AudioManager.cpp

/***************************************************************************
 *	AudioManager.cpp
 *	Part of Rivill
 *	2015-  Florent Berthaut / Luka Claeys
 *	https://gitlab.univ-lille.fr/mint/rivill
 ****************************************************************************/
/*
 *	This program 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; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program 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 this program; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "AudioManager.hpp"

void* audioThreadFunction(void* pvParam) {
    AudioManager *pThis=(AudioManager*)pvParam;
    pThis->startStream();
    return 0;
}

AudioManager* AudioManager::getInstance() {
    static AudioManager rev;
    return &rev;
}

AudioManager::~AudioManager() {}

int AudioManager::getRate(){
    return data.nRate;
}

int AudioManager::getBufferSize(){
    return m_bufSize;
}

int AudioManager::getMixSize(){
    return data.mixSize;
}

int AudioManager::rtaudio_callback(void *outbuf, void *inbuf, unsigned int nFrames, 
        double streamtime, RtAudioStreamStatus	status, void *userdata) {
    (void)inbuf;
    float *buf = (float*)outbuf;
    AudioManager::CallbackData *data = (AudioManager::CallbackData*) userdata;

    //if we've reached the first buffer again, retrieve values from the ring
    if(data->bufCounter==0) {
        if(ringbuffer_read_space(data->ringBuffer) >= data->bufSize) {

            //read all the audio values
            ringbuffer_read(data->ringBuffer, data->buffer, data->bufSize);

            //mix the first buffer with the last of the previous
            float step = 1.0/float(nFrames);
            float cnt = 0.0;
            for(int i=0; i < nFrames; ++i) {
                buf[i*2] = data->buffer[i]*cnt + data->mixBuffer[i]*(1.0-cnt);
                buf[i*2+1] = buf[i*2];
                cnt+=step;
            }

            //save the last buffer for crossfading
            memcpy(&data->mixBuffer[0], 
                    data->buffer+(data->bufSize-data->mixSize), 
                    data->mixSize*sizeof(float));
        }
        else {
            memset(buf, 0, nFrames*data->nChannel*sizeof(float));
            memset(data->buffer, 0, data->bufSize*sizeof(float));
            memset(data->mixBuffer, 0, nFrames*sizeof(float));
            //cout<<"AudioManager : Could not read buffer"<<endl;
        }
    }
    else {
        //read the next buffer
        for(int i=0; i<nFrames; ++i) {
            buf[i*2] = data->buffer[data->bufCounter*nFrames+i];
            buf[i*2+1] = buf[i*2];
        }
    }

    //move to the next buffer
    data->bufCounter=(data->bufCounter+1)%(data->nbBufs-1);

    return 0;
}

AudioManager::AudioManager() {
    m_init=false;
}

void AudioManager::init() {
    //m_rtAudio = new RtAudio(RtAudio::LINUX_PULSE);
    m_rtAudio = new RtAudio(RtAudio::UNIX_JACK);
    param = new RtAudio::StreamParameters();
    param->deviceId = m_rtAudio->getDefaultOutputDevice();
    param->nChannels = 2;
    options = new RtAudio::StreamOptions();
    options->streamName = "Rivill";
    data.nRate = m_rtAudio->getDeviceInfo(param->deviceId).preferredSampleRate;

    m_rtBufSize = 1024;

    bool init=true;
    try{
        m_rtAudio->openStream(param, NULL, RTAUDIO_FLOAT32, data.nRate, 
                &m_rtBufSize, 
                AudioManager::rtaudio_callback, &data, options); 
    }
    catch(const exception& e) {
        init=false;
    }

    if(init) {
        int nbBufs = 6-m_rtBufSize/256;
        m_bufSize = m_rtBufSize*nbBufs;

        data.ringBuffer = ringbuffer_create(m_bufSize*3);

        data.nChannel = param->nChannels;
        data.bufSize = m_bufSize;
        data.buffer = new float[m_bufSize];
        data.nbBufs = nbBufs;
        data.bufCounter = 0;
        memset(&data.buffer[0], 0, data.bufSize*sizeof(float));

        data.mixSize = m_rtBufSize;
        data.mixBuffer = new float[data.mixSize];
        memset(&data.mixBuffer[0], 0, data.mixSize*sizeof(float));

        m_thread = new std::thread(audioThreadFunction, this);
        m_init = true;
    }
}


bool AudioManager::changeBuf(float* outputBuf, float maxSinValue) {
    if(m_init) {
        //check if there is space to write the new values
        size_t write_space = ringbuffer_write_space(data.ringBuffer);
        if(write_space >= m_bufSize) {
            //write all data to the ringbuffer
            ringbuffer_write(data.ringBuffer, outputBuf, data.bufSize);	
            return true;
        }
        else {
            //cout<<"AudioManager : Could not write buffer"<<endl;
        }
    }
    return false;
}