From 7fd7c49538998906535fc0c446f6e04ad0a0cb0d Mon Sep 17 00:00:00 2001
From: Stijn Van der Borght <stijnvanderborght@gmail.com>
Date: Sun, 10 May 2020 13:26:32 +0100
Subject: [PATCH] wasapi: added listener for getting system volume

---
 client/player/wasapi_player.cpp | 43 +++++++++++++++++-
 client/player/wasapi_player.h   | 77 +++++++++++++++++++++++++++++++++
 2 files changed, 119 insertions(+), 1 deletion(-)

diff --git a/client/player/wasapi_player.cpp b/client/player/wasapi_player.cpp
index 2a94e8c2..4f223560 100644
--- a/client/player/wasapi_player.cpp
+++ b/client/player/wasapi_player.cpp
@@ -45,6 +45,7 @@ const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
 const IID IID_IAudioClient = __uuidof(IAudioClient);
 const IID IID_IAudioRenderClient = __uuidof(IAudioRenderClient);
 const IID IID_IAudioClock = __uuidof(IAudioClock);
+const IID IID_IAudioEndpointVolume = _uuidof(IAudioEndpointVolume);
 
 _COM_SMARTPTR_TYPEDEF(IMMDevice, __uuidof(IMMDevice));
 _COM_SMARTPTR_TYPEDEF(IMMDeviceCollection, __uuidof(IMMDeviceCollection));
@@ -229,6 +230,8 @@ void WASAPIPlayer::worker()
     hr = device->Activate(__uuidof(IAudioSessionManager), CLSCTX_INPROC_SERVER, NULL, (void**)&sessionManager);
     CHECK_HR(hr);
 
+    
+
     // Get the control interface for the process-specific audio
     // session with session GUID = GUID_NULL. This is the session
     // that an audio stream for a DirectSound, DirectShow, waveOut,
@@ -241,6 +244,11 @@ void WASAPIPlayer::worker()
     hr = control->RegisterAudioSessionNotification(audioEventListener_);
     CHECK_HR(hr);
 
+    AudioEndpointVolumeCallback audioEndpointVolumeCallback;
+    hr = device->Activate(IID_IAudioEndpointVolume, CLSCTX_ALL, NULL, (void**)&audioEndpointListener_);
+
+    audioEndpointListener_->RegisterControlChangeNotify((IAudioEndpointVolumeCallback*)&audioEndpointVolumeCallback);
+
     // Get the device period
     REFERENCE_TIME hnsRequestedDuration = REFTIMES_PER_SEC;
     hr = audioClient->GetDevicePeriod(NULL, &hnsRequestedDuration);
@@ -335,7 +343,16 @@ void WASAPIPlayer::worker()
             break;
 
         // update our volume from IAudioControl
-        volCorrection_ = audioEventListener_->getVolume();
+        if (mode_ == ClientSettings::SharingMode::exclusive)
+        {
+            volCorrection_ = audioEventListener_->getVolume();
+            // muteOverride = audioEventListener_->getMuted(); // use this for also applying audio mixer mute state
+        }
+        
+        // get audio device volume from IAudioEndpointVolume
+        // float deviceVolume = audioEndpointVolumeCallback.getVolume(); // system volume (for this audio device)
+        // bool deviceMuted = audioEndpointVolumeCallback.getMuted(); // system mute (for this audio device)
+
 
         clock->GetPosition(&position, NULL);
 
@@ -406,6 +423,8 @@ HRESULT STDMETHODCALLTYPE AudioSessionEventListener::QueryInterface(REFIID riid,
 HRESULT STDMETHODCALLTYPE AudioSessionEventListener::OnSimpleVolumeChanged(float NewVolume, BOOL NewMute, LPCGUID EventContext)
 {
     volume_ = NewVolume;
+    muted_ = NewMute;
+
     if (NewMute)
     {
         LOG(DEBUG, LOG_TAG) << ("MUTE\n");
@@ -463,5 +482,27 @@ HRESULT STDMETHODCALLTYPE AudioSessionEventListener::OnSessionDisconnected(Audio
     }
     LOG(INFO, LOG_TAG) << "Audio session disconnected (reason: " << pszReason << ")";
 
