Sound.cpp

#include "Sound.h"
#include "../util/Logger.h"
#include "../util/OptionsDB.h"
#include "../util/Directories.h"

#ifdef FREEORION_MACOSX
#include <OpenAL/al.h>
#include <OpenAL/alc.h>
#else
#include <AL/alc.h>
#include <AL/al.h>
#endif

#include <vorbis/vorbisfile.h>

#include <atomic>
#include <map>
#include <mutex>

class Sound::Impl {
public:
    Impl();
    ~Impl();

    /** Enables the sound system.  Throws Sound::InitializationFailureException on failure. */
    void Enable();

    /** Disable the sound system. */
    void Disable();

    /**Initialize OpenAL*/
    void InitOpenAL();

    /**Shutdown OpenAL.*/
    void ShutdownOpenAL();

    /** Plays a music file.  The file will be played in an infinitve loop if \a loop is < 0, and it will be played \a
        loops + 1 times otherwise. */
    void PlayMusic(const boost::filesystem::path& path, int loops = 0);

    /** Pauses music play, to be continued from the same position */
    void PauseMusic();

    /** Resumes music play */
    void ResumeMusic();

    /** Stops playing music. */
    void StopMusic();

    /** Plays a sound file. */
    void PlaySound(const boost::filesystem::path& path, bool is_ui_sound = false);

    /** Frees the cached sound data associated with the filename. */
    void FreeSound(const boost::filesystem::path& path);

    /** Frees all cached sound data. */
    void FreeAllSounds();

    /** Sets the music volume from 0 (muted) to 255 (full volume); \a vol is range-adjusted. */
    void SetMusicVolume(int vol);

    /** Sets the UI sounds volume from 0 (muted) to 255 (full volume); \a vol is range-adjusted. */
    void SetUISoundsVolume(int vol);

    /** Does the work that must be done by the sound system once per frame. */
    void DoFrame();

    bool UISoundsTemporarilyDisabled() const;

    /**Increment the temporary disabled depth.*/
    void IncDisabledCount();

    /** Decrease the temporary disabled depth.*/
    void DecDisabledCount();

private:
    static constexpr int NUM_SOURCES = 16; // The number of sources for OpenAL to create. Should be 2 or more.
    static constexpr int NUM_MUSIC_BUFFERS = 2; // The number of music buffers.

    ALuint                        m_sources[NUM_SOURCES] = {0};             ///< OpenAL sound sources. The first one is used for music
    int                           m_music_loops = 0;                        ///< the number of loops of the current music to play (< 0 for loop forever)
    std::string                   m_music_name;                             ///< the name of the currently-playing music file
    std::map<std::string, ALuint> m_sound_buffers;                          ///< the currently-cached (and possibly playing) sounds, if any; keyed on filename

    ALuint                        m_music_buffers[NUM_MUSIC_BUFFERS] = {0}; ///< additional buffers for music.
    OggVorbis_File                m_music_ogg_file = {};                    ///< the currently open music ogg file
    ALenum                        m_music_ogg_format = 0;                   ///< mono or stereo for current music
    ALsizei                       m_music_ogg_freq = 0;                     ///< sampling frequency for current music

    std::atomic<unsigned int>     m_temporary_disable_count = 0;            ///< Count of the number of times sound was disabled. Sound is enabled when this is zero.

