Shaders for various emulators

[Dr.Venom]

Originally Posted by guest.r

@Dr. Venom
I think the best option is to add a mask 7 without phosphor effect. It's affected only by the cutoff parameter. Implemented now.

Thanks , only something seems not right. It still applies the phosphor effect to some colors but not all. See snap (enlarged) below.

Better calibrated IPS/VA should correctly reproduce about 99% of the (sRGB, Adobe...) colorspace. Dunno about TN (gaming) monitors, they might have some issues here. I think CRT's might follow a different standard(s) and the technology is completely different also. The shader setting about color temperature might help a bit here. I think it's important to consider color reproduction when buying a new display. Personally it's hard to decide for me whether to buy an IPS or a fast refresh TN (1440p). First might be better for emulation and shaders, second for PC gaming. Tough one.

Always a tough choice. I currently have an IPS panel with 3ms g-t-g (it's Gsync also) and am very happy with it. I guess IPS these days doesn't have to rule out fast response times anymore.

After sitting for a longer time behind a CRT playing some of these game with black backgrounds, it really stands out that black on a CRT is really much more black, compared to LCD. It's really something that pushes me to OLED HDR, if and when these will ever come out in monitor size.

With regards to the red, I forgot to mention it's the CRTs that have the "different" red, not the IPS panel which actually has a "real" red (it's accurately replicating sRGB space). But now I want the incorrect red . Not that important, because everything is looking beautiful.


I read something interesting about LUT shading though, could that be a way to mimic CRT colors more accurately? (It's probably not and too complicated, but just in case.. )

http://filthypants.blogspot.com/2017...ut-shader.html

fwiw, The LUT shader is in this folder
ttps://github.com/libretro/glsl-shaders/tree/master/reshade

[guest.r]

Yeah, color cutoff has to alternate between pixels with low brightness and it may look like a size 2 mask.
Complete cutoff would just produce wrong colors or. black areas, would not look good at all.

Dot separation (blackness between pixels) for single R, G and B colors ( = mask 5&6 cutoff)

Maybe you had in mind a steep transition from cut colors to blank lines? Well, i'll implement it...

I read something interesting about LUT shading though, could that be a way to mimic CRT colors more accurately? (It's probably not and too complicated, but just in case.. )

I think it's more about core tweaks, like GBA has it's own color pallete, there are some for NES etc. All other crt shaders i know are neutral here, since LCD's have a pretty good color reproduction by now and this should really be core provided.

Edit: I'll take a look at the Sony Trinitron LUT, maybe it will look better here.

Edit2: LUT implemented, looks like a bit warmer colors. It's OK for testing i guess...

[Dr.Venom]

Maybe you had in mind a steep transition from cut colors to blank lines? Well, i'll implement it...

No no, I didn't have that in mind. Let's forget about the test shader

Originally Posted by guest.r

Yeah, color cutoff has to alternate between pixels with low brightness and it may look like a size 2 mask.
Complete cutoff would just produce wrong colors or. black areas, would not look good at all.

OK. Good to know it works as it should, I guess I expected it to work out differently.

Basicly I expected the whole image to get brighter when going from mask 5 to 7, because the phosphor tinting is lifted / not there in 7.

Instead only the brighter parts of the image get brighter with 7 (the door on the right), but the darker parts actually stays about the same with 7 (left part). See image below.

I guess my main issue / misunderstanding is why the darker (left) part of the image doesn't get brighter with mask 7?


Also if you look up close, the darker part still has that green / magenta tinting, but what I understand that is actually how it should work with mask 7, right? Just reaffirming.

I think it's more about core tweaks, like GBA has it's own color pallete, there are some for NES etc. All other crt shaders i know are neutral here, since LCD's have a pretty good color reproduction by now and this should really be core provided.

Edit: I'll take a look at the Sony Trinitron LUT, maybe it will look better here.

OK that's interesting .

I also learned you can create your own LUT png, by pasting the existing palette.png below an existing image (extend the canvas), then change hue, contrast, curves etc, then cutout the palette in the image (the part of the extended canvas) and save it as a new lut.png. Seems quite complicated to make color adjustments for single colors that way though. (apparently someone in the libretro forum, used this succesfully, to only change the blue of the water in sonic to what he thought was the "real" blue..)


Edit: I'll take a look at the updated shader with lut now

Edit 2:

Edit2: LUT implemented, looks like a bit warmer colors. It's OK for testing i guess...

