k3d/share/shaders/k3d_dturb.sl:18:  width = filterwidth_point(PP);
k3d/share/shaders/k3d_stones.sl:53:#define filterwidth_point(p) (max(sqrt(area(p)), MINFILTERWIDTH))
k3d/share/shaders/k3d_stones.sl:161:       float width = filterwidth_point(PP);
