New CRT shader from Guest + CRT Guest Advanced updates

Nesguy · 26 April 2022 17:35

I think this deserves a new thread, maybe?

On the subject of color management, can someone with expertise please articulate clearly why it is that color bars always get clipped when you just change the shader from 6500K to 9300K, but this doesn’t happen when you leave the shader at 6500K and change the monitor itself to 9300K? I kind of understand it but I don’t know the right words. To put it another way, why is it that the shader can get so much brighter at 6500K without clipping anything (vs 9300K)?

It seems like leaving the shader at 6500K and changing the monitor itself to 9300K would result in the “intended” colors for NTSC-J content, is this correct? If so, what are the pros/cons of doing this vs. changing the shader’s white point?

HereticZero · 28 April 2022 04:39

I’m not seeing anything in either Nvidia control panel, windows settings, or retroarch settings and I can’t think of anything else.

In Nvidia Conrtol Panel 3d settings are set to “Let the applicatacton decide”, Resolution is set to “3840 x 2160 (native)”, Color settings are set to “reference mode” and I set scaing to “No Scaling” just to be sure. In windows settings scaling is set to “100%” for both apps and text.

I seem to have everything set up to keep things outside of the application from interfering. I’ts been consistent across 2 computers 3 displays and I don’t know whats causing it.

This actually still sounds pretty amazing considering all the options there are for adding more black (although, I guess they’re not quite the same as royale’s contrast setting).

This started because I requested a CMY mask. We went into color managment because I had to explain why. If you want to make a dedicated thread, however, it sounds like it could become a great resource.

guest.r · 30 April 2022 12:32

Rincewind:

Like I wrote, the saturation control in the WinUaeColor reshade filter is broken (it applies the saturation after the target colour profile has been applied; that’s wrong and leads to some very funny results even at moderate settings; it only works as intended if no colour profile emulation is being used). Would it be possible to fix that? I’ve offered a workaround in my article (just use another saturation shader before your colour profile filter), but it would be nice to have it all in one shader.

Your colour contrast control, on the other hand, works very well. Would it be possible to add a brightness control as well? Then with the fixed saturation control we’d have brightness, contrast and saturation in a single ReShade shader that’s easy to adjust on the fly, like on a real 1084S.

I updated the ReShade shader with a new saturation implementation and brightness control. As usual, you can get the updated version here:

When i find some more opportunity i’ll probably update the mask options to be on-pair with the new guest-advanced shader. I belive it will be much more versatile with the update.

Rincewind · 30 April 2022 13:14

Awesome! I’ve been playing with it for the last 15 minutes and they work great! With saturation 1.17, contrast 0.8 and brightness 1.05 I’m getting this very nice vivid “pop” that I loved on my Philips monitor and no VGA monitor could replicate that for some reason. I’ll update my article in the coming days (I advised people not to use the saturation control because it’s broken).

Looking forward to it! You keep me busy, that will probably necessitate another article rewrite

guest.r · 30 April 2022 23:03

I added another version to my WinUAE shader github. With some improvements now almost all guest-advanced mask features are present, together with curvature option. Maybe i could add deconvergence too, but probably not ‘today’.

I would be glad if you test it a bit, mostly for driver compatibility.

Here is also the description of present masks:

guest.r:

-1.0: no mask
0.0: a dense magenta-green mask
1.0: Lottes RGB mask with a some sort of slotmask
2.0: Lottes RGB mask
3.0: Lottes - a bit enlarged and shifted RGB mask
4.0: Lottes - 2x enlarged and shifted RGB mask, looks nicer with 4k+
5.0: a dense magenta green mask (trinitron mask controls)
6.0: RGB mask (trinitron mask controls)
7.0: BW mask (trinitron mask controls)
8.0: BWW mask (trinitron mask controls)
9.0: magenta-green-black mask (trinitron mask controls)
10.0: RGBX mask (trinitron mask controls)
11.0: Red-Yellow-Cyan-Blue mask (nice for 1440p+)
12.0: Red-Magenta-Cyan-Green mask (similar to 11.0, but for BGR panel layout)

RealNC · 1 May 2022 05:26

@guest.r Tip: when you want to post fixed-width text, to avoid annoying highlighting detection, use the “text” tag for the code block:

```text
blah blah
```

Cyber · 1 May 2022 05:35

Don’t forget this one:

guest.r · 1 May 2022 05:46

It’s an automatically formatted quote of a formatted text. I don’t mind the highlights.

Dunno about this, needed fmod(x,y) call failed to compile with ReShade, so i removed it for now. I could write the function by myself, maybe at some later time.

Rincewind · 1 May 2022 10:59

Excellent, I gave it a good workout in the last two hours and all the features work flawlessly on my NVidia RTX 3060, zero issues. I don’t care about curvature stuff personally, but some people might find it handy. I really like the new halation and separate dark and light pixel controls for the slot mask. I tried all mask variations and I’m still finding the simple magenta/green mask (type 0) combined with the separate slot mask to work best for my purposes (C=1084 monitor emulation at 3x-3.5x on 1080p). With the aid of the new brightness and colour controls in the colour shader, I was able to make some subtle but important improvements to my previous preset, namely better control of bright highlights without strange artifacts and zero luminance loss compared to the raw image. So great additions, thanks for updating these!

