Let's talk about "Curvature" effects in Shaders

[Bonus!]

While I enjoy looking at MAME HLSL screenshots, I do think that all those curvature shaders are missing the point. If you spend a lot of time looking at a non-flat CRT then your brain will start playing tricks on you and you will eventually perceive it to be a plane surface.

In fact, I was once time working in IT support when a company replaced all their bulky PC monitors with TFTs. The funny thing was that a lot of the employees were complaining that the image was now "bent inward" and asked us to fix this. But this was just because their brain had to adopt looking at a non-curved surface. So we told them that it would take a few days or a week for them to adjust, and it did.

So, for all you "purists" out there: if you had been using a CRT as your main monitor for playing games, you would not at all perceive it like those curvature shaders in MAME look like. You're trying to recreate something that never existed. Only the most "casual" user would actually notice the curvature of a CRT. Thus, the question is: do you, by emulating curvature, intend to use those presets so extensively until your brain flattens the image again? (This is not a serious question.)

[blizzz]

I'm not a fan of curved shaders. A very minor curve might be nice to remind you that it is in fact a retro game, but I prefer a flat display. Plus, you need a much higher resolution than 1080p to emulate the curvature without artifacts like moiré patterns.

[Xyga]

Curvature effects suck. They change the picture in away you don't actually see when in front of a real curved crt.
And indeed they don't go well with scanlines effects, messing up the pixel lines consistency - ending up looking like total garbage, not like a real crt, not at all.
Wrong and ugly.

[TrisMcC]

I agree that the effect is not the same as seeing it on a curved CRT. The approximation is worse for the CRT curvature than the current state of NTSC/scanline emulation.

[cools]

Go play on a machine that has a CRT at a steep angle. You'll notice the curve then.

[Bonus!]

Do it for five to eight hours a day for months or years, without going near any kind of flat screen, and you won't anymore. Again, a very common reaction to the first flat-screen monitors was that the screen was curved inwards because the human brain adapts to those changes.

[gray117]

There's perhaps ways to improve it, but it's the best you're going to easily get, and in the same breath whilst I like a touch of curvature, I set it to far less than what would be symptomatic of the actual real effect, and far less than what you'd see in some of the exaggerated implementations that show up in example screenshots.

Bent inwards perception is bizarre to me, but these were probably poor excel sheeting workers with 14/15" monitors previously... that and I bet at least half those poor people had 50-60 hz refresh rates because they never knew better and/or it got reset at some point. That crap sold glasses and pain killers.

... You want to talk bad screen effects though? The winner has to be that supposed field of view correction effect you used to get on some early lcd tvs where the image is compacted in the middle and stretched on the sides - as if something like a 32" size is so fcking wide we'd better adapt it so your head can fit it in ... oh wait it's no where near that big, you're sitting on a sofa, often at a slight angle, and this just looks awful...