4 ms·

Some CRTs do have visible scanlines, some do not. Check out this thread https://shmups.system11.org/viewtopic.php?f=6&t=63197 https://shmups.system11.org/viewto

by Asooka 4y ago

Some CRTs do have visible scanlines, some do not. Check out this thread https://shmups.system11.org/viewtopic.php?f=6&t=63197 https://shmups.system11.org/viewtopic.php?f=6&t=63197 . Personally I'd like the simulated CRT to have no scanlines, rather what I want is temporal ghosting (previous frame blending in the next one, used for transparency effects in games by blinking two images rapidly); and a filter to make pixels less blocky and implement colour bleed. Given the great number of CRTs out there you probably can't have a single one be the best ever, but perhaps emulating several known ones by twiddling the parameters of the shader and letting people pick would be the best.

jeroenhd 4y ago
When I look at CRT emulation, I always feel like I'm going crazy. It's been years since I last saw a CRT image but I don't remember visible scanlines at all. I know the retro space is often specifically emulating old hardware, was thing a thing in the 80s, perhaps? Or were visible scanlines more common in America than in Europe? I know the weird colours and lowered resolution of some (emulated) games are an artifact of differences in NTSC/PAL/etc., could that explain the difference?
- jerf 4y ago
  They seem obsessed with simulated really bad CRTs. I think you could see such scanlines if you were hooking up your Atari 2600 to a TV that was already a decade old, then sat right on top of it instead of across the living room because the cords were short and you wanted to see your games. I've seen it on some arcade games, for similar reasons. But in general, CRTs didn't have those plainly obvious lines, no, because... the engineers would have engineered them out! And did. They're plainly unsightly and it isn't that hard to remove them, after all. I imagine part of it is the need to have visible differences strongly emphasized so it looks like the filters are doing something. A true CRT filter would be much more subtle and people might not thing anything has happened when you turn it on.
  - orbital-decay 4y ago
    >They seem obsessed with simulated really bad CRTs. ... I imagine part of it is the need to have visible differences strongly emphasized so it looks like the filters are doing something. The main reason for that is that games of the era were targeted at the most common hardware, using very cheap composite circuits and CRTs as medium for artistic expression. In many games, you could easily miss gradients, rainbow effects, transparency, or something else with a high-end CRT.
    - Asooka 4y ago
      That seems pretty far-fetched. Do you have examples of such effects being shown wrong on CRTs without scanlines?
      - doubled112 4y ago
        I don't think they're referring to scanlines specifically. Something like the waterfalls in Sonic the Hedgehog come to mind. https://gamedev.stackexchange.com/questions/167804/did-retro-pixel-artists-design-with-crts-in-mind https://gamedev.stackexchange.com/questions/167804/did-retro... There's an image on this page. The waterfalls don't look very good with sharp pixels. A CRT would blur and blend, and you'd have to assume the game designers knew it would happen. It's probably not just a happy accident.
      - speeder 4y ago
        doubled112 comment is excellent. Another example that is harder to show, is that many games used intentional flickering or other tricks to create some funky effects only possible with CRT. For example: if you transmit the data correctly (one frame is only odd lines, next frame only even lines) and flicker sprites at certain speeds, you can achieve some fancy transparency and overlay effects. Another trick is toy with timings to screw with resolution, color range and pixel shape. A less reliable trick is sub-pixel anti-alias relying on the TV geometry, since each manufacturer had their own patented geometry this was more problematic (for example Sony's Trinitron was aperture grille, each pixel was composed of columns of each color. Many other manufacturers went for triangular pixels instead. With the 3 primary colors arranged as round dots in a triangular pattern).
- 323 4y ago
  Really really old monitors had visible scan lines, like before 1985 or so: https://i.redd.it/o6gezzyw8dv61.jpg https://i.redd.it/o6gezzyw8dv61.jpg
- ogurechny 4y ago
  It could be the opposite. Big high resolution multisync CRT monitors had to have fine dot pitch and finely focused beam. However, in lower resolutions the distance between scanlines was more noticeable, as there was limit to how wide and powerful electron beam could be. As for the lowest res CGA/EGA modes, VGA and later adapters simply had to use double scan to output anything decent on the CRT, so it was part of the standard. So people might be trying to mimic running 1987 games on 1997 hardware and not the look of original CGA/EGA/VGA monitors. Recreating some style is an artistic choice altogether anyway, and I think it's better to discuss it this way.
rikroots 4y ago
I think I understood your requirements, so I tried to knock up a 2d canvas filter demo[1] which met them. Sadly I don't think I met them, but I did end up creating a crazy weird motion blur effect (that's new to me) so thank you for helping me to accidentally create it! [1] - https://codepen.io/kaliedarik/pen/OJZzJJB https://codepen.io/kaliedarik/pen/OJZzJJB ... warning: demo requests access to the device camera.

