Fix #1168 deregister registered actors on "OnDestroyed" event

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Actor/ActorDispatcher.cpp

@@ -12,7 +12,7 @@
 
 #include "GameFramework/Controller.h"
 
-void FActorDispatcher::Bind(FActorDefinition Definition, SpawnFunctionType Functor)
+void UActorDispatcher::Bind(FActorDefinition Definition, SpawnFunctionType Functor)
 {
   if (UActorBlueprintFunctionLibrary::CheckActorDefinition(Definition))
   {
@@ -27,7 +27,7 @@ void FActorDispatcher::Bind(FActorDefinition Definition, SpawnFunctionType Funct
   }
 }
 
-void FActorDispatcher::Bind(ACarlaActorFactory &ActorFactory)
+void UActorDispatcher::Bind(ACarlaActorFactory &ActorFactory)
 {
   for (const auto &Definition : ActorFactory.GetDefinitions())
   {
@@ -37,7 +37,7 @@ void FActorDispatcher::Bind(ACarlaActorFactory &ActorFactory)
   }
 }
 
-TPair<EActorSpawnResultStatus, FActorView> FActorDispatcher::SpawnActor(
+TPair<EActorSpawnResultStatus, FActorView> UActorDispatcher::SpawnActor(
     const FTransform &Transform,
     FActorDescription Description)
 {
@@ -59,7 +59,7 @@ TPair<EActorSpawnResultStatus, FActorView> FActorDispatcher::SpawnActor(
     Result.Status = EActorSpawnResultStatus::UnknownError;
   }
 
-  auto View = Result.IsValid() ? Registry.Register(*Result.Actor, std::move(Description)) : FActorView();
+  auto View = Result.IsValid() ? RegisterActor(*Result.Actor, std::move(Description)) : FActorView();
 
   if (!View.IsValid())
   {
@@ -70,7 +70,7 @@ TPair<EActorSpawnResultStatus, FActorView> FActorDispatcher::SpawnActor(
   return MakeTuple(Result.Status, View);
 }
 
-bool FActorDispatcher::DestroyActor(AActor *Actor)
+bool UActorDispatcher::DestroyActor(AActor *Actor)
 {
   if (Actor == nullptr) {
     UE_LOG(LogCarla, Error, TEXT("Trying to destroy nullptr actor"));
@@ -102,9 +102,18 @@ bool FActorDispatcher::DestroyActor(AActor *Actor)
   UE_LOG(LogCarla, Log, TEXT("Destroying actor: '%s'"), *Id);
   if (Actor->Destroy())
   {
-    Registry.Deregister(Actor);
     return true;
   }
   UE_LOG(LogCarla, Error, TEXT("Failed to destroy actor: '%s'"), *Id);
   return false;
 }
+
+FActorView UActorDispatcher::RegisterActor(AActor &Actor, FActorDescription Description)
+{
+  auto View = Registry.Register(Actor, std::move(Description));
+  if (View.IsValid())
+  {
+    Actor.OnDestroyed.AddDynamic(this, &UActorDispatcher::OnActorDestroyed);
+  }
+  return View;
+}

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Actor/ActorDispatcher.h

@@ -14,12 +14,17 @@
 #include "Containers/Array.h"
 #include "Templates/Function.h"
 
+#include "ActorDispatcher.generated.h"
+
 class ACarlaActorFactory;
 
-/// Actor in charge of binding ActorDefinitions to spawn functions, as well as
+/// Object in charge of binding ActorDefinitions to spawn functions, as well as
 /// keeping the registry of all the actors spawned.
-class FActorDispatcher
+UCLASS()
+class CARLA_API UActorDispatcher : public UObject
 {
+  GENERATED_BODY()
+
 public:
 
   using SpawnFunctionType = TFunction<FActorSpawnResult(const FTransform &, const FActorDescription &)>;
@@ -51,16 +56,15 @@ public:
   /// destruction, false if indestructible or nullptr.
   bool DestroyActor(AActor *Actor);
 
+  /// Register an actor that was not created using "SpawnActor" function but
+  /// that should be kept in the registry.
+  FActorView RegisterActor(AActor &Actor, FActorDescription ActorDescription);
+
   const TArray<FActorDefinition> &GetActorDefinitions() const
   {
     return Definitions;
   }
 
-  FActorRegistry &GetActorRegistry()
-  {
-    return Registry;
-  }
-
   const FActorRegistry &GetActorRegistry() const
   {
     return Registry;
@@ -68,6 +72,12 @@ public:
 
 private:
 
+  UFUNCTION()
+  void OnActorDestroyed(AActor *Actor)
+  {
+    Registry.Deregister(Actor);
+  }
+
   TArray<FActorDefinition> Definitions;
 
   TArray<SpawnFunctionType> SpawnFunctions;

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

@@ -38,7 +38,9 @@ UCarlaEpisode::UCarlaEpisode(const FObjectInitializer &ObjectInitializer)
     Id([]() {
       static uint32 COUNTER = 0u;
       return ++COUNTER;
-    }()) {}
+    }()) {
+  ActorDispatcher = CreateDefaultSubobject<UActorDispatcher>(TEXT("ActorDispatcher"));
+}
 