Wow, insane! This looks much closer to the real deal. Not sure about all the colors (yet), but red is so much closer to the real trinitron it's unreal. Please keep this option in here! Given that one can also create their own tweaked LUT (replace the trinitron-50.png), it only makes even more a must have!

I guess it's good to mention for others, that you need to load the preset freshly and switch on "trinitron colors" to try it.

[Retro-Nerd]

Indeed. Trinitron Colors looks perfectly fine. Even better than the "warmer colors" tweaking (d65 to d50 strenght %).

[Dr.Venom]

Originally Posted by guest.r

Edit: I'll take a look at the Sony Trinitron LUT, maybe it will look better here.

Edit2: LUT implemented, looks like a bit warmer colors. It's OK for testing i guess...

Further to my previous post. I spent some more time evaluating the LUT shader addition, and the Trinitron colors are quite an improvement. It's not only red that is "fixed" but the others seem more accurate also.

There's only one issue, it's slightly too dark. This is noticable in SNES and PSX games, for example in Addams Family on SNES, dark is so dark that details are missing from the parallax background in some levels. This cannot be fixed with the gamma adjustment in the shader.

Below compares the default and the trinitron LUT in the 240p suite. In the color bars test it can be seen that the darkest colors disappear when the LUT is applied. Also when you run the pluge test, the dark bue bars don't appear at all with the trinitron colors.

I did a little experiment in Paint.NET just raising the levels slightly and saving the LUT again as PNG 24-bit, and it seems to fix the too dark issue, but it will not show the (very) dark blue vertical bars in the pluge test.

Do you have an idea what adjustment should be best made to the LUT to have it pass the suite test?

Default


Trinitron LUT

[Retro-Nerd]

There's only one issue, it's slightly too dark.

Yeah, noticed this too. Looks a bit like a black frame insertion. Could be problematic for several games with a darker palette as you already said.

[guest.r]

Yeah, i noticed darker colors too. It looks much better now for my taste. I also fixed incorrect very dark colors a bit, dark blue bar was red on pluge...
It's a shader fix since it might be a coordinate issue. Lut is still the same.

I also changed the slotmask a bit (together with another try on mask 7). Since it applies in gamma space the application on blight dots is mitigated by default, so it's a bit darker now.

About the shaders posted here, please delete the "guest" folder before extraction since i moved the lut's into it's seperate folder, so no junk code is around.

[Retro-Nerd]

Thanks for the fast fix. Now it's really perfect.

[Dr.Venom]

Originally Posted by guest.r

Yeah, i noticed darker colors too. It looks much better now for my taste. I also fixed incorrect very dark colors a bit, dark blue bar was red on pluge...
It's a shader fix since it might be a coordinate issue. Lut is still the same.

I also changed the slotmask a bit (together with another try on mask 7). Since it applies in gamma space the application on blight dots is mitigated by default, so it's a bit darker now.

I think you nailed it on both counts now . There's now so many possibilities to have a great CRT look, that whatever your preference is, it's actually becoming harder to choose which one to go for!

With regards to the LUT, it may give some interesting opportunities in the future. The following is an interesting video about someone showing possibilities with 3D LUT Creator:

[ Show youtube player ]

Now around 12:00 he shows how to map the color tint from one scene out of a movie onto a photo to recreate the same setting in the photograph. The result seems quite accurate, as if the photo was a shot out of the movie. The color LUT can be saved from within 3D LUT Creator I assume.

In a similar fashion it could possibly allow to recreate a few color profiles from real CRTs that way (more candy! ). It's definitely something I want to take a closer look at somewhere down the line. (Unfortunately 3D LUT creator is not free..)

Lastly, I was wondering when HDR lands, would you think only a "contrast" parameter setting would be needed to take full use of HDR with the shader, or do you foresee other uses? Also, would WCG have any benefit for CRT shading?

Thanks again for the shader work, now back to enjoying it

EDIT: I noticed you removed the Raster Bloom Grade / R. Bloom Smoothing setting, so now the issue with the "breathing" is back . As reported in post #123.

EDIT 2: If it would make the shader much slower / too slow, I can understand fully why you'd rather not include it anymore. Benefit / "cost" ratio must be good enough

[guest.r]

@Dr. Venom

In a similar fashion it could possibly allow to recreate a few color profiles from real CRTs that way (more candy! ). It's definitely something I want to take a closer look at somewhere down the line. (Unfortunately 3D LUT creator is not free..)

I'll wait a bit if something new shows up in the RA lut section, but i think the Sony Trinitron lut pretty nailed the spot. Options here are open, but i don't want to add luts that do only minor changes regarding the default "profile".

Lastly, I was wondering when HDR lands, would you think only a "contrast" parameter setting would be needed to take full use of HDR with the shader, or do you foresee other uses? Also, would WCG have any benefit for CRT shading?

It's still a bit far away for the mainstream speaking about SW and HW. I'll wait for a RA implementation first i guess to grasp the coding concept a bit. WCG is not that important here, i expect minor differences regarding current IPS's and sRGB/Adobe color spaces. HDR support and a good display (like the Asus ROG) can make a far greater difference.

EDIT: I noticed you removed the Raster Bloom Grade / R. Bloom Smoothing setting, so now the issue with the "breathing" is back . As reported in post #123.

EDIT 2: If it would make the shader much slower / too slow, I can understand fully why you'd rather not include it anymore. Benefit / "cost" ratio must be good enough

Naa, the changes are merged, they are only "hard-coded" now to avoid too much parameters. MSlug issue is still here, i know.

Lastly i updated the shader again with a better brightness profile for Trinitron Colors, also added it to the fast version.

[nobody]

Real Trinitron colors are not so warm like "Trinitron colors" setting except if you choose "Movie" color profile from the menu. They are close to what i see on my PC monitor and even colder than that. Tweaked a bit more with "240p suite" on CRT and PC for proper white/gray/contrast/saturation levels. Almost there now, close to a real Trinitron.

[guest.r]

Those are "D50 colors", i'll add that as a comment to avoid confusion. I think i'll modify the color temperature pass, so we can compare it with luts.

[Retro-Nerd]

Your current colors are pretty accurate for the most Trinitron colors. Except for all greys+white. They have strong sepia tint, which my Sony Trinitron doesn't have at all. Would be great if you could tweak this (or making it tweakable via an option setting). I know that the strong sepia tint is pretty normal for "movie" profile settings, but older CRT TVs mostly didn't have this back then.

[guest.r]

This one is for testing vs. lut, vanilla version.

I think "Color Temperature" is a better option (see shader parameters), because of the correct bightness profile.
I also chose better conversion in this version.

The problem is that the white point changes with color temperature, most of us can test it via lcd display calibration, so i think the shader is pretty accurate here. Warm colors have a bit yellowish whites/grays therefore.

Feedback (lut vs. color temperature) is welcome.

Edit: previously warmer colors were not correctly implemented, so the lut might looked better.

[Retro-Nerd]

Well, Trinitron Colors enabled in combination with Color Temperature % -40 is the best i can get. I have now the Sony Trinitron TV next to my PC. Most colors looks very similar but not 100%. The blue sky in Turrican has more teal on the Trinitron, Red is a bit darker. Tried to tweak it with Gamma settings a bit, but it destroys the whole image then.

I assume all colors slightly differs from Trinitron CRT to Trintron CRT anyway. I think this is good enough for me.





Any chance we can get similar color settings in WinUAE via shader? Or does it only work properly via lut files?

[guest.r]

I assume all colors slightly differs from Trinitron CRT to Trintron CRT anyway. I think this is good enough for me.

Thanks for some testing. I'll leave it as it is now i guess.

Any chance we can get similar color settings in WinUAE via shader? Or does it only work properly via lut files?

In WinUAE "Warm Colors" shader has to do for now.

[guest.r]

Another version of trinitron colors.
Note: the lut author mentioned it was created from the original sony trinitron driver profile, sepia tones were removed (i think it's for the better now).
...and blue looks a bit more tealish. Red looks a bit "wrong", so everything should be fine.

[Retro-Nerd]

Nice, looks much better without the sepia tint. But i guess the teal you've added changed the dark blue to a lighter blue and the green from the Turrican life energy meter is also a brighter one now. The rest looks really good to me.


Trinitron Colors (yesterday version)







Trinitron Colors (from today)

[guest.r]

But i guess the teal you've added changed the dark blue to a lighter blue and the green from the Turrican life energy meter is also a brighter one now.

I didn't edit the lut, unfortunatelly. It's an alternate trinitron preset, no more are arround i think. I can add both to the shader though.

[Retro-Nerd]

Ah ok. Yes please, to have both versions would be nice.