Seems mesa has a quirk where
define THING(x) (#x)
is the same as
define THING(x) (##x)
Didn't realize I messed it up since it just worked since I only tested on Mesa.
This class loads all the common PP shader configuration options and passes those options through to a inherited class that OpenGL or D3D will have.
Makes it so all the common code for PP shaders is in VideoCommon instead of duplicating the code across each backend.