Attached an example for you to see where my preset stands now. I’ll wait a bit with updating the article as I have a feeling you’ll eventually port the deconvergence too, and that will bump the realism up a notch again… so I’ll wait for that (hint, hint… )

guest.r · 2 May 2022 06:12

Really nice screenies. I would like to add that a nice shadowmask setup could work with mask 10.0 and mask shift of 2.0. Mask 10.0 is a bit coarse for 1080p, but looks really nice with mask shift.

As promised, i added deconvergence to the WinUaeMaskGlowAdvanced.fx shader. Works really nice and does not interfere with masks, on-pair with the current guest-advanced shaders. It’s quite simple to setup, a good start for example is horizontal red to 1.0 and horizontal blue to -1.0. Ofc. many combinations are possible.

The shaders for WinUAE and ReShade can be found here:

Rincewind · 2 May 2022 11:19

Great! You’re doing God’s work! It makes a nice difference in homeopathic amounts like you suggested. The penny dropped just after about 30 mins of tweaking that in fact I also need to increase the sharpness in the shader to compensate, otherwise there will be too much blur going on…

Indeed, I tried it and I think I prefer it to my previous method now. The only problem is that it’s more prone to moire in the lightest shades when anything is added to it (extra brightness with colour shader, or even just bloom or halation). Somehow it’s much more sensitive than my previous mask 0 + slotmask method.

For the record, this is my shader chain:

CRT-A2080 -> WinUaeMaskGlowAdvanced -> WinUaeColor

I think the problem is, at least with brightness and colour adjustments in the colour shader, that it disturbs the masks & scanlines too much. I’m quite sure this would be the ideal chain:

Brightness/Contrast/Saturation (on the raw image) -> CRT-A02080 -> WinUaeMaskGlowAdvanced -> WinUaeColor (profile only)

And indeed, if I raise the brightness using the “Brightness” control in WinUAE’s Display panel, then there’s zero extra artifacts, which makes perfect sense. It’s a shame because I really like this new Brightness control… But like you said, we’d need a better multipass shader architecture in WinUAE to be able to move the ReShade stuff into WinUAE with total control over the order of stages.

Anyway, not complaining, I can still obtain good results with this workaround

BT-Kimosabe · 3 May 2022 01:21

i really wish that guest.r could take a look at Tyrell’s CRT Shaders for dosbox, i would love to see some presets for ECE and X, mainly for old windows games and dos games that uses SVGA

TheNamec · 3 May 2022 15:57

Taking notes! Thanks as always master @guest.r

Rincewind · 5 May 2022 01:45

Adding some very subtle deconvergence and halation was definitely an improvement, I like the quite “organic” look I’m getting. I had to dial back the halation though, around 0.7 red horizontal shift and -0.7 horizontal blue, plus reduced the strength to about 0.7 as well. That’s probably because I’m using 3x to 3.5x scaling.

Some screenies:

Syh · 5 May 2022 06:46

Adding just the smallest tiniest amount of noise/film-grain will go a long way towards that “organic” look imho.

RealNC · 5 May 2022 06:52

Noise ruins the black level. The image gets that “washed out” look.

Syh · 5 May 2022 07:07

Ruins is a tad dramatic, and it seriously depends on how much noise we’re adding to the image, I’m literally suggesting just one or two notches of it. (Barely going to affect the black levels, it definitely will but w/e).

I understand what you’re complaining about as I’ve personally dealt with it myself, I just don’t care

Rincewind · 5 May 2022 07:06

Depends on how you do it, it doesn’t have to be.

Just tried it quickly in Photoshop with some gaussian BW noise on a mid-gray layer added with Overlay mode at 50% opacity. That leaves the blacks and the overall luminance 100% intact, it only disturbs the luminance of a few pixels a little. It’s quite nice, indeed @Syh, thanks for the tip! It breaks up the synthetic look even more, which makes sense, nothing is 100% perfect in manufacturing in real life. Now I’ll only need to find a way how replicate this with some ReShade filter as the last layer Any tips? I guess some simple shader will do that can overlay any texture with pixel-perfect mapping with some PS overlay-like blending.

RealNC · 5 May 2022 07:44

I believe they meant the shader option for noise. If it’s available in the winuae version, of course.

0 noise. The black around the shader output is the same as the black inside the shader output:

Noise set to 0.3. The black inside the shader output is not really black:

Some people like this effect though. It makes the image look similar to what a CRT looks when you view it in a lit room. (The light reflects off the CRT screen and it’s not black anymore.)

Rincewind · 5 May 2022 07:52

Cheers, it’s not bad, but I find the noise a bit too much personally. What I’ve done in literally 2 minutes is:

create new layer in PS, fill with 128 gray
Filter -> Add Noise -> Gaussian / 4% / Monochromatic
Blend 40%, Overlay blend mode

That’s it, I find the effect quite nice. Should be dead easy to do in a ReShade shader (no, the WinUAE shaders don’t have built-in noise functionality). The PS blend modes are documented here, it doesn’t seem too heavy calculation wise, it just screws around with the sRGB pixels like half of the PS blend modes… I might even implement myself if I don’t find something that does it already.

(Target > 0.5) * (1 - (1-2*(Target-0.5)) * (1-Blend)) + (Target <= 0.5) * ((2*Target) * Blend)

https://www.deepskycolors.com/archivo/2010/04/21/formulas-for-Photoshop-blending-modes.html