overte/Source/audio.cpp
2013-01-22 17:56:12 -08:00

132 lines
4.3 KiB
C++

//
// audio.cpp
// interface
//
// Created by Stephen Birarda on 1/22/13.
// Copyright (c) 2013 Rosedale Lab. All rights reserved.
//
#include "audio.h"
bool Audio::initialized;
PaError Audio::err;
PaStream *Audio::stream;
Audio::AudioData *Audio::data;
/**
* Audio callback used by portaudio.
* Communicates with Audio via a shared pointer to Audio::data.
* Writes input audio channels (if they exist) into Audio::data->buffer,
multiplied by Audio::data->inputGain.
* Then writes Audio::data->buffer into output audio channels, and clears
the portion of Audio::data->buffer that has been read from for reuse.
*
* @param[in] inputBuffer A pointer to an internal portaudio data buffer containing data read by portaudio.
* @param[out] outputBuffer A pointer to an internal portaudio data buffer to be read by the configured output device.
* @param[in] frames Number of frames that portaudio requests to be read/written.
(Valid size of input/output buffers = frames * number of channels (2) * sizeof data type (float)).
* @param[in] timeInfo Portaudio time info. Currently unused.
* @param[in] statusFlags Portaudio status flags. Currently unused.
* @param[in] userData Pointer to supplied user data (in this case, a pointer to Audio::data).
Used to communicate with external code (since portaudio calls this function from another thread).
* @return Should be of type PaStreamCallbackResult. Return paComplete to end the stream, or paContinue to continue (default).
Can be used to end the stream from within the callback.
*/
int audioCallback (const void *inputBuffer,
void *outputBuffer,
unsigned long frames,
const PaStreamCallbackTimeInfo *timeInfo,
PaStreamCallbackFlags statusFlags,
void *userData)
{
Audio::AudioData *data = (Audio::AudioData *) userData;
int16_t *input = (int16_t *) inputBuffer;
int16_t *output = (int16_t *) outputBuffer;
// check if we have input data
if (input != NULL) {
memcpy(data->buffer, input, data->bufferLength * 2);
}
memcpy(output, data->buffer, data->bufferLength * 2);
return paContinue;
}
/**
* Initialize portaudio and start an audio stream.
* Should be called at the beginning of program exection.
* @seealso Audio::terminate
* @return Returns true if successful or false if an error occurred.
Use Audio::getError() to retrieve the error code.
*/
bool Audio::init()
{
return Audio::init(NULL);
}
bool Audio::init(Head* mainHead)
{
initialized = true;
data = new AudioData();
data->linkedHead = mainHead;
err = Pa_Initialize();
if (err != paNoError) goto error;
err = Pa_OpenDefaultStream(&stream,
1, // input channels
1, // output channels
paInt16, // sample format
22050, // sample rate (hz)
512, // frames per buffer
audioCallback, // callback function
(void *) data); // user data to be passed to callback
if (err != paNoError) goto error;
err = Pa_StartStream(stream);
if (err != paNoError) goto error;
return paNoError;
error:
fprintf(stderr, "-- Failed to initialize portaudio --\n");
fprintf(stderr, "PortAudio error (%d): %s\n", err, Pa_GetErrorText(err));
initialized = false;
delete[] data;
return false;
}
/**
* Close the running audio stream, and deinitialize portaudio.
* Should be called at the end of program execution.
* @return Returns true if the initialization was successful, or false if an error occured.
The error code may be retrieved by Audio::getError().
*/
bool Audio::terminate ()
{
if (!initialized) {
return true;
} else {
initialized = false;
err = Pa_CloseStream(stream);
if (err != paNoError) goto error;
delete data;
err = Pa_Terminate();
if (err != paNoError) goto error;
return true;
}
error:
fprintf(stderr, "-- portaudio termination error --\n");
fprintf(stderr, "PortAudio error (%d): %s\n", err, Pa_GetErrorText(err));
return false;
}