GBJAM is coming up this weekend (it's a jam where the only rules are that the game has to be 4 colors and 160x144, a la the Game Boy). I was thinking about how to do Super Game Boy-style palette swaps game-wide. I was experimenting with extending FlxSprite to a new class called a GBSprite, which automatically does 4 replaceColors when created based on whatever the palette is, but I worry that might get too resource-intensive. Camera filters seem like a more efficient way to go, but it seems a lot harder to define a custom 4 color palette using that RGBA matrix.
Anybody else doing the GBJAM that might have some ideas about how to set up swappable game-wide 4 color palettes?