 TArray<FTransform> UCarlaEpisode::GetRecommendedSpawnPoints() const
 {
@@ -90,7 +92,7 @@ void UCarlaEpisode::InitializeAtBeginPlay()
     FActorDescription Description;
     Description.Id = TEXT("spectator");
     Description.Class = Spectator->GetClass();
-    ActorDispatcher.GetActorRegistry().Register(*Spectator, Description);
+    ActorDispatcher->RegisterActor(*Spectator, Description);
   }
   else
   {
@@ -104,6 +106,6 @@ void UCarlaEpisode::InitializeAtBeginPlay()
     FActorDescription Description;
     Description.Id = UCarlaEpisode_GetTrafficSignId(Actor->GetTrafficSignState());
     Description.Class = Actor->GetClass();
-    ActorDispatcher.GetActorRegistry().Register(*Actor, Description);
+    ActorDispatcher->RegisterActor(*Actor, Description);
   }
 }

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Game/CarlaEpisode.h

@@ -58,7 +58,7 @@ public:
   UFUNCTION(BlueprintCallable)
   const TArray<FActorDefinition> &GetActorDefinitions() const
   {
-    return ActorDispatcher.GetActorDefinitions();
+    return ActorDispatcher->GetActorDefinitions();
   }
 
   /// Return the list of recommended spawn points for vehicles.
@@ -90,7 +90,7 @@ public:
 
   const FActorRegistry &GetActorRegistry() const
   {
-    return ActorDispatcher.GetActorRegistry();
+    return ActorDispatcher->GetActorRegistry();
   }
 
   // ===========================================================================
@@ -105,7 +105,7 @@ public:
   /// invalid.
   FActorView FindActor(FActorView::IdType ActorId) const
   {
-    return ActorDispatcher.GetActorRegistry().Find(ActorId);
+    return ActorDispatcher->GetActorRegistry().Find(ActorId);
   }
 
   /// Find the actor view of @a Actor.
@@ -114,7 +114,7 @@ public:
   /// invalid.
   FActorView FindActor(AActor *Actor) const
   {
-    return ActorDispatcher.GetActorRegistry().Find(Actor);
+    return ActorDispatcher->GetActorRegistry().Find(Actor);
   }
 
   /// Find the actor view of @a Actor. If the actor is not found, a "fake" view
@@ -124,7 +124,7 @@ public:
   /// If the actor is pending kill, the returned view is invalid.
   FActorView FindOrFakeActor(AActor *Actor) const
   {
-    return ActorDispatcher.GetActorRegistry().FindOrFake(Actor);
+    return ActorDispatcher->GetActorRegistry().FindOrFake(Actor);
   }
 
   // ===========================================================================
@@ -143,7 +143,7 @@ public:
       const FTransform &Transform,
       FActorDescription ActorDescription)
   {
-    return ActorDispatcher.SpawnActor(Transform, std::move(ActorDescription));
+    return ActorDispatcher->SpawnActor(Transform, std::move(ActorDescription));
   }
 
   /// Spawns an actor based on @a ActorDescription at @a Transform. To properly
@@ -170,7 +170,7 @@ public:
   UFUNCTION(BlueprintCallable)
   bool DestroyActor(AActor *Actor)
   {
-    return ActorDispatcher.DestroyActor(Actor);
+    return ActorDispatcher->DestroyActor(Actor);
   }
 
   // ===========================================================================
@@ -194,7 +194,7 @@ private:
 
   void RegisterActorFactory(ACarlaActorFactory &ActorFactory)
   {
-    ActorDispatcher.Bind(ActorFactory);
+    ActorDispatcher->Bind(ActorFactory);
   }
 
   const uint32 Id = 0u;
@@ -202,7 +202,8 @@ private:
   UPROPERTY(VisibleAnywhere)
   FString MapName;
 
-  FActorDispatcher ActorDispatcher;
+  UPROPERTY(VisibleAnywhere)
+  UActorDispatcher *ActorDispatcher = nullptr;
 
   UPROPERTY(VisibleAnywhere)
   APawn *Spectator = nullptr;

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Sensor/WorldObserver.cpp

@@ -75,21 +75,21 @@ static carla::Buffer AWorldObserver_Serialize(
   write_data(header);
 
   // Write every actor.
-  for (auto &&actor_view : Registry) {
-    check(actor_view.GetActor() != nullptr);
+  for (auto &&View : Registry) {
+    check(View.IsValid());
     constexpr float TO_METERS = 1e-2;
-    const auto velocity = TO_METERS * actor_view.GetActor()->GetVelocity();
+    const auto velocity = TO_METERS * View.GetActor()->GetVelocity();
     // get the angular velocity
-    const auto RootComponent = Cast<UPrimitiveComponent>(actor_view.GetActor()->GetRootComponent());
+    const auto RootComponent = Cast<UPrimitiveComponent>(View.GetActor()->GetRootComponent());
     FVector angularVelocity { 0.0f, 0.0f, 0.0f };
     if (RootComponent != nullptr)
        angularVelocity = RootComponent->GetPhysicsAngularVelocityInDegrees();
     ActorDynamicState info = {
-      actor_view.GetActorId(),
-      actor_view.GetActor()->GetActorTransform(),
+      View.GetActorId(),
+      View.GetActor()->GetActorTransform(),
       carla::geom::Vector3D{velocity.X, velocity.Y, velocity.Z},
       carla::geom::Vector3D{angularVelocity.X, angularVelocity.Y, angularVelocity.Z},
-      AWorldObserver_GetActorState(actor_view)
+      AWorldObserver_GetActorState(View)
     };
     write_data(info);
   }