k3d/share/shaders/k3d_uberlight.sl:352:  point Pb2 = transform(blockercoords, P2);
k3d/share/shaders/k3d_uberlight.sl:354:  if(zcomp(Pb2) * zcomp(Pb1) < 0)
k3d/share/shaders/k3d_uberlight.sl:356:      vector Vlight = (Pb1 - Pb2);
