I'm not sure when things broke on my laptop (I thought I got warp and
fisheye working on my laptop), but it turns out things weren't quite
right, thus warp (and presumably fisheye) weren't working properly due
to GLSL errors that I only just noticed. This fixes water warp (and
probably fisheye).
Finally, after a decade :P Looks pretty good, too, and is (almost)
properly scaled to the resolution (almost because the effect is a little
squashed, but I think the sw renderer does the same).
