public int compare(Drawable3D d1, Drawable3D d2) {
/*
Drawable3D d1 = (Drawable3D) arg1;
Drawable3D d2 = (Drawable3D) arg2;
*/
return d1.comparePickingTo(d2, false);
}
public int compare(TreeSet<Drawable3D> set1, TreeSet<Drawable3D> set2) {
/*
TreeSet set1 = (TreeSet) arg1;
TreeSet set2 = (TreeSet) arg2;
*/
// check if one set is empty
if (set1.isEmpty()) return 1;
if (set2.isEmpty()) return -1;
Drawable3D d1 = (Drawable3D) set1.first();
Drawable3D d2 = (Drawable3D) set2.first();
return d1.comparePickingTo(d2, true);
}