windows-audio-sync/AudioManager/CAudioEndpointVolumeCallback.h

#pragma once

#include <endpointvolume.h>
#include <algorithm>
#include <iostream>

class CAudioEndpointVolumeCallback : public IAudioEndpointVolumeCallback
{
private:
	LONG _cRef;
	IAudioEndpointVolume* g_pEndptVol;
	IAudioEndpointVolume* g_cEndptVol;
	GUID g_guidContext;

public:
	CAudioEndpointVolumeCallback(IAudioEndpointVolume* g_pEndptVol, IAudioEndpointVolume* g_cEndptVol, GUID g_guidContext) :
		_cRef(1), g_pEndptVol(g_pEndptVol), g_cEndptVol(g_cEndptVol), g_guidContext(g_guidContext)
	{
	}

	~CAudioEndpointVolumeCallback()
	{
	}

	// 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)
	{
		if (pNotify == NULL)
		{
			return E_INVALIDARG;
		}
		if (pNotify->guidEventContext != this->g_guidContext)
		{
			HRESULT hr = this->g_cEndptVol->SetMasterVolumeLevelScalar(min(pNotify->fMasterVolume * 6 / 5, 1.0), &this->g_guidContext);
			if (hr != S_OK) {
				std::cerr << "Error while setting volume" << std::endl;
			}

			float  commVolume;
			hr = g_cEndptVol->GetMasterVolumeLevelScalar(&commVolume);
			if (hr == S_OK) {
				std::cout << "\r\033[2KMain Volume : " << pNotify->fMasterVolume * 100 << ", Communication Volume : " << commVolume * 100;
			}
		}
		return S_OK;
	}
};