Fixed pipelines s*cks

Up to now, splatting was achieved using the fixed-pipeline. But 1/ PSSM needs for itself 3 texture units so I won’t be able to integrate this on a one-pass texture. And 2/ Fixed and programmable pipelines can’t deal together… I have to say good-bye to my old beloved fixed texture unit functions and switch to a full vertex shaders solution. That’s life…