We were generating a texture without ever setting the data to a known value.
This happened on the old code as well, just that PP shaders are receiving some love and people are using it and noticing some of its issues.
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.