    /** The system will not be initialized if both sound effects and
        music are disabled, or if initialization failed. */
    bool                          m_initialized = false;
};

namespace {
    constexpr int MUSIC_BUFFER_SIZE = 409600; // initial size of the buffer sound and music data is read into
    constexpr ogg_int64_t MAX_BUFFER_SIZE = 8 * 1024 * 1024;

    std::vector<char> audio_data_buffer(MUSIC_BUFFER_SIZE, 0);
    std::mutex buffer_mutex;

    constexpr int endian = 0; // 0 for little-endian (x86), 1 for big-endian (ppc)
    constexpr int MIN_CHUNK_SIZE = 4096;

#ifdef FREEORION_WIN32
    int _fseek64_wrap(FILE *f, ogg_int64_t off, int whence) {
        if (!f)
            return -1;
        return fseek(f, off, whence);
    }
#endif

    /// Returns 1 on failure or 0 on success
    int RefillBuffer(OggVorbis_File* ogg_file, ALenum ogg_format, ALsizei ogg_freq,
                     ALuint buffer_id, int file_required_buffer_size, int& loops)
    {
        if (!alcGetCurrentContext())
            return 1;

        if (file_required_buffer_size > MAX_BUFFER_SIZE) {
            ErrorLogger() << "RefillBuffer requested size " << file_required_buffer_size << " too big";
            return 1;
        }

        std::unique_lock buffer_lock(buffer_mutex);
        if (std::cmp_less(audio_data_buffer.size(), file_required_buffer_size)) {
            try {
                audio_data_buffer.resize(file_required_buffer_size, 0);
                DebugLogger() << "RefillBuffer buffer expanded to " << file_required_buffer_size;
            } catch (...) {
                ErrorLogger() << "RefilBuffer unable to reallocate buffer to size << " << file_required_buffer_size;
                return 1;
            }
        }

        const auto AUDIO_BUFFER_SIZE = audio_data_buffer.size();
        int space_left_in_audio_buffer = AUDIO_BUFFER_SIZE;
        int prev_bytes_new = 0;
        ALsizei bytes_read = 0;
        int file_bytes_remaining = file_required_buffer_size - bytes_read;
        int bit_stream = 0;
        static constexpr int word = 2;
        static constexpr int sgned = 1;

        // Fill buffer. We need the loop, as ov_read treats (buffer_size - bytes_read) to read as a suggestion only
        while (file_bytes_remaining > 0 && space_left_in_audio_buffer > MIN_CHUNK_SIZE) {
            //std::cout << "file rem: " << file_bytes_remaining << " buf ref: " << space_left_in_audio_buffer << std::endl;
            auto* buffer_pos = std::next(audio_data_buffer.data(), bytes_read);
            const auto bytes_new = ov_read(ogg_file, buffer_pos, file_bytes_remaining, endian, word, sgned, &bit_stream);
            bytes_read += bytes_new;
            file_bytes_remaining = file_required_buffer_size - bytes_read;
            space_left_in_audio_buffer = AUDIO_BUFFER_SIZE - bytes_read;

            if (bytes_new == 0) {
                if (loops != 0) {   // enter here to play the same file again
                    if (loops > 0)
                        loops--;
                    ov_time_seek(ogg_file, 0.0); // rewind to beginning
                } else {
                    break;
                }
            }


            // safety check
            if (bytes_new == 0 && prev_bytes_new == 0) {
                ErrorLogger() << "RefillBuffer aborting filling buffer due to repeatedly getting no new bytes";
                break;
            }
            prev_bytes_new = bytes_new;
        }

        if (bytes_read > 0) {
            alBufferData(buffer_id, ogg_format, audio_data_buffer.data(), bytes_read, ogg_freq);
            const auto openal_error = alGetError();
            if (openal_error != AL_NONE)
                ErrorLogger() << "RefillBuffer unable to set OpenAL ERROR: " << alGetString(openal_error);
        } else {
            ov_clear(ogg_file); // the app might think we still have something to play.
            return 1;
        }
        return 0;
    }
}

////////////////////////////////////////////////////////////
// TempUISoundDisabler
////////////////////////////////////////////////////////////
Sound::TempUISoundDisabler::TempUISoundDisabler()
{ Sound::GetSound().m_impl->IncDisabledCount(); }

Sound::TempUISoundDisabler::~TempUISoundDisabler()
{ Sound::GetSound().m_impl->DecDisabledCount(); }

