/* * $Id: patest_maxsines.c,v 1.2 2003/03/02 08:01:42 dmazzoni Exp $ * patest_maxsines.c * How many sine waves can we calculate and play in less than 80% CPU Load. * * Authors: *    Ross Bencina <rossb@audiomulch.com> *    Phil Burk <philburk@softsynth.com> * * This program uses the PortAudio Portable Audio Library. * For more information see: http://www.audiomulch.com/portaudio/ * 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 MAX_SINES     (500)#define MAX_USAGE     (0.8)#define SAMPLE_RATE   (44100)#define FREQ_TO_PHASE_INC(freq)   (freq/(float)SAMPLE_RATE)#define MIN_PHASE_INC  FREQ_TO_PHASE_INC(200.0f)#define MAX_PHASE_INC  (MIN_PHASE_INC * (1 << 5))#define FRAMES_PER_BUFFER  (512)#ifndef M_PI#define M_PI  (3.14159265)#endif#define TWOPI (M_PI * 2.0)#define TABLE_SIZE   (512)typedef struct paTestData{    int numSines;    float sine[TABLE_SIZE + 1]; /* add one for guard point for interpolation */    float phases[MAX_SINES];}paTestData;/* Convert phase between and 1.0 to sine value * using linear interpolation. */float LookupSine( paTestData *data, float phase );float LookupSine( paTestData *data, float phase ){    float fIndex = phase*TABLE_SIZE;    int   index = (int) fIndex;    float fract = fIndex - index;    float lo = data->sine[index];    float hi = data->sine[index+1];    float val = lo + fract*(hi-lo);    return val;}/* 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 ){    paTestData *data = (paTestData*)userData;    float *out = (float*)outputBuffer;    float outSample;    float scaler;    int numForScale;    unsigned long i;    int j;    int finished = 0;    (void) outTime; /* Prevent unused variable warnings. */    (void) inputBuffer;/* Detemine amplitude scaling factor */    numForScale = data->numSines;    if( numForScale < 8 ) numForScale = 8;  /* prevent pops at beginning */    scaler = 1.0f / numForScale;        for( i=0; i<framesPerBuffer; i++ )    {        float output = 0.0;        float phaseInc = MIN_PHASE_INC;        float phase;        for( j=0; j<data->numSines; j++ )        {            /* Advance phase of next oscillator. */            phase = data->phases[j];            phase += phaseInc;            if( phase >= 1.0 ) phase -= 1.0;            output += LookupSine(data, phase);             data->phases[j] = phase;                        phaseInc *= 1.02f;            if( phaseInc > MAX_PHASE_INC ) phaseInc = MIN_PHASE_INC;        }        outSample = (float) (output * scaler);        *out++ = outSample; /* Left */        *out++ = outSample; /* Right */    }    return finished;}/*******************************************************************/int main(void);int main(void){	int i;    PortAudioStream *stream;    PaError err;    paTestData data = {0};    double load;    printf("PortAudio Test: output sine wave. SR = %d, BufSize = %d\n", SAMPLE_RATE, FRAMES_PER_BUFFER);    /* initialise sinusoidal wavetable */    for( i=0; i<TABLE_SIZE; i++ )    {        data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );    }    data.sine[TABLE_SIZE] = data.sine[0]; /* set guard point */    err = Pa_Initialize();    if( err != paNoError ) goto error;    err = Pa_OpenStream(              &stream,              paNoDevice,              0,              /* no input */              paFloat32,              NULL,              Pa_GetDefaultOutputDeviceID(), /* default output device */              2,              /* stereo output */              paFloat32,      /* 32 bit floating point output */              NULL,              SAMPLE_RATE,              FRAMES_PER_BUFFