MapHelper.hpp

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#pragma once

#include <ros/ros.h>
#include <nav_msgs/GetMap.h>
#include <nav_msgs/OccupancyGrid.h>
#include <nav_msgs/Path.h>
#include <nav_msgs/GetPlan.h>
#include <geometry_msgs/PoseStamped.h>
#include <cmath>
#include <vector>
#include <boost/tuple/tuple.hpp>
#include <costmap_2d/costmap_2d_ros.h>
#include <tf/transform_listener.h>
#include "next_best_view/helper/DebugHelper.hpp"
#include "next_best_view/helper/MathHelper.hpp"
#include "next_best_view/helper/TypeHelper.hpp"
#include "typedef.hpp"

namespace next_best_view {
        struct RayTracingIndex {
                int32_t x;
                int32_t y;
                int8_t occupancy;
        public:
            /* Compare two positions (firstIndex, secondIndex) on the map which one is closer two the source. 
                 *
                 */
                static bool topologicalCompare(const RayTracingIndex &source, const RayTracingIndex &firstIndex, const RayTracingIndex &secondIndex) {
                        SimpleVector2 sourceVector(source.x, source.y);
                        SimpleVector2 firstIndexVector(firstIndex.x, firstIndex.y);
                        SimpleVector2 secondIndexVector(secondIndex.x, secondIndex.y);

                        return (firstIndexVector - sourceVector).squaredNorm() < (secondIndexVector - sourceVector).squaredNorm();
                }

                static bool equals(const RayTracingIndex &firstIndex, const RayTracingIndex &secondIndex) {
                        SimpleVector2 firstIndexVector(firstIndex.x, firstIndex.y);
                        SimpleVector2 secondIndexVector(secondIndex.x, secondIndex.y);
                        return firstIndexVector == secondIndexVector;
                }
        };
        typedef boost::shared_ptr<RayTracingIndex> RayTracingIndexPtr;
        typedef std::vector<RayTracingIndex> Ray;


        class MapHelper {
        private:
        DebugHelperPtr mDebugHelperPtr;

        bool mMapReceived;
                int8_t mCollisionThreshold;
                ros::NodeHandle mGlobalNodeHandle;
                ros::ServiceClient mGetPlanServiceClient;
                nav_msgs::OccupancyGrid mMap;
        costmap_2d::Costmap2D mCostmap;
        nav_msgs::OccupancyGrid mRaytracingMap;
        // table to translate from values 0-255 in Costmap2D to values -1 to 100 in OccupancyGrid
        int8_t mCostTranslationTable[256];
        public:
        MapHelper(const std::string &mapTopicName = "map", const std::string &getPlanServiceName = "move_base/make_plan") : mMapReceived(false), mCollisionThreshold(45) {
            mDebugHelperPtr = DebugHelper::getInstance();

            // set cost translation table to transform the costmap_2d_ros cost to next_best_view cost of the map.
            mCostTranslationTable[0] = 0;  // NO obstacle
            mCostTranslationTable[253] = 99;  // INSCRIBED obstacle
            mCostTranslationTable[254] = 100;  // LETHAL obstacle
            mCostTranslationTable[255] = -1;  // UNKNOWN

                        // Specific calculation of the costs on the map.
            for (int i = 1; i < 253; i++) {
                mCostTranslationTable[i] = int8_t(1 + (97 * (i - 1)) / 251);
            }

            ros::Subscriber mapSubscriber = mGlobalNodeHandle.subscribe<nav_msgs::OccupancyGrid>(mapTopicName, 1, &MapHelper::mapReceived, this);
            while(ros::ok() && !mMapReceived) {
                mDebugHelperPtr->write(std::stringstream() << "Waiting for map to arrive on topic '" << mapSubscriber.getTopic() << "'",
                            DebugHelper::MAP);

                                ros::spinOnce();
                                ros::Duration(0.5).sleep();
                        }