////////////////////////////////////////////////////////////
// Sound
////////////////////////////////////////////////////////////
namespace {
    Sound sound;
}

Sound& Sound::GetSound()
{ return sound; }

Sound::Sound() :
    m_impl(std::make_unique<Impl>())
{}

// Require here because Sound::Impl is defined in this file.
Sound::~Sound() = default;

void Sound::Enable()
{ m_impl->Enable(); }

void Sound::Disable()
{ m_impl->Disable(); }

void Sound::PlayMusic(const boost::filesystem::path& path, int loops)
{ m_impl->PlayMusic(path, loops); }

void Sound::PauseMusic()
{ m_impl->PauseMusic(); }

void Sound::ResumeMusic()
{ m_impl->ResumeMusic(); }

void Sound::StopMusic()
{ m_impl->StopMusic(); }

void Sound::PlaySound(const boost::filesystem::path& path, bool is_ui_sound)
{ m_impl->PlaySound(path, is_ui_sound); }

void Sound::FreeSound(const boost::filesystem::path& path)
{ m_impl->FreeSound(path); }

void Sound::FreeAllSounds()
{ m_impl->FreeAllSounds(); }

void Sound::SetMusicVolume(int vol)
{ m_impl->SetMusicVolume(vol); }

void Sound::SetUISoundsVolume(int vol)
{ m_impl->SetUISoundsVolume(vol); }

void Sound::DoFrame()
{ m_impl->DoFrame(); }


Sound::Impl::Impl() = default;

Sound::Impl::~Impl()
{ Disable(); }

void Sound::Impl::Enable() {
    if (m_initialized)
        return;
    if (!GetOptionsDB().Get<bool>("audio.effects.enabled") && !GetOptionsDB().Get<bool>("audio.music.enabled"))
        return;

    // Reset playing audio
    m_music_loops = 0;
    m_sound_buffers.clear();
    m_temporary_disable_count = 0;

    InitOpenAL();
    if (!m_initialized) {
        ErrorLogger() << "Unable to initialize audio.  Sound effects and music are disabled.";
        // TODO: Let InitOpenAL throw the OpenAL error message which might be more useful.
        throw InitializationFailureException("ERROR_SOUND_INITIALIZATION_FAILED");
    }

    DebugLogger() << "Audio " << (m_initialized ? "enabled." : "disabled.");
}

void Sound::Impl::Disable() {
    if (!m_initialized)
        return;
    StopMusic();

    ShutdownOpenAL();

    //Reset playing audio
    m_music_loops = 0;
    m_sound_buffers.clear();
    m_temporary_disable_count = 0;

    m_initialized = false;
    DebugLogger() << "Audio " << (m_initialized ? "enabled." : "disabled.");
}

void Sound::Impl::InitOpenAL() {
    // TODO: Rewrite with std::unique_ptr and custom deleter to remove long chain of "destructor" code.

    ALCdevice* device = alcOpenDevice(nullptr);
    if (!device) {
        ErrorLogger() << "Unable to initialise default OpenAL device.";
        m_initialized = false;
        return;
    }

    ALCcontext* context = alcCreateContext(device, nullptr);
    if (!context) {
        ALenum error_code = alGetError();
        ErrorLogger() << "Unable to create OpenAL context: " << alGetString(error_code) << "\n";
        alcCloseDevice(device);
        m_initialized = false;
        return;
    }

