public Vector3f multNormal(Vector3f vec, Vector3f store) {
        if (store == null) {
            store = new Vector3f();
        }

        float vx = vec.x, vy = vec.y, vz = vec.z;
        store.x = m00 * vx + m01 * vy + m02 * vz;
        store.y = m10 * vx + m11 * vy + m12 * vz;
        store.z = m20 * vx + m21 * vy + m22 * vz;

        return store;
    }
Rotate and scale the specified vector, but don't translate it.

@param vec the vector to transform (not null, unaffected)
@param store storage for the result (modified) or null to create a new
vector
@return the transformed vector (either store or a new vector)
jme3-core/src/main/java/com/jme3/math/Matrix4f.java