private static int parity(Vector3f n1, Vector3f n) {
        if (n1.dot(n) < 0) {
            return -1;
        } else {
            return 1;
        }
    }
A private constructor to inhibit instantiation of this class.
jme3-core/src/main/java/com/jme3/util/TangentBinormalGenerator.java