SoundStream.cpp

//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2009 Laurent Gomila (laurent.gom@gmail.com)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
//    you must not claim that you wrote the original software.
//    If you use this software in a product, an acknowledgment
//    in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
//    and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//

// Headers
#include <SFML/Audio/SoundStream.hpp>
#include <SFML/Audio/AudioDevice.hpp>
#include <SFML/Audio/OpenAL.hpp>
#include <SFML/System/Sleep.hpp>
 
 
namespace sf
{
SoundStream::SoundStream() :
myIsStreaming     (false),
myChannelsCount   (0),
mySampleRate      (0),
myFormat          (0),
myLoop            (false),
mySamplesProcessed(0)
{
 
}
 

SoundStream::~SoundStream()
{
    // Stop the sound if it was playing
    Stop();
}
 

void SoundStream::Initialize(unsigned int ChannelsCount, unsigned int SampleRate)
{
    myChannelsCount = ChannelsCount;
    mySampleRate    = SampleRate;
 
    // Deduce the format from the number of channels
    myFormat = priv::AudioDevice::GetInstance().GetFormatFromChannelsCount(ChannelsCount);
 
    // Check if the format is valid
    if (myFormat == 0)
    {
        myChannelsCount = 0;
        mySampleRate    = 0;
        std::cerr << "Unsupported number of channels (" << myChannelsCount << ")" << std::endl;
    }
}
 

void SoundStream::Play()
{
    // Check if the sound parameters have been set
    if (myFormat == 0)
    {
        std::cerr << "Failed to play audio stream : sound parameters have not been initialized (call Initialize first)" << std::endl;
        return;
    }
 
    // If the sound is already playing (probably paused), just resume it
    if (myIsStreaming)
    {
        Sound::Play();
        return;
    }
 
    // Notify the derived class
    if (OnStart())
    {
        // Start updating the stream in a separate thread to avoid blocking the application
        mySamplesProcessed = 0;
        myIsStreaming = true;
        Launch();
    }
}
 

void SoundStream::Stop()
{
    // Wait for the thread to terminate
    myIsStreaming = false;
    Wait();
}
 

unsigned int SoundStream::GetChannelsCount() const
{
    return myChannelsCount;
}
 

unsigned int SoundStream::GetSampleRate() const
{
    return mySampleRate;
}
 

Sound::Status SoundStream::GetStatus() const
{
    Status Status = Sound::GetStatus();
 
    // To compensate for the lag between Play() and alSourcePlay()
    if ((Status == Stopped) && myIsStreaming)
        Status = Playing;
 
    return Status;
}
 

float SoundStream::GetPlayingOffset() const
{
    return Sound::GetPlayingOffset() + static_cast<float>(mySamplesProcessed) / mySampleRate / myChannelsCount;
}
 

void SoundStream::SetLoop(bool Loop)
{
    myLoop = Loop;
}
 

bool SoundStream::GetLoop() const
{
    return myLoop;
}
 

void SoundStream::Run()
{
    // Create the buffers
    ALCheck(alGenBuffers(BuffersCount, myBuffers));
    for (int i = 0; i < BuffersCount; ++i)
        myEndBuffers[i] = false;
 
    // Fill the queue
    bool RequestStop = FillQueue();
 
    // Play the sound
    Sound::Play();
 
    while (myIsStreaming)
    {
        // The stream has been interrupted !
        if (Sound::GetStatus() == Stopped)
        {
            if (!RequestStop)
            {
                // Just continue
                Sound::Play();
            }
            else
            {
                // End streaming
                myIsStreaming = false;
            }
        }
 
        // Get the number of buffers that have been processed (ie. ready for reuse)
        ALint NbProcessed;
        ALCheck(alGetSourcei(Sound::mySource, AL_BUFFERS_PROCESSED, &NbProcessed));
 
        while (NbProcessed--)
        {
            // Pop the first unused buffer from the queue
            ALuint Buffer;
            ALCheck(alSourceUnqueueBuffers(Sound::mySource, 1, &Buffer));
 
            // Find its number
            unsigned int BufferNum = 0;
            for (int i = 0; i < BuffersCount; ++i)
                if (myBuffers[i] == Buffer)
                {
                    BufferNum = i;
                    break;
                }
 
            // Retrieve its size and add it to the samples count
            if (myEndBuffers[BufferNum])
            {
                // This was the last buffer: reset the sample count
                mySamplesProcessed = 0;
                myEndBuffers[BufferNum] = false;
            }
            else
            {
                ALint Size;
                ALCheck(alGetBufferi(Buffer, AL_SIZE, &Size));
                mySamplesProcessed += Size / sizeof(Int16);
            }
 
            // Fill it and push it back into the playing queue
            if (!RequestStop)
            {
                if (FillAndPushBuffer(BufferNum))
                    RequestStop = true;
            }
        }
 
        // Leave some time for the other threads if the stream is still playing
        if (Sound::GetStatus() != Stopped)
            Sleep(0.1f);
    }
 
    // Stop the playback
    Sound::Stop();
 
    // Unqueue any buffer left in the queue
    ClearQueue();
 
    // Delete the buffers
    ALCheck(alSourcei(Sound::mySource, AL_BUFFER, 0));
    ALCheck(alDeleteBuffers(BuffersCount, myBuffers));
}
 

bool SoundStream::FillAndPushBuffer(unsigned int BufferNum)
{
    bool RequestStop = false;
 
    // Acquire audio data
    Chunk Data = {NULL, 0};
    if (!OnGetData(Data))
    {
        // Mark the buffer as the last one (so that we know when to reset the playing position)
        myEndBuffers[BufferNum] = true;
 
        // Check if the stream must loop or stop
        if (myLoop && OnStart())
        {
            // If we succeeded to restart and we previously had no data, try to fill the buffer once again
            if (!Data.Samples || (Data.NbSamples == 0))
            {
                return FillAndPushBuffer(BufferNum);
            }
        }
        else
        {
            // Not looping or restart failed: request stop
            RequestStop = true;
        }
    }
 
    // Fill the buffer if some data was returned
    if (Data.Samples && Data.NbSamples)
    {
        unsigned int Buffer = myBuffers[BufferNum];
 
        // Fill the buffer
        ALsizei Size = static_cast<ALsizei>(Data.NbSamples) * sizeof(Int16);
        ALCheck(alBufferData(Buffer, myFormat, Data.Samples, Size, mySampleRate));
 
        // Push it into the sound queue
        ALCheck(alSourceQueueBuffers(Sound::mySource, 1, &Buffer));
    }
 
    return RequestStop;
}
 

bool SoundStream::FillQueue()
{
    // Fill and enqueue all the available buffers
    bool RequestStop = false;
    for (int i = 0; (i < BuffersCount) && !RequestStop; ++i)
    {
        if (FillAndPushBuffer(i))
            RequestStop = true;
    }
 
    return RequestStop;
}
 

void SoundStream::ClearQueue()
{
    // Get the number of buffers still in the queue
    ALint NbQueued;
    ALCheck(alGetSourcei(Sound::mySource, AL_BUFFERS_QUEUED, &NbQueued));
 
    // Unqueue them all
    ALuint Buffer;
    for (ALint i = 0; i < NbQueued; ++i)
        ALCheck(alSourceUnqueueBuffers(Sound::mySource, 1, &Buffer));
}
 

bool SoundStream::OnStart()
{
    // Does nothing by default
 
    return true;
}
 
} // namespace sf