code: public Matrix4x3d normalize3x3(Matrix4x3d dest) {
          double invXlen = 1.0 / Math.sqrt(m00 * m00 + m01 * m01 + m02 * m02);
          double invYlen = 1.0 / Math.sqrt(m10 * m10 + m11 * m11 + m12 * m12);
          double invZlen = 1.0 / Math.sqrt(m20 * m20 + m21 * m21 + m22 * m22);
          dest.m00 = m00 * invXlen; dest.m01 = m01 * invXlen; dest.m02 = m02 * invXlen;
          dest.m10 = m10 * invYlen; dest.m11 = m11 * invYlen; dest.m12 = m12 * invYlen;
          dest.m20 = m20 * invZlen; dest.m21 = m21 * invZlen; dest.m22 = m22 * invZlen;
          return dest;
      }
docs: /* (non-Javadoc)
  @see org.joml.Matrix4x3dc#normalize3x3(org.joml.Matrix4x3d)