#include <iostream>
#include <cstdlib>
int saw( void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames,
{
unsigned int i, j;
double *buffer = (double *) outputBuffer;
double *lastValues = (double *) userData;
if ( status )
std::cout << "Stream underflow detected!" << std::endl;
for ( i=0; i<nBufferFrames; i++ ) {
for ( j=0; j<2; j++ ) {
*buffer++ = lastValues[j];
lastValues[j] += 0.005 * (j+1+(j*0.1));
if ( lastValues[j] >= 1.0 ) lastValues[j] -= 2.0;
}
}
return 0;
}
int main()
{
std::cout << "\nNo audio devices found!\n";
exit( 0 );
}
unsigned int sampleRate = 44100;
unsigned int bufferFrames = 256;
double data[2];
try {
dac.
openStream( ¶meters, NULL, RTAUDIO_FLOAT64,
sampleRate, &bufferFrames, &saw, (void *)&data );
}
exit( 0 );
}
char input;
std::cout << "\nPlaying ... press <enter> to quit.\n";
std::cin.get( input );
try {
}
}
return 0;
}
unsigned int RtAudioStreamStatus
RtAudio stream status (over- or underflow) flags.
Definition: RtAudio.h:144
Exception handling class for RtAudio.
Definition: RtAudio.h:204
virtual void printMessage(void) const
Prints thrown error message to stderr.
Definition: RtAudio.h:227
Realtime audio i/o C++ classes.
Definition: RtAudio.h:264
unsigned int getDefaultOutputDevice(void)
A function that returns the index of the default output device.
Definition: RtAudio.h:833
void openStream(RtAudio::StreamParameters *outputParameters, RtAudio::StreamParameters *inputParameters, RtAudioFormat format, unsigned int sampleRate, unsigned int *bufferFrames, RtAudioCallback callback, void *userData=NULL, RtAudio::StreamOptions *options=NULL, RtAudioErrorCallback errorCallback=NULL)
A public function for opening a stream with the specified parameters.
unsigned int getDeviceCount(void)
A public function that queries for the number of audio devices available.
Definition: RtAudio.h:830
void closeStream(void)
A function that closes a stream and frees any associated stream memory.
Definition: RtAudio.h:834
bool isStreamOpen(void) const
Returns true if a stream is open and false if not.
Definition: RtAudio.h:838
void startStream(void)
A function that starts a stream.
Definition: RtAudio.h:835
void stopStream(void)
Stop a stream, allowing any samples remaining in the output queue to be played.
Definition: RtAudio.h:836
The structure for specifying input or ouput stream parameters.
Definition: RtAudio.h:301
unsigned int nChannels
Definition: RtAudio.h:303
unsigned int deviceId
Definition: RtAudio.h:302
unsigned int firstChannel
Definition: RtAudio.h:304
We open the stream in exactly the same way as the previous example (except with a data format change) and specify the address of our callback function "saw()". The callback function will automatically be invoked when the underlying audio system needs data for output. Note that the callback function is called only when the stream is "running" (between calls to the RtAudio::startStream() and RtAudio::stopStream() functions). We can also pass a pointer value to the RtAudio::openStream() function that is made available in the callback function. In this way, it is possible to gain access to arbitrary data created in our main() function from within the globally defined callback function.