Newest version of your mod for 1.12.2

There are come color glitches. Ingame and in JEI. Maybe it is caused by optifine. I can test it without it if it'd help you.

Looks like shader issues to me. Try without shaders first.

You were absolutely right! It works without a shader. In case you want to fix the shader issue, I'm using this one: http://bitslablab.wixsite.com/main/bsl-shaders

Unfortunately, both of my integrated GPUs are too slow to handle any reasonable shader pack. Can't help you there, sorry.

I looked a bit though your code and tested a few things.
The default redstone wire and the bundled wire (uncoloured) are rendered properly. Only the colored ones have problems. Maybe this helps.
I thought this line was interesting int c = 0xFF000000 | EnumDyeColor.byMetadata(v).getColorValue(); but it should be all black if there is an error with that.

Found something that looked off, and fixed it in 0.5.5.5. Might help, might not. Let me know!

I'd check myself, but OptiFine crashes Mesa drivers on both of my Intel/Linux-powered laptops. And that's without shaders! :/

I'll test it! Have you already published it on Curse?
Feel free to send me jars for testing purposes

It's on my website. It will appear on Curse whenever they get around to it.

Okay. I'm currently at work. I'll test it in a few hours. Thanks for your work

Yep, it does work! The colors are now rendering perfect. Thank you :)

Excellent :)

I checked your website (https://charset.asie.pl/download/) but there is no version 0.5.5.5) and wasn't able to find a download from today

It was there all along, forgot to propagate the links. Fixed now.