/**
   * Compute the amount of rotation to apply to a label in order to keep it oriented toward its
   * orientation position.
   *
   * @param screenPoint Geographic position of the text, projected onto the screen.
   * @param orientationScreenPoint Orientation position, projected onto the screen.
   * @return The rotation angle to apply when drawing the label.
   */
  protected Angle computeRotation(Vec4 screenPoint, Vec4 orientationScreenPoint) {
    // Determine delta between the orientation position and the label position
    double deltaX = screenPoint.x - orientationScreenPoint.x;
    double deltaY = screenPoint.y - orientationScreenPoint.y;

    if (deltaX != 0) {
      double angle = Math.atan(deltaY / deltaX);
      return Angle.fromRadians(angle);
    } else {
      return Angle.POS90; // Vertical label
    }
  }
    public AppFrame() {
      super(true, true, false);

      IconLayer layer = new IconLayer();
      layer.setPickEnabled(true);
      layer.setAllowBatchPicking(false);
      layer.setRegionCulling(true);

      UserFacingIcon icon =
          new UserFacingIcon(
              "src/images/32x32-icon-nasa.png",
              new Position(Angle.fromRadians(0), Angle.fromRadians(0), 0));
      icon.setSize(new Dimension(24, 24));
      layer.addIcon(icon);

      icon =
          new UserFacingIcon(
              "src/images/32x32-icon-nasa.png",
              new Position(Angle.fromRadians(0.1), Angle.fromRadians(0.0), 0));
      icon.setSize(new Dimension(24, 24));
      layer.addIcon(icon);

      icon =
          new UserFacingIcon(
              "src/images/32x32-icon-nasa.png",
              new Position(Angle.fromRadians(0.0), Angle.fromRadians(0.1), 0));
      icon.setSize(new Dimension(24, 24));
      layer.addIcon(icon);

      icon =
          new UserFacingIcon(
              "src/images/32x32-icon-nasa.png",
              new Position(Angle.fromRadians(0.1), Angle.fromRadians(0.1), 0));
      icon.setSize(new Dimension(24, 24));
      layer.addIcon(icon);

      icon =
          new UserFacingIcon(
              "src/images/32x32-icon-nasa.png",
              new Position(Angle.fromRadians(0), Angle.fromDegrees(180), 0));
      icon.setSize(new Dimension(24, 24));
      layer.addIcon(icon);

      ApplicationTemplate.insertAfterPlacenames(this.getWwd(), layer);

      this.getWwd()
          .addSelectListener(
              new SelectListener() {
                @Override
                public void selected(SelectEvent event) {
                  if (event.getEventAction().equals(SelectEvent.ROLLOVER)) {
                    PickedObjectList pol = event.getObjects();
                    System.out.println(" Picked Objects Size " + pol.size());
                    for (PickedObject po : pol) {
                      System.out.println(
                          " Class "
                              + po.getObject().getClass().getName()
                              + "  isTerrian="
                              + po.isTerrain());
                    }
                  }
                }
              });
      this.getWwd().getSceneController().setDeepPickEnabled(true);
    }