add the multicast loopback option (was always disabled)

OSC/Source/OSC/Private/OscModule.cpp

@@ -105,7 +105,7 @@ public:
         uint32_t receivePort;
         if(UOscSettings::Parse(settings->ReceiveFrom, &receiveAddress, &receivePort))
         {
-            _dispatcher->Listen(receiveAddress, receivePort);
+            _dispatcher->Listen(receiveAddress, receivePort, settings->MulticastLoopback);
         }
         else
         {

OSC/Source/OSC/Private/OscSettings.cpp

@@ -6,6 +6,7 @@
 
 UOscSettings::UOscSettings()
  :  ReceiveFrom("8000"),
+    MulticastLoopback(true),
     _sendSocket(FUdpSocketBuilder(TEXT("OscSender")).Build())
 {
     SendTargets.Add(TEXT("127.0.0.1:8000"));

OSC/Source/OSC/Private/OscSettings.h

@@ -44,6 +44,9 @@ public:
     UPROPERTY(Config, EditAnywhere, Category=Input)
     TArray<FString> Inputs;
 
+    UPROPERTY(Config, EditAnywhere, Category=Network)
+    bool MulticastLoopback;
+
 public:
     void InitSendTargets();
 

OSC/Source/OSC/Private/Receive/OscDispatcher.cpp

@@ -25,7 +25,7 @@ UOscDispatcher * UOscDispatcher::Get()
     return UOscDispatcher::StaticClass()->GetDefaultObject<UOscDispatcher>();
 }
 
-void UOscDispatcher::Listen(FIPv4Address address, uint32_t port)
+void UOscDispatcher::Listen(FIPv4Address address, uint32_t port, bool multicastLoopback)
 {
     if(_listening != std::make_pair(address, port))
     {
@@ -36,6 +36,10 @@ void UOscDispatcher::Listen(FIPv4Address address, uint32_t port)
         if(address.IsMulticastAddress())
         {
             builder.JoinedToGroup(address);
+            if(multicastLoopback)
+            {
+                builder.WithMulticastLoopback();
+            }
         }
         else
         {

OSC/Source/OSC/Private/Receive/OscDispatcher.h

@@ -16,7 +16,7 @@ class UOscDispatcher : public UObject
 
     friend class FOscModule;
 
-    void Listen(FIPv4Address address, uint32_t port);
+    void Listen(FIPv4Address address, uint32_t port, bool multicastLoopback);
     void Stop();
 
 public: