Is it possible to color fnf notes similar to how the Psych engine does it?

Godot version: 4.2.2

Hey! So I’m currently making my own Friday Night Funkin’ engine in Godot, and I don’t exactly know much about shaders, but I want to make note colors similar to the Psych engine. (I think you can see the problem).
in Psych engine, each note has 3 pure colors (Red 255, Green 255, and Blue 255)
LEFT, not glowing, note colored
LEFT, not colored, glowing
The shader in Psych engine somewhat combines the colors’ values.
My goal is to color the notes like this:
LEFT, colored, not glowing
LEFT, colored, glowing
Obviously, they will not be the exact same, however I do want to make something similar.
I believe this can be done with distance shaders? I’m not entirely sure.
If anybody can, please help. Thanks in advance!