private static void renderHull(PtEntry pt) {
    Inf inf = Inf.create();
    int count = 30;
    PtEntry ptStart = pt;
    do {
      inf.update();
      if (pt.prev(true) != null) {
        boolean valley = false;

        valley =
            (pt.prev(true).source() == pt.source() && pt.prev(true).orig().next(true) != pt.orig());

        V.pushColor(MyColor.cBLUE);
        V.pushStroke(valley ? STRK_RUBBERBAND : STRK_THICK);
        V.drawLine(pt.prev(true), pt);
        V.pop(2);
      }
      V.pushColor(MyColor.cDARKGREEN);
      V.mark(pt, MARK_DISC, .6);
      V.pop();
      if (Editor.withLabels(true)) {
        StringBuilder sb = new StringBuilder();
        sb.append(" #" + pt.id());
        if (pt.source() != null) sb.append(" <" + pt.source() + ">");

        V.pushScale(.6);
        V.draw(sb.toString(), MyMath.ptOnCircle(pt, MyMath.radians(30), 3), TX_FRAME | TX_BGND);
        V.pop();
      }
      pt = pt.next(true);
      if (count-- == 0) V.draw("too many points rendering!", 50, 50, TX_CLAMP);
    } while (pt != ptStart && count > 0);
  }
  public void paintView() {
    if (simple != null) simple.fill(MyColor.cLIGHTGRAY);

    Editor.render();
    // T.show(traceHull);

    COper3.dbPaint();

    if (traceHullPt != null) {
      renderHull(traceHullPt);
    }

    T.show(possHull, MyColor.cDARKGREEN, STRK_THICK, -1);
    T.show(valleyTri, MyColor.cDARKGREEN, STRK_RUBBERBAND, -1);
    T.show(traceValley, null, -1, -1);
    T.show(focusPt, MyColor.cRED, -1, MARK_DISC);
  }