空间点到空间直线的垂点计算

 有一个参考的博客，大家搜一下就可以找到，这是我用到的用eigen库的

    //pt 空间外一点
//begin-end 直线上的两个点
Eigen::Vector3d GetFootOfPerpendicular(const Eigen::Vector3d &pt, const Eigen::Vector3d &begin, const Eigen::Vector3d &end)
        //pt:point outside line
    {
        auto diff = end - begin;
        auto diff_sqr_norm = diff.squaredNorm();
        if (diff_sqr_norm < 0.00000001)
        {
            return begin;
        }

        double u = ((pt - begin).transpose() * diff)(0) / diff_sqr_norm;;
      

        return begin + u * diff;
    }