    ALboolean status = alcMakeContextCurrent(context);
    ALenum error_code = alGetError();
    if (status != AL_TRUE || error_code != AL_NO_ERROR) {
        ErrorLogger() << "Unable to make OpenAL context current: " << alGetString(error_code) << "\n";
        alcDestroyContext(context);
        alcCloseDevice(device);
        m_initialized = false;
        return;
    }

    alListenerf(AL_GAIN, 1.0);
    error_code = alGetError();
    if (error_code != AL_NO_ERROR) {
        ErrorLogger() << "Unable to create OpenAL listener: " << alGetString(error_code) << "\n"
                      << "Disabling OpenAL sound system!\n";
        alcMakeContextCurrent(nullptr);
        alcDestroyContext(context);
        alcCloseDevice(device);
        m_initialized = false;
        return;
    }

    alGenSources(NUM_SOURCES, m_sources);
    error_code = alGetError();
    if (error_code != AL_NO_ERROR) {
        ErrorLogger() << "Unable to create OpenAL sources: " << alGetString(error_code) << "\n"
                      << "Disabling OpenAL sound system!\n";
        alcMakeContextCurrent(nullptr);
        alcDestroyContext(context);
        alcCloseDevice(device);
        m_initialized = false;
        return;
    }

    alGenBuffers(NUM_MUSIC_BUFFERS, m_music_buffers);
    error_code = alGetError();
    if (error_code != AL_NO_ERROR) {
        ErrorLogger() << "Unable to create OpenAL buffers: " << alGetString(error_code) << "\n"
                      << "Disabling OpenAL sound system!\n";
        alDeleteSources(NUM_SOURCES, m_sources);
        alcMakeContextCurrent(nullptr);
        alcDestroyContext(context);
        alcCloseDevice(device);
        m_initialized = false;
        return;
    }

    for (int i = 0; i < NUM_SOURCES; ++i) {
        alSourcei(m_sources[i], AL_SOURCE_RELATIVE, AL_TRUE);
        error_code = alGetError();
        if (error_code != AL_NO_ERROR) {
            ErrorLogger() << "Unable to set OpenAL source to relative: " << alGetString(error_code) << "\n"
                          << "Disabling OpenAL sound system!\n";
            alDeleteBuffers(NUM_MUSIC_BUFFERS, m_music_buffers);
            alDeleteSources(NUM_SOURCES, m_sources);
            alcMakeContextCurrent(nullptr);
            alcDestroyContext(context);
            alcCloseDevice(device);
            m_initialized = false;
            return;
        }
    }

    DebugLogger() << "OpenAL initialized. Version " << alGetString(AL_VERSION)
                  << " Renderer " << alGetString(AL_RENDERER)
                  << " Vendor " << alGetString(AL_VENDOR) << "\n"
                  << " Extensions: " << alGetString(AL_EXTENSIONS) << "\n";
    m_initialized = true;
}

void Sound::Impl::ShutdownOpenAL() {
    ALCcontext* context = alcGetCurrentContext();

    if (!context)
        return;

    alDeleteSources(NUM_SOURCES, m_sources); // Automatically stops currently playing sources

    alDeleteBuffers(NUM_MUSIC_BUFFERS, m_music_buffers);
    for (auto& buffer : m_sound_buffers)
        alDeleteBuffers(1, &(buffer.second));

    ALCdevice* device = alcGetContextsDevice(context);

    alcMakeContextCurrent(nullptr);
    alcDestroyContext(context);

    if (device)
        alcCloseDevice(device);
}

namespace {
#ifdef FREEORION_WIN32
    ov_callbacks callbacks = {
        (size_t (*)(void *, size_t, size_t, void *)) fread,
        (int (*)(void *, ogg_int64_t, int))          _fseek64_wrap,
        (int (*)(void *))                            fclose,
        (long (*)(void *))                           ftell
    };
#endif

    int FileIsBad(OggVorbis_File& ogg_file, FILE* file) {
#ifdef FREEORION_WIN32
        return ov_test_callbacks(file, &ogg_file, nullptr, 0, callbacks);
#else
        return ov_test(file, &ogg_file, nullptr, 0);
#endif
    }

    // Returns buffer ID and if (true/false) if the id is a valid buffer
    std::pair<ALuint, bool> GetSoundBuffer(std::map<std::string, ALuint>& buffers, const std::string& filename) {
        // Check if the sound data of the file we want to play is already buffered
        {
            const auto it = buffers.find(filename);
            if (it != buffers.end())
                return {it->second, true};
        }


