public Vector2d normalizedPositiveX(Vector2d dir) {
        dir.x =  m11;
        dir.y = -m01;
        return dir;
    }
public Vector2d normalizedPositiveX ( Vector2d dir ) { dir . x = m11 ; dir . y = - m01 ; return dir ; }
/* (non-Javadoc)
@see org.joml.Matrix3x2dc#normalizedPositiveX(org.joml.Vector2d)