static L<Pt> wrapLongBufferAsPtList(LongBuffer buf default new LongBuffer) {
  ret new RandomAccessAbstractList<Pt>() {
    public int size() { ret buf.size(); }
    
    public Pt get(int i) {
      ret longToPt(buf.get(i));
    }
    
    public Pt set(int i, Pt val) {
      Pt old = get(i);
      buf.set(i, ptToLong(val));
      ret old;
    }
    
    public bool add(Pt p) {
      buf.add(ptToLong(p));
      true;
    }
  };
}