        // not already buffered, so buffer it
        auto file = fopen(filename.c_str(), "rb");
        if (!file)
            return {0, false};

        OggVorbis_File ogg_file;
        if (FileIsBad(ogg_file, file)) {
            ErrorLogger() << "GetSoundBuffer: unable to open file " << filename
                          << " possibly not a .ogg vorbis file. Aborting\n";
            return {0, false};
        }

        // file is OK, so now fully open the file
        ov_test_open(&ogg_file);

        // take some info needed later...
        const auto vorbis_info_ptr = ov_info(&ogg_file, -1);
        const ALenum ogg_format = (vorbis_info_ptr->channels == 1) ? AL_FORMAT_MONO16 : AL_FORMAT_STEREO16;
        const ALsizei ogg_freq = vorbis_info_ptr->rate;
        const ogg_int64_t byte_size = ov_pcm_total(&ogg_file, -1) * vorbis_info_ptr->channels * 2;

        // check that size of file isn't too huge
        if (byte_size > MAX_BUFFER_SIZE) {
            ErrorLogger() << "PlaySound: unable to open file " << filename
                          << " : Too big (" << byte_size << ") for buffer (" << MAX_BUFFER_SIZE << ")";
            return {0, false};
        }

        // fill up the buffers and queue them up for the first time
        ALuint sound_handle;
        alGenBuffers(1, &sound_handle);
        ALenum openal_error = alGetError();
        if (openal_error != AL_NONE)
            ErrorLogger() << "RefillBuffer: OpenAL ERROR: " << alGetString(openal_error);

        int loop = 0;
        RefillBuffer(&ogg_file, ogg_format, ogg_freq, sound_handle, byte_size, loop);

        // create new buffer for this sound. should be no pre-existing buffer
        // stored under that filename due to check above
        buffers.emplace(filename, sound_handle);

        ov_clear(&ogg_file);
        return {sound_handle, true};
    }
}

void Sound::Impl::PlayMusic(const boost::filesystem::path& path, int loops) {
    if (!m_initialized)
        return;
    if (!alcGetCurrentContext())
        return;

    std::string filename = PathToString(path);
    m_music_loops = 0;

    if (m_music_name.size() > 0)
        StopMusic();

    FILE* file = fopen(filename.c_str(), "rb");
    if (!file) {
        ErrorLogger() << "PlayMusic: unable to open file " << filename << " I/O Error. Aborting\n";
        return;
    }

    int file_bad = FileIsBad(m_music_ogg_file, file);
    if (file_bad > 0) {
        ErrorLogger() << "PlayMusic: unable to open file " << filename
                      << " possibly not a .ogg vorbis file. Aborting\n";
        m_music_name.clear();
        ov_clear(&m_music_ogg_file);
        return;
    }

    // file is OK, so now fully open the file
    ov_test_open(&m_music_ogg_file);

    // take some info needed later...
    auto vorbis_info_ptr = ov_info(&m_music_ogg_file, -1);
    if (vorbis_info_ptr->channels == 1)
        m_music_ogg_format = AL_FORMAT_MONO16;
    else
        m_music_ogg_format = AL_FORMAT_STEREO16;
    m_music_ogg_freq = vorbis_info_ptr->rate;
    m_music_loops = loops;