                        // Wait for planner services for the path calculation. Could used to calculate the drive costs to a viewpoint.
            mDebugHelperPtr->write(std::stringstream() << "waiting for service: " << getPlanServiceName, DebugHelper::MAP);
            ros::service::waitForService(getPlanServiceName, -1);
                        mGetPlanServiceClient = mGlobalNodeHandle.serviceClient<nav_msgs::GetPlan>(getPlanServiceName, true);
                        while(ros::ok() && !mGetPlanServiceClient.exists()) {
                mDebugHelperPtr->write(std::stringstream() << "Waiting for planning server to start on service '"
                                        << mGetPlanServiceClient.getService(), DebugHelper::MAP);
                                ros::spinOnce();
                                ros::Duration(0.5).sleep();
                        }
            this->setCostmap();
            this->aggregateRaytracingMap();
                }

                virtual ~MapHelper() { }
        private:
                /* Write Debug Info of the map if it received.
                 * \param map the received map
                 */
                void mapReceived(nav_msgs::OccupancyGrid map) {
            mDebugHelperPtr->write("Map received", DebugHelper::MAP);
                        mMap = map;
                        mMapReceived = true;
            mDebugHelperPtr->write(std::stringstream() << "Map resolution: " << mMap.info.resolution, DebugHelper::MAP);
            mDebugHelperPtr->write(std::stringstream() << "Map translation: " << this->getTranslation(), DebugHelper::MAP);
            mDebugHelperPtr->write(std::stringstream() << "Map orientation: " << this->getOrientation().w() << ", "
                                                                                << this->getOrientation().x() << ", "
                                                                                << this->getOrientation().y() << ", "
                                                                                << this->getOrientation().z(),
                                                                                                        DebugHelper::MAP);
            mDebugHelperPtr->write(std::stringstream() << "Map metric width: " << this->getMetricWidth(), DebugHelper::MAP);
            mDebugHelperPtr->write(std::stringstream() << "Map metric height: " << this->getMetricHeight(), DebugHelper::MAP);
                }

                /* Gets the costmap of the navigation and set it to global variable of the helper.
                 *
                 */
        void setCostmap() {

            tf2_ros::Buffer buffer(ros::Duration(10));
            tf2_ros::TransformListener tf(buffer);
            std::string name = "global_costmap";
            costmap_2d::Costmap2DROS costmapRos(name, buffer);
            costmapRos.start();
            costmapRos.updateMap();
            costmapRos.stop();

            mCostmap = *(costmapRos.getCostmap());

            // get output path
            std::string path;
            mGlobalNodeHandle.getParam("/nbv/mMapsImagePath", path);

            // output costmap
            std::string costmapPath = path + "/costmap.pgm";
            mDebugHelperPtr->write("Outputting calculated costmap to " + costmapPath,
                        DebugHelper::MAP);
            mCostmap.saveMap(costmapPath);
        }

                /* Transform the costmap to next_best_view parameters.
                 *
                 */
        void aggregateRaytracingMap() {
            mDebugHelperPtr->write("Aggregating raytracing map.", DebugHelper::MAP);
            if (mMap.info.width != mCostmap.getSizeInCellsX() || mMap.info.height != mCostmap.getSizeInCellsY()) {
                ROS_ERROR("Cannot aggregate raytracing map. Dimensions of map and costmap do not match!");
                mDebugHelperPtr->write(std::stringstream() << "Map size: " << mMap.info.width << "x" << mMap.info.height, DebugHelper::MAP);
                mDebugHelperPtr->write(std::stringstream() << "Costmap size: " << mCostmap.getSizeInCellsX() << "x" << mCostmap.getSizeInCellsY(), DebugHelper::MAP);
                assert(mMap.info.width == mCostmap.getSizeInCellsX() && mMap.info.height == mCostmap.getSizeInCellsY());
            }

            mRaytracingMap.info = mMap.info;
            mRaytracingMap.data.reserve(mMap.data.size());
            for (unsigned int y = 0; y < mMap.info.height; y++) {
                for (unsigned int x = 0; x < mMap.info.width; x++) {
                    unsigned int index = y * mMap.info.width + x;
                    int8_t mapOccupancyValue = mMap.data[index];
                    int8_t costmapOccupancyValue = mCostTranslationTable[mCostmap.getCost(x, y)];
                    int8_t aggregatedOccupancyValue = mapOccupancyValue == -1 ? -1 : costmapOccupancyValue;

                    mRaytracingMap.data[index] = aggregatedOccupancyValue;
                }
            }
            mDebugHelperPtr->write("Aggregation done.", DebugHelper::MAP);
        }

                int8_t getOccupancyValue(const nav_msgs::OccupancyGrid &map, const SimpleVector3 &position) {
                        int32_t mapX, mapY;
                        this->worldToMapCoordinates(position, mapX, mapY);
                        return this->getOccupancyValue(map, mapX, mapY);
                }

        int8_t getOccupancyValue(const costmap_2d::Costmap2D &costmap, const SimpleVector3 &position) {
            int32_t mapX, mapY;
            this->worldToMapCoordinates(position, mapX, mapY);
            return this->getOccupancyValue(costmap, mapX, mapY);
        }

                int8_t getOccupancyValue(const nav_msgs::OccupancyGrid &map, const int32_t &mapX, const int32_t &mapY) {
                        uint32_t width = map.info.width;
                        uint32_t height = map.info.height;

            if (mapX < 0 || mapY < 0 || mapX >= (int32_t)width || mapY >= (int32_t)height) {
                                return -1;
                        }

