xaudio2_s.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#include "../stdafx.h"
#include "../openttd.h"
#include "../driver.h"
#include "../mixer.h"
#include "../debug.h"
#include "../core/bitmath_func.hpp"
#include "../core/math_func.hpp"
 
/* Windows 8 SDK required for XAudio2 */
#undef NTDDI_VERSION
#undef _WIN32_WINNT
 
#define NTDDI_VERSION    NTDDI_WIN8
#define _WIN32_WINNT     _WIN32_WINNT_WIN8
 
#include "xaudio2_s.h"
 
#include <windows.h>
#include <mmsystem.h>
#include <wrl\client.h>
#include <xaudio2.h>
 
using Microsoft::WRL::ComPtr;
 
#include "../os/windows/win32.h"
#include "../safeguards.h"
 
/* Definition of the "XAudio2Create" call used to initialise XAudio2 */
typedef HRESULT(__stdcall *API_XAudio2Create)(_Outptr_ IXAudio2 **ppXAudio2, UINT32 Flags, XAUDIO2_PROCESSOR XAudio2Processor);
 
static FSoundDriver_XAudio2 iFSoundDriver_XAudio2;

class StreamingVoiceContext : public IXAudio2VoiceCallback
{
private:
  std::vector<BYTE> buffer;
 
public:
  IXAudio2SourceVoice *source_voice = nullptr;
 
  StreamingVoiceContext(int buffer_length)
  {
    this->buffer.resize(buffer_length);
  }
 
  /* This needs to be virtual because the XAudio2 API declares the interface without
   * a virtual destructor, even though it has functions that need to be overridden. */
  virtual ~StreamingVoiceContext() = default;
 
  HRESULT SubmitBuffer()
  {
    /* Ensure we do have a valid voice */
    if (this->source_voice == nullptr) {
      return E_FAIL;
    }
 
    MxMixSamples(this->buffer.data(), static_cast<uint>(this->buffer.size() / 4));
 
    XAUDIO2_BUFFER buf = { 0 };
    buf.AudioBytes = static_cast<UINT32>(this->buffer.size());
    buf.pAudioData = this->buffer.data();
 
    return source_voice->SubmitSourceBuffer(&buf);
  }
 
  STDMETHOD_(void, OnVoiceProcessingPassStart)(UINT32) override
  {
  }
 
  STDMETHOD_(void, OnVoiceProcessingPassEnd)() override
  {
  }
 
  STDMETHOD_(void, OnStreamEnd)() override
  {
  }
 
  STDMETHOD_(void, OnBufferStart)(void*) override
  {
  }
 
  STDMETHOD_(void, OnBufferEnd)(void*) override
  {
    SubmitBuffer();
  }
 
  STDMETHOD_(void, OnLoopEnd)(void*) override
  {
  }
 
  STDMETHOD_(void, OnVoiceError)(void*, HRESULT) override
  {
  }
};
 
static HMODULE _xaudio_dll_handle;
static IXAudio2SourceVoice *_source_voice = nullptr;
static IXAudio2MasteringVoice *_mastering_voice = nullptr;
static ComPtr<IXAudio2> _xaudio2;
static std::unique_ptr<StreamingVoiceContext> _voice_context;

static HRESULT CreateXAudio(API_XAudio2Create xAudio2Create)
{
  HRESULT hr;
  __try {
    UINT32 flags = 0;
    hr = xAudio2Create(_xaudio2.GetAddressOf(), flags, XAUDIO2_DEFAULT_PROCESSOR);
  } __except (EXCEPTION_EXECUTE_HANDLER) {
    hr = GetExceptionCode();
  }
 
  return hr;
}

std::optional<std::string_view> SoundDriver_XAudio2::Start(const StringList &parm)
{
  HRESULT hr = CoInitializeEx(nullptr, COINIT_MULTITHREADED);
 
  if (FAILED(hr)) {
    Debug(driver, 0, "xaudio2_s: CoInitializeEx failed ({:08x})", (uint)hr);
    return "Failed to initialise COM";
  }
 
  _xaudio_dll_handle = LoadLibraryA(XAUDIO2_DLL_A);
 
  if (_xaudio_dll_handle == nullptr) {
    CoUninitialize();
 
