[XP] Get the ground elevation under the own aircraft

src/plugins/simulator/xplane/simulatorxplane.cpp

@@ -321,6 +321,7 @@ namespace BlackSimPlugin::XPlane
             m_serviceProxy->getOwnAircraftCom2DataAsync(&m_xplaneData);
             m_serviceProxy->getOwnAircraftXpdrAsync(&m_xplaneData);
             m_serviceProxy->getAllWheelsOnGroundAsync(&m_xplaneData.onGroundAll);
+            m_serviceProxy->getGroundElevationAsync(&m_xplaneData.groundElevation);
 
             CAircraftSituation situation;
             situation.setPosition({ m_xplaneData.latitudeDeg, m_xplaneData.longitudeDeg, 0 });
@@ -333,6 +334,8 @@ namespace BlackSimPlugin::XPlane
             situation.setPitch({ m_xplaneData.pitchDeg, CAngleUnit::deg() });
             situation.setBank({ m_xplaneData.rollDeg, CAngleUnit::deg() });
             situation.setGroundSpeed({ m_xplaneData.groundspeedMs, CSpeedUnit::m_s() });
+            const CAltitude elevation { std::isnan(m_xplaneData.groundElevation) ? 0 : m_xplaneData.groundElevation, CAltitude::MeanSeaLevel, CLengthUnit::m() };
+            situation.setGroundElevation(elevation, CAircraftSituation::FromProvider);
             situation.setVelocity({ m_xplaneData.localXVelocityMs, m_xplaneData.localYVelocityMs, m_xplaneData.localZVelocityMs,
                 CSpeedUnit::m_s(), m_xplaneData.pitchRadPerSec, m_xplaneData.rollRadPerSec, m_xplaneData.headingRadPerSec,
                 CAngleUnit::rad(), CTimeUnit::s()});

src/plugins/simulator/xplane/simulatorxplane.h

@@ -86,6 +86,7 @@ namespace BlackSimPlugin::XPlane
         double rollRadPerSec = 0;           //!< Roll angular velocity [rad/s]
         double headingRadPerSec = 0;        //!< Heading angular velocity [rad/s]
         bool onGroundAll = false;           //!< All wheels on ground?
+        double groundElevation = 0;         //!< Elevation of ground [m]
         int com1ActiveKhz = 122800;         //!< COM1 active  [kHz]
         int com1StandbyKhz = 122800;        //!< COM1 standby [kHz]
         bool isCom1Receiving = true;        //!< COM1 receiving

src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp

@@ -544,6 +544,16 @@ namespace BlackSimPlugin::XPlane
         m_dbusInterface->callDBusAsync(QLatin1String("getAllWheelsOnGround"), setterCallback(o_allWheels));
     }
 
+    double CXSwiftBusServiceProxy::getGroundElevation() const
+    {
+        return m_dbusInterface->callDBusRet<double>(QLatin1String("getGroundElevation"));
+    }
+
+    void CXSwiftBusServiceProxy::getGroundElevationAsync(double* o_elevationM)
+    {
+        m_dbusInterface->callDBusAsync(QLatin1String("getGroundElevation"), setterCallback(o_elevationM));
+    }
+
     int CXSwiftBusServiceProxy::getCom1ActiveKhz() const
     {
         return m_dbusInterface->callDBusRet<int>(QLatin1String("getCom1ActiveKhz"));

src/plugins/simulator/xplane/xswiftbusserviceproxy.h

@@ -329,6 +329,12 @@ namespace BlackSimPlugin::XPlane
         void getAllWheelsOnGroundAsync(bool *o_allWheels);
         //! @}
 
+        //! Get elevation of ground under the plane (in meters)
+        //! @{
+        double getGroundElevation() const;
+        void getGroundElevationAsync(double *o_elevationM);
+        //! @}
+
         //! \copydoc XSwiftBus::CService::getCom1ActiveKhz
         //! @{
         int getCom1ActiveKhz() const;

src/xswiftbus/service.cpp

@@ -766,6 +766,13 @@ namespace XSwiftBus
                     sendDBusReply(sender, serial, getAllWheelsOnGround());
                 });
             }
+            else if (message.getMethodName() == "getGroundElevation")
+            {
+                queueDBusCall([ = ]()
+                {
+                    sendDBusReply(sender, serial, getGroundElevation());
+                });
+            }
             else if (message.getMethodName() == "getCom1ActiveKhz")
             {
                 queueDBusCall([ = ]()

src/xswiftbus/service.h

@@ -19,6 +19,7 @@
 #include "datarefs.h"
 #include "messages.h"
 #include "navdatareference.h"
+#include "terrainprobe.h"
 #include <XPLM/XPLMNavigation.h>
 #include <string>
 #include <chrono>
@@ -174,6 +175,9 @@ namespace XSwiftBus
         //! Get whether all wheels are on the ground
         bool getAllWheelsOnGround() const { return m_onGroundAll.get(); }
 
+        //! Get elevation of ground under the plane in meters
+        double getGroundElevation() const { return m_terrainProbe.getElevation(m_latitude.get(), m_longitude.get(), m_elevation.get())[0]; }
+
         //! COM Selection 6/7
         //! @{
         int getComSelection() const { return m_comAudioSelection.get(); }
@@ -333,6 +337,7 @@ namespace XSwiftBus
         int  m_disapperMessageWindowTimeMs = 5000;
         std::chrono::system_clock::time_point m_disappearMessageWindowTime;
         std::vector<CNavDataReference> m_airports;
+        CTerrainProbe m_terrainProbe;
 
         void readAirportsDatabase();
         std::vector<CNavDataReference> findClosestAirports(int number, double latitude, double longitude);

src/xswiftbus/terrainprobe.cpp

@@ -18,6 +18,13 @@ namespace XSwiftBus
 
     CTerrainProbe::~CTerrainProbe() { XPLMDestroyProbe(m_ref); }
 
+    std::array<double, 3> CTerrainProbe::getElevation(double degreesLatitude, double degreesLongitude, double metersAltitude) const
+    {
+        static const std::string callsign = "myself";
+        bool unused = false;
+        return getElevation(degreesLatitude, degreesLongitude, metersAltitude, callsign, unused);
+    }
+
     std::array<double, 3> CTerrainProbe::getElevation(double degreesLatitude, double degreesLongitude, double metersAltitude, const std::string &callsign, bool &o_isWater) const
     {
         double x, y, z;

src/xswiftbus/terrainprobe.h

@@ -36,7 +36,10 @@ namespace XSwiftBus
         //! Get the elevation in meters at the given point in OpenGL space.
         //! \note Due to the Earth's curvature, the OpenGL vertical axis may not be exactly perpendicular to the surface of the geoid.
         //! \return NaN if no ground was detected.
+        //! @{
+        std::array<double, 3> getElevation(double degreesLatitude, double degreesLongitude, double metersAltitude) const;
         std::array<double, 3> getElevation(double degreesLatitude, double degreesLongitude, double metersAltitude, const std::string &callsign, bool &o_isWater) const;
+        //! @}
 
     private:
         XPLMProbeRef m_ref = nullptr;