Rainbow with composite - MOD preset for Sega Genesis Games

I’m sorry for the mistake. I have confused myself with another file. Please take a look again in the rainbow v3.0 link. It should work now.

Hardly matters now with the new 4.0/4.1 version.

Wish me luck… Because it looks amazing on your end.

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Tried it again. It’s the same exact problem.

I even tried the new 3.0 you just linked.

Must be a hardware problem then… Maybe it’s meant for systems with dedicated GPUs or something. Oh well… :man_shrugging:

Or maybe the issue is that I need a “shaders” folder with all of the .slang files present.

Assuming placing it in it’s own folder in the “shaders_slang” folder isn’t a wrong move…

I wish at some point you can give these versions a try ! Decent GPUs are not that expensive. Thank you a lot for your interest into them !! Have a good day.

P.D: just has to be placed in the main shaders folder from Retroarch folder.

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That was the issue all along! :joy:

I just had to place it in the main folder, nowhere else!

The same thing happened to the 3.0 before the new link, so I assumed that the same would happen.

Now it looks great, though I still need to get a Laptop/PC with a good GPU, since it runs very slowly on it 30-40 FPS.

So basically a warning: Needs a good GPU to run it.


i hope at some point you can get a fluent experience. Good vibes to you for giving a try to those little things I found.


Apart from color, there are no perceptible differences between PAL and SECAM, in several shaders you have the option to change the color space.

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You didn’t read this, did you?


Well no. :sweat_smile:

Anyway, you have to have a little care with SECAM, when it comes to emulation, especially with old consolas like the 2600. In analog video or radio were very similar to PAL, but in consoles with decoded color it was something else.


Hey alex, did you manage to bring any try to these rainbow versions ? Not sure if people liked them or not, accurate or not, beautiful or ugly. Any feedback is welcome!

@ynnad4 Excuse the forgetfulness, I’ve had a lot of work.

In a first look, it looks very good, although my memories are not reliable to have them as a reference, I notice that the noise effect makes it look more as pointillist drawing than as the vibrant analog signal of a CRT TV.

Some errors. I can not see the scanlines in any way. Tvout Signal and Luma have no effect, they should change the resolution. And some properties have repeated values (Hum Bar Frequency, Shadow Mask UV, NTSC Color Carrier).

In general it looks very good, the rainbow effect is well achieved, but I feel very heavy and about loading options.

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Have you seen this shader preset @HyperspaceMadness?

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Yup, it’s a cool one :slight_smile:

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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.


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


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)


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.