[FG] Fetching elevation from sim

src/plugins/simulator/flightgear/fgswiftbustrafficproxy.cpp

@@ -105,5 +105,26 @@ namespace BlackSimPlugin
             };
             m_dbusInterface->callDBusAsync(QLatin1String("getRemoteAircraftData"), callback, callsigns);
         }
+
+        void CFGSwiftBusTrafficProxy::getElevationAtPosition(const CCallsign &callsign, double latitudeDeg, double longitudeDeg, double altitudeMeters,
+                const ElevationCallback &setter) const
+        {
+            std::function<void(QDBusPendingCallWatcher *)> callback = [ = ](QDBusPendingCallWatcher * watcher)
+            {
+                QDBusPendingReply<QString, double> reply = *watcher;
+                if (!reply.isError())
+                {
+                    const CCallsign cs(reply.argumentAt<0>());
+                    const double elevationMeters = reply.argumentAt<1>();
+                    const CAltitude elevationAlt = std::isnan(elevationMeters) ? CAltitude::null() : CAltitude(elevationMeters, CLengthUnit::m(), CLengthUnit::ft());
+                    const CElevationPlane elevation(CLatitude(latitudeDeg, CAngleUnit::deg()),
+                                                    CLongitude(longitudeDeg, CAngleUnit::deg()),
+                                                    elevationAlt, CElevationPlane::singlePointRadius());
+                    setter(elevation, cs);
+                }
+                watcher->deleteLater();
+            };
+            m_dbusInterface->callDBusAsync(QLatin1String("getElevationAtPosition"), callback, callsign.asString(), latitudeDeg, longitudeDeg, altitudeMeters);
+        }
     } // ns
 } // ns

src/plugins/simulator/flightgear/fgswiftbustrafficproxy.h

@@ -216,6 +216,10 @@ namespace BlackSimPlugin
             //! Get remote aircrafts data (lat, lon, elevation and CG)
             void getRemoteAircraftData(const QStringList &callsigns, const RemoteAircraftDataCallback &setter) const;
 
+            //! \copydoc XSwiftBus::CTraffic::getElevationAtPosition
+            void getElevationAtPosition(const BlackMisc::Aviation::CCallsign &callsign, double latitudeDeg, double longitudeDeg, double altitudeMeters,
+                                        const ElevationCallback &setter) const;
+
         private:
             BlackMisc::CGenericDBusInterface *m_dbusInterface = nullptr;
         };

src/plugins/simulator/flightgear/simulatorflightgear.cpp

@@ -824,6 +824,35 @@ namespace BlackSimPlugin
             emit this->aircraftRenderingChanged(addedRemoteAircraft);
         }
 
+        bool CSimulatorFlightgear::requestElevation(const BlackMisc::Geo::ICoordinateGeodetic &reference, const BlackMisc::Aviation::CCallsign &callsign)
+        {
+            if (this->isShuttingDownOrDisconnected()) { return false; }
+            if(reference.isNull()) { return false; }
+
+            CCoordinateGeodetic pos(reference);
+            if(!pos.hasMSLGeodeticHeight()){
+                // testing showed: height has an influence on the returned result
+                // - the most accurate value seems to be returned if the height is close to the elevation
+                // - in normal scenarios there is no much difference of the results if 0 is used
+                // - in Lukla (9200ft MSL) the difference between 0 and 9200 is around 1ft
+                // - in the LOWW scenario using 50000ft MSL results in around 3ft too low elevation
+                static const CAltitude alt(0, CAltitude::MeanSeaLevel, CLengthUnit::ft());
+                pos.setGeodeticHeight(alt);
+            }
+
+            using namespace std::placeholders;
+            auto callback = std::bind(&CSimulatorFlightgear::callbackReceivedRequestedElevation, this, _1, _2);
+
+            // Request
+            m_trafficProxy->getElevationAtPosition(callsign,
+                                                   pos.latitude().value(CAngleUnit::deg()),
+                                                   pos.longitude().value(CAngleUnit::deg()),
+                                                   pos.geodeticHeight().value(CLengthUnit::m()),
+                                                   callback);
+            emit this->requestedElevation(callsign);
+            return true;
+        }
+
         void CSimulatorFlightgear::onRemoteAircraftAddingFailed(const QString &callsign)
         {
             BLACK_VERIFY_X(!callsign.isEmpty(), Q_FUNC_INFO, "Need callsign");

src/plugins/simulator/flightgear/simulatorflightgear.h

@@ -137,6 +137,7 @@ namespace BlackSimPlugin
             virtual void resetAircraftStatistics() override;
             virtual BlackMisc::CStatusMessageList getInterpolationMessages(const BlackMisc::Aviation::CCallsign &callsign) const override;
             virtual bool testSendSituationAndParts(const BlackMisc::Aviation::CCallsign &callsign, const BlackMisc::Aviation::CAircraftSituation &situation, const BlackMisc::Aviation::CAircraftParts &parts) override;
+            virtual bool requestElevation(const BlackMisc::Geo::ICoordinateGeodetic &reference, const BlackMisc::Aviation::CCallsign &callsign) override;
             //! @}
 
         protected: