Use new dataref to compensate for XP12 temperature effect on altitude

src/plugins/simulator/xplane/simulatorxplane.cpp

@@ -322,14 +322,26 @@ namespace BlackSimPlugin::XPlane
             m_serviceProxy->getOwnAircraftXpdrAsync(&m_xplaneData);
             m_serviceProxy->getAllWheelsOnGroundAsync(&m_xplaneData.onGroundAll);
             m_serviceProxy->getHeightAglMAsync(&m_xplaneData.heightAglM);
+            m_serviceProxy->getPressureAltitudeFtAsync(&m_xplaneData.pressureAltitudeFt);
 
             CAircraftSituation situation;
             situation.setPosition({ m_xplaneData.latitudeDeg, m_xplaneData.longitudeDeg, 0 });
             const CAltitude altitude { m_xplaneData.altitudeM, CAltitude::MeanSeaLevel, CLengthUnit::m() };
-            situation.setAltitude(altitude);
             const CPressure seaLevelPressure({ m_xplaneData.seaLevelPressureInHg, CPressureUnit::inHg() });
             const CAltitude pressureAltitude(altitude.toPressureAltitude(seaLevelPressure));
+            if (std::isnan(m_xplaneData.pressureAltitudeFt))
+            {
+                situation.setAltitude(altitude);
                 situation.setPressureAltitude(pressureAltitude);
+            }
+            else
+            {
+                const CAltitude pressureAltitudeXP12(m_xplaneData.pressureAltitudeFt, CAltitude::MeanSeaLevel, CAltitude::PressureAltitude, CLengthUnit::ft());
+                m_altitudeDelta = pressureAltitude - pressureAltitudeXP12;
+
+                situation.setAltitude({ altitude - m_altitudeDelta, CAltitude::MeanSeaLevel });
+                situation.setPressureAltitude(pressureAltitudeXP12);
+            }
             situation.setHeading({ m_xplaneData.trueHeadingDeg, CHeading::True, CAngleUnit::deg() });
             situation.setPitch({ m_xplaneData.pitchDeg, CAngleUnit::deg() });
             situation.setBank({ m_xplaneData.rollDeg, CAngleUnit::deg() });
@@ -1076,7 +1088,13 @@ namespace BlackSimPlugin::XPlane
             const CInterpolationResult result = xplaneAircraft.getInterpolation(currentTimestamp, setup, aircraftNumber++);
             if (result.getInterpolationStatus().hasValidSituation())
             {
-                const CAircraftSituation interpolatedSituation(result);
+                CAircraftSituation interpolatedSituation(result);
+
+                // adjust altitude to compensate for XP12 temperature effect
+                const CLength relativeAltitude = interpolatedSituation.geodeticHeight() - getOwnAircraftPosition().geodeticHeight();
+                const double altitudeDeltaWeight = 2 - qBound(3000.0, relativeAltitude.abs().value(CLengthUnit::ft()), 6000.0) / 3000;
+                const CLength alt = interpolatedSituation.getAltitude() + m_altitudeDelta * altitudeDeltaWeight;
+                interpolatedSituation.setAltitude({ alt, interpolatedSituation.getAltitude().getReferenceDatum() });
 
                 // update situation
                 if (updateAllAircraft || !this->isEqualLastSent(interpolatedSituation))

src/plugins/simulator/xplane/simulatorxplane.h

@@ -75,6 +75,7 @@ namespace BlackSimPlugin::XPlane
         double latitudeDeg = 0;             //!< Longitude [deg]
         double longitudeDeg = 0;            //!< Latitude  [deg]
         double altitudeM = 0;               //!< Altitude  [m]
+        double pressureAltitudeFt = 0;      //!< Pressure altitude [ft, XP12]
         double heightAglM = 0;              //!< Height AGL [m]
         double groundspeedMs = 0;           //!< Ground speed [m/s]
         double pitchDeg = 0;                //!< Pitch [deg]
@@ -283,6 +284,7 @@ namespace BlackSimPlugin::XPlane
         BlackMisc::Simulation::CSimulatedAircraftList m_aircraftAddedFailed;           //!< aircraft for which adding failed
         BlackMisc::PhysicalQuantities::CLength m_minSuspicousTerrainProbe { nullptr }; //!< min. distance of "failed" (suspicious) terrain probe requests
         XPlaneData m_xplaneData; //!< XPlane data
+        BlackMisc::PhysicalQuantities::CLength m_altitudeDelta;     //!< XP12 altitude difference cause by temperature effect
 
