是否能够发布livox_ros_driver::CustomMsg消息？

[cckaixin]

  您好，首先感谢您开源的这个Livox雷达模拟器，给我带来了很大的方便。
  我在使用的过程中遇到了点云消息格式上的问题。我的需求是在gazebo中仿真livox雷达，并使用fast-lio来做定位。但是livox_laser_simulation发布的点云格式为sensor_msgs::PointCloud，并不是按照Livox的驱动格式livox_ros_driver::CustomMsg发布的，这就导致我没有办法用fast-lio来做定位导航。
   所以我的问题是：目前的livox_laser_simulation是否本就可以发布livox_ros_driver::CustomMsg格式的点云；另外，如果目前的模拟器不能发布livox_ros_driver::CustomMsg格式的点云，那么我应该如何修改这个模拟器，使之能够满足我的需求？

[cckaixin]

自问自答：目前已通过修改消息格式，将发布的点云更改成我需要的livox_ros_driver::CustomMsg格式

[engcang]

Hi @cckaixin.
Can you share the modified version of the code please?

[cckaixin]

ok, i have revised the following function:

void LivoxPointsPlugin::OnNewLaserScans() {
    if (rayShape) 
    {
        std::vector<std::pair<int, AviaRotateInfo>> points_pair;
        InitializeRays(points_pair, rayShape);
        rayShape->Update();

        msgs::Set(laserMsg.mutable_time(), world->SimTime());
        msgs::LaserScan *scan = laserMsg.mutable_scan();
        InitializeScan(scan);

        SendRosTf(parentEntity->WorldPose(), world->Name(), raySensor->ParentName());

        auto rayCount = RayCount();
        auto verticalRayCount = VerticalRayCount();
        auto angle_min = AngleMin().Radian();
        auto angle_incre = AngleResolution();
        auto verticle_min = VerticalAngleMin().Radian();
        auto verticle_incre = VerticalAngleResolution();
////////////////////////////////////////////////
//revised by ckx frome cloud to cloud2 msg
//////////////////////////////////////////////// START

        livox_ros_driver::CustomMsg pp_livox;
        pp_livox.header.stamp = ros::Time::now();
        pp_livox.header.frame_id = "livox";
        int count = 0;
        boost::chrono::high_resolution_clock::time_point start_time = boost::chrono::high_resolution_clock::now();
        
        for (auto &pair : points_pair)
        {
            auto range = rayShape->GetRange(pair.first);
            auto intensity = rayShape->GetRetro(pair.first);
            if (range >= RangeMax()) {
                range = 0;
            } else if (range <= RangeMin()) {
                range = 0;
            }
            auto rotate_info = pair.second;
            ignition::math::Quaterniond ray;
            ray.Euler(ignition::math::Vector3d(0.0, rotate_info.zenith, rotate_info.azimuth));
            auto axis = ray * ignition::math::Vector3d(1.0, 0.0, 0.0);
            auto point = range * axis;

            livox_ros_driver::CustomPoint p;
            p.x = point.X();
            p.y = point.Y();
            p.z = point.Z();
            p.reflectivity = intensity;
            boost::chrono::high_resolution_clock::time_point end_time = boost::chrono::high_resolution_clock::now();
            boost::chrono::nanoseconds elapsed_time = boost::chrono::duration_cast<boost::chrono::nanoseconds>(end_time - start_time);
            // std::cout << "Elapsed time: " << elapsed_time.count() << " microseconds" << std::endl;

            p.offset_time = elapsed_time.count();
            pp_livox.points.push_back(p);
            count ++;
        }

        if (scanPub && scanPub->HasConnections()) scanPub->Publish(laserMsg);
        pp_livox.point_num = count;
        // ROS_INFO_STREAM("pp_livox.point_num: " << pp_livox.point_num << " !");

        livox_pub.publish(pp_livox);
        ros::spinOnce();
    }

////////////////////////////////////////////////
// revised by ckx frome cloud to cloud2 msg
//////////////////////////////////////////////// END
}

and include this header:

#include <livox_ros_driver/CustomMsg.h>

also, you should modify CMakelists.txt by adding livox_ros_driver:

find_package(catkin REQUIRED COMPONENTS
  roscpp
  tf
  livox_ros_driver
)

and include livox_ros_driver package into your worksapce accordingly.

hope you can fix it : )
ckx

[engcang]

@cckaixin Hi. Thank you for sharing the code!
I coded myself right after the question but yours looks much better :) I will change mine referring yours.
For future users, you guys can refer this repo: https://github.com/engcang/livox_laser_simulation