*/
  public void clip_plane (int plane, double [] equation) {
    RequestOutputStream o = display.out;
    synchronized (o) {
      begin_render_request (o, 77, 40);
      o.write_double (equation [0]);
      o.write_double (equation [1]);
      o.write_double (equation [2]);
      o.write_double (equation [3]);
      o.write_int32 (plane);
    }
  }