main.cpp

#include <uWS/uWS.h>
#include <iostream>
#include <fstream>
#include "json.hpp"
#include <math.h>
#include "FusionEKF.h"
#include "tools.h"

using namespace std;

// for convenience
using json = nlohmann::json;

// Checks if the SocketIO event has JSON data.
// If there is data the JSON object in string format will be returned,
// else the empty string "" will be returned.
std::string hasData(std::string s) {
  auto found_null = s.find("null");
  auto b1 = s.find_first_of("[");
  auto b2 = s.find_first_of("]");
  if (found_null != std::string::npos) {
    return "";
  }
  else if (b1 != std::string::npos && b2 != std::string::npos) {
    return s.substr(b1, b2 - b1 + 1);
  }
  return "";
}

int main()
{
  uWS::Hub h;

  // Create a Kalman Filter instance
  FusionEKF fusionEKF;

  // used to compute the RMSE later
  Tools tools;
  vector<VectorXd> estimations;
  vector<VectorXd> ground_truth;

    ofstream myfile;
    myfile.open("obj_pose-laser-radar-ekf-output.txt");

  h.onMessage([&fusionEKF,&tools,&estimations,&ground_truth, &myfile](uWS::WebSocket<uWS::SERVER> ws, char *data, size_t length, uWS::OpCode opCode) {
    // "42" at the start of the message means there's a websocket message event.
    // The 4 signifies a websocket message
    // The 2 signifies a websocket event

    if (length && length > 2 && data[0] == '4' && data[1] == '2')
    {

      auto s = hasData(std::string(data));
      if (s != "") {
        
        auto j = json::parse(s);

        std::string event = j[0].get<std::string>();
        
        if (event == "telemetry") {
          // j[1] is the data JSON object
          
          string sensor_measurment = j[1]["sensor_measurement"];
          
          MeasurementPackage meas_package;
          istringstream iss(sensor_measurment);
        long long timestamp;

        // reads first element from the current line
        string sensor_type;
        iss >> sensor_type;

        if (sensor_type.compare("L") == 0) {
              meas_package.sensor_type_ = MeasurementPackage::LASER;
              meas_package.raw_measurements_ = VectorXd(2);
              float px;
              float py;
              iss >> px;
              iss >> py;
              meas_package.raw_measurements_ << px, py;
              iss >> timestamp;
              meas_package.timestamp_ = timestamp;
          } else if (sensor_type.compare("R") == 0) {

              meas_package.sensor_type_ = MeasurementPackage::RADAR;
              meas_package.raw_measurements_ = VectorXd(3);
              float ro;
              float theta;
              float ro_dot;
              iss >> ro;
              iss >> theta;
              iss >> ro_dot;
              meas_package.raw_measurements_ << ro,theta, ro_dot;
              iss >> timestamp;
              meas_package.timestamp_ = timestamp;
          }
          float x_gt;
        float y_gt;
        float vx_gt;
        float vy_gt;
        iss >> x_gt;
        iss >> y_gt;
        iss >> vx_gt;
        iss >> vy_gt;
        VectorXd gt_values(4);
        gt_values(0) = x_gt;
        gt_values(1) = y_gt; 
        gt_values(2) = vx_gt;
        gt_values(3) = vy_gt;
        ground_truth.push_back(gt_values);
          
          //Call ProcessMeasurment(meas_package) for Kalman filter
        fusionEKF.ProcessMeasurement(meas_package);       

        //Push the current estimated x,y positon from the Kalman filter's state vector

        VectorXd estimate(4);

        double p_x = fusionEKF.ekf_.x_(0);
        double p_y = fusionEKF.ekf_.x_(1);
        double v1  = fusionEKF.ekf_.x_(2);
        double v2 = fusionEKF.ekf_.x_(3);

        estimate(0) = p_x;
        estimate(1) = p_y;
        estimate(2) = v1;
        estimate(3) = v2;

            // Write to txt file for visualisation
            myfile << p_x << '\t' << p_y << '\t' << v1 << '\t' << v2 << '\t';
            if (meas_package.sensor_type_ == MeasurementPackage::LASER) {
                myfile << meas_package.raw_measurements_[0] << '\t' << meas_package.raw_measurements_[1] << '\t';
            } else if (meas_package.sensor_type_ == MeasurementPackage::RADAR) {
                double rho = meas_package.raw_measurements_[0];
                double phi = meas_package.raw_measurements_[1];
                myfile << rho*cos(phi) << '\t' << rho*sin(phi) << '\t';
            }
            myfile << gt_values(0) << '\t' << gt_values(1) << '\t' << gt_values(2) << '\t' << gt_values(3) << endl;

        estimations.push_back(estimate);

        VectorXd RMSE = tools.CalculateRMSE(estimations, ground_truth);

          json msgJson;
          msgJson["estimate_x"] = p_x;
          msgJson["estimate_y"] = p_y;
          msgJson["rmse_x"] =  RMSE(0);
          msgJson["rmse_y"] =  RMSE(1);
          msgJson["rmse_vx"] = RMSE(2);
          msgJson["rmse_vy"] = RMSE(3);
          auto msg = "42[\"estimate_marker\"," + msgJson.dump() + "]";
          // std::cout << msg << std::endl;
          ws.send(msg.data(), msg.length(), uWS::OpCode::TEXT);
    
        }
      } else {
        
        std::string msg = "42[\"manual\",{}]";
        ws.send(msg.data(), msg.length(), uWS::OpCode::TEXT);
      }
    }

  });

  // We don't need this since we're not using HTTP but if it's removed the program
  // doesn't compile :-(
  h.onHttpRequest([](uWS::HttpResponse *res, uWS::HttpRequest req, char *data, size_t, size_t) {
    const std::string s = "<h1>Hello world!</h1>";
    if (req.getUrl().valueLength == 1)
    {
      res->end(s.data(), s.length());
    }
    else
    {
      // i guess this should be done more gracefully?
      res->end(nullptr, 0);
    }
  });

  h.onConnection([&h](uWS::WebSocket<uWS::SERVER> ws, uWS::HttpRequest req) {
    std::cout << "Connected!!!" << std::endl;
  });

  h.onDisconnection([&h](uWS::WebSocket<uWS::SERVER> ws, int code, char *message, size_t length) {
    ws.close();
    std::cout << "Disconnected" << std::endl;
  });

  int port = 4567;
  if (h.listen(port))
  {
    std::cout << "Listening to port " << port << std::endl;
  }
  else
  {
    std::cerr << "Failed to listen to port" << std::endl;
    return -1;
  }
  h.run();

    myfile.close();
}