Issue #37 Emit signal when FPS drops below threshold

src/blackcore/context/contextsimulator.h

@@ -120,6 +120,9 @@ namespace BlackCore
             //! A formerly vital driver is no longer vital/responding
             void vitalityLost();
 
+            //! Frame rate has fallen too far below the threshold to maintain consistent sim rate
+            void insufficientFrameRateDetected(bool fatal);
+
             //! Render restrictions have been changed
             void renderRestrictionsChanged(bool restricted, bool enabled, int maxAircraft, const BlackMisc::PhysicalQuantities::CLength &maxRenderedDistance);
 

src/blackcore/context/contextsimulatorimpl.cpp

@@ -534,6 +534,10 @@ namespace BlackCore
             c = connect(simulator, &ISimulator::autoPublishDataWritten, this, &IContextSimulator::autoPublishDataWritten);
             Q_ASSERT(c);
 
+            // disconnect for X-Plane FPS below 20
+            c = connect(simulator, &ISimulator::insufficientFrameRateDetected, this, &IContextSimulator::insufficientFrameRateDetected);
+            Q_ASSERT(c);
+
             // log from context to simulator
             c = connect(CLogHandler::instance(), &CLogHandler::localMessageLogged, this, &CContextSimulator::relayStatusMessageToSimulator);
             Q_ASSERT(c);

src/blackcore/context/contextsimulatorproxy.cpp

@@ -104,6 +104,9 @@ namespace BlackCore
             s = connection.connect(serviceName, IContextSimulator::ObjectPath(), IContextSimulator::InterfaceName(),
                                    "validatedModelSet", this, SIGNAL(validatedModelSet(BlackMisc::Simulation::CSimulatorInfo, BlackMisc::Simulation::CAircraftModelList, BlackMisc::Simulation::CAircraftModelList, bool, BlackMisc::CStatusMessageList)));
             Q_ASSERT(s);
+            s = connection.connect(serviceName, IContextSimulator::ObjectPath(), IContextSimulator::InterfaceName(),
+                                   "insufficientFrameRateDetected", this, SIGNAL(insufficientFrameRateDetected(bool)));
+            Q_ASSERT(s);
             Q_UNUSED(s)
             this->relayBaseClassSignals(serviceName, connection, IContextSimulator::ObjectPath(), IContextSimulator::InterfaceName());
         }

src/blackcore/simulator.h

@@ -411,6 +411,9 @@ namespace BlackCore
         //! Auto publish data written for simulator
         void autoPublishDataWritten(const BlackMisc::Simulation::CSimulatorInfo &simulator);
 
+        //! Frame rate has fallen too far below the threshold to maintain consistent sim rate
+        void insufficientFrameRateDetected(bool fatal);
+
     protected:
         //! Constructor with all the providers
         ISimulator(const BlackMisc::Simulation::CSimulatorPluginInfo &pluginInfo,

src/plugins/simulator/xplane/simulatorxplane.cpp

@@ -444,10 +444,23 @@ namespace BlackSimPlugin
                 }
 
                 // FPS
+                // reading FPS resets average, so we only monitor over some time
                 if ((m_slowTimerCalls % 5u) == 0u)
                 {
-                    // reading FPS resets average, so we only monitor over some time
+                    constexpr double warningMiles = 1;
+                    constexpr double disconnectMiles = 2;
+                    const double previousMiles = m_trackMilesShort;
+
                     m_serviceProxy->getFrameStats(&m_averageFps, &m_simTimeRatio, &m_trackMilesShort, &m_minutesLate);
+
+                    if (previousMiles < disconnectMiles && m_trackMilesShort >= disconnectMiles)
+                    {
+                        emit insufficientFrameRateDetected(true);
+                    }
+                    else if (previousMiles < warningMiles && m_trackMilesShort >= warningMiles)
+                    {
+                        emit insufficientFrameRateDetected(false);
+                    }
                 }
             }
         }