zynaddsubfx

ZynAddSubFX open source synthesizer
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PaEngine.cpp (2672B)

      1 /*
      2   ZynAddSubFX - a software synthesizer
      3 
      4   PaEngine.cpp - Audio output for PortAudio
      5   Copyright (C) 2002 Nasca Octavian Paul
      6   Author: Nasca Octavian Paul
      7 
      8   This program is free software; you can redistribute it and/or
      9   modify it under the terms of the GNU General Public License
     10   as published by the Free Software Foundation; either version 2
     11   of the License, or (at your option) any later version.
     12 */
     13 
     14 #include "PaEngine.h"
     15 #include <iostream>
     16 using namespace std;
     17 
     18 namespace zyn {
     19 
     20 PaEngine::PaEngine(const SYNTH_T &synth)
     21     :AudioOut(synth), stream(NULL)
     22 {
     23     name = "PA";
     24 }
     25 
     26 
     27 PaEngine::~PaEngine()
     28 {
     29     Stop();
     30 }
     31 
     32 bool PaEngine::Start()
     33 {
     34     if(getAudioEn())
     35         return true;
     36     Pa_Initialize();
     37 
     38     PaStreamParameters outputParameters;
     39     outputParameters.device = Pa_GetDefaultOutputDevice();
     40     if(outputParameters.device == paNoDevice) {
     41         cerr << "Error: No default output device." << endl;
     42         Pa_Terminate();
     43         return false;
     44     }
     45     outputParameters.channelCount     = 2; /* stereo output */
     46     outputParameters.sampleFormat     = paFloat32; /* 32 bit floating point output */
     47     outputParameters.suggestedLatency =
     48         Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;
     49     outputParameters.hostApiSpecificStreamInfo = NULL;
     50 
     51 
     52     Pa_OpenStream(&stream,
     53                   NULL,
     54                   &outputParameters,
     55                   synth.samplerate,
     56                   synth.buffersize,
     57                   0,
     58                   PAprocess,
     59                   (void *) this);
     60     Pa_StartStream(stream);
     61     return true;
     62 }
     63 
     64 void PaEngine::setAudioEn(bool nval)
     65 {
     66     if(nval)
     67         Start();
     68     else
     69         Stop();
     70 }
     71 
     72 bool PaEngine::getAudioEn() const
     73 {
     74     return stream;
     75 }
     76 
     77 int PaEngine::PAprocess(const void *inputBuffer,
     78                         void *outputBuffer,
     79                         unsigned long framesPerBuffer,
     80                         const PaStreamCallbackTimeInfo *outTime,
     81                         PaStreamCallbackFlags flags,
     82                         void *userData)
     83 {
     84     (void) inputBuffer;
     85     (void) outTime;
     86     (void) flags;
     87     return static_cast<PaEngine *>(userData)->process((float *) outputBuffer,
     88                                                       framesPerBuffer);
     89 }
     90 
     91 int PaEngine::process(float *out, unsigned long framesPerBuffer)
     92 {
     93     const Stereo<float *> smp = getNext();
     94     for(unsigned i = 0; i < framesPerBuffer; ++i) {
     95         *out++ = smp.l[i];
     96         *out++ = smp.r[i];
     97     }
     98 
     99     return 0;
    100 }
    101 
    102 void PaEngine::Stop()
    103 {
    104     if(!getAudioEn())
    105         return;
    106     Pa_StopStream(stream);
    107     Pa_CloseStream(stream);
    108     stream = NULL;
    109     Pa_Terminate();
    110 }
    111 
    112 }