    // fill up the buffers and queue them up for the first time
    auto refill_failed = RefillBuffer(&m_music_ogg_file, m_music_ogg_format, m_music_ogg_freq,
                                      m_music_buffers[0], MUSIC_BUFFER_SIZE, m_music_loops);

    if (refill_failed == 0) {
        alSourceQueueBuffers(m_sources[0], 1, &m_music_buffers[0]); // queue up the buffer if we manage to fill it
        auto openal_error = alGetError();
        if (openal_error != AL_NONE)
            ErrorLogger() << "PlayMusic: OpenAL ERROR: " << alGetString(openal_error);

        refill_failed = RefillBuffer(&m_music_ogg_file, m_music_ogg_format, m_music_ogg_freq,
                                     m_music_buffers[1], MUSIC_BUFFER_SIZE, m_music_loops);
        if (refill_failed == 0) {
            alSourceQueueBuffers(m_sources[0], 1, &m_music_buffers[1]);
            m_music_name = filename; //playing something that takes up more than 2 buffers
        } else {
            openal_error = alGetError();
            if (openal_error != AL_NONE)
                ErrorLogger() << "PlayMusic: OpenAL ERROR: " << alGetString(openal_error);
        }

        alSourcePlay(m_sources[0]); // play if at least one buffer is queued
    }

    if (refill_failed != 0)
        m_music_name.clear();

    auto openal_error = alGetError();
    if (openal_error != AL_NONE)
        ErrorLogger() << "PlayMusic: OpenAL ERROR: " << alGetString(openal_error);
}

void Sound::Impl::PauseMusic() {
    if (!m_initialized)
        return;
    if (alcGetCurrentContext())
        alSourcePause(m_sources[0]);
}

void Sound::Impl::ResumeMusic() {
    if (!m_initialized)
        return;
    if (alcGetCurrentContext())
        alSourcePlay(m_sources[0]);
}

void Sound::Impl::StopMusic() {
    if (!m_initialized)
        return;
    if (!alcGetCurrentContext())
        return;

    alSourceStop(m_sources[0]);
    if (m_music_name.size() > 0) {
        m_music_name.clear();  // do this to avoid music being re-started by other functions
        ov_clear(&m_music_ogg_file); // and unload the music file for good measure. the file itself is closed now, don't re-close it again
    }
    alSourcei(m_sources[0], AL_BUFFER, 0);
}

void Sound::Impl::PlaySound(const boost::filesystem::path& path, bool is_ui_sound) {
    if (!m_initialized || !GetOptionsDB().Get<bool>("audio.effects.enabled") || (is_ui_sound && UISoundsTemporarilyDisabled()))
        return;

    if (!alcGetCurrentContext()) {
        ErrorLogger() << "Sound::Impl::PlaySound : No AL context, aborting";
        return;
    }

    std::string filename = PathToString(path);
    auto [current_buffer, found_buffer] = GetSoundBuffer(m_sound_buffers, filename);

    if (found_buffer) {
        bool found_source = false;
        ALenum source_state;
        // Send buffer to a paused non-music source.
        // As we're playing sounds, we start at buffer 1 (buffer 0 is reserved for music)
        for (auto m_i = 1; m_i < NUM_SOURCES; ++m_i) {
            alGetSourcei(m_sources[m_i], AL_SOURCE_STATE, &source_state);
            if ((source_state != AL_PLAYING) && (source_state != AL_PAUSED)) {
                found_source = true;
                alSourcei(m_sources[m_i], AL_BUFFER, current_buffer);
                alSourcePlay(m_sources[m_i]);
                break; // so that the sound won't block all the sources
            }
        }

        if (!found_source)
            ErrorLogger() << "PlaySound: Could not find avialble source - playback aborted\n";
    }


    // check for errors. some functions won't work properly if they are called
    // when there is a unchecked previous error.
    auto source_state = alGetError();
    if (source_state != AL_NONE)
        ErrorLogger() << "PlaySound: OpenAL ERROR: " << alGetString(source_state);
}

void Sound::Impl::FreeSound(const boost::filesystem::path& path) {
    if (!m_initialized)
        return;
    std::string filename = PathToString(path);

