I have never played doom but I do have a idea for graphics filt can set deco color of something made by cray if the cray particle line passes through it also filt has blue,cyan,green,yellow, and red so you could have 2^29 colors(I think) hopefully that helps

edit:or 536,870,912 colors which is way more than you need

well kinda, to be honest its not DECO its more like SPECTRA + its better not because hardware for that would be extremely hard to do

Oh

edit:Maybe make a little piece of code that shortens it to 8 bits