/* * $Id: patest_saw.c,v 1.2 2003/03/02 08:01:42 dmazzoni Exp $ * patest_saw.c * Play a simple sawtooth wave. * * Author: Phil Burk  http://www.softsynth.com * * This program uses the PortAudio Portable Audio Library. * For more information see: http://www.portaudio.com * Copyright (c) 1999-2000 Ross Bencina and Phil Burk * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files * (the "Software"), to deal in the Software without restriction, * including without limitation the rights to use, copy, modify, merge, * publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * Any person wishing to distribute modifications to the Software is * requested to send the modifications to the original developer so that * they can be incorporated into the canonical version. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * */#include <stdio.h>#include <math.h>#include "portaudio.h"#define NUM_SECONDS   (4)#define SAMPLE_RATE   (44100)typedef struct{    float left_phase;    float right_phase;}paTestData;/* This routine will be called by the PortAudio engine when audio is needed.** It may called at interrupt level on some machines so don't do anything** that could mess up the system like calling malloc() or free().*/static int patestCallback( void *inputBuffer, void *outputBuffer,                           unsigned long framesPerBuffer,                           PaTimestamp outTime, void *userData ){    /* Cast data passed through stream to our structure. */    paTestData *data = (paTestData*)userData;    float *out = (float*)outputBuffer;    unsigned int i;    (void) outTime; /* Prevent unused variable warnings. */    (void) inputBuffer;    for( i=0; i<framesPerBuffer; i++ )    {        *out++ = data->left_phase;  /* left */        *out++ = data->right_phase;  /* right */        /* Generate simple sawtooth phaser that ranges between -1.0 and 1.0. */        data->left_phase += 0.01f;        /* When signal reaches top, drop back down. */        if( data->left_phase >= 1.0f ) data->left_phase -= 2.0f;        /* higher pitch so we can distinguish left and right. */        data->right_phase += 0.03f;        if( data->right_phase >= 1.0f ) data->right_phase -= 2.0f;    }    return 0;}/*******************************************************************/static paTestData data;int main(void);int main(void){    PortAudioStream *stream;    PaError err;    printf("PortAudio Test: output sawtooth wave.\n");    /* Initialize our data for use by callback. */    data.left_phase = data.right_phase = 0.0;    /* Initialize library before making any other calls. */    err = Pa_Initialize();    if( err != paNoError ) goto error;    /* Open an audio I/O stream. */    err = Pa_OpenDefaultStream(              &stream,              0,              /* no input channels */              2,              /* stereo output */              paFloat32,      /* 32 bit floating point output */              SAMPLE_RATE,              256,            /* frames per buffer */              0,              /* number of buffers, if zero then use default minimum */              patestCallback,              &data );    if( err != paNoError ) goto error;    err = Pa_StartStream( stream );    if( err != paNoError ) goto error;    /* Sleep for several seconds. */    Pa_Sleep(NUM_SECONDS*1000);    err = Pa_StopStream( stream );    if( err != paNoError ) goto error;    err = Pa_CloseStream( stream );    if( err != paNoError ) goto error;    Pa_Terminate();    printf("Test finished.\n");    return err;error:    Pa_Terminate();    fprintf( stderr, "An error occured while using the portaudio stream\n" );    fprintf( stderr, "Error number: %d\n", err );    fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );    return err;}