         // statistics
         qint64 m_statsAddMaxTimeMs     = -1;

src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp

@@ -409,6 +409,15 @@ namespace BlackSimPlugin::XPlane
         m_dbusInterface->callDBusAsync(QLatin1String("getAltitudeMslM"), setterCallback(o_altitude));
     }
 
+    double CXSwiftBusServiceProxy::getPressureAltitudeFt() const
+    {
+        return m_dbusInterface->callDBusRet<double>(QLatin1String("getPressureAltitudeFt"));
+    }
+    void CXSwiftBusServiceProxy::getPressureAltitudeFtAsync(double* o_altitude)
+    {
+        m_dbusInterface->callDBusAsync(QLatin1String("getPressureAltitudeFt"), setterCallback(o_altitude));
+    }
+
     double CXSwiftBusServiceProxy::getHeightAglM() const
     {
         return m_dbusInterface->callDBusRet<double>(QLatin1String("getHeightAglM"));

src/plugins/simulator/xplane/xswiftbusserviceproxy.h

@@ -239,6 +239,12 @@ namespace BlackSimPlugin::XPlane
         void getAltitudeMslMAsync(double *o_altitude);
         //! @}
 
+        //! \copydoc XSwiftBus::CService::getPressureAltitudeFt
+        //! @{
+        double getPressureAltitudeFt() const;
+        void getPressureAltitudeFtAsync(double *o_altitude);
+        //! @}
+
         //! \copydoc XSwiftBus::CService::getHeightAglM
         //! @{
         double getHeightAglM() const;

src/xswiftbus/org.swift_project.xswiftbus.service.xml

@@ -124,6 +124,9 @@ R"XML(<node>
     <method name="getAltitudeMslM">
       <arg type="d" direction="out"/>
     </method>
+    <method name="getPressureAltitudeFt">
+      <arg type="d" direction="out"/>
+    </method>
     <method name="getHeightAglM">
       <arg type="d" direction="out"/>
     </method>

src/xswiftbus/service.cpp

@@ -661,6 +661,13 @@ namespace XSwiftBus
                     sendDBusReply(sender, serial, getAltitudeMslM());
                 });
             }
+            else if (message.getMethodName() == "getPressureAltitudeFt")
+            {
+                queueDBusCall([=]()
+                {
+                    sendDBusReply(sender, serial, getPressureAltitudeFt());
+                });
+            }
             else if (message.getMethodName() == "getHeightAglM")
             {
                 queueDBusCall([ = ]()

src/xswiftbus/service.h

@@ -23,6 +23,7 @@
 #include <XPLM/XPLMNavigation.h>
 #include <string>
 #include <chrono>
+#include <limits>
 
 //! \cond PRIVATE
 #define XSWIFTBUS_SERVICE_INTERFACENAME "org.swift_project.xswiftbus.service"
@@ -134,6 +135,10 @@ namespace XSwiftBus
         //! Get aircraft altitude in meters
         double getAltitudeMslM() const { return m_elevation.get(); }
 
+        //! Get aircraft pressure altitude in feet in standard atmosphere in X-Plane 12.
+        //! NaN in earlier versions of X-Plane.
+        double getPressureAltitudeFt() const { return m_pressureAlt.isValid() ? m_pressureAlt.get() : std::numeric_limits<double>::quiet_NaN(); }
+
         //! Get aircraft height in meters
         double getHeightAglM() const { return m_agl.get(); }
 
@@ -359,6 +364,7 @@ namespace XSwiftBus
         DataRef<xplane::data::sim::flightmodel::position::latitude> m_latitude;
         DataRef<xplane::data::sim::flightmodel::position::longitude> m_longitude;
         DataRef<xplane::data::sim::flightmodel::position::elevation> m_elevation;
+        DataRef<xplane::data::sim::flightmodel2::position::pressure_altitude> m_pressureAlt;
         DataRef<xplane::data::sim::flightmodel::position::y_agl> m_agl;
         DataRef<xplane::data::sim::flightmodel::position::groundspeed> m_groundSpeed;
         DataRef<xplane::data::sim::flightmodel::position::indicated_airspeed2> m_indicatedAirspeed;