#34 Do not set custom depth pass if semantic segmentation is not needed

Source/Carla/CityMapGenerator.cpp

@@ -224,7 +224,7 @@ void ACityMapGenerator::GenerateRoadMap()
   check(GetWorld() != nullptr);
   check(RoadMap != nullptr);
 
-  ATagger::TagActorsInLevel(*GetWorld()); // We need the tags.
+  ATagger::TagActorsInLevel(*GetWorld(), bTagForSemanticSegmentation); // We need the tags.
 
   const float IntersectionSize = CityMapMeshTag::GetRoadIntersectionSize();
   const uint32 Margin = IntersectionSize / 2u;

Source/Carla/CityMapGenerator.h

@@ -152,6 +152,14 @@ private:
   UPROPERTY(Category = "Road Map", EditAnywhere, AdvancedDisplay)
   bool bGenerateRoadMapOnSave = true;
 
+  /** If true, activate the custom depth pass of each tagged actor in the level.
+    * This pass is necessary for rendering the semantic segmentation. However,
+    * it may add a performance penalty since occlusion doesn't seem to be
+    * applied to objects having this value active.
+    */
+  UPROPERTY(Category = "Road Map", EditAnywhere, AdvancedDisplay)
+  bool bTagForSemanticSegmentation = false;
+
   UPROPERTY()
   URoadMap *RoadMap;
 

Source/Carla/Game/CarlaGameMode.cpp

@@ -70,7 +70,9 @@ void ACarlaGameMode::RestartPlayer(AController* NewPlayer)
 void ACarlaGameMode::BeginPlay()
 {
   Super::BeginPlay();
-  TagActorsForSemanticSegmentation();
+  if (GameInstance->GetCarlaSettings().bSemanticSegmentationEnabled) {
+    TagActorsForSemanticSegmentation();
+  }
   GameController->BeginPlay();
 }
 
@@ -105,7 +107,7 @@ void ACarlaGameMode::AttachCaptureCamerasToPlayer(AController &Player)
 void ACarlaGameMode::TagActorsForSemanticSegmentation()
 {
   check(GetWorld() != nullptr);
-  ATagger::TagActorsInLevel(*GetWorld());
+  ATagger::TagActorsInLevel(*GetWorld(), true);
 }
 
 APlayerStart *ACarlaGameMode::FindUnOccupiedStartPoints(

Source/Carla/Game/CarlaSettings.cpp

@@ -112,6 +112,11 @@ static void ValidateCameraDescription(FCameraDescription &Camera)
   Camera.ImageSizeY = (Camera.ImageSizeY == 0u ? 512u : Camera.ImageSizeY);
 }
 
+static bool RequestedSemanticSegmentation(const FCameraDescription &Camera)
+{
+  return (Camera.PostProcessEffect == EPostProcessEffect::SemanticSegmentation);
+}
+
 static void LoadSettingsFromFile(const FString &FileName, UCarlaSettings &Settings)
 {
   UE_LOG(LogCarla, Log, TEXT("Loading settings from \"%s\""), *FileName);
@@ -141,6 +146,7 @@ static void LoadSettingsFromFile(const FString &FileName, UCarlaSettings &Settin
     }
 
     ValidateCameraDescription(Camera);
+    Settings.bSemanticSegmentationEnabled |= RequestedSemanticSegmentation(Camera);
   }
 }
 
