protected void assembleVertexControlPoints(DrawContext dc) {
    Terrain terrain = dc.getTerrain();
    ExtrudedPolygon polygon = this.getPolygon();

    Position refPos = polygon.getReferencePosition();
    Vec4 refPoint = terrain.getSurfacePoint(refPos.getLatitude(), refPos.getLongitude(), 0);

    int altitudeMode = polygon.getAltitudeMode();
    double height = polygon.getHeight();

    Vec4 vaa = null;
    double vaaLength = 0; // used to compute independent length of each cap vertex
    double vaLength = 0;

    int i = 0;
    for (LatLon location : polygon.getOuterBoundary()) {
      Vec4 vert;

      // Compute the top/cap point.
      if (altitudeMode == WorldWind.CONSTANT || !(location instanceof Position)) {
        if (vaa == null) {
          // Compute the vector lengths of the top and bottom points at the reference position.
          vaa = refPoint.multiply3(height / refPoint.getLength3());
          vaaLength = vaa.getLength3();
          vaLength = refPoint.getLength3();
        }

        // Compute the bottom point, which is on the terrain.
        vert = terrain.getSurfacePoint(location.getLatitude(), location.getLongitude(), 0);

        double delta = vaLength - vert.dot3(refPoint) / vaLength;
        vert = vert.add3(vaa.multiply3(1d + delta / vaaLength));
      } else if (altitudeMode == WorldWind.RELATIVE_TO_GROUND) {
        vert =
            terrain.getSurfacePoint(
                location.getLatitude(),
                location.getLongitude(),
                ((Position) location).getAltitude());
      } else // WorldWind.ABSOLUTE
      {
        vert =
            terrain
                .getGlobe()
                .computePointFromPosition(
                    location.getLatitude(),
                    location.getLongitude(),
                    ((Position) location).getAltitude() * terrain.getVerticalExaggeration());
      }

      Position vertexPosition = this.wwd.getModel().getGlobe().computePositionFromPoint(vert);

      this.controlPoints.add(
          new ControlPointMarker(
              MOVE_VERTEX_ACTION, vertexPosition, vert, this.vertexControlAttributes, i));
      i++;
    }
  }
Beispiel #2
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  /**
   * Compute the positions of the arrow head of the graphic's legs.
   *
   * @param dc Current draw context
   * @param base Position of the arrow's starting point.
   * @param tip Position of the arrow head tip.
   * @param arrowLength Length of the arrowhead as a fraction of the total line length.
   * @param arrowAngle Angle of the arrow head.
   * @return Positions required to draw the arrow head.
   */
  protected List<Position> computeArrowheadPositions(
      DrawContext dc, Position base, Position tip, double arrowLength, Angle arrowAngle) {
    // Build a triangle to represent the arrowhead. The triangle is built from two vectors, one
    // parallel to the
    // segment, and one perpendicular to it.

    Globe globe = dc.getGlobe();

    Vec4 ptA = globe.computePointFromPosition(base);
    Vec4 ptB = globe.computePointFromPosition(tip);

    // Compute parallel component
    Vec4 parallel = ptA.subtract3(ptB);

    Vec4 surfaceNormal = globe.computeSurfaceNormalAtPoint(ptB);

    // Compute perpendicular component
    Vec4 perpendicular = surfaceNormal.cross3(parallel);

    double finalArrowLength = arrowLength * parallel.getLength3();
    double arrowHalfWidth = finalArrowLength * arrowAngle.tanHalfAngle();

    perpendicular = perpendicular.normalize3().multiply3(arrowHalfWidth);
    parallel = parallel.normalize3().multiply3(finalArrowLength);

    // Compute geometry of direction arrow
    Vec4 vertex1 = ptB.add3(parallel).add3(perpendicular);
    Vec4 vertex2 = ptB.add3(parallel).subtract3(perpendicular);

    return TacticalGraphicUtil.asPositionList(globe, vertex1, vertex2, ptB);
  }
Beispiel #3
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  /**
   * Determine the positions that make up the arrowhead.
   *
   * @param dc Current draw context.
   * @param startPosition Position of the arrow's base.
   * @param endPosition Position of the arrow head tip.
   * @return Positions that define the arrowhead.
   */
  protected List<Position> computeArrowheadPositions(
      DrawContext dc, Position startPosition, Position endPosition) {
    Globe globe = dc.getGlobe();

    // Arrowhead looks like this:
    //                  _
    //        A\         | 1/2 width
    // ________B\       _|
    // Pt. 1    /
    //        C/
    //         | |
    //      Length

    Vec4 p1 = globe.computePointFromPosition(startPosition);
    Vec4 pB = globe.computePointFromPosition(endPosition);

    // Find vector in the direction of the arrow
    Vec4 vB1 = p1.subtract3(pB);

    double arrowLengthFraction = this.getArrowLength();

    // Find the point at the base of the arrowhead
    Vec4 arrowBase = pB.add3(vB1.multiply3(arrowLengthFraction));

    Vec4 normal = globe.computeSurfaceNormalAtPoint(arrowBase);

    // Compute the length of the arrowhead
    double arrowLength = vB1.getLength3() * arrowLengthFraction;
    double arrowHalfWidth = arrowLength * this.getArrowAngle().tanHalfAngle();

    // Compute a vector perpendicular to the segment and the normal vector
    Vec4 perpendicular = vB1.cross3(normal);
    perpendicular = perpendicular.normalize3().multiply3(arrowHalfWidth);

    // Find points A and C
    Vec4 pA = arrowBase.add3(perpendicular);
    Vec4 pC = arrowBase.subtract3(perpendicular);

    return TacticalGraphicUtil.asPositionList(globe, pA, pB, pC);
  }