コード例 #1
0
  protected void makeTessellatedLocations(
      Globe globe, int subdivisions, List<LatLon> locations, List<LatLon> tessellatedLocations) {
    ArrayList<Vec4> points = new ArrayList<Vec4>();
    for (LatLon ll : locations) {
      points.add(globe.computePointFromLocation(ll));
    }

    //noinspection StringEquality
    if (WWMath.computeWindingOrderOfLocations(locations) != AVKey.COUNTER_CLOCKWISE)
      Collections.reverse(locations);

    Vec4 centerPoint = Vec4.computeAveragePoint(points);
    Vec4 surfaceNormal = globe.computeSurfaceNormalAtPoint(centerPoint);

    int numPoints = points.size();
    float[] coords = new float[3 * numPoints];
    for (int i = 0; i < numPoints; i++) {
      points.get(i).toFloatArray(coords, 3 * i, 3);
    }

    GeometryBuilder gb = new GeometryBuilder();
    GeometryBuilder.IndexedTriangleArray tessellatedPoints =
        gb.tessellatePolygon(0, numPoints, coords, surfaceNormal);

    for (int i = 0; i < subdivisions; i++) {
      gb.subdivideIndexedTriangleArray(tessellatedPoints);
    }

    for (int i = 0; i < tessellatedPoints.getVertexCount(); i++) {
      Vec4 v = Vec4.fromFloatArray(tessellatedPoints.getVertices(), 3 * i, 3);
      tessellatedLocations.add(globe.computePositionFromPoint(v));
    }
  }
コード例 #2
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  @Override
  protected List<Vec4> computeMinimalGeometry(Globe globe, double verticalExaggeration) {
    double[] angles = this.computeAngles();
    // Angles are equal, fall back to building a closed cylinder.
    if (angles == null) return super.computeMinimalGeometry(globe, verticalExaggeration);

    double[] radii = this.getRadii();
    Matrix transform = this.computeTransform(globe, verticalExaggeration);

    GeometryBuilder gb = this.getGeometryBuilder();
    int count = gb.getPartialDiskVertexCount(MINIMAL_GEOMETRY_SLICES, MINIMAL_GEOMETRY_LOOPS);
    int numCoords = 3 * count;
    float[] verts = new float[numCoords];
    gb.makePartialDiskVertices(
        (float) radii[0],
        (float) radii[1], // Inner radius, outer radius.
        MINIMAL_GEOMETRY_SLICES,
        MINIMAL_GEOMETRY_LOOPS, // Slices, loops,
        (float) angles[0],
        (float) angles[2], // Start angle, sweep angle.
        verts);

    List<LatLon> locations = new ArrayList<LatLon>();
    for (int i = 0; i < numCoords; i += 3) {
      Vec4 v = new Vec4(verts[i], verts[i + 1], verts[i + 2]);
      v = v.transformBy4(transform);
      locations.add(globe.computePositionFromPoint(v));
    }

    ArrayList<Vec4> points = new ArrayList<Vec4>();
    this.makeExtremePoints(globe, verticalExaggeration, locations, points);

    return points;
  }
コード例 #3
0
  private void makePartialCylinderTerrainConformant(
      DrawContext dc,
      int slices,
      int stacks,
      float[] verts,
      double[] altitudes,
      boolean[] terrainConformant,
      Vec4 referenceCenter) {
    Globe globe = dc.getGlobe();
    Matrix transform = this.computeTransform(dc.getGlobe(), dc.getVerticalExaggeration());

    for (int i = 0; i <= slices; i++) {
      int index = i * (stacks + 1);
      index = 3 * index;
      Vec4 vec = new Vec4(verts[index], verts[index + 1], verts[index + 2]);
      vec = vec.transformBy4(transform);
      Position p = globe.computePositionFromPoint(vec);

      for (int j = 0; j <= stacks; j++) {
        double elevation = altitudes[j];
        if (terrainConformant[j])
          elevation += this.computeElevationAt(dc, p.getLatitude(), p.getLongitude());
        vec = globe.computePointFromPosition(p.getLatitude(), p.getLongitude(), elevation);

