Various potential merges to cherry pick.

FMODStudio/Source/FMODStudio/Classes/FMODAudioComponent.h

@@ -326,6 +326,7 @@ class FMODSTUDIO_API UFMODAudioComponent : public USceneComponent
     /** Called when the event has finished stopping. */
     void OnPlaybackCompleted();
 
+protected:
 // Begin ActorComponent interface.
     /** Called when a component is registered, after Scene is set, but before CreateRenderState_Concurrent or OnCreatePhysicsState are called. */
     virtual void OnRegister() override;
@@ -340,6 +341,8 @@ class FMODSTUDIO_API UFMODAudioComponent : public USceneComponent
     virtual void TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction) override;
 // End ActorComponent interface.
 
+private:
+
 #if WITH_EDITORONLY_DATA
     void UpdateSpriteTexture();
 #endif

FMODStudio/Source/FMODStudio/Classes/FMODBlueprintStatics.h

@@ -70,12 +70,16 @@ class FMODSTUDIO_API UFMODBlueprintStatics : public UBlueprintFunctionLibrary
 	 * @param LocationType - Specifies whether Location is a relative offset or an absolute world position
 	 * @param bStopWhenAttachedToDestroyed - Specifies whether the sound should stop playing when the owner of the attach to component is destroyed.
 	 * @param bAutoPlay - Start the event automatically.
-	 * @param bAutoDestroy - Automatically destroy the audio component when the sound is stopped.
+	 * @param bAutoDestroy - Automatically destroy the audio component when the sound is stopped.     
+     * @param bEnableOcclusion - Whether to enable occlusion for event.
+	 * @param OcclusionTraceChannel - If occlusion is enabled, which collision channel should be used for determining occlusion.
+	 * @param bUseComplexCollisionForOcclusion - If occlusion is enabled, should the simple or complex collision of objects be used to determine occlusion.
 	 */
     UFUNCTION(BlueprintCallable, Category = "Audio|FMOD",
         meta = (AdvancedDisplay = "2", UnsafeDuringActorConstruction = "true", bAutoPlay = "true", bAutoDestroy = "true"))
     static class UFMODAudioComponent *PlayEventAttached(UFMODEvent *Event, USceneComponent *AttachToComponent, FName AttachPointName,
-        FVector Location, EAttachLocation::Type LocationType, bool bStopWhenAttachedToDestroyed, bool bAutoPlay, bool bAutoDestroy);
+		FVector Location, EAttachLocation::Type LocationType, bool bStopWhenAttachedToDestroyed, bool bAutoPlay, bool bAutoDestroy,
+		bool bEnableOcclusion = false, ECollisionChannel OcclusionTraceChannel = ECollisionChannel::ECC_Visibility, bool bUseComplexCollisionForOcclusion = false);
 
     /** Find an asset by name.
 	 * @param EventName - The asset name

FMODStudio/Source/FMODStudio/Private/FMODBlueprintStatics.cpp

@@ -59,7 +59,8 @@ FFMODEventInstance UFMODBlueprintStatics::PlayEventAtLocation(
 }
 
 class UFMODAudioComponent *UFMODBlueprintStatics::PlayEventAttached(class UFMODEvent *Event, class USceneComponent *AttachToComponent,
-    FName AttachPointName, FVector Location, EAttachLocation::Type LocationType, bool bStopWhenAttachedToDestroyed, bool bAutoPlay, bool bAutoDestroy)
+	FName AttachPointName, FVector Location, EAttachLocation::Type LocationType, bool bStopWhenAttachedToDestroyed, bool bAutoPlay, bool bAutoDestroy,
+	bool bEnableOcclusion /* = false */, ECollisionChannel OcclusionTraceChannel /* ECollisionChannel:: ECC_Visibility */, bool bUseComplexCollisionForOcclusion /* = false*/)
 {
     if (!IFMODStudioModule::Get().UseSound())
     {
@@ -103,6 +104,14 @@ class UFMODAudioComponent *UFMODBlueprintStatics::PlayEventAttached(class UFMODE
 #if WITH_EDITORONLY_DATA
     AudioComponent->bVisualizeComponent = false;
 #endif
+
+    // Create and apply Occlusion details.
+    FFMODOcclusionDetails OcclusionDetails = FFMODOcclusionDetails();
+	OcclusionDetails.bEnableOcclusion = bEnableOcclusion;
+	OcclusionDetails.bUseComplexCollisionForOcclusion = bUseComplexCollisionForOcclusion;
+	OcclusionDetails.OcclusionTraceChannel = OcclusionTraceChannel;
+	AudioComponent->OcclusionDetails = OcclusionDetails;
+
     AudioComponent->RegisterComponentWithWorld(AttachToComponent->GetWorld());
 
     AudioComponent->AttachToComponent(AttachToComponent, FAttachmentTransformRules::KeepRelativeTransform, AttachPointName);

FMODStudio/Source/FMODStudio/Private/FMODStudioModule.cpp

@@ -41,6 +41,10 @@
 #include <AVFoundation/AVAudioSession.h>
 #endif
 
+#if WITH_EDITOR
+#include "LevelEditorViewport.h"
+#endif
+
 #define LOCTEXT_NAMESPACE "FMODStudio"
 