    Debug(driver, 0, "xaudio2_s: Unable to load " XAUDIO2_DLL_A);
    return "Failed to load XAudio2 DLL";
  }
 
  API_XAudio2Create xAudio2Create = (API_XAudio2Create) GetProcAddress(_xaudio_dll_handle, "XAudio2Create");
 
  if (xAudio2Create == nullptr) {
    FreeLibrary(_xaudio_dll_handle);
    CoUninitialize();
 
    Debug(driver, 0, "xaudio2_s: Unable to find XAudio2Create function in DLL");
    return "Failed to load XAudio2 DLL";
  }
 
  /* Create the XAudio engine */
  hr = CreateXAudio(xAudio2Create);
 
  if (FAILED(hr)) {
    FreeLibrary(_xaudio_dll_handle);
    CoUninitialize();
 
    Debug(driver, 0, "xaudio2_s: XAudio2Create failed ({:08x})", (uint)hr);
    return "Failed to initialise the XAudio2 engine";
  }
 
  /* Create a mastering voice */
  hr = _xaudio2->CreateMasteringVoice(&_mastering_voice);
 
  if (FAILED(hr)) {
    _xaudio2.Reset();
    FreeLibrary(_xaudio_dll_handle);
    CoUninitialize();
 
    Debug(driver, 0, "xaudio2_s: CreateMasteringVoice failed ({:08x})", (uint)hr);
    return "Failed to create a mastering voice";
  }
 
  /* Create a source voice to stream our audio */
  WAVEFORMATEX wfex;
 
  wfex.wFormatTag = WAVE_FORMAT_PCM;
  wfex.nChannels = 2;
  wfex.wBitsPerSample = 16;
  wfex.nSamplesPerSec = GetDriverParamInt(parm, "hz", 44100);
  wfex.nBlockAlign = (wfex.nChannels * wfex.wBitsPerSample) / 8;
  wfex.nAvgBytesPerSec = wfex.nSamplesPerSec * wfex.nBlockAlign;
 
  /* Limit buffer size to prevent overflows */
  int bufsize = GetDriverParamInt(parm, "samples", 1024);
  bufsize = std::min<int>(bufsize, UINT16_MAX);
 
  _voice_context = std::make_unique<StreamingVoiceContext>(bufsize * 4);
 
  if (_voice_context == nullptr) {
    _mastering_voice->DestroyVoice();
    _xaudio2.Reset();
    FreeLibrary(_xaudio_dll_handle);
    CoUninitialize();
 
    return "Failed to create streaming voice context";
  }
 
  hr = _xaudio2->CreateSourceVoice(&_source_voice, &wfex, 0, 1.0f, _voice_context.get());
 
  if (FAILED(hr)) {
    _mastering_voice->DestroyVoice();
    _xaudio2.Reset();
    FreeLibrary(_xaudio_dll_handle);
    CoUninitialize();
 
    Debug(driver, 0, "xaudio2_s: CreateSourceVoice failed ({:08x})", (uint)hr);
    return "Failed to create a source voice";
  }
 
  _voice_context->source_voice = _source_voice;
  hr = _source_voice->Start(0, 0);
 
  if (FAILED(hr)) {
    Debug(driver, 0, "xaudio2_s: _source_voice->Start failed ({:08x})", (uint)hr);
 
    Stop();
    return "Failed to start the source voice";
  }
 
  MxInitialize(wfex.nSamplesPerSec);
 
  /* Submit the first buffer */
  hr = _voice_context->SubmitBuffer();
 
  if (FAILED(hr)) {
    Debug(driver, 0, "xaudio2_s: _voice_context->SubmitBuffer failed ({:08x})", (uint)hr);
 
    Stop();
    return "Failed to submit the first audio buffer";
  }
 
  return std::nullopt;
}

void SoundDriver_XAudio2::Stop()
{
  /* Clean up XAudio2 */
  _source_voice->DestroyVoice();
 
  _voice_context = nullptr;
 
  _mastering_voice->DestroyVoice();
 
  _xaudio2.Reset();
 
  FreeLibrary(_xaudio_dll_handle);
  CoUninitialize();
}