        index = j + i * (stacks + 1);
        index = 3 * index;
        verts[index] = (float) (vec.x - referenceCenter.x);
        verts[index + 1] = (float) (vec.y - referenceCenter.y);
        verts[index + 2] = (float) (vec.z - referenceCenter.z);
      }
    }
  }
コード例 #4
0
  private void makePartialDiskTerrainConformant(
      DrawContext dc,
      int numCoords,
      float[] verts,
      double altitude,
      boolean terrainConformant,
      Vec4 referenceCenter) {
    Globe globe = dc.getGlobe();
    Matrix transform = this.computeTransform(dc.getGlobe(), dc.getVerticalExaggeration());

    for (int i = 0; i < numCoords; i += 3) {
      Vec4 vec = new Vec4(verts[i], verts[i + 1], verts[i + 2]);
      vec = vec.transformBy4(transform);
      Position p = globe.computePositionFromPoint(vec);

      double elevation = altitude;
      if (terrainConformant)
        elevation += this.computeElevationAt(dc, p.getLatitude(), p.getLongitude());

      vec = globe.computePointFromPosition(p.getLatitude(), p.getLongitude(), elevation);
      verts[i] = (float) (vec.x - referenceCenter.x);
      verts[i + 1] = (float) (vec.y - referenceCenter.y);
      verts[i + 2] = (float) (vec.z - referenceCenter.z);
    }
  }
コード例 #5
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    protected boolean areShapesIntersecting(Airspace a1, Airspace a2) {
      if ((a1 instanceof SphereAirspace) && (a2 instanceof SphereAirspace)) {
        SphereAirspace s1 = (SphereAirspace) a1;
        SphereAirspace s2 = (SphereAirspace) a2;

        LatLon location1 = s1.getLocation();
        LatLon location2 = s2.getLocation();
        double altitude1 = s1.getAltitudes()[0];
        double altitude2 = s2.getAltitudes()[0];
        boolean terrainConforming1 = s1.isTerrainConforming()[0];
        boolean terrainConforming2 = s2.isTerrainConforming()[0];

        // We have to compute the 3D coordinates of the sphere's center ourselves here.
        Vec4 p1 =
            terrainConforming1
                ? this.getSurfacePoint(location1, altitude1)
                : this.getPoint(location1, altitude1);
        Vec4 p2 =
            terrainConforming2
                ? this.getSurfacePoint(location2, altitude2)
                : this.getPoint(location2, altitude2);
        double r1 = s1.getRadius();
        double r2 = s2.getRadius();

        double d = p1.distanceTo3(p2);

        return d <= (r1 + r2);
      }

      return false;
    }
コード例 #6
0
    /**
     * Performs one line of sight calculation between the reference position and a specified grid
     * position.
     *
     * @param gridPosition the grid position.
     * @throws InterruptedException if the operation is interrupted.
     */
    protected void performIntersection(Position gridPosition) throws InterruptedException {
      // Intersect the line between this grid point and the selected position.
      Intersection[] intersections = this.terrain.intersect(this.referencePosition, gridPosition);
      if (intersections == null || intersections.length == 0) {
        // No intersection, so the line goes from the center to the grid point.
        this.sightLines.add(new Position[] {this.referencePosition, gridPosition});
        return;
      }

      // Only the first intersection is shown.
      Vec4 iPoint = intersections[0].getIntersectionPoint();
      Vec4 gPoint =
          terrain.getSurfacePoint(
              gridPosition.getLatitude(), gridPosition.getLongitude(), gridPosition.getAltitude());

      // Check to see whether the intersection is beyond the grid point.
      if (iPoint.distanceTo3(this.referencePoint) >= gPoint.distanceTo3(this.referencePoint)) {
        // Intersection is beyond the grid point; the line goes from the center to the grid point.
        this.addSightLine(this.referencePosition, gridPosition);
        return;
      }

      // Compute the position corresponding to the intersection.
      Position iPosition = this.terrain.getGlobe().computePositionFromPoint(iPoint);

      // The sight line goes from the user-selected position to the intersection position.
      this.addSightLine(this.referencePosition, new Position(iPosition, 0));

      // Keep track of the intersection positions.
      this.addIntersectionPosition(iPosition);

      this.updateProgress();
    }
コード例 #7
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  public static void main(String[] args) {
    BarycentricPlanarShape bc = new BarycentricQuadrilateral(i0, i1, i2, i3);

    for (Vec4 point : testPoints) {
      double[] w = bc.getBarycentricCoords(point);
      Vec4 p = bc.getPoint(w);
      double[] uv = bc.getBilinearCoords(w[1], w[2]);

      System.out.printf(
          "%s, %s: ( %f, %f, %f) : ( %f, %f), %s\n",
          point, p, w[0], w[1], w[2], uv[0], uv[1], p.equals(point) ? "true" : "false");
    }
    //
    //        BarycentricPlanarShape bc = new BarycentricQuadrilateral(new Vec4(4, 3, 0), new
    // Vec4(7, 1, 0),
    //            new Vec4(10, 5, 0), new Vec4(7, 7, 0));
    //
    //        ArrayList<Vec4> points = makePoints(0, 0, 14, 10);
    //        for (Vec4 point : points)
    //        {
    //            double[] w = bc.getBarycentricCoords(point);
    //            Vec4 p = bc.getPoint(w);
    //            double[] uv = bc.getBilinearCoords(w[1], w[2]);
    //
    //            System.out.printf("%s, %s: ( %f, %f, %f) : ( %f, %f), %s\n",
    //                point, p, w[0], w[1], w[2], uv[0], uv[1], p.equals(point) ? "true" : "false");
    //        }
  }
コード例 #8
0
  private void makeRadialWallTerrainConformant(
      DrawContext dc,
      int pillars,
      int stacks,
      float[] verts,
      double[] altitudes,
      boolean[] terrainConformant,
      Vec4 referenceCenter) {
    Globe globe = dc.getGlobe();
    Matrix transform = this.computeTransform(dc.getGlobe(), dc.getVerticalExaggeration());

    for (int p = 0; p <= pillars; p++) {
      int index = p;
      index = 3 * index;
      Vec4 vec = new Vec4(verts[index], verts[index + 1], verts[index + 2]);
      vec = vec.transformBy4(transform);
      Position pos = globe.computePositionFromPoint(vec);

      for (int s = 0; s <= stacks; s++) {
        double elevation = altitudes[s];
        if (terrainConformant[s])
          elevation += this.computeElevationAt(dc, pos.getLatitude(), pos.getLongitude());
        vec = globe.computePointFromPosition(pos.getLatitude(), pos.getLongitude(), elevation);

        index = p + s * (pillars + 1);
        index = 3 * index;
        verts[index] = (float) (vec.x - referenceCenter.x);
        verts[index + 1] = (float) (vec.y - referenceCenter.y);
        verts[index + 2] = (float) (vec.z - referenceCenter.z);
      }
    }
  }
コード例 #9
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  protected void requestTile(DrawContext dc, Tile tile) {
    Vec4 centroid = dc.getGlobe().computePointFromPosition(tile.getSector().getCentroid(), 0);
    if (this.getReferencePoint() != null)
      tile.setPriority(centroid.distanceTo3(this.getReferencePoint()));

    RequestTask task = new RequestTask(tile, this);
    this.getRequestQ().add(task);
  }
コード例 #10
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  protected static boolean isNameVisible(
      DrawContext dc, PlaceNameService service, Position namePosition) {
    double elevation = dc.getVerticalExaggeration() * namePosition.getElevation();
    Vec4 namePoint =
        dc.getGlobe()
            .computePointFromPosition(
                namePosition.getLatitude(), namePosition.getLongitude(), elevation);
    Vec4 eyeVec = dc.getView().getEyePoint();

    double dist = eyeVec.distanceTo3(namePoint);
    return dist >= service.getMinDisplayDistance() && dist <= service.getMaxDisplayDistance();
  }
コード例 #11
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  private void makeCap(
      DrawContext dc,
      GeometryBuilder.IndexedTriangleArray ita,
      double altitude,
      boolean terrainConformant,
      int orientation,
      Matrix locationTransform,
      Vec4 referenceCenter,
      int indexPos,
      int[] indices,
      int vertexPos,
      float[] vertices,
      float[] normals) {
    GeometryBuilder gb = this.getGeometryBuilder();
    Globe globe = dc.getGlobe();

    int indexCount = ita.getIndexCount();
    int vertexCount = ita.getVertexCount();
    int[] locationIndices = ita.getIndices();
    float[] locationVerts = ita.getVertices();

    this.copyIndexArray(
        indexCount,
        (orientation == GeometryBuilder.INSIDE),
        locationIndices,
        vertexPos,
        indexPos,
        indices);

    for (int i = 0; i < vertexCount; i++) {
      int index = 3 * i;
      Vec4 vec = new Vec4(locationVerts[index], locationVerts[index + 1], locationVerts[index + 2]);
      vec = vec.transformBy4(locationTransform);

