Please show off what crt shaders can do!

LinerCRT · 7 July 2020 09:22

1080p with the HLSL default shader, with humbar effect and distortion and jitter. Thanks again to @hunterk. HLSL still not bloom effect ported from mame.

DISTORTION effect, is used for some games/developer because in some games, most common shooters, is like a rotation effect, in the vertical sides, or like 360 circle rotation. IS part of the image.

pd: update the core of mame to 0.222 today and retroarch block when lauch any game.

Remember that your colors of your monitors/TV or resolution make that this image post above not look good.

Syh · 7 July 2020 09:24

So are you saying the bloom isn’t working properly?

LinerCRT · 7 July 2020 09:30

I mean that bloom inst in the HLSL shader of retroarch, like msdos mame.

hunterk · 7 July 2020 12:55

The BGFX version doesn’t include bloom, evidently, so when I switched over to it from the older HLSL-based version, we lost it. It could probably be added back in, though, if someone were inclined to do so.

DariusG · 9 July 2020 11:13

@linercrt man where have you seen a monitor with such big curvature? I doubt there ever was a TV with so much curvature. That’s really huge

One from me, guest.r shader on my cellphone (slang) tweaked to look a bit like a professional video monitor

LinerCRT · 9 July 2020 13:43

… your scanlines is very big and notorious, at least, on my monitor they look very exaggerated and unreal, and in a little screen maybe is ok.

Yes…the old crt screens had big curvatures.

And, i play with these settings that the shader with deffault offer me… i like how look the curvature of the screens that put here, but a less is ok, because ( obiusly word here too ) if you want a correct distortion effect at the sides, you need to put that curvature, is thing of the option that offer the shader…and the same for all the other options too.

If the shader offers the options, you have to do what it offers you.

I tried to combine shaders too as possible, but lots and lots of crack…some shader for d3d, ohter for vulkan, intel…etc

LinerCRT · 9 July 2020 13:41

The people that know how to code a shader or how shader works in retroarch, and they are usually around here a lot spending their time with the hobby, they should come together to create a great shader, and all people win.

Anyway, thanks to all for the work.

Nesguy · 9 July 2020 17:30

That curvature is most definitely exaggerated.

DariusG · 9 July 2020 17:43

I have had at least 10 CRTs with curvature and never had such big curvature, but something like this instead

hunterk · 9 July 2020 18:35

I believe the curvature is a function of the total depth of the tube from the surface to the electron gun. The electron beam needs to hit the phosphor at ~90 degree angle, so the curvature is used to maintain that perpendicularity across the surface of the screen vs the point-source of the gun.

There were some comparatively very shallow models made toward the end of the CRT heyday, but they suffered from poor convergence and a blurrier image as you approach the corners and the angle of deflection increases.

tl;dr, perhaps LinerCRT is fond of very shallow displays that need that heavy curvature to maintain consistent picture quality.

1001010 · 13 July 2020 09:56

Z-Fast is lightweight and fast. The mask is similar to that of a Trinitron TV.

Nesguy · 14 July 2020 21:53

I used zfast on the raspberry pi before I built a proper emulation PC; it’s a decent shader if you lack the power to run better shaders. I prefer it to the crt-pi shader. Looks like a Trinitron TV at 720p, looks like a PVM at 1080p. The phosphor emulation isn’t accurate but it does a decent job of conveying the aperture grille texture. I’m not the biggest fan of that scaling, though- it’s too sharp. Guest-dr-venom with horizontal sharpness at 3.00 and subtractive sharpness at 1.00 is more accurate than any other shader with the possible exception of CRT Royale (with certain settings). All other shaders have the problem of being either too sharp or too blurry no matter what you do, or the scaling results in ringing artifacts, etc.

Zfast also lacks good color management options, but you can just add grade for that.

lfan · 15 July 2020 01:00

Could someone convert the Z-Fast shader to slang?

hunterk · 15 July 2020 02:04

I did this just today, coincidentally: https://github.com/libretro/slang-shaders/commit/375c6220d7da007bba8da2726d12d516e3a2da24

1001010 · 16 July 2020 10:52

Here is Z-Fast combined with pass2 from gtu-v50 just to blur the image.

Nesguy · 16 July 2020 19:05

That looks decent with that particular content and gtu is a nice older shader. However, anything sprite-based will have overly blurred high-contrast edges, which can have a bad effect on the artwork. Details like small text, small icons, drop shadows, etc will also be overly blurred with such settings. On a (well-maintained) CRT, high-contrast edges remain nice and sharp. That’s why you need something like guest-dr-venom’s subtractive sharpening. CRT-royale has bicubic sharpening which does something similar (they might actually be the same thing, not sure tbh).

@hunterk can bicubic-sharp be ported to glsl and slang, and can parameters be added to adjust the level of sharpening?

Edit: here are some examples illustrating what I’m talking about.

horizontal sharpness 3.00, subtractive sharpness 1.00

horizontal sharpness 3.00, subtractive sharpness 0.00

horizontal sharpness 3.00, subtractive sharpness 1.00

horizontal sharpness 3.00, subtractive sharpness 0.00

hunterk · 16 July 2020 21:14

Sure, done. Lower Bs and higher Cs make it sharper at the cost of ringing. 0.333 is the default for both (the Mitchel-Netravali coefficients, whatever that means).

bicubic-sharp is B = 0.1 and C = 0.5

bicubic-sharper is B = 0.0 and C = 0.75

Nesguy · 17 July 2020 15:40

I guess we don’t actually need to add bicubic sharpening to zfast? It didn’t seem to do anything, after all. The blur/scaling in zfast already does a decent job of keeping high-contrast edges sharp.

Something about the blurring/scaling in zfast doesn’t sit right with me, though. It seems like zfast is blurring using the regular sRGB color space instead of blurring in linear gamma sRGB color space (I might have this backwards), so you get weird-looking stuff like the text and the border around Link’s shield in the below example.

Zfast-crt, horizontal blur 1.00