From 768354e49f915cd29bfa0c4a698b7840099778f9 Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zach@highfidelity.io>
Date: Thu, 29 Sep 2016 12:06:09 -0700
Subject: [PATCH] loopback local injectors on server echo

---
 libraries/audio-client/src/AudioClient.h     |  3 ++-
 libraries/audio/src/AbstractAudioInterface.h |  1 +
 libraries/audio/src/AudioInjector.cpp        | 12 ++++++++----
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/libraries/audio-client/src/AudioClient.h b/libraries/audio-client/src/AudioClient.h
index 97b5c14512..eeca9fbd02 100644
--- a/libraries/audio-client/src/AudioClient.h
+++ b/libraries/audio-client/src/AudioClient.h
@@ -167,7 +167,8 @@ public slots:
 
     int setOutputBufferSize(int numFrames, bool persist = true);
 
-    virtual bool outputLocalInjector(bool isStereo, AudioInjector* injector) override;
+    bool outputLocalInjector(bool isStereo, AudioInjector* injector) override;
+    bool shouldLoopbackInjectors() override { return _shouldEchoToServer; }
 
     bool switchInputToAudioDevice(const QString& inputDeviceName);
     bool switchOutputToAudioDevice(const QString& outputDeviceName);
diff --git a/libraries/audio/src/AbstractAudioInterface.h b/libraries/audio/src/AbstractAudioInterface.h
index 223421a7ab..ec96462e73 100644
--- a/libraries/audio/src/AbstractAudioInterface.h
+++ b/libraries/audio/src/AbstractAudioInterface.h
@@ -33,6 +33,7 @@ public:
 
 public slots:
     virtual bool outputLocalInjector(bool isStereo, AudioInjector* injector) = 0;
+    virtual bool shouldLoopbackInjectors() { return false; }
     
     virtual void setIsStereoInput(bool stereo) = 0;
 };
diff --git a/libraries/audio/src/AudioInjector.cpp b/libraries/audio/src/AudioInjector.cpp
index 43701a51d8..6f6534e2d2 100644
--- a/libraries/audio/src/AudioInjector.cpp
+++ b/libraries/audio/src/AudioInjector.cpp
@@ -211,6 +211,7 @@ int64_t AudioInjector::injectNextFrame() {
     }
 
     // if we haven't setup the packet to send then do so now
+    static int loopbackOptionOffset = -1;
     static int positionOptionOffset = -1;
     static int volumeOptionOffset = -1;
     static int audioDataOffset = -1;
@@ -260,10 +261,9 @@ int64_t AudioInjector::injectNextFrame() {
             // pack the stereo/mono type of the stream
             audioPacketStream << _options.stereo;
 
-            // pack the flag for loopback.  Now, we don't loopback
-            // and _always_ play locally, so loopbackFlag should be
-            // false always.
-            uchar loopbackFlag = (uchar)false;
+            // pack the flag for loopback, if requested
+            loopbackOptionOffset = _currentPacket->pos();
+            uchar loopbackFlag = (_localAudioInterface && _localAudioInterface->shouldLoopbackInjectors());
             audioPacketStream << loopbackFlag;
 
             // pack the position for injected audio
@@ -293,6 +293,7 @@ int64_t AudioInjector::injectNextFrame() {
             return NEXT_FRAME_DELTA_ERROR_OR_FINISHED;
         }
     }
+
     if (!_frameTimer->isValid()) {
         // in the case where we have been restarted, the frame timer will be invalid and we need to start it back over here
         _frameTimer->restart();
@@ -317,6 +318,9 @@ int64_t AudioInjector::injectNextFrame() {
     // pack the sequence number
     _currentPacket->writePrimitive(_outgoingSequenceNumber);
 
+    _currentPacket->seek(loopbackOptionOffset);
+    _currentPacket->writePrimitive((uchar)(_localAudioInterface && _localAudioInterface->shouldLoopbackInjectors()));
+
     _currentPacket->seek(positionOptionOffset);
     _currentPacket->writePrimitive(_options.position);
     _currentPacket->writePrimitive(_options.orientation);