      Position pos = globe.computePositionFromPoint(vec);
      vec =
          this.computePointFromPosition(
              dc, pos.getLatitude(), pos.getLongitude(), altitude, terrainConformant);

      index = 3 * (vertexPos + i);
      vertices[index] = (float) (vec.x - referenceCenter.x);
      vertices[index + 1] = (float) (vec.y - referenceCenter.y);
      vertices[index + 2] = (float) (vec.z - referenceCenter.z);
    }

    gb.makeIndexedTriangleArrayNormals(
        indexPos, indexCount, indices, vertexPos, vertexCount, vertices, normals);
  }
コード例 #12
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  private void makeSectionVertices(
      DrawContext dc,
      int locationPos,
      float[] locations,
      double[] altitude,
      boolean[] terrainConformant,
      int subdivisions,
      Matrix locationTransform,
      Vec4 referenceCenter,
      int vertexPos,
      float[] vertices) {
    GeometryBuilder gb = this.getGeometryBuilder();
    int numPoints = gb.getSubdivisionPointsVertexCount(subdivisions);

    Globe globe = dc.getGlobe();
    int index1 = 3 * locationPos;
    int index2 = 3 * (locationPos + 1);

    float[] locationVerts = new float[3 * numPoints];
    gb.makeSubdivisionPoints(
        locations[index1],
        locations[index1 + 1],
        locations[index1 + 2],
        locations[index2],
        locations[index2 + 1],
        locations[index2 + 2],
        subdivisions,
        locationVerts);

    for (int i = 0; i < numPoints; i++) {
      int index = 3 * i;
      Vec4 vec = new Vec4(locationVerts[index], locationVerts[index + 1], locationVerts[index + 2]);
      vec = vec.transformBy4(locationTransform);
      Position pos = globe.computePositionFromPoint(vec);

      for (int j = 0; j < 2; j++) {
        vec =
            this.computePointFromPosition(
                dc, pos.getLatitude(), pos.getLongitude(), altitude[j], terrainConformant[j]);

        index = 2 * i + j;
        index = 3 * (vertexPos + index);
        vertices[index] = (float) (vec.x - referenceCenter.x);
        vertices[index + 1] = (float) (vec.y - referenceCenter.y);
        vertices[index + 2] = (float) (vec.z - referenceCenter.z);
      }
    }
  }
コード例 #13
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  protected Extent computeExtent(Globe globe, double verticalExaggeration) {
    List<Vec4> points = this.computeMinimalGeometry(globe, verticalExaggeration);
    if (points == null || points.isEmpty()) return null;

    // Add a point at the center of this polygon to the points used to compute its extent. The
    // center point captures
    // the curvature of the globe when the polygon's minimal geometry only contain any points near
    // the polygon's
    // edges.
    Vec4 centerPoint = Vec4.computeAveragePoint(points);
    LatLon centerLocation = globe.computePositionFromPoint(centerPoint);
    this.makeExtremePoints(globe, verticalExaggeration, Arrays.asList(centerLocation), points);

    return Box.computeBoundingBox(points);
  }
コード例 #14
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  /**
   * Compute points on either side of a line segment. This method requires a point on the line, and
   * either a next point, previous point, or both.
   *
   * @param point Center point about which to compute side points.
   * @param prev Previous point on the line. May be null if {@code next} is non-null.
   * @param next Next point on the line. May be null if {@code prev} is non-null.
   * @param leftPositions Left position will be added to this list.
   * @param rightPositions Right position will be added to this list.
   * @param halfWidth Distance from the center line to the left or right lines.
   * @param globe Current globe.
   */
  protected void generateParallelPoints(
      Vec4 point,
      Vec4 prev,
      Vec4 next,
      List<Position> leftPositions,
      List<Position> rightPositions,
      double halfWidth,
      Globe globe) {
    if ((point == null) || (prev == null && next == null)) {
      String message = Logging.getMessage("nullValue.PointIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (leftPositions == null || rightPositions == null) {
      String message = Logging.getMessage("nullValue.PositionListIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (globe == null) {
      String message = Logging.getMessage("nullValue.GlobeIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }

