add desktop interaction

Source/WidgetInteraction/Private/WidgetInteraction.cpp

@@ -2,6 +2,8 @@
 
 #include "WidgetInteraction.h"
 #include "HeadMountedDisplayFunctionLibrary.h"
+#include "IDisplayCluster.h"
+#include "IDisplayClusterClusterManager.h"
 #include "Engine.h"
 
 #define LOCTEXT_NAMESPACE "FWidgetInteractionModule"
@@ -21,9 +23,14 @@ void FWidgetInteractionModule::OnWorldTickStart(ELevelTick level_tick, float val
 {
   auto worlds = GEngine->GetWorldContexts();
 
-	if (widget_interaction_cmp_ != nullptr && widget_interaction_cmp_->IsValidLowLevel() == true)
+  if (widget_interaction_cmp_ != nullptr) {
+    if (widget_interaction_cmp_->IsValidLowLevel() == true) {
       return;
-
+    }
+    else {
+      widget_interaction_cmp_ = nullptr;
+    }
+  }
 
   for (auto & world_context : worlds)
   {
@@ -36,14 +43,28 @@ void FWidgetInteractionModule::OnWorldTickStart(ELevelTick level_tick, float val
     if (vr_pawn == nullptr)
       continue;
 
-		FString name = FString("flystick");
-		auto component_class = UMotionControllerComponent::StaticClass();
-		if (UHeadMountedDisplayFunctionLibrary::IsHeadMountedDisplayEnabled())
-		{
+    FString name = "";
+    UClass* component_class = UMotionControllerComponent::StaticClass();
+
+
+    if (IDisplayCluster::Get().GetClusterMgr()->IsStandalone()) {
+      //if this is a standalone setup ...
+      if (UHeadMountedDisplayFunctionLibrary::IsHeadMountedDisplayEnabled()) {
+        //.. with an HMD, we attach the intercation component to the right hand
         name = FString("RightMotionController");
         component_class = UMotionControllerComponent::StaticClass();
       }
-
+      else {
+        //... without an HMD, we also attach it to the virtual right hand, since it exists in this case
+        name = TEXT("RightMotionController");
+        component_class = UMotionControllerComponent::StaticClass();
+      }
+    }
+    else {
+      //if this is a cluster setup we attach it to the flystick
+      name = TEXT("flystick");
+      component_class = UMotionControllerComponent::StaticClass();
+    }
 
     auto parent_vec = vr_pawn->GetComponentsByClass(component_class);
     for (auto parent : parent_vec)