As i mentioned, you might go with a custom setup (-1.0) and either merge fields or leave custom fringing at 0.0. It’s worth the time to use the custom option.
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Merge fields = 1
or
Presets (Svideo=0 …) = 0
(The game is World Championship Soccer II for the Genesis/MegaDrive)
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Hi @hunterk I’m not sure but I’m slightly confused here. So you say we’ll be able to ‘disable the automatic inverse-tonemapping’ which is fine and I’ll add what we’ve discussed on the Discord channel but then you go on to say that you should be able to do your own tonemapping.
Do you mean you’ll be able to do your inverse tonemapping which again is fine or do you mean you’ll be able to do your own tonemapping which kind of doesn’t make sense to me, at least from my understanding that for the vast majority of time you’ll be starting with an standrard dynamic range image and therefore you absolutely need an inverse tonemapper to remap that out to a high dyanmic range image. Tonemapping is the opposite of that process high dynamic range down to standard dynamic range.
Sorry I’m just trying to make sure I understand what your requirements are or that you’re just using loose terminology.
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loose terminology. No worries. We’re happy with whatever we can get lol
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Fantastic - I thought we might have been dealing with some custom renderer when you said this. Ok we’re all good.
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hello, thansk for the lovely shaders. as my system is not so powerful i wanted to know, if you people know why crt-guest-advanced-fastest is just flickering wildly. i hope the shots make it somewhat clear… thx…
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Hello there!
The shader contains some modern speedup techniques, but otherwise is should work quite nicely with the glcore driver. I guess there are some issues with vulkan/d3d which would require some nitpicky polishing.
Alright thanks. I ll just use venom normal instead
- are the default shader presets of dr.venom and advanced a recreation of a certain tv?
- is it possible to recommend royale-kurozumi over venom-advanced or vice-versa or are they different shaders for different purposes?
- could someon give me a hint on how to use afterglow sort of correctly i’m a tad overwhelmed w that feature…? thx
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I stated a couple of times that the default presets are a bit “shy”, not aiming for a specific crt tv model and mostly suitable for a 1080p display. It’s so on purpose.
I guess the “kurozumi” preset could get a better tweak with the new iteration on the shader than the older guest-dr-venom, but the purpose is quite the same as the royale-kurozumi that’s to achieve a PVM crt look. But ofc. you can tweak further both if you like. 
Tweaking afterglow:
- more persistence means longer trails
- if unsure persistence for different RGB values is best the same
- afterglow manifests itself on black pixels/areas (for authenticity)
And that’s not too hard i guess. Ofc afterglow looks better with some games which use black background etc.
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I think you need a high refresh rate for afterglow, otherwise it’s just blur city.
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Just a friendly reminder phosphor persistence/afterglow happens on any color that contrasts enough is my guess (doesn’t care if it’s black).
I was playing a NES game while back on CRT can’t remember which game, I posted a long drawn out comment in on the the shader threads about it. Regardless, it had blue backgrounds, and I don’t mean dark blue, I mean like baby/sky blue and I was able to see afterglow from 6ft away to the point that I decided to confirm by getting closer 
Granted that CRT is like almost 14-21 years old at this point, and I haven’t had either serviced. (I can’t remember which of my two CRTs I used, I’m going by their manufacturing dates btw)
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Synced displays (for example) are quite fine for afterglow with ordinary framerates, since crt’s also didn’t produce continuous effects between movements. I guess the base effect is as good as it gets.
Afterglow is definitely manifesting on black background on many types of crt displays. Didn’t notice it on my crt tv’s though as a general ghosting effect though. I could get a bit more nitpicky here, treating afterglow per color component instead.
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Yeah this persistence vs afterglow is a tricky one.
@hunterk has mentioned that on his crts that he has only seen it appear over black
Long persistence, like you see on old LCDs the glow appears equivalently over brighter and darker colors, so looks blurry in movement. The afterglow on the other hand seems to only noticeable on darker areas. I’m no expert on this, just what I’ve observed…
One thing that I’ve seen about the afterglow in GDV is that the cutoff between what is considered black and where afterglow appears and where lighter colors start to appear and no afterglow appears can be abrupt and cause a harsh edge between them. So you can end up with the afterglow being much brighter than the area it is right next to (which is almost black)
I think the ‘Raise Black Level’ is also hooked to this identification of what was black, so can give a weird result too if it is increased depending on the game if there are gradients close to black, I’m sure it would work quite well for something like Pacman.
Here’s an example of when the
I haven’t played with this stuff for a while though, so hopefully that’s all still accurate
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Yeah, the way it seems to work (which is unfortunately very hard to express in code) is: the phosphorescence decays almost instantly on blue and green but the reds last longer and exhibit a long tail of up to a couple of seconds, depending on the phosphor material. If a given pixel is re-lit during that falloff period, anything greater than the current fading value completely overrides it (i.e., there’s no additive brightness from the previous decay). There will be some visible rolloff even on nonblack stuff, as long as it’s a brighter->darker transition, but due to the big-initial-drop-with-long-tail behavior, you’re never going to see it unless the darker pixel is very dark indeed.
I’m also not sure how/if different follow-on colors affect things (e.g., red decay followed by bright green) and/or chromatic aberration.
I agree that anything using thresholds looks bad the closer you are to that threshold, but I’m not sure that a better, more realistic method is feasible.
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This looks really good! I think it’ll be a great addition!!
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Thanks for the answer. I didn’t want to appear lazy or something…
I tried to search for these things before asking. But I didn’t use the search function. Just tried to manually read through this bigger thread.
I am thankful for your work on these shaders and the detailed answers, I’m just rather new to a more technical approach of using shaders…
Sadly the kurozumi-guest.slang preset doesn’t work anymore on my macbook air 2015. These days I use kurozumi-royale or your guest-venom version.
I did’t want criticize your default preset. Just curious.
I think I’ll just leave out the afterglow feature for now. I first want to get colors as right as possible, but I’m struggling to be satisfied.
Maybe another question: would you guys prefer to use the lut parameter, or the crt-color-profile for adjusting your color settings? I couldn’t get the saturation parameter to anything I wantrd. Is it advisable to crank scanline saturation up to 2 or do I have to bear artifacts in mind? Same for scanline-spike-removal?
So thanks for the work and this nice thread.
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