Implement Audio Backend Capabilities querying

Also renames "AudioThread" to "AudioBackend". The new name is more
descriptive of what the class really is responsible for, since the
backends are not responsible for managing the audio thread.

NOTE: Right now only XAudio2 is supported

rpcs3/Emu/Audio/XAudio2/XAudio28Backend.cpp

@@ -0,0 +1,192 @@
+#ifdef _WIN32
+
+#include "Utilities/Log.h"
+#include "Utilities/StrFmt.h"
+#include "Emu/System.h"
+
+#include "XAudio2Backend.h"
+#include "3rdparty/minidx12/Include/xaudio2.h"
+
+static thread_local HMODULE s_tls_xaudio2_lib{};
+static thread_local IXAudio2* s_tls_xaudio2_instance{};
+static thread_local IXAudio2MasteringVoice* s_tls_master_voice{};
+static thread_local IXAudio2SourceVoice* s_tls_source_voice{};
+
+void XAudio2Backend::xa28_init(void* lib)
+{
+	s_tls_xaudio2_lib = (HMODULE)lib;
+
+	const auto create = (XAudio2Create)GetProcAddress(s_tls_xaudio2_lib, "XAudio2Create");
+
+	HRESULT hr = S_OK;
+
+	hr = CoInitializeEx(nullptr, COINIT_MULTITHREADED);
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : CoInitializeEx() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+		return;
+	}	
+
+	hr = create(&s_tls_xaudio2_instance, 0, XAUDIO2_DEFAULT_PROCESSOR);
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : XAudio2Create() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+		return;
+	}
+
+	hr = s_tls_xaudio2_instance->CreateMasteringVoice(&s_tls_master_voice, g_cfg.audio.downmix_to_2ch ? 2 : 8, 48000);
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : CreateMasteringVoice() failed(0x%08x)", (u32)hr);
+		s_tls_xaudio2_instance->Release();
+		Emu.Pause();
+	}
+}
+
+void XAudio2Backend::xa28_destroy()
+{
+	if (s_tls_source_voice != nullptr)
+	{
+		s_tls_source_voice->Stop();
+		s_tls_source_voice->DestroyVoice();
+	}
+
+	if (s_tls_master_voice != nullptr)
+	{
+		s_tls_master_voice->DestroyVoice();
+	}
+
+	if (s_tls_xaudio2_instance != nullptr)
+	{
+		s_tls_xaudio2_instance->StopEngine();
+		s_tls_xaudio2_instance->Release();
+	}
+
+	CoUninitialize();
+
+	FreeLibrary(s_tls_xaudio2_lib);
+}
+
+void XAudio2Backend::xa28_play()
+{
+	AUDIT(s_tls_source_voice != nullptr);
+
+	HRESULT hr = s_tls_source_voice->Start();
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : Start() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+	}
+}
+
+void XAudio2Backend::xa28_flush()
+{
+	AUDIT(s_tls_source_voice != nullptr);
+
+	HRESULT hr = s_tls_source_voice->FlushSourceBuffers();
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : FlushSourceBuffers() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+	}
+}
+
+void XAudio2Backend::xa28_stop()
+{
+	AUDIT(s_tls_source_voice != nullptr);
+
+	HRESULT hr = s_tls_source_voice->Stop();
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : Stop() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+	}
+}
+
+bool XAudio2Backend::xa28_is_playing()
+{
+	AUDIT(s_tls_source_voice != nullptr);
+
+	XAUDIO2_VOICE_STATE state;
+	s_tls_source_voice->GetState(&state, XAUDIO2_VOICE_NOSAMPLESPLAYED);
+
+	return state.BuffersQueued > 0 || state.pCurrentBufferContext != nullptr;
+}
+
+void XAudio2Backend::xa28_open()
+{
+	HRESULT hr;
+
+	const u32 sample_size = get_sample_size();
+	const u32 channels = get_channels();
+	const u32 sampling_rate = get_sampling_rate();
+
+	WAVEFORMATEX waveformatex;
+	waveformatex.wFormatTag = g_cfg.audio.convert_to_u16 ? WAVE_FORMAT_PCM : WAVE_FORMAT_IEEE_FLOAT;
+	waveformatex.nChannels = channels;
+	waveformatex.nSamplesPerSec = sampling_rate;
+	waveformatex.nAvgBytesPerSec = static_cast<DWORD>(sampling_rate * channels * sample_size);
+	waveformatex.nBlockAlign = channels * sample_size;
+	waveformatex.wBitsPerSample = sample_size * 8;
+	waveformatex.cbSize = 0;
+
+	hr = s_tls_xaudio2_instance->CreateSourceVoice(&s_tls_source_voice, &waveformatex, 0, XAUDIO2_DEFAULT_FREQ_RATIO);
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : CreateSourceVoice() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+		return;
+	}
+
+	AUDIT(s_tls_source_voice != nullptr);
+	s_tls_source_voice->SetVolume(channels == 2 ? 1.0 : 4.0);
+}
+
+bool XAudio2Backend::xa28_add(const void* src, int size)
+{
+	AUDIT(s_tls_source_voice != nullptr);
+
+	XAUDIO2_VOICE_STATE state;
+	s_tls_source_voice->GetState(&state, XAUDIO2_VOICE_NOSAMPLESPLAYED);
+
+	if (state.BuffersQueued >= MAX_AUDIO_BUFFERS)
+	{
+		LOG_WARNING(GENERAL, "XAudio2Backend : too many buffers enqueued (%d, pos=%u)", state.BuffersQueued, state.SamplesPlayed);
+		return false;
+	}
+
+	XAUDIO2_BUFFER buffer;
+
+	buffer.AudioBytes = size * get_sample_size();
+	buffer.Flags = 0;
+	buffer.LoopBegin = XAUDIO2_NO_LOOP_REGION;
+	buffer.LoopCount = 0;
+	buffer.LoopLength = 0;
+	buffer.pAudioData = (const BYTE*)src;
+	buffer.pContext = 0;
+	buffer.PlayBegin = 0;
+	buffer.PlayLength = AUDIO_BUFFER_SAMPLES;
+
+	HRESULT hr = s_tls_source_voice->SubmitSourceBuffer(&buffer);
+	if (FAILED(hr))
+	{
+		LOG_ERROR(GENERAL, "XAudio2Backend : AddData() failed(0x%08x)", (u32)hr);
+		Emu.Pause();
+		return false;
+	}
+
+	return true;
+}
+
+u64 XAudio2Backend::xa28_enqueued_samples()
+{
+	XAUDIO2_VOICE_STATE state;
+	s_tls_source_voice->GetState(&state);
+
+	// all buffers contain AUDIO_BUFFER_SAMPLES, so we can easily calculate how many samples there are remaining
+	return (AUDIO_BUFFER_SAMPLES - state.SamplesPlayed % AUDIO_BUFFER_SAMPLES) + (state.BuffersQueued * AUDIO_BUFFER_SAMPLES);
+}
+
+#endif