   GL Texture transformations
  I've done this successfully before, but for some reason I can't get my head straight about this today.  I have a quad mapped to texcoords (0,0) in the bottom left and (1,1) in the top right.  If I want to rotate its texture around the center of the quad, what combination of translations and rotations would I need to go about doing that?   
  Nevermind.  I'm a moron.  I had a sign wrong on the "un-translate" call.   