@@ -183,7 +189,7 @@ void UCarlaSettings::LoadSettings()
   }
 }
 
-void UCarlaSettings::LogSettings()
+void UCarlaSettings::LogSettings() const
 {
   UE_LOG(LogCarla, Log, TEXT("== CARLA Settings =============================================================="));
   UE_LOG(LogCarla, Log, TEXT("Settings file: %s"), *CurrentFileName);
@@ -194,6 +200,7 @@ void UCarlaSettings::LogSettings()
   UE_LOG(LogCarla, Log, TEXT("Read Port = %d"), ReadPort);
   UE_LOG(LogCarla, Log, TEXT("[%s]"), S_CARLA_SCENECAPTURE);
   UE_LOG(LogCarla, Log, TEXT("Added %d cameras."), CameraDescriptions.Num());
+  UE_LOG(LogCarla, Log, TEXT("Semantic Segmentation = %s"), (bSemanticSegmentationEnabled ? TEXT("enabled") : TEXT("disabled")));
   for (auto &Item : CameraDescriptions) {
     UE_LOG(LogCarla, Log, TEXT("[%s/%s]"), S_CARLA_SCENECAPTURE, *Item.Key);
     UE_LOG(LogCarla, Log, TEXT("Image Size = %dx%d"), Item.Value.ImageSizeX, Item.Value.ImageSizeY);

Source/Carla/Game/CarlaSettings.h

@@ -18,7 +18,7 @@ public:
   void LoadSettings();
 
   /** Log settings values. */
-  void LogSettings();
+  void LogSettings() const;
 
 private:
 
@@ -59,5 +59,12 @@ public:
   UPROPERTY(Category = "Scene Capture", EditDefaultsOnly)
   TMap<FString, FCameraDescription> CameraDescriptions;
 
+  /** Whether semantic segmentation should be activated. The mechanisms for
+    * semantic segmentation impose some performance penalties even if it is not
+    * used, we only enable it if necessary.
+    */
+  UPROPERTY(Category = "Scene Capture", EditDefaultsOnly)
+  bool bSemanticSegmentationEnabled = false;
+
   /// @}
 };

Source/Carla/Tagger.cpp

@@ -62,18 +62,21 @@ static ECityObjectLabel GetLabelByPath(const T *Object)
   return (StringArray.Num() > 3 ? GetLabelByFolderName(StringArray[3]) : ECityObjectLabel::None);
 }
 
-static void SetStencilValue(UPrimitiveComponent *comp, const ECityObjectLabel &Label) {
-  if (Label != ECityObjectLabel::None) {
-    comp->SetRenderCustomDepth(true);
-    comp->SetCustomDepthStencilValue(CastEnum(Label));
-  }
+static void SetStencilValue(
+    UPrimitiveComponent &Component,
+    const ECityObjectLabel &Label,
+    const bool bSetRenderCustomDepth) {
+  Component.SetRenderCustomDepth(
+      bSetRenderCustomDepth &&
+      !ATagger::MatchComponent(Component, ECityObjectLabel::None));
+  Component.SetCustomDepthStencilValue(CastEnum(Label));
 }
 
 // =============================================================================
 // -- static ATagger functions -------------------------------------------------
 // =============================================================================
 
-void ATagger::TagActor(const AActor &Actor)
+void ATagger::TagActor(const AActor &Actor, bool bTagForSemanticSegmentation)
 {
 #ifdef CARLA_TAGGER_EXTRA_LOG
   UE_LOG(LogCarla, Log, TEXT("Actor: %s"), *Actor.GetName());
@@ -84,7 +87,7 @@ void ATagger::TagActor(const AActor &Actor)
   Actor.GetComponents<UStaticMeshComponent>(StaticMeshComponents);
   for (UStaticMeshComponent *Component : StaticMeshComponents) {
     const auto Label = GetLabelByPath(Component->GetStaticMesh());
-    SetStencilValue(Component, Label);
+    SetStencilValue(*Component, Label, bTagForSemanticSegmentation);
 #ifdef CARLA_TAGGER_EXTRA_LOG
     UE_LOG(LogCarla, Log, TEXT("  + StaticMeshComponent: %s"), *Component->GetName());
     UE_LOG(LogCarla, Log, TEXT("    - Label: \"%s\""), *GetLabelAsString(Label));
@@ -96,7 +99,7 @@ void ATagger::TagActor(const AActor &Actor)
   Actor.GetComponents<USkeletalMeshComponent>(SkeletalMeshComponents);
   for (USkeletalMeshComponent *Component : SkeletalMeshComponents) {
     const auto Label = GetLabelByPath(Component->GetPhysicsAsset());
-    SetStencilValue(Component, Label);
+    SetStencilValue(*Component, Label, bTagForSemanticSegmentation);
 #ifdef CARLA_TAGGER_EXTRA_LOG
     UE_LOG(LogCarla, Log, TEXT("  + SkeletalMeshComponent: %s"), *Component->GetName());
     UE_LOG(LogCarla, Log, TEXT("    - Label: \"%s\""), *GetLabelAsString(Label));
@@ -104,21 +107,13 @@ void ATagger::TagActor(const AActor &Actor)
   }
 }
 