                        return map.data[mapX + mapY * width];
                }

        int8_t getOccupancyValue(const costmap_2d::Costmap2D &costmap, const int32_t &mapX, const int32_t &mapY) {
            uint32_t width = costmap.getSizeInCellsX();
            uint32_t height = costmap.getSizeInCellsY();

            if (mapX < 0 || mapY < 0 || mapX >= (int32_t)width || mapY >= (int32_t)height) {
                return -1;
            }

            unsigned char cost = costmap.getCost(mapX, mapY);
            return mCostTranslationTable[cost];
        }

        public:
        // 4 combinations: (occupancyGrid, costMap) x (Vector3, mapPosition)
                int8_t getMapOccupancyValue(const SimpleVector3 &position) {
                        return this->getOccupancyValue(mMap, position);
                }

                int8_t getMapOccupancyValue(const int32_t &mapX, const int32_t &mapY) {
                        return this->getOccupancyValue(mMap, mapX, mapY);
                }


                int8_t getCostmapOccupancyValue(const SimpleVector3 &position) {
                        return this->getOccupancyValue(mCostmap, position);
                }

                int8_t getCostmapOccupancyValue(const int32_t &mapX, const int32_t &mapY) {
                        return this->getOccupancyValue(mCostmap, mapX, mapY);
                }


                int8_t getRaytracingMapOccupancyValue(const SimpleVector3 &position) {
                        return this->getOccupancyValue(mRaytracingMap, position);
                }

                int8_t getRaytracingMapOccupancyValue(const int32_t &mapX, const int32_t &mapY) {
                        return this->getOccupancyValue(mRaytracingMap, mapX, mapY);
                }

                bool doRaytracing(const SimpleVector3 &fromPoint, const SimpleVector3 &toPoint) {
                        Ray ray;
                        bool retVal = this->doRaytracing(fromPoint, toPoint, ray);
                        return retVal;
                }

                /* Calculates the raytrace between to points and save them in ray array.
                 *
                 */
                bool doRaytracing(const SimpleVector3 &fromPoint, const SimpleVector3 &toPoint, Ray &ray) {
                        // clear ray
                        ray.clear();

                        // get the discrete coordinates from world coordinates
                        int32_t fromMapX, fromMapY;
                        this->worldToMapCoordinates(fromPoint, fromMapX, fromMapY);

                        int32_t toMapX, toMapY;
                        this->worldToMapCoordinates(toPoint, toMapX, toMapY);

                        // calculate the distances
                        int32_t distanceX = toMapX - fromMapX;
                        int32_t distanceY = toMapY - fromMapY;

                        // return the result of a zero length raytracing
                        if (distanceX == 0 && distanceY == 0) {
                                int8_t occupancyValue = this->getRaytracingMapOccupancyValue(fromMapX, fromMapY);
                                return this->isOccupancyValueAcceptable(occupancyValue);
                        }

                        // get the bounds - needed to prevent non feasible results
                        int32_t minX = std::min(fromMapX, toMapX);
                        int32_t maxX = std::max(fromMapX, toMapX);
                        int32_t minY = std::min(fromMapY, toMapY);
                        int32_t maxY = std::max(fromMapY, toMapY);

                        // get the resolution
                        float resolution = mRaytracingMap.info.resolution;

                        // get the signum of the distance
                        int32_t signumX = distanceX < 0 ? - 1 : 1;
                        int32_t signumY = distanceY < 0 ? - 1 : 1;

                        // calculate the difference between the two points
                        SimpleVector2 diff = (toPoint - fromPoint).block<2, 1>(0, 0);

                        // contains the value about success of raytracing
                        bool rayTracingSucceeded = true;

                        // tracing along the x-axis
                        for (int32_t offsetX = 0; offsetX <= std::abs(distanceX) + 1 && diff[0] != 0; offsetX += 1) {
                                double x = (fromMapX + signumX * offsetX) * resolution;
                                double t = (x - fromPoint[0]) / diff[0];
                                double y = fromPoint[1] + t * diff[1];

                                RayTracingIndex idx;
                                idx.x = (int32_t) (x / resolution);
                                idx.y = (int32_t) (y / resolution);
                                idx.occupancy = this->getRaytracingMapOccupancyValue(idx.x, idx.y);

                                if (idx.x < minX || idx.x > maxX || idx.y < minY || idx.y > maxY) {
                                        continue;
                                }

                                if (!this->isOccupancyValueAcceptable(idx.occupancy)) {
                                        rayTracingSucceeded = false;
                                }

                                ray.push_back(idx);
                        }

                        // tracing along the y axis.
                        for (int32_t offsetY = 0; offsetY <= std::abs(distanceY) + 1 && diff[1] != 0; offsetY += 1) {
                                double y = (fromMapY + signumY * offsetY) * resolution;
                                double t = (y - fromPoint[1]) / diff[1];
                                double x = fromPoint[0] + t * diff[0];

                                RayTracingIndex idx;
                                idx.x = (int32_t) (x / resolution);
                                idx.y = (int32_t) (y / resolution);
                                idx.occupancy = this->getRaytracingMapOccupancyValue(idx.x, idx.y);

                                if (idx.x < minX || idx.x > maxX || idx.y < minY || idx.y > maxY) {
                                        continue;
                                }

                                if (!this->isOccupancyValueAcceptable(idx.occupancy)) {
                                        rayTracingSucceeded = false;
                                }

                                ray.push_back(idx);
                        }

                        // do a topological sort by distance to the fromPoint
            RayTracingIndex source = {fromMapX, fromMapY, 0};
                        std::stable_sort(ray.begin(), ray.end(), boost::bind(&RayTracingIndex::topologicalCompare, source, _1, _2));

                        // remove duplicate values
                        Ray::iterator endIterator = std::unique(ray.begin(), ray.end(), &RayTracingIndex::equals);
                        ray.resize(std::distance(ray.begin(), endIterator));

                        return rayTracingSucceeded;
                }

                float getMetricWidth() {
                        return mMap.info.width * mMap.info.resolution;
                }

                float getMetricHeight() {
                        return mMap.info.height * mMap.info.resolution;
                }

                void worldToMapCoordinates(const SimpleVector3 &position, int32_t &x, int32_t &y) {
            SimpleVector3 continuousMapCoords;
            worldToMapCoordinates(position, continuousMapCoords);

                        // get the map coords
                        x = (int32_t) floor(continuousMapCoords[0]);
                        y = (int32_t) floor(continuousMapCoords[1]);
                }

        void worldToMapCoordinates(const SimpleVector3 &position, SimpleVector3 &result) {
            SimpleVector3 translation = this->getTranslation();
            SimpleQuaternion orientation = this->getOrientation();
            SimpleMatrix3 rotationMatrix = orientation.toRotationMatrix();

            // the map is rotated by rotation matrix, for back transform do a transpose.
            result = (rotationMatrix.transpose() * position - translation) / mMap.info.resolution;
        }

                void mapToWorldCoordinates(const int32_t &x, const int32_t &y, SimpleVector3 &result) {
            mapToWorldCoordinates(SimpleVector3(x, y, 0.0), result);
                }

        void mapToWorldCoordinates(const SimpleVector3 &position, SimpleVector3 &result) {
            SimpleVector3 translation = this->getTranslation();
            SimpleQuaternion orientation = this->getOrientation();
            result = orientation.toRotationMatrix() * position * mMap.info.resolution + translation;
        }

        void mapToWorldSize(const double &size, double &result) {
            result = size * mMap.info.resolution;
        }

        void worldToMapSize(const double &size, double &result) {
            result = size / mMap.info.resolution;
        }

                SimpleVector3 getTranslation() {
                        return SimpleVector3(mMap.info.origin.position.x, mMap.info.origin.position.y, mMap.info.origin.position.z);
                }

                SimpleQuaternion getOrientation() {
                        return TypeHelper::getSimpleQuaternion(mMap.info.origin.orientation);
                }

                bool isOccupancyValueAcceptable(const int8_t &occupancyValue) {
                        return occupancyValue >= 0 && occupancyValue <= mCollisionThreshold;
                }

                void setCollisionThreshold(int8_t thresholdValue) {
                        mCollisionThreshold = thresholdValue;
                }

                int8_t getCollisionThreshold () {
                        return mCollisionThreshold;
                }

                float getSquaredDistance(const SimpleVector3 &start, const SimpleVector3 &goal) {
                        return (goal - start).squaredNorm();
                }
        };

        typedef boost::shared_ptr<MapHelper> MapHelperPtr;
}