By JoshA single object that has too highly saturated of a color can look out of place in your game level. This post-processing effect will convert each screen pixel to HSV, clamp the saturation with a specified range, and then convert back to RGB and display the result. Unlike a regular desaturation filter, pixels that are already within the allowed range will be unaffected.
By JoshThis adds a layer of noise to the screen. It was meant as a radiation effect but could also be used for film grain.