by Asooka 4y ago

jeroenhd 4y ago

When I look at CRT emulation, I always feel like I'm going crazy. It's been years since I last saw a CRT image but I don't remember visible scanlines at all. I know the retro space is often specifically emulating old hardware, was thing a thing in the 80s, perhaps? Or were visible scanlines more common in America than in Europe? I know the weird colours and lowered resolution of some (emulated) games are an artifact of differences in NTSC/PAL/etc., could that explain the difference?

jerf 4y ago
They seem obsessed with simulated really bad CRTs. I think you could see such scanlines if you were hooking up your Atari 2600 to a TV that was already a decade old, then sat right on top of it instead of across the living room because the cords were short and you wanted to see your games. I've seen it on some arcade games, for similar reasons. But in general, CRTs didn't have those plainly obvious lines, no, because... the engineers would have engineered them out! And did. They're plainly unsightly and it isn't that hard to remove them, after all. I imagine part of it is the need to have visible differences strongly emphasized so it looks like the filters are doing something. A true CRT filter would be much more subtle and people might not thing anything has happened when you turn it on.
- orbital-decay 4y ago
  >They seem obsessed with simulated really bad CRTs. ... I imagine part of it is the need to have visible differences strongly emphasized so it looks like the filters are doing something. The main reason for that is that games of the era were targeted at the most common hardware, using very cheap composite circuits and CRTs as medium for artistic expression. In many games, you could easily miss gradients, rainbow effects, transparency, or something else with a high-end CRT.
  - Asooka 4y ago
    That seems pretty far-fetched. Do you have examples of such effects being shown wrong on CRTs without scanlines?
    - doubled112 4y ago
      I don't think they're referring to scanlines specifically. Something like the waterfalls in Sonic the Hedgehog come to mind. https://gamedev.stackexchange.com/questions/167804/did-retro-pixel-artists-design-with-crts-in-mind https://gamedev.stackexchange.com/questions/167804/did-retro... There's an image on this page. The waterfalls don't look very good with sharp pixels. A CRT would blur and blend, and you'd have to assume the game designers knew it would happen. It's probably not just a happy accident.
    - speeder 4y ago
      doubled112 comment is excellent. Another example that is harder to show, is that many games used intentional flickering or other tricks to create some funky effects only possible with CRT. For example: if you transmit the data correctly (one frame is only odd lines, next frame only even lines) and flicker sprites at certain speeds, you can achieve some fancy transparency and overlay effects. Another trick is toy with timings to screw with resolution, color range and pixel shape. A less reliable trick is sub-pixel anti-alias relying on the TV geometry, since each manufacturer had their own patented geometry this was more problematic (for example Sony's Trinitron was aperture grille, each pixel was composed of columns of each color. Many other manufacturers went for triangular pixels instead. With the 3 primary colors arranged as round dots in a triangular pattern).
323 4y ago
Really really old monitors had visible scan lines, like before 1985 or so: https://i.redd.it/o6gezzyw8dv61.jpg https://i.redd.it/o6gezzyw8dv61.jpg
ogurechny 4y ago
It could be the opposite. Big high resolution multisync CRT monitors had to have fine dot pitch and finely focused beam. However, in lower resolutions the distance between scanlines was more noticeable, as there was limit to how wide and powerful electron beam could be. As for the lowest res CGA/EGA modes, VGA and later adapters simply had to use double scan to output anything decent on the CRT, so it was part of the standard. So people might be trying to mimic running 1987 games on 1997 hardware and not the look of original CGA/EGA/VGA monitors. Recreating some style is an artistic choice altogether anyway, and I think it's better to discuss it this way.

rikroots 4y ago

I think I understood your requirements, so I tried to knock up a 2d canvas filter demo[1] which met them. Sadly I don't think I met them, but I did end up creating a crazy weird motion blur effect (that's new to me) so thank you for helping me to accidentally create it! [1] - https://codepen.io/kaliedarik/pen/OJZzJJB https://codepen.io/kaliedarik/pen/OJZzJJB ... warning: demo requests access to the device camera.