    Vec4 offset;
    Vec4 normal = globe.computeSurfaceNormalAtPoint(point);

    // Compute vector in the direction backward along the line.
    Vec4 backward = (prev != null) ? prev.subtract3(point) : point.subtract3(next);

    // Compute a vector perpendicular to segment BC, and the globe normal vector.
    Vec4 perpendicular = backward.cross3(normal);

    double length;
    // If both next and previous points are supplied then calculate the angle that bisects the angle
    // current, next, prev.
    if (next != null && prev != null && !Vec4.areColinear(prev, point, next)) {
      // Compute vector in the forward direction.
      Vec4 forward = next.subtract3(point);

      // Calculate the vector that bisects angle ABC.
      offset = forward.normalize3().add3(backward.normalize3());
      offset = offset.normalize3();

      // Compute the scalar triple product of the vector BC, the normal vector, and the offset
      // vector to
      // determine if the offset points to the left or the right of the control line.
      double tripleProduct = perpendicular.dot3(offset);
      if (tripleProduct < 0) {
        offset = offset.multiply3(-1);
      }

      // Determine the length of the offset vector that will keep the left and right lines parallel
      // to the control
      // line.
      Angle theta = backward.angleBetween3(offset);
      if (!Angle.ZERO.equals(theta)) length = halfWidth / theta.sin();
      else length = halfWidth;
    } else {
      offset = perpendicular.normalize3();
      length = halfWidth;
    }
    offset = offset.multiply3(length);

    // Determine the left and right points by applying the offset.
    Vec4 ptRight = point.add3(offset);
    Vec4 ptLeft = point.subtract3(offset);

    // Convert cartesian points to geographic.
    Position posLeft = globe.computePositionFromPoint(ptLeft);
    Position posRight = globe.computePositionFromPoint(ptRight);

    leftPositions.add(posLeft);
    rightPositions.add(posRight);
  }
コード例 #15
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  public static double[] invertBilinear(Vec4 U, Vec4 X, Vec4 Y, Vec4 Z, Vec4 W) {
    Vec4 s1 = W.subtract3(X);
    Vec4 s2 = Z.subtract3(Y);
    Vec4 UminX = U.subtract3(X);
    Vec4 UminY = U.subtract3(Y);
    Vec4 normal = Z.subtract3(X).cross3(W.subtract3(Y));

    double A = s1.cross3(s2).dot3(normal);
    double B = s2.cross3(UminX).dot3(normal) - s1.cross3(UminY).dot3(normal);
    double C = UminX.cross3(UminY).dot3(normal);

    double descriminant = B * B - 4d * A * C;
    if (descriminant < 0) return null;
    descriminant = Math.sqrt(descriminant);

    double beta = B > 0 ? (-B - descriminant) / (2d * A) : 2d * C / (-B + descriminant);

    Vec4 Sbeta1 = Vec4.mix3(beta, X, W);
    Vec4 Sbeta2 = Vec4.mix3(beta, Y, Z);

    double alpha =
        U.subtract3(Sbeta1).dot3(Sbeta2.subtract3(Sbeta1)) / Sbeta2.subtract3(Sbeta1).dotSelf3();

    return new double[] {alpha, beta};
  }
コード例 #16
0
ファイル: SearchArea.java プロジェクト: metsci/worldwind
  /**
   * 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);
  }
コード例 #17
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  protected int computeCartesianPolygon(
      Globe globe,
      List<? extends LatLon> locations,
      List<Boolean> edgeFlags,
      Vec4[] points,
      Boolean[] edgeFlagArray,
      Matrix[] transform) {
    if (globe == null) {
      String message = Logging.getMessage("nullValue.GlobeIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (locations == null) {
      String message = "nullValue.LocationsIsNull";
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (points == null) {
      String message = "nullValue.LocationsIsNull";
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (points.length < (1 + locations.size())) {
      String message =
          Logging.getMessage(
              "generic.ArrayInvalidLength", "points.length < " + (1 + locations.size()));
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (transform == null) {
      String message = "nullValue.TransformIsNull";
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }
    if (transform.length < 1) {
      String message = Logging.getMessage("generic.ArrayInvalidLength", "transform.length < 1");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }

