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/******************************************/
/*
call_saw.c
by Gary P. Scavone, 2001
Play sawtooth waveforms of distinct frequency.
Takes number of channels and sample rate as
input arguments. Use callback functionality.
*/
/******************************************/
#include "RtAudio.h"
#include <iostream>
/*
typedef signed long MY_TYPE;
#define FORMAT RTAUDIO_SINT24
#define SCALE 2147483647.0
typedef char MY_TYPE;
#define FORMAT RTAUDIO_SINT8
#define SCALE 127.0
typedef signed short MY_TYPE;
#define FORMAT RTAUDIO_SINT16
#define SCALE 32767.0
typedef signed long MY_TYPE;
#define FORMAT RTAUDIO_SINT32
#define SCALE 2147483647.0
*/
typedef float MY_TYPE;
#define FORMAT RTAUDIO_FLOAT32
#define SCALE 1.0
/*
typedef double MY_TYPE;
#define FORMAT RTAUDIO_FLOAT64
#define SCALE 1.0
*/
#define BASE_RATE 0.005
#define TIME 1.0
void usage(void) {
/* Error function in case of incorrect command-line
argument specifications
*/
std::cout << "\nuseage: call_saw N fs <device>\n";
std::cout << " where N = number of channels,\n";
std::cout << " fs = the sample rate,\n";
std::cout << " and device = the device to use (default = 0).\n\n";
exit(0);
}
int chans;
int saw(char *buffer, int buffer_size, void *data)
{
int i, j;
extern int chans;
MY_TYPE *my_buffer = (MY_TYPE *) buffer;
double *my_data = (double *) data;
for (i=0; i<buffer_size; i++) {
for (j=0; j<chans; j++) {
*my_buffer++ = (MY_TYPE) (my_data[j] * SCALE);
my_data[j] += BASE_RATE * (j+1+(j*0.1));
if (my_data[j] >= 1.0) my_data[j] -= 2.0;
}
}
return 0;
}
int main(int argc, char *argv[])
{
int buffer_size, fs, device = 0;
RtAudio *audio;
double *data;
char input;
// minimal command-line checking
if (argc != 3 && argc != 4 ) usage();
chans = (int) atoi(argv[1]);
fs = (int) atoi(argv[2]);
if ( argc == 4 )
device = (int) atoi(argv[3]);
// Open the realtime output device
buffer_size = 1024;
try {
audio = new RtAudio(device, chans, 0, 0,
FORMAT, fs, &buffer_size, 4);
}
catch (RtError &error) {
error.printMessage();
exit(EXIT_FAILURE);
}
data = (double *) calloc(chans, sizeof(double));
try {
audio->setStreamCallback(&saw, (void *)data);
audio->startStream();
}
catch (RtError &error) {
error.printMessage();
goto cleanup;
}
std::cout << "\nPlaying ... press <enter> to quit (buffer size = " << buffer_size << ").\n";
std::cin.get(input);
// Stop the stream.
try {
audio->stopStream();
}
catch (RtError &error) {
error.printMessage();
}
cleanup:
audio->closeStream();
delete audio;
if (data) free(data);
return 0;
}
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