// calc axes @Override public final void compute() { // only parabola has directrix if (c.type == GeoConicNDConstants.CONIC_PARABOLA) { // directrix has direction of second eigenvector // through point (b - p/2* eigenvec1) directrix.x = -eigenvec[1].getY(); directrix.y = eigenvec[1].getX(); double px = b.getX() - c.p / 2.0 * eigenvec[0].getX(); double py = b.getY() - c.p / 2.0 * eigenvec[0].getY(); directrix.z = -(directrix.x * px + directrix.y * py); P.setCoords(px, py, 1.0); } else directrix.setUndefined(); }