+    return S_OK;
+}
+
+
+
+HRESULT STDMETHODCALLTYPE AudioEndpointVolumeCallback::OnNotify(PAUDIO_VOLUME_NOTIFICATION_DATA pNotify)
+{
+    if (pNotify == NULL)
+    {
+        return E_INVALIDARG;
+    }
+
+    if (pNotify->bMuted)
+    {
+        LOG(DEBUG, LOG_TAG) << ("MASTER MUTE\n");
+    }
+
+    LOG(DEBUG, LOG_TAG) << "Volume = " << (UINT32)(100 * pNotify->fMasterVolume + 0.5) << " percent\n";
+
+    volume_ = pNotify->fMasterVolume;
+    muted_ = pNotify->bMuted;
+
     return S_OK;
 }
\ No newline at end of file
diff --git a/client/player/wasapi_player.h b/client/player/wasapi_player.h
index 0d987767..c21db94e 100644
--- a/client/player/wasapi_player.h
+++ b/client/player/wasapi_player.h
@@ -21,12 +21,14 @@
 #include "client_settings.hpp"
 #include "player.hpp"
 #include <audiopolicy.h>
+#include <endpointvolume.h>
 
 class AudioSessionEventListener : public IAudioSessionEvents
 {
     LONG _cRef;
 
     float volume_ = 1.f;
+    bool muted_ = false;
 
 public:
     AudioSessionEventListener() : _cRef(1)
@@ -38,6 +40,11 @@ public:
         return volume_;
     }
 
+    bool getMuted()
+    {
+        return muted_;
+    }
+
     ~AudioSessionEventListener()
     {
     }
@@ -90,6 +97,75 @@ public:
     HRESULT STDMETHODCALLTYPE OnSessionDisconnected(AudioSessionDisconnectReason DisconnectReason);
 };
 
+
+class AudioEndpointVolumeCallback : public IAudioEndpointVolumeCallback
+{
+    LONG _cRef;
+    float volume_ = 1.f;
+    bool muted_ = false;
+
+public:
+    AudioEndpointVolumeCallback() : _cRef(1)
+    {
+    }
+
+    ~AudioEndpointVolumeCallback()
+    {
+    }
+
+    float getVolume()
+    {
+        return volume_;
+    }
+
+    bool getMuted()
+    {
+        return muted_;
+    }
+
+    // IUnknown methods -- AddRef, Release, and QueryInterface
+
+    ULONG STDMETHODCALLTYPE AddRef()
+    {
+        return InterlockedIncrement(&_cRef);
+    }
+
+    ULONG STDMETHODCALLTYPE Release()
+    {
+        ULONG ulRef = InterlockedDecrement(&_cRef);
+        if (0 == ulRef)
+        {
+            delete this;
+        }
+        return ulRef;
+    }
+
+    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, VOID** ppvInterface)
+    {
+        if (IID_IUnknown == riid)
+        {
+            AddRef();
+            *ppvInterface = (IUnknown*)this;
+        }
+        else if (__uuidof(IAudioEndpointVolumeCallback) == riid)
+        {
+            AddRef();
+            *ppvInterface = (IAudioEndpointVolumeCallback*)this;
+        }
+        else
+        {
+            *ppvInterface = NULL;
+            return E_NOINTERFACE;
+        }
+
+        return S_OK;
+    }
+
+    // Callback method for endpoint-volume-change notifications.
+
+    HRESULT STDMETHODCALLTYPE OnNotify(PAUDIO_VOLUME_NOTIFICATION_DATA pNotify);
+};
+
 class WASAPIPlayer : public Player
 {
 public:
@@ -103,6 +179,7 @@ protected:
 
 private:
     AudioSessionEventListener* audioEventListener_;
+    IAudioEndpointVolume* audioEndpointListener_;
     ClientSettings::SharingMode mode_;
 };