All use the default GM:Studio vertex shader.
What they do:
These shaders simulate what a color-blind person would perceive when viewing one's game. There are different forms of color-blindness and these simulate common ones.
shDeuteranopia - simulates dueteranopia color-blindness
shProtanopia - simulates protanopia color-blindness
shTritanopia - simulates tritanopia color-blindness
The intended use is to render a game to a surface and draw the surface to the screen using one of the simulation shaders. In this way developers can identify game features which may be difficult to distinguish for people with limited color perception. From there one can go about recoloring these parts of the game or providing color-blind alternatives for those who desire them. These shaders are to aid development and are not intended to be present in the final game.
This project also includes a few other shaders which alter the color space in similar ways.
shDogVision - simulates the color perception of dogs
shDesaturate - grayscale conversion treats RGB channels equally
shLumCIE - grayscale conversion based on the CIE television standard
shLumNTSC - grayscale conversion based on the NTSC television standard
Dropbox - color-blindness-shaders.gmz