Have you seen this shader preset @HyperspaceMadness?
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Yup, it’s a cool one 
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hello there again. Just sharing some experimental presets left aiming to give some similar results from available samples:
Rainbow sega v6.26 is intended to work either for BlastEm OR Genesis Plus GX with core options >> borders (overscan) = Full OR left/right being set available. video sample: Sonic the Hedgehog 2 (Sega Genesis - Composite VS. S-Video) - YouTube
Also, a video available as a proof for v6.26 in Sonic waterfall to expose dithering + rainbow effect.
Left side is Genesis console Model 2 VS Genesis Plus GX
presets v6.291 + v6.292 are based from another sample. These 2 presets are NOT intended for BlastEm but just for GPGX to let the Rainbow effect mostly fit the accuracy. Also, GPGX options >> borders: set to OFF Sonic the Hedgehog 2 Sega Genesis Real Hardware 60fps Demonstration - YouTube
v6.291 is flat screen with no CRT effects v6.292 same as the previous but with CRT effects
Left side is Model 1 VA6.8 vs Genesis Plus GX
Did you get any luck to get it combined with your preset @Cyber ? Nice to see you around buddy.
I hope any of you guys can incorporate somehow this wonderful rainbow effect to other composite-blurry looking shader/presets, by the fact seeing how many other dithering effects can be achieved through the shader/presets available on here.
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My preset does just that, gives you the rainbow effect and all, you can get it here. It’s the “8/16 bit” preset, try it out and see what you think
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Wow! This looks like you’ve really fine tuned and perfected it! Looks very much like the original hardware.
I’ve not able to combine this with my presets since I use HSM Mega Bezel Reflection Shader. I don’t know if it’s possible to add it to the chain or what would be the best way to integrate it. It might be possible though but maybe someone like @HyperspaceMadness or @DariusG might be better able to accomplish such a task or at least give advice as to how to go about it.
I’m glad to see that you kept at it!
The info in this post should still apply, for the most part: Rainbow with composite - MOD preset for Sega Genesis Games
Those 2 passes from the mame_hlsl shader are doing the heavy lifting along with danny’s settings
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I have taken a little look into it and tried several options from the preset. Thanks for sharing your different game experience for Genesis games.
The rainbow has a different looking but it’s not “that accurate” as the one I’m trying to achieve or exposing through these presets. Without any intention to disregard your wonderful work into your preset, I’m looking up if there’s some way to make more accurate your rainbow effect more than what I could achieve with your preset. The rainbow sega preset versions I have shared here have the capability to allow in how separate from each other are those red/green/blue bars are from each other, which fits greatly the intended effect.
I think just saw some similar rainbow result in other preset around the forum months ago, but can’t really remember who was the one who posted it. Still, the result was very similar to the one achievable through this preset.
Here you can take a little view from what it looks like to me:
Here’s where you can see a video comparison from original hardware VS Genesis Plus GX with the effect: Rainbow with composite - MOD preset for Sega Genesis Games - RetroArch Additions / Shaders - Libretro Forums
Rainbow sega danny v4.0 video comparison demostration.mkv (dropbox.com)
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In the parameters did you switch the “NTSC Preset” to RF to achieve that? Maybe my memory fails me but I thought that rainbow effect showed with the composite NTSC Preset parameter since I definitely get that rainbow effect in the bar stage of SOR2:
The rainbow is even more prominent when you switch it to RF.
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Here it is, but in Sonic games is where I would like to see it more accurate though.
I think there’s another preset out there from a guy called Mr. falafel or similar username, but still not as accurate in the Sonic 2 pipes
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It’s strange you get the rainbow in the bar but not in sonic 2. I’m also curious of the tweaks you did to my shader preset. Mind posting up the settings that you used in your streets of rage 2 pic?
Depending on where they’re at in sonic 2 results may be different, as the sor2 shot is of a checkerboard “transparency”, whereas depending on what we’re looking at in sonic 2 it may be a different patter (the waterfall for example is just vertical lines with a empty space between each line".
I mean it may not matter at all, but differences on patterns could skew results imo (maybe I’m just talking out my ass idk 
)
Hue: 18.00
Hue vs Sat red: 0.45
NTSC preset: 2.00
This behavior happens to me the same as with Mr falafel’s preset for sega genesis. It shows the rainbow in streets of rage but the rainbow is NOT complete in sonic 2.
The opposite happens if you use my rainbow preset here in sonic 2 and then streets of rage where it does NOT show the rainbow.
But again, I have looked up another preset which i can’t remember it’s thread and the options were very similar to what are available with your preset with very similar result.
If there may be some way to make the rainbow more accurate in sonic 2, it would be seen better if I can know how to get ride of these black dots around the rainbow bars. It may have to be related to the scanlines but didn’t manage to find it.
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Sonic 2 chemical plant pipes are the best place I have ever found to see the rainbow effect as a sample to test the effect.
I figured it was the RF setting you used. I just leave it on auto and it usually just chooses composite. I’ll be on the look out to see how you solve this issue, it might the case ad Syh says and it’s just different patterns that cause the rainbow depending on the game
unfortunately, i don’t have a sample from Composite with rainbow for Streets of rage 2 in bar. If you ever knew, I could attempt to do more adjustments.
I used to have a sega genesis till some years ago with composite connection but not with streets of rage 2. At least I can tell you that Sonic 2 had this type of rainbow within it’s pipes… Let’s see if can find a little picture that took back then:
Tbc, the rainbow is definitely a thing that happens.
When I feel less dead, I’ll do s little digging into what sonic 2 has going on graphically there. (It might be a checkerboard pattern as well, or maybe it’s a color combination in tandem with the psuedo-transpariency effect that’s causing said rainbows.)
This is a very recent sample. Big thanks to the guy who made it possible.
So there it seems to match pretty well what is done with the rainbow sega v6.26 preset. This is how it looks to me with that version in streets of rage 2:
I will look if can give a bit more accurate rainbow with your 8-16bits preset, however I may really appreciate if this effect can be combined with OTHER composite-blurry looking shader/presets. I’d like if there was some way to mix the rainbow with other color tweaking shaders since Composite in sega genesis seem to affect some colors like yellow and blue (a bit lighter yellow/blue as far as I’m concerned. Also, take a look in Blargg: composite shader from GPGX settings to see more of this).
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rainbow sega v6.3 preset:
Took as reference those 2 pictures I have from a sega genesis I sold since a couple of years ago
Reminder that this version is intended for Genesis Plus GX with Borders set to Full (or left/right) in core options.
Well, I think @hunterk already mentioned how it could be done at least twice in this thread.
Perhaps @HyperspaceMadness, @guest.r or @DariusG can further break it down in layman’s terms and maybe walk us through the process using existing shaders that we might be more familiar with for example, HSM MegaBezel, CRT-Guest-Advance or GDV-Mini?
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rainbow sega v6.4. Thanks to Hunterk for his ntsc adaptive suggestion:
Don’t know Genesis model here but source is:
Real hardware Sega Genesis Sonic 1 connected with RF vs Genesis Plus GX rainbow sega v6.4
GPGX with borders set to full (and it should fit as well with BlastEm core).
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