explore_frontier.h

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#ifndef EXPLORE_FRONTIER_H_
#define EXPLORE_FRONTIER_H_

#include <nav_msgs/OccupancyGrid.h>
#include <geometry_msgs/Pose.h>
#include <visualization_msgs/MarkerArray.h>
#include <tf/LinearMath/Vector3.h>

#include <explore/costmap_client.h>

/* I have been using modified version of navfn for a long time here.
Unfornutely my changes are affecting ABI of the component, so the can't be
accepted for ROS Jade or below. I expect them be accepted for ROS Karmic. Then
this should be moved back to using standard ROS navfn `<navfn/navfn_ros.h>`.
For the meanwhile, to allow seamless building, I will be using internal
version included from ROS. */

#include <explore/navfn_ros.h>

namespace explore {

struct FrontierPoint {
  size_t idx;     //position
  tf::Vector3 d; //direction

  FrontierPoint() : idx(0) {}
  FrontierPoint(size_t idx_, const tf::Vector3& d_) : idx(idx_), d(d_) {}
};

struct Frontier {
  size_t size;
  geometry_msgs::Pose pose;

  Frontier() : size(0) {}
  Frontier(size_t size_, const geometry_msgs::Pose& pose_) : size(size_), pose(pose_) {}
};

struct WeightedFrontier {
  double cost;
  Frontier frontier;

  WeightedFrontier() : cost(1e9) {}
  WeightedFrontier(double cost_, const Frontier& frontier_) : cost(cost_), frontier(frontier_) {}
  bool operator<(const WeightedFrontier& o) const { return cost < o.cost; }
};

class ExploreFrontier {
private:
  // can't be const as we will do locking
  Costmap2DClient* const costmap_client_;
  costmap_2d::Costmap2D* const costmap_;
  navfn::NavfnROS* const planner_;

  nav_msgs::OccupancyGrid map_;
  std::vector<Frontier> frontiers_;

  size_t last_markers_count_;

  void findFrontiers();

  double getFrontierCost(const Frontier& frontier);

  double getOrientationChange(const Frontier& frontier, const tf::Stamped<tf::Pose>& robot_pose) const;

  double getFrontierGain(const Frontier& frontier) const;

public:
  ExploreFrontier(Costmap2DClient* costmap, navfn::NavfnROS* planner);

  bool getFrontiers(std::vector<geometry_msgs::Pose>& frontiers);

  bool getExplorationGoals(
    tf::Stamped<tf::Pose> start,
    std::vector<geometry_msgs::Pose>& goals,
    double cost_scale, double orientation_scale, double gain_scale
  );

  void getVisualizationMarkers(visualization_msgs::MarkerArray& markers);
};

}

#endif /* EXPLORE_FRONTIER_H_ */