Fix the initial weather request in case last position is null

calculateGreatCircleDistance returns false immediately if any of the
arguments was null.

ref T324

src/blackcore/simulator.h

@@ -533,7 +533,7 @@ namespace BlackCore
         // weather
         bool m_isWeatherActivated = false;                         //!< Is simulator weather activated?
         BlackMisc::Geo::CCoordinateGeodetic m_lastWeatherPosition; //!< Own aircraft position at which weather was fetched and injected last
-        BlackMisc::CSetting<BlackMisc::Simulation::Settings::TSelectedWeatherScenario> m_weatherScenarioSettings { this, &ISimulator::reloadWeatherSettings }; //!< Selected weather scenario
+        BlackMisc::CSettingReadOnly<BlackMisc::Simulation::Settings::TSelectedWeatherScenario> m_weatherScenarioSettings { this, &ISimulator::reloadWeatherSettings }; //!< Selected weather scenario
 
     private:
         // remote aircraft provider ("rap") bound

src/blackgui/components/weathercomponent.cpp

@@ -174,7 +174,7 @@ namespace BlackGui
 
             if (CWeatherScenario::isRealWeatherScenario(scenario))
             {
-                if (!useOwnAcftPosition ||
+                if (m_lastOwnAircraftPosition.isNull() ||
                         calculateGreatCircleDistance(position, m_lastOwnAircraftPosition).value(CLengthUnit::km()) > 20)
                 {
                     requestWeatherGrid(position);

src/plugins/simulator/emulated/simulatoremulated.cpp

@@ -229,7 +229,9 @@ namespace BlackSimPlugin
             if (m_isWeatherActivated)
             {
                 const auto currentPosition = CCoordinateGeodetic { situation.latitude(), situation.longitude() };
-                if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()) &&
+                if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()))
+                {
+                    if (m_lastWeatherPosition.isNull() ||
                             calculateGreatCircleDistance(m_lastWeatherPosition, currentPosition).value(CLengthUnit::mi()) > 20)
                     {
                         m_lastWeatherPosition = currentPosition;
@@ -237,6 +239,7 @@ namespace BlackSimPlugin
                         requestWeatherGrid(weatherGrid, { this, &CSimulatorEmulated::injectWeatherGrid });
                     }
                 }
+            }
 
             return this->updateOwnSituation(situation);
         }

src/plugins/simulator/fs9/simulatorfs9.cpp

@@ -334,7 +334,9 @@ namespace BlackSimPlugin
                     if (m_isWeatherActivated)
                     {
                         const auto currentPosition = CCoordinateGeodetic { aircraftSituation.latitude(), aircraftSituation.longitude() };
-                        if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()) &&
+                        if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()))
+                        {
+                            if (m_lastWeatherPosition.isNull() ||
                                     calculateGreatCircleDistance(m_lastWeatherPosition, currentPosition).value(CLengthUnit::mi()) > 20)
                             {
                                 m_lastWeatherPosition = currentPosition;
@@ -342,6 +344,7 @@ namespace BlackSimPlugin
                                 requestWeatherGrid(weatherGrid, { this, &CSimulatorFs9::injectWeatherGrid });
                             }
                         }
+                    }
                     break;
                 }
             case CFs9Sdk::MPCHAT_PACKET_ID_CHAT_TEXT_SEND:

src/plugins/simulator/fsxcommon/simulatorfsxcommon.cpp

@@ -621,7 +621,9 @@ namespace BlackSimPlugin
                 if (m_isWeatherActivated)
                 {
                     const auto currentPosition = CCoordinateGeodetic { aircraftSituation.latitude(), aircraftSituation.longitude() };
-                    if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()) &&
+                    if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()))
+                    {
+                        if (m_lastWeatherPosition.isNull() ||
                                 calculateGreatCircleDistance(m_lastWeatherPosition, currentPosition).value(CLengthUnit::mi()) > 20)
                         {
                             m_lastWeatherPosition = currentPosition;
@@ -629,6 +631,7 @@ namespace BlackSimPlugin
                             requestWeatherGrid(weatherGrid, { this, &CSimulatorFsxCommon::injectWeatherGrid });
                         }
                     }
+                }
 
                 if (this->m_useFsxTerrainProbe && m_addedProbes < 1)
                 {

src/plugins/simulator/xplane/simulatorxplane.cpp

@@ -234,16 +234,19 @@ namespace BlackSimPlugin
                 if (m_isWeatherActivated)
                 {
                     const auto currentPosition = CCoordinateGeodetic { situation.latitude(), situation.longitude() };
-                    if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()) &&
+                    if (CWeatherScenario::isRealWeatherScenario(m_weatherScenarioSettings.get()))
+                    {
+                        if (m_lastWeatherPosition.isNull() ||
                                 calculateGreatCircleDistance(m_lastWeatherPosition, currentPosition).value(CLengthUnit::mi()) > 20)
                         {
                             m_lastWeatherPosition = currentPosition;
-                        const auto weatherGrid = CWeatherGrid { { "", currentPosition } };
+                            const auto weatherGrid = CWeatherGrid { { "GLOB", currentPosition } };
                             requestWeatherGrid(weatherGrid, { this, &CSimulatorXPlane::injectWeatherGrid });
                         }
                     }
                 }
             }
+        }
 
         void CSimulatorXPlane::slowTimerTimeout()
         {