public float determinant(Vector2f v) {
        return (x * v.y) - (y * v.x);
    }
Returns the Z component of the cross product with the argument. The
current instance is unaffected.

@param v the right factor (not null, unaffected)
@return the Z component of {@code this} cross {@code v}
jme3-core/src/main/java/com/jme3/math/Vector2f.java