    auto it = m_sound_buffers.find(filename);
    if (it != m_sound_buffers.end()) {
        alDeleteBuffers(1, &(it->second));
        ALenum openal_error = alGetError();
        // don't erase if there was an error, as the buffer may not have been removed - potential memory leak
        if (openal_error != AL_NONE)
            ErrorLogger() << "FreeSound: OpenAL ERROR: " << alGetString(openal_error);
        else
            m_sound_buffers.erase(it);
    }
}

void Sound::Impl::FreeAllSounds() {
    if (!m_initialized)
        return;

    for (auto it = m_sound_buffers.begin(); it != m_sound_buffers.end();) {
        alDeleteBuffers(1, &(it->second));
        ALenum openal_error = alGetError();
        if (openal_error != AL_NONE) {
            ErrorLogger() << "FreeAllSounds: OpenAL ERROR: " << alGetString(openal_error);
            ++it;
        } else {
            auto temp = it;
            ++it;
            m_sound_buffers.erase(temp);  // invalidates erased iterator only
        }
    }
}

void Sound::Impl::SetMusicVolume(int vol) {
    if (!m_initialized)
        return;

    // normalize value, then apply to all sound sources
    vol = std::max(0, std::min(vol, 255));
    GetOptionsDB().Set("audio.music.volume", vol);

    if (!alcGetCurrentContext())
        return;

    alSourcef(m_sources[0], AL_GAIN, static_cast<ALfloat>(vol) / 255.0f);
    // it is highly unlikely to get an error here, but better safe than sorry
    ALenum openal_error = alGetError();
    if (openal_error != AL_NONE)
        ErrorLogger() << "PlaySound: OpenAL ERROR: " << alGetString(openal_error);
}

void Sound::Impl::SetUISoundsVolume(int vol) {
    if (!m_initialized)
        return;

    // normalize value, then apply to all sound sources
    vol = std::max(0, std::min(vol, 255));
    GetOptionsDB().Set("audio.effects.volume", vol);
    if (!alcGetCurrentContext())
        return;

    for (int it = 1; it < NUM_SOURCES; ++it) // skip source 0, which is music
        alSourcef(m_sources[it], AL_GAIN, static_cast<ALfloat>(vol) / 255.0f);
    // it is highly unlikely to get an error here, but better safe than sorry
    ALenum openal_error = alGetError();
    if (openal_error != AL_NONE)
        ErrorLogger() << "PlaySound: OpenAL ERROR: " << alGetString(openal_error);
}

void Sound::Impl::DoFrame() {
    if (!m_initialized)
        return;
    if (m_music_name.empty())
        return;
    if (!alcGetCurrentContext())
        return;

    int num_buffers_processed = 0;
    alGetSourcei(m_sources[0], AL_BUFFERS_PROCESSED, &num_buffers_processed);
    while (num_buffers_processed > 0) {
        ALuint buffer_name_yay;
        alSourceUnqueueBuffers(m_sources[0], 1, &buffer_name_yay);
        if (RefillBuffer(&m_music_ogg_file, m_music_ogg_format, m_music_ogg_freq,
                         buffer_name_yay, MUSIC_BUFFER_SIZE, m_music_loops))
        {
            m_music_name.clear();  // m_music_name.clear() must always be called before ov_clear
            break; // this happens if RefillBuffer returns 1, meaning it encountered EOF and the file shouldn't be repeated
        }
        alSourceQueueBuffers(m_sources[0], 1, &buffer_name_yay);
        num_buffers_processed--;
    }

    ALint state;
    alGetSourcei(m_sources[0], AL_SOURCE_STATE, &state);
    if (state == AL_STOPPED)  /// this may happen if the source plays all its buffers before we manage to refill them
        alSourcePlay(m_sources[0]);
}

bool Sound::Impl::UISoundsTemporarilyDisabled() const
{ return m_temporary_disable_count > 0; }

void Sound::Impl::IncDisabledCount()
{ ++m_temporary_disable_count; }

void Sound::Impl::DecDisabledCount()
{ --m_temporary_disable_count; }