 DEFINE_LOG_CATEGORY(LogFMOD);
@@ -212,7 +216,7 @@ class FFMODStudioModule : public IFMODStudioModule
     virtual FMOD::Studio::EventInstance *CreateAuditioningInstance(const UFMODEvent *Event) override;
     virtual void StopAuditioningInstance() override;
 
-    virtual void SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, float DeltaSeconds) override;
+    virtual void SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, const FTransform &listenerAttenuationTransform, float DeltaSeconds) override;
     virtual void FinishSetListenerPosition(int ListenerCount) override;
 
     virtual const FFMODListener &GetNearestListener(const FVector &Location) override;
@@ -876,6 +880,11 @@ void FFMODStudioModule::UpdateListeners()
 #if WITH_EDITOR
     if (bSimulating)
     {
+        if (GEngine && GEngine->GameViewport)
+        {
+            UpdateWorldListeners(GEngine->GameViewport->GetWorld(), &ListenerIndex);
+        }
+
         return;
     }
 
@@ -934,7 +943,32 @@ void FFMODStudioModule::UpdateWorldListeners(UWorld *World, int *ListenerIndex)
             ListenerTransform.SetTranslation(Location);
             ListenerTransform.NormalizeRotation();
 
-            SetListenerPosition(*ListenerIndex, World, ListenerTransform, DeltaSeconds);
+			APawn* ControlledPawn = PlayerController->GetPawn();
+			FTransform ListenerAttenuationTransform(FTransform::Identity);
+			if (IsValid(ControlledPawn))
+			{
+				ListenerAttenuationTransform = ControlledPawn->GetActorTransform(); // actor
+				ListenerAttenuationTransform.SetLocation(ControlledPawn->GetPawnViewLocation()); // head
+			}
+
+#if WITH_EDITOR
+			if (bSimulating)
+			{
+				for (FLevelEditorViewportClient* LevelVC : GEditor->GetLevelViewportClients())
+				{
+					if (LevelVC && LevelVC->IsPerspective())
+					{
+						ListenerTransform.SetLocation(LevelVC->GetViewLocation());
+						ListenerTransform.SetRotation(LevelVC->GetViewRotation().Quaternion());
+						break;
+					}
+				}
+
+				ListenerAttenuationTransform = ListenerTransform;
+			}
+#endif
+
+            SetListenerPosition(*ListenerIndex, World, ListenerTransform, ListenerAttenuationTransform, DeltaSeconds);
 
             (*ListenerIndex)++;
         }
@@ -971,7 +1005,7 @@ const FFMODListener &FFMODStudioModule::GetNearestListener(const FVector &Locati
 }
 
 // Partially copied from FAudioDevice::SetListener
-void FFMODStudioModule::SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, float DeltaSeconds)
+void FFMODStudioModule::SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, const FTransform &ListenerAttenuationTransform, float DeltaSeconds)
 {
     FMOD::Studio::System *System = IFMODStudioModule::Get().GetStudioSystem(EFMODSystemContext::Runtime);
     if (System && ListenerIndex < MAX_LISTENERS)
@@ -1009,7 +1043,10 @@ void FFMODStudioModule::SetListenerPosition(int ListenerIndex, UWorld *World, co
         Attributes.forward = FMODUtils::ConvertUnitVector(Forward);
         Attributes.up = FMODUtils::ConvertUnitVector(Up);
         Attributes.velocity = FMODUtils::ConvertWorldVector(Listeners[ListenerIndex].Velocity);
-        verifyfmod(System->setListenerAttributes(ListenerIndex, &Attributes));
+
+        FMOD_VECTOR AttenuationLocation = FMODUtils::ConvertWorldVector(ListenerAttenuationTransform.GetTranslation());
+
+        verifyfmod(System->setListenerAttributes(ListenerIndex, &Attributes, &AttenuationLocation));
         bListenerMoved = true;
     }
 }

FMODStudio/Source/FMODStudio/Public/FMODStudioModule.h

@@ -127,7 +127,7 @@ class IFMODStudioModule : public IModuleInterface
     /**
 	 * Called to change the listener position for editor mode
 	 */
-    virtual void SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, float DeltaSeconds) = 0;
+    virtual void SetListenerPosition(int ListenerIndex, UWorld *World, const FTransform &ListenerTransform, const FTransform& ListenerAttenuationTransform, float DeltaSeconds) = 0;
 
     /**
 	 * Called to change the listener position for editor mode

FMODStudio/Source/FMODStudioEditor/Private/FMODStudioEditorModule.cpp

@@ -1157,7 +1157,7 @@ void FFMODStudioEditorModule::ViewportDraw(UCanvas *Canvas, APlayerController *)
         ListenerTransform.SetTranslation(ViewLocation);
         ListenerTransform.NormalizeRotation();
 
-        IFMODStudioModule::Get().SetListenerPosition(0, World, ListenerTransform, 0.0f);
+        IFMODStudioModule::Get().SetListenerPosition(0, World, ListenerTransform, FTransform::Identity, 0.0f);
         IFMODStudioModule::Get().FinishSetListenerPosition(1);
     }
 }