k3d/share/shaders/k3d_fire.sl:47:  surface_opac = union(surface_opac, layer_opac);
k3d/share/shaders/k3d_graphic_lines.sl:311:#define union(a,b) ((a) + (b) - (a) * (b))
k3d/share/shaders/k3d_graphic_lines.sl:359:	gline_opac = union(gline_opac, layer_opac);
k3d/share/shaders/k3d_graphic_lines.sl:374:	gline_opac = union(gline_opac, layer_opac);
k3d/share/shaders/k3d_toonmap.sl:105:#define union(a,b) ((a) + (b) - (a) * (b))
k3d/share/shaders/k3d_toonmap.sl:153:toon_opac = union(toon_opac, layer_opac);
k3d/share/shaders/k3d_toonmap.sl:168:toon_opac = union(toon_opac, layer_opac);
