* should be allocated by the user.   * @return <code>true</code> if the segment intersects the point,   *  <code>false</code> if the segment does not intersect the object.   */   public static boolean segmentAndPoint( PickSegment segment, Point3d pnt, 					 double dist[] ) {        Point3d start = new Point3d();    Point3d end = new Point3d();    Vector3d direction = new Vector3d();        segment.get(start, end);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;    if((rayAndPoint(pnt, start, direction, dist)==true) && (dist[0] <= 1.0))      return true;        return false;  }  /**   * Return true if point intersects with segment and the distance, from   * the start of segment to the intersection point, is stored in dist[0].   *   * @param segment The segment that is used in intersection test.   * @param pnt The point that is used in intersection test.   * @param dist On return dist[0] contains the distance between segment's start and the point    * intersection, if exist.   * @return true if segment intersects point, else return false.   */   public static boolean segmentAndPoint( PickSegment segment, Point3f pnt, 					 double dist[] ) {        Point3d start = new Point3d();    Point3d end = new Point3d();    Vector3d direction = new Vector3d();        segment.get(start, end);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;    if((rayAndPoint(new Point3d(pnt), start, direction, dist)==true)        && (dist[0] <= 1.0))      return true;        return false;  }  /**   * Determines if the <code>PickPoint</code> and <code>Point3d</code>   * objects intersect.     *   * @param point The PickPoint that is used in the intersection test.   * @param pnt The Point3d that is used in intersection test.   * @return <code>true</code> if the PickPoint and Point3d objects   *  intersect, <code>false</code> if the do not intersect.   */   public static boolean pointAndPoint( PickPoint point, Point3d pnt) {        Point3d location = new Point3d();        point.get(location);    if ((location.x == pnt.x) && (location.y == pnt.y) &&       (location.z == pnt.z))      return true;         return false;  }  /**   * Return true if pnt intersects with point.   *   * @param point The point that is used in intersection test.   * @param pnt The point that is used in intersection test.   * @return true if point intersects pnt, else return false.   */     public static boolean pointAndPoint( PickPoint point, Point3f pnt) {        Point3d location = new Point3d();        point.get(location);        if(((float) location.x == pnt.x) && ((float) location.y == pnt.y)        && ((float) location.z == pnt.z))      return true;        return false;  }    /**   * Determines if the <code>PickRay</code> and Line   * objects intersect.     * The line is defined as <code>coordinates[index]</code> to   * <code>coordinates[index+1]</code>.   *   * @param ray The ray that is used in the intersection test.   * @param coordinates An array holding the line data.   * @param dist On return dist[0] contains the distance between ray's origin and the point of   * intersection, if it exists. The dist array   * should be allocated by the user.   * @return <code>true</code> if the ray intersects the line,   *  <code>false</code> if the ray does not intersect the object.   */   public static boolean rayAndLine(PickRay ray, Point3d coordinates[],                                   int index,  				   double dist[] ) {    Point3d origin = new Point3d();    Vector3d direction = new Vector3d();    if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect11"));           ray.get(origin, direction);    Point3d start = coordinates[index++];    Point3d end = coordinates[index];        return lineAndRay( start, end, origin, direction, dist );      }  /**   * Return true if line intersects with ray and the distance, from   * the origin of ray to the intersection point, is stored in dist[0].   * The line is defined by coordinates[index] to coordinates[index+1]   *   * @param ray The ray that is used in intersection test.   * @param coordinates an array of vertices.   * @param index the vertex index   * @param dist On return dist[0] contains the distance between ray's origin and the point intersection, if   * exist.   * @return true if ray intersects line, else return false.   */   public static boolean rayAndLine(PickRay ray, Point3f coordinates[], int index,  				   double dist[] ) {    Point3d origin = new Point3d();    Vector3d direction = new Vector3d();    if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect11"));           ray.get(origin, direction);    Point3d start = new Point3d(coordinates[index++]);    Point3d end = new Point3d(coordinates[index]);        return lineAndRay( start, end, origin, direction, dist );      }    /**   * Determines if the <code>PickSegment</code> and Line   * objects intersect.   * The line is defined as <code>coordinates[index]</code> to   * <code>coordinates[index+1]</code>.   *   * @param segment The segment that is used in the intersection test.   * @param coordinates An array holding the line data.   * @param dist On return dist[0] contains the distance between segment's origin and the point of   * intersection, if it exists. The dist array   * should be allocated by the user.   * @return <code>true</code> if the segment intersects the line,   *  <code>false</code> if the segment does not intersect the object.   */   public static boolean segmentAndLine(PickSegment segment,                                       Point3d coordinates[],				       int index, double dist[] ) {    Point3d start = new Point3d();    Point3d end = new Point3d();    Vector3d direction = new Vector3d();            if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect13"));           segment.get(start, end);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;        Point3d startpnt = coordinates[index++];    Point3d endpnt = coordinates[index];        if(lineAndRay(startpnt, endpnt, start, direction, dist)==true)      if(dist[0] <= 1.0)	return true;        return false;  }  /**   * Return true if line intersects with segment and the distance, from   * the start of segment to the intersection point, is stored in dist[0].   * The line is defined by coordinates[index] to coordinates[index+1]   *   * @param segment The segment that is used in intersection test.   * @param coordinates an array of vertices.   * @param index the vertex index   * @param dist On return dist[0] contains the distance between segment's start and the point    * intersection, if exist.   * @return true if segment intersects line, else return false.   */   public static boolean segmentAndLine(PickSegment segment, Point3f coordinates[],				       int index, double dist[] ) {    Point3d start = new Point3d();    Point3d end = new Point3d();    Vector3d direction = new Vector3d();            if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect13"));           segment.get(start, end);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;        Point3d startpnt = new Point3d(coordinates[index++]);    Point3d endpnt = new Point3d(coordinates[index]);        if(lineAndRay(startpnt, endpnt, start, direction, dist)==true)      if(dist[0] <= 1.0)	return true;        return false;  }    /**   * Determines if the <code>PickPoint</code> and Line   * objects intersect.   * The line is defined as <code>coordinates[index]</code> to   * <code>coordinates[index+1]</code>.   *   * @param point The point that is used in the intersection test.   * @param coordinates An array holding the line data.   * @return <code>true</code> if the the point intersects the line,   *  <code>false</code> if the the point does not intersect the object.   */   public static boolean pointAndLine(PickPoint point, Point3d coordinates[],				     int index ) {    if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect13"));           double dist[] = new double[1];    Point3d start = coordinates[index++];    Point3d end = coordinates[index];    Point3d location = new Point3d();    Vector3d direction = new Vector3d();        point.get(location);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;    if ((rayAndPoint(location, start, direction, dist)==true) &&        (dist[0] <= 1.0))      return true;        return false;      }  /**   * Return true if line intersects with point.   * The line is defined by coordinates[index] to coordinates[index+1]   *   * @param point The point that is used in intersection test.   * @param coordinates an array of vertices.   * @param index the vertex index   * @return true if point intersects line, else return false.   */     public static boolean pointAndLine(PickPoint point, Point3f coordinates[],				     int index ) {    if((coordinates.length - index) < 2)       throw new RuntimeException(J3dUtilsI18N.getString("Intersect13"));           double dist[] = new double[1];    Point3d start = new Point3d(coordinates[index++]);    Point3d end = new Point3d(coordinates[index]);    Point3d location = new Point3d();    Vector3d direction = new Vector3d();        point.get(location);    direction.x = end.x - start.x;    direction.y = end.y - start.y;    direction.z = end.z - start.z;        if((rayAndPoint(location, start, direction, dist)==true) && (dist[0] <= 1.0))      return true;        return false;      }  /**   *  Return true if point is on the inside of halfspace test. The   *  halfspace is    * partition by the plane of triangle or quad.   * */       private static boolean pointAndPoly( Point3d coordinates[], PickPoint point) {        Vector3d vec0 = new Vector3d(); // Edge vector from point 0 to point 1;    Vector3d vec1 = new Vector3d(); // Edge vector from point 0 to point 2 or 3;    Vector3d pNrm = new Vector3d();    double  absNrmX, absNrmY, absNrmZ, pD = 0.0;    Vector3d tempV3d = new Vector3d();    double pNrmDotrDir = 0.0;         double tempD;    int i, j;    // Compute plane normal.    for(i=0; i<coordinates.length-1;) {      vec0.x = coordinates[i+1].x - coordinates[i].x;      vec0.y = coordinates[i+1].y - coordinates[i].y;      vec0.z = coordinates[i+1].z - coordinates[i++].z;      if(vec0.length() > 0.0)	break;    }            for(j=i; j<coordinates.length-1; j++) {      vec1.x = coordinates[j+1].x - coordinates[j].x;      vec1.y = coordinates[j+1].y - coordinates[j].y;      vec1.z = coordinates[j+1].z - coordinates[j].z;      if(vec1.length() > 0.0)	break;    }        if(j == (coordinates.length-1)) {      // System.out.println("(1) Degenerated polygon.");      return false;  // Degenerated polygon.    }    /*        System.out.println("Ray orgin : " + ray.origin + " dir " + ray.direction);       System.out.println("Triangle/Quad :");       for(i=0; i<coordinates.length; i++)        System.out.println("P" + i + " " + coordinates[i]);       */    pNrm.cross(vec0,vec1);        if(pNrm.length() == 0.0) {      // System.out.println("(2) Degenerated polygon.");      return false;  // Degenerated polygon.    }    // Compute plane D.    tempV3d.set((Tuple3d) coordinates[0]);    pD = pNrm.dot(tempV3d);    Point3d location = new Point3d();    point.get(location);    tempV3d.set((Tuple3d) location);        if((pD - pNrm.dot(tempV3d)) == 0.0 )      return true;        return false;      }  private static boolean lineAndRay(Point3d start, Point3d end, 				    Point3d ori, Vector3d dir, 				    double dist[] ) {        double m00, m01, m10, m11;    double mInv00, mInv01, mInv10, mInv11;    double dmt, t, s, tmp1, tmp2;    Vector3d lDir;    lDir = new Vector3d(end.x - start.x, end.y - start.y,			end.z - start.z);        m00 = lDir.x;    m01 = -dir.x;    m10 = lDir.y;    m11 = -dir.y;    // Get the determinant.    dmt = (m00 * m11) - (m10 * m01);    if(dmt==0.0) // No solution, hence no intersect.      return false;    // Find the inverse.    tmp1 = 1/dmt;    mInv00 = tmp1 * m11;    mInv01 = tmp1 * (-m01);    mInv10 = tmp1 * (-m10);    mInv11 = tmp1 * m00;    tmp1 = ori.x - start.x;    tmp2 = ori.y - start.y;    t = mInv00 * tmp1 + mInv01 * tmp2;    s = mInv10 * tmp1 + mInv11 * tmp2;        if(s<0.0) // Before the origin of ray.      return false;    if((t<0)||(t>1.0)) // Before or after the end points of line.      return false;    tmp1 = ori.z + s * dir.z;    tmp2 = start.z + t * lDir.z;      if((tmp1 < (tmp2 - Double.MIN_VALUE)) || (tmp1 > (tmp2 + Double.MIN_VALUE)))      return false;    dist[0] = s;    return true;  }  private static boolean rayAndPoint( Point3d pnt, Point3d ori,				     Vector3d dir, double dist[] ) {    int flag = 0;    double temp;        if(dir.x != 0.0) {      flag = 0;      dist[0] = (pnt.x - ori.x)/dir.x;    }