    // Allocate space to hold the list of locations and location vertices.
    int locationCount = locations.size();

    // Compute the cartesian points for each location.
    for (int i = 0; i < locationCount; i++) {
      LatLon ll = locations.get(i);
      points[i] = globe.computePointFromPosition(ll.getLatitude(), ll.getLongitude(), 0.0);

      if (edgeFlagArray != null) edgeFlagArray[i] = (edgeFlags != null) ? edgeFlags.get(i) : true;
    }

    // Compute the average of the cartesian points.
    Vec4 centerPoint = Vec4.computeAveragePoint(Arrays.asList(points));

    // Test whether the polygon is closed. If it is not closed, repeat the first vertex.
    if (!points[0].equals(points[locationCount - 1])) {
      points[locationCount] = points[0];
      if (edgeFlagArray != null) edgeFlagArray[locationCount] = edgeFlagArray[0];

      locationCount++;
    }

    // Compute a transform that will map the cartesian points to a local coordinate system centered
    // at the average
    // of the points and oriented with the globe surface.
    Position centerPos = globe.computePositionFromPoint(centerPoint);
    Matrix tx = globe.computeSurfaceOrientationAtPosition(centerPos);
    Matrix txInv = tx.getInverse();
    // Map the cartesian points to a local coordinate space.
    for (int i = 0; i < locationCount; i++) {
      points[i] = points[i].transformBy4(txInv);
    }

    transform[0] = tx;

    return locationCount;
  }
コード例 #18
0
  /**
   * Determines whether this sector intersects the specified geographic line segment. The line
   * segment is specified by a begin location and an end location. The locations are are assumed to
   * be connected by a linear path in geographic space. This returns true if any location along that
   * linear path intersects this sector, including the begin and end locations.
   *
   * @param begin the line segment begin location.
   * @param end the line segment end location.
   * @return true <code>true</code> if this sector intersects the line segment, otherwise <code>
   *     false</code>.
   * @throws IllegalArgumentException if either the begin location or the end location is null.
   */
  public boolean intersectsSegment(LatLon begin, LatLon end) {
    if (begin == null) {
      throw new IllegalArgumentException("Begin Is Null");
    }

    if (end == null) {
      throw new IllegalArgumentException("End Is Null");
    }

    Vec4 segmentBegin = new Vec4(begin.getLongitude().degrees, begin.getLatitude().degrees, 0);
    Vec4 segmentEnd = new Vec4(end.getLongitude().degrees, end.getLatitude().degrees, 0);
    Vec4 tmp = segmentEnd.subtract3(segmentBegin);
    Vec4 segmentCenter = segmentBegin.add3(segmentEnd).divide3(2);
    Vec4 segmentDirection = tmp.normalize3();
    double segmentExtent = tmp.getLength3() / 2.0;

    LatLon centroid = this.getCentroid();
    Vec4 boxCenter = new Vec4(centroid.getLongitude().degrees, centroid.getLatitude().degrees, 0);
    double boxExtentX = this.getDeltaLonDegrees() / 2.0;
    double boxExtentY = this.getDeltaLatDegrees() / 2.0;

    Vec4 diff = segmentCenter.subtract3(boxCenter);

    if (Math.abs(diff.x) > (boxExtentX + segmentExtent * Math.abs(segmentDirection.x))) {
      return false;
    }

    if (Math.abs(diff.y) > (boxExtentY + segmentExtent * Math.abs(segmentDirection.y))) {
      return false;
    }

    //noinspection SuspiciousNameCombination
    Vec4 segmentPerp = new Vec4(segmentDirection.y, -segmentDirection.x, 0);

    return Math.abs(segmentPerp.dot3(diff))
        <= (boxExtentX * Math.abs(segmentPerp.x) + boxExtentY * Math.abs(segmentPerp.y));
  }
コード例 #19
0
ファイル: SearchArea.java プロジェクト: metsci/worldwind
  /**
   * 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);
  }