Fixing a race condition in the MultiRotor, where the reset function c…

…an sometimes be skipped over. This can happen if the reset task is created in between the updateRenderedState and updateRendering function calls.

Unreal/Plugins/AirSim/Source/Multirotor/MultiRotorConnector.cpp

@@ -54,6 +54,7 @@ MultiRotorConnector::MultiRotorConnector(VehiclePawnWrapper* vehicle_pawn_wrappe
     last_pose_ = pending_pose_ = last_debug_pose_ = Pose::nanPose();
     pending_pose_status_ = PendingPoseStatus::NonePending;
     reset_pending_ = false;
+    did_reset_ = false;
 
     std::string message;
     if (!vehicle_.getController()->isAvailable(message)) {
@@ -146,6 +147,7 @@ void MultiRotorConnector::updateRenderedState(float dt)
     //if reset is pending then do it first, no need to do other things until next tick
     if (reset_pending_) {
         reset_task_();
+        did_reset_ = true;
         return;
     }
 
@@ -200,8 +202,15 @@ void MultiRotorConnector::updateRendering(float dt)
 {
     //if we did reset then don't worry about synchrnozing states for this tick
     if (reset_pending_) {
-        reset_pending_ = false;
-        return;
+        // Continue to wait for reset
+        if (!did_reset_) {
+            return;
+        }
+        else {
+            reset_pending_ = false;
+            did_reset_ = false;
+            return;
+        }
     }
 
     try {
@@ -363,6 +372,7 @@ void MultiRotorConnector::reset()
         reset_task_ = std::packaged_task<void()>([this]() { resetPrivate(); });
         std::future<void> reset_result = reset_task_.get_future();
         reset_pending_ = true;
+        did_reset_ = false;
         reset_result.wait();
     }
 }

Unreal/Plugins/AirSim/Source/Multirotor/MultiRotorConnector.h

@@ -113,6 +113,7 @@ class MultiRotorConnector : public msr::airlib::VehicleConnectorBase
 
     //reset must happen while World is locked so its async task initiated from API thread
     bool reset_pending_;
+    bool did_reset_;
     std::packaged_task<void()> reset_task_;
 
     Pose last_pose_; //for trace lines showing vehicle path