Example: hwdrivers_openni2_2d_icp_slam

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2024, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/gui/CDisplayWindow3D.h>
#include <mrpt/hwdrivers/COpenNI2Sensor.h>
#include <mrpt/img/TColor.h>
#include <mrpt/opengl.h>
#include <mrpt/opengl/CPlanarLaserScan.h>  // This class is in mrpt-maps
#include <mrpt/system/CTicTac.h>

#include <iostream>

using namespace mrpt;
using namespace mrpt::obs;
using namespace mrpt::opengl;
using namespace mrpt::hwdrivers;
using namespace mrpt::img;
using namespace std;

const float vert_FOV = 4.0_deg;

// This demo records from an OpenNI2 device, convert observations to 2D scans
// and runs 2d-icp-slam with them.

int main(int argc, char** argv)
{
    try
    {
        if (argc > 2)
        {
            cerr << "Usage: " << argv[0] << " <sensor_id/sensor_serial\n";
            cerr << "Example: " << argv[0] << " 0 \n";
            return 1;
        }

        // const unsigned sensor_id = 0;
        COpenNI2Sensor rgbd_sensor;
        // rgbd_sensor.loadConfig_sensorSpecific(const
        // mrpt::config::CConfigFileBase &configSource, const std::string
        // &iniSection );

        unsigned sensor_id_or_serial = 0;
        if (argc == 2)
        {
            sensor_id_or_serial = atoi(argv[1]);
            if (sensor_id_or_serial > 10)
                rgbd_sensor.setSerialToOpen(sensor_id_or_serial);
            else
                rgbd_sensor.setSensorIDToOpen(sensor_id_or_serial);
        }

        // Open:
        // cout << "Calling COpenNI2Sensor::initialize()...";
        rgbd_sensor.initialize();

        if (rgbd_sensor.getNumDevices() == 0) return 0;

        cout << "OK " << rgbd_sensor.getNumDevices() << " available devices."
             << endl;
        cout << "\nUse device " << sensor_id_or_serial << endl << endl;

        // Create window and prepare OpenGL object in the scene:
        // --------------------------------------------------------
        mrpt::gui::CDisplayWindow3D win3D("OpenNI2 3D view", 800, 600);

        win3D.setCameraAzimuthDeg(140);
        win3D.setCameraElevationDeg(20);
        win3D.setCameraZoom(8.0);
        win3D.setFOV(90);
        win3D.setCameraPointingToPoint(2.5, 0, 0);

        mrpt::opengl::CPointCloudColoured::Ptr gl_points =
            mrpt::opengl::CPointCloudColoured::Create();
        gl_points->setPointSize(2.5);

        // The 2D "laser scan" OpenGL object:
        mrpt::opengl::CPlanarLaserScan::Ptr gl_2d_scan =
            mrpt::opengl::CPlanarLaserScan::Create();
        gl_2d_scan->enablePoints(true);
        gl_2d_scan->enableLine(true);
        gl_2d_scan->enableSurface(true);
        gl_2d_scan->setSurfaceColor(0, 0, 1, 0.3);  // RGBA

        opengl::Viewport::Ptr viewInt;  // Extra viewports for the RGB images.
        {
            mrpt::opengl::Scene::Ptr& scene = win3D.get3DSceneAndLock();

            // Create the Opengl object for the point cloud:
            scene->insert(gl_points);
            scene->insert(mrpt::opengl::CGridPlaneXY::Create());
            scene->insert(mrpt::opengl::stock_objects::CornerXYZ());
            scene->insert(gl_2d_scan);

            const double aspect_ratio = 480.0 / 640.0;
            const int VW_WIDTH =
                400;  // Size of the viewport into the window, in pixel units.
            const int VW_HEIGHT = aspect_ratio * VW_WIDTH;

            // Create an extra opengl viewport for the RGB image:
            viewInt = scene->createViewport("view2d_int");
            viewInt->setViewportPosition(5, 30, VW_WIDTH, VW_HEIGHT);
            win3D.addTextMessage(10, 30 + VW_HEIGHT + 10, "Intensity data", 2);

            win3D.addTextMessage(5, 5, "'o'/'i'-zoom out/in, ESC: quit", 110);

            win3D.unlockAccess3DScene();
            win3D.repaint();
        }

        //                          Grab frames continuously and show
        //========================================================================================

        bool bObs = false, bError = true;
        mrpt::system::TTimeStamp last_obs_tim = INVALID_TIMESTAMP;

        while (!win3D.keyHit())  // Push any key to exit // win3D.isOpen()
        {
            //    cout << "Get new observation\n";
            CObservation3DRangeScan::Ptr newObs =
                CObservation3DRangeScan::Create();
            rgbd_sensor.getNextObservation(*newObs, bObs, bError);

            CObservation2DRangeScan::Ptr obs_2d;  // The equivalent 2D scan

            if (bObs && !bError && newObs &&
                newObs->timestamp != INVALID_TIMESTAMP &&
                newObs->timestamp != last_obs_tim)
            {
                // It IS a new observation:
                last_obs_tim = newObs->timestamp;

                // Convert ranges to an equivalent 2D "fake laser" scan:
                if (newObs->hasRangeImage)
                {
                    // Convert to scan:
                    obs_2d = CObservation2DRangeScan::Create();

                    T3DPointsTo2DScanParams p2s;
                    p2s.angle_sup = .5f * vert_FOV;
                    p2s.angle_inf = .5f * vert_FOV;
                    p2s.sensorLabel = "KINECT_2D_SCAN";
                    newObs->convertTo2DScan(*obs_2d, p2s);
                }

                // Update visualization ---------------------------------------

                win3D.get3DSceneAndLock();

                // Estimated grabbing rate:
                win3D.addTextMessage(
                    -350, -13,
                    format(
                        "Timestamp: %s",
                        mrpt::system::dateTimeLocalToString(last_obs_tim)
                            .c_str()),
                    100);

                // Show intensity image:
                if (newObs->hasIntensityImage)
                {
                    viewInt->setImageView(
                        newObs->intensityImage);  // This is not "_fast" since
                    // the intensity image may be
                    // needed later on.
                }
                win3D.unlockAccess3DScene();

                // -------------------------------------------------------
                //           Create 3D points from RGB+D data
                //
                // There are several methods to do this.
                //  Switch the #if's to select among the options:
                // See also:
                // https://www.mrpt.org/Generating_3D_point_clouds_from_RGB_D_observations
                // -------------------------------------------------------
                if (newObs->hasRangeImage)
                {
                    // Pathway: RGB+D --> XYZ+RGB opengl
                    win3D.get3DSceneAndLock();
                    mrpt::obs::T3DPointsProjectionParams pp;
                    pp.takeIntoAccountSensorPoseOnRobot = false;
                    newObs->unprojectInto(
                        *gl_points, pp /* without obs.sensorPose */);
                    win3D.unlockAccess3DScene();
                }

                // And load scan in the OpenGL object:
                gl_2d_scan->setScan(*obs_2d);

                win3D.repaint();
            }  // end update visualization:
        }

        cout << "\nClosing RGBD sensor...\n";

        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
}