Merge remote-tracking branch 'origin/ue4-dev' into mai/ue4-extend-ros2-step1-server-changes

Author: berndgassmann

LibCarla/source/carla/ThreadPool.h

@@ -16,6 +16,7 @@
 
 #include <future>
 #include <thread>
+#include <chrono>
 #include <type_traits>
 
 namespace carla {
@@ -29,6 +30,11 @@ namespace carla {
     /// Stops the ThreadPool and joins all its threads.
     ~ThreadPool() {
       Stop();
+      // Give some time to boost asio to properly stop.
+      // below 20ms this might be useless if there is heavy load.
+      // Without this, segmentation faults were observed
+      // within the boost asio code on destruction of the io_context.
+      std::this_thread::sleep_for(std::chrono::milliseconds(20));
     }
 
     /// Return the underlying io_context.

PythonAPI/examples/sensor_synchronization.py

@@ -32,10 +32,14 @@
 # process it as you liked and the important part is that,
 # at the end, it should include an element into the sensor queue.
 def sensor_callback(sensor_data, sensor_queue, sensor_name):
-    # Do stuff with the sensor_data data like save it to disk
-    # Then you just need to add to the queue
+    # Do stuff with the sensor_data data like save it to disk,
+    # then you add it to the queue so the main loop is aware of it.
     sensor_queue.put((sensor_data.frame, sensor_name))
 
+    # # You could also put the sensor data in the queue
+    # # and process it in the main loop
+    # sensor_queue.put((sensor_name, sensor_data.frame, sensor_data))
+
 
 def main():
     # We start creating the client
@@ -105,18 +109,17 @@ def main():
             w_frame = world.get_snapshot().frame
             print("\nWorld's frame: %d" % w_frame)
 
-            # Now, we wait to the sensors data to be received.
-            # As the queue is blocking, we will wait in the queue.get() methods
-            # until all the information is processed and we continue with the next frame.
-            # We include a timeout of 1.0 s (in the get method) and if some information is
-            # not received in this time we continue.
+            # Now, we wait to the sensors data to be received. The queue.get() method retrieves
+            # and item from the queue, blocking for up to the given 1.0s if the queue is empty,
+            # raising an Empty error if the queue hasn't been filled in that time.
             try:
                 for _ in range(len(sensor_list)):
                     s_frame = sensor_queue.get(True, 1.0)
                     print("    Frame: %d   Sensor: %s" % (s_frame[0], s_frame[1]))
-
             except Empty:
                 print("    Some of the sensor information is missed")
+                # # Or raise an error if it is paramount that all data is received
+                # raise RuntimeError(" Some of the sensor information is missed")
 
     finally:
         world.apply_settings(original_settings)

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Game/CarlaGameModeBase.cpp

@@ -190,6 +190,11 @@ void ACarlaGameModeBase::BeginPlay()
   LoadMapLayer(GameInstance->GetCurrentMapLayer());
   ReadyToRegisterObjects = true;
 
+  if (true) { /// @todo If semantic segmentation enabled.
+    ATagger::TagActorsInLevel(*World, true);
+    TaggerDelegate->SetSemanticSegmentationEnabled();
+  }
+
   // HACK: fix transparency see-through issues
   // The problem: transparent objects are visible through walls.
   // This is due to a weird interaction between the SkyAtmosphere component,

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Util/ObjectRegister.cpp

@@ -300,7 +300,8 @@ void UObjectRegister::RegisterSMComponents(AActor* Actor)
   const bool IsActorTickEnabled = Actor->IsActorTickEnabled();
 
   ATrafficSignBase* TrafficSign = Cast<ATrafficSignBase>(Actor);
-  if (!IsValid(TrafficSign) || BBs.Num() == 0)
+  
+  if (BBs.Num() == 0)
   {
     return;
   }