤷‍♂️

Edit: Found a matching YT video.

CRT Monitor Anti-Glare, Anti-Radiation Filters. Unboxing and Usage with Retro Computers

https://www.youtube.com/watch?v=grqgQVSTPO8

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 154 of 162, by Mr_Blastman

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Yes, some monitors from the 1980s and 90s had anti-glare coatings on them. They actually altered the image on screen, somewhat, too! This is especially noticeable on IBM's PS/1 and PS/2 monitors, as a "glinting sheen" of the image. Hard to describe unless witnessed in person. In a way, these coatings seemed to dull an image--not in brightness, but softened the actual light being emitted, as well as reflected. The same applies of sorts to LCD/LED monitors with an anti-glare coating. My long time glossy monitor I chose for purity of color emission, but my newer G9(with anti glare coating) has a higher bit depth so the color produced is even better than this 90% NTSC gamut screen(which has visual color distortion flaws in some text situation similar to that of an Apple IIe on a composite monitor).

I wouldn't mind an option to emulate this glare, and I believe the mega bezel crew are working on such an adjustable feature.

Reply 155 of 162, by Jo22

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Mr_Blastman wrote on 2023-04-02, 15:22:

I wouldn't mind an option to emulate this glare, and I believe the mega bezel crew are working on such an adjustable feature.

I feel the same here. If it's optional, no harm is done.
But to those who want to relieve or experience the old days, it would be really cool. 😎
It may sound a bit cheesy, but future generations (including future us) will be grateful about that extra work.
Because now the real monitors for comparison are still available.
Just like VHS tapes and CDs were all around us in daily life +20 years ago.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 156 of 162, by Deffnator

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Mr_Blastman wrote on 2023-03-30, 07:37:
Somehow I removed some artifacts and now we have the gap between the bezel and the image, as is on the real monitor. I also am […]
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rucuk0kt wrote on 2023-03-24, 18:11:
On my picture the r/g/b line colours are visible, but they look grey to me with the naked eye. […]
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Mr_Blastman wrote on 2023-03-21, 02:24:

The phosphors distinct on the CM-5. Mine has vertical grey lines that are definitely visible when off, and midly so when on. That will be more difficult to produce.

On my picture the r/g/b line colours are visible, but they look grey to me with the naked eye.

Mr_Blastman wrote on 2023-03-21, 02:24:

At the moment my Tandy 1000's 20 megabyte hard drive has decided to stop working, so the only thing I can do with the machine is boot up into Deskmate. I can't even play games. 🙁

I'm wondering if there's a way to hook up a USB stick through a port in the back, similar to what folks do on Amigas and C64s.

Maybe use a GoTek USB Floppy Emulator if you only use programs that fit on floppy. Should work on a Tandy, but may require some modifications for some models / floppy cable types, because those have different wiring (e.g. dangerous 12V power). Note that I've not tried it myself.

Somehow I removed some artifacts and now we have the gap between the bezel and the image, as is on the real monitor. I also am working on scaling the size to match the actual monitor 1:1 on my 27 inch display(which should look the same on a 32:9 as well if centered and not stretched).

sDw76uF.jpg

I know that this is retroarch stuff, but is still hope for X or ECE to add 1080p + bezel shaders like this.

i remember my 1st CRT screen being smooth for pixel dos games and early snes/megadrive genesis Emulators with bilinear.

Reply 157 of 162, by VileR

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Yeah, it'd be nice to have these shaders accessible outside of a specific library's "walled garden" so to speak.

Someone has ported crt-royale from libretro to ReShade (https://github.com/akgunter/crt-royale-reshade), so I suppose this should be possible. Haven't tested it yet, but I've been thinking of trying to port some features from my ffmpeg-based CRT script to something that gives more real-time results... so that could be a good starting point.

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Reply 158 of 162, by superfury

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Just a little question: is it possible to make shaders that don't need to be recompiled for each new platform and can be exchanged between emulators (so something that can be parsed by simply adding some files to any possible platform and rebuild of the emulator (or at least the ones supported by SDL/SDL2))? Something that's cross-platform by design without requiring any extra libraries (only using SDL/SDL2)?
Perhaps some kind of text file containing a shader script that can be loaded and used on any SDL/SDL2 platform?

Last edited by superfury on 2023-05-06, 10:54. Edited 1 time in total.

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Reply 159 of 162, by Deffnator

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VileR wrote on 2023-05-03, 16:15:

Yeah, it'd be nice to have these shaders accessible outside of a specific library's "walled garden" so to speak.

Someone has ported crt-royale from libretro to ReShade (https://github.com/akgunter/crt-royale-reshade), so I suppose this should be possible. Haven't tested it yet, but I've been thinking of trying to port some features from my ffmpeg-based CRT script to something that gives more real-time results... so that could be a good starting point.

there is a updated version of royale reshade on github
i forgot the link