-void ATagger::TagActorsInLevel(UWorld &World)
+void ATagger::TagActorsInLevel(UWorld &World, bool bTagForSemanticSegmentation)
 {
   for (TActorIterator<AActor> it(&World); it; ++it) {
-    TagActor(**it);
+    TagActor(**it, bTagForSemanticSegmentation);
   }
 }
 
-ECityObjectLabel ATagger::GetTagOfTaggedComponent(const UPrimitiveComponent &Component)
-{
-  return
-      (Component.bRenderCustomDepth ?
-          static_cast<ECityObjectLabel>(Component.CustomDepthStencilValue) :
-          ECityObjectLabel::None);
-}
-
 void ATagger::GetTagsOfTaggedActor(const AActor &Actor, TArray<ECityObjectLabel> &Tags)
 {
   TArray<UPrimitiveComponent *> Components;
@@ -148,7 +143,7 @@ void ATagger::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent
   Super::PostEditChangeProperty(PropertyChangedEvent);
   if (PropertyChangedEvent.Property) {
     if (bTriggerTagObjects && (GetWorld() != nullptr)) {
-      TagActorsInLevel(*GetWorld());
+      TagActorsInLevel(*GetWorld(), bTagForSemanticSegmentation);
     }
   }
   bTriggerTagObjects = false;

Source/Carla/Tagger.h

@@ -3,6 +3,7 @@
 #pragma once
 
 #include "GameFramework/Actor.h"
+#include "Components/PrimitiveComponent.h"
 #include "Tagger.generated.h"
 
 enum class ECityObjectLabel : uint8
@@ -34,15 +35,29 @@ class CARLA_API ATagger : public AActor
 public:
 
   /// Set the tag of an actor.
-  static void TagActor(const AActor &Actor);
+  ///
+  /// If bTagForSemanticSegmentation true, activate the custom depth pass. This
+  /// pass is necessary for rendering the semantic segmentation. However, it may
+  /// add a performance penalty since occlusion doesn't seem to be applied to
+  /// objects having this value active.
+  static void TagActor(const AActor &Actor, bool bTagForSemanticSegmentation);
 
   /// Set the tag of every actor in level.
-  static void TagActorsInLevel(UWorld &World);
+  ///
+  /// If bTagForSemanticSegmentation true, activate the custom depth pass. This
+  /// pass is necessary for rendering the semantic segmentation. However, it may
+  /// add a performance penalty since occlusion doesn't seem to be applied to
+  /// objects having this value active.
+  static void TagActorsInLevel(UWorld &World, bool bTagForSemanticSegmentation);
 
   /// Retrieve the tag of an already tagged component.
-  static ECityObjectLabel GetTagOfTaggedComponent(const UPrimitiveComponent &Component);
+  static ECityObjectLabel GetTagOfTaggedComponent(const UPrimitiveComponent &Component)
+  {
+    return static_cast<ECityObjectLabel>(Component.CustomDepthStencilValue);
+  }
 
-  /// Retrieve the tags of an already tagged actor.
+  /// Retrieve the tags of an already tagged actor. ECityObjectLabel::None is
+  /// not added to the array.
   static void GetTagsOfTaggedActor(const AActor &Actor, TArray<ECityObjectLabel> &Tags);
 
   /// Return true if @a Component has been tagged with the given @a Tag.
@@ -63,4 +78,7 @@ private:
 
   UPROPERTY(Category = "Tagger", EditAnywhere)
   bool bTriggerTagObjects = false;
+
+  UPROPERTY(Category = "Tagger", EditAnywhere)
+  bool bTagForSemanticSegmentation = false;
 };