pr2_laser_snapshotter.cpp

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#include <ros/ros.h>

// Services
#include "laser_assembler/AssembleScans.h"

// Messages
#include "sensor_msgs/PointCloud.h"
#include "pr2_msgs/LaserScannerSignal.h"

/***
 * This uses the point_cloud_assembler's build_cloud service call to grab all the scans/clouds between two tilt-laser shutters
 * params
 *  * "~target_frame_id" (string) - This is the frame that the scanned data transformed into.  The
 *                                  output clouds are also published in this frame.
 *  * "~num_skips" (int)          - If set to N>0, then the snapshotter will skip N signals before
 *                                  requesting a new snapshot. This will make the snapshots be N times
 *                                  larger. Default 0 - no skipping.
 */

namespace pr2_laser_snapshotter
{

class PR2LaserSnapshotter
{

public:
  ros::NodeHandle n_;
  ros::NodeHandle private_ns_;
  ros::Publisher pub_;
  ros::Subscriber sub_;

  pr2_msgs::LaserScannerSignal prev_signal_;

  bool first_time_;

  int num_skips_;
  int num_skips_left_;

  std::string fixed_frame_;

  PR2LaserSnapshotter() : private_ns_("~")
  {
    prev_signal_.header.stamp.fromNSec(0);

    pub_ = n_.advertise<sensor_msgs::PointCloud> ("full_cloud", 1);
    sub_ = n_.subscribe("laser_scanner_signal", 40, &PR2LaserSnapshotter::scannerSignalCallback, this);

    private_ns_.param("num_skips", num_skips_, 0);
    num_skips_left_=num_skips_;

    first_time_ = true;
  }

  ~PR2LaserSnapshotter()
  {

  }

  void scannerSignalCallback(const pr2_msgs::LaserScannerSignalConstPtr& cur_signal)
  {
    if (cur_signal->signal == 128 || cur_signal->signal == 129)       // These codes imply that this is the first signal during a given profile type
      first_time_ = true;


    if (first_time_)
    {
      prev_signal_ = *cur_signal;
      first_time_ = false;
    }
    else
    {
      if(num_skips_>0)
      {
        if(num_skips_left_>0)
        {
          num_skips_left_ -= 1;
          return;
        }
        else
        {
          num_skips_left_=num_skips_;
        }
      }

      laser_assembler::AssembleScans::Request req;
      laser_assembler::AssembleScans::Response resp;

      req.begin = prev_signal_.header.stamp;
      req.end   = cur_signal->header.stamp;

      if (!ros::service::call("assemble_scans", req, resp))
        ROS_ERROR("Failed to call service on point cloud assembler or laser scan assembler.");

      pub_.publish(resp.cloud);
      ROS_DEBUG("Snapshotter::Published Cloud size=%u", resp.cloud.points.size());

      prev_signal_ = *cur_signal;
    }
  }
} ;

}

using namespace pr2_laser_snapshotter;

int main(int argc, char **argv)
{
  ros::init(argc, argv, "pr2_laser_snapshotter");
  PR2LaserSnapshotter snapshotter ;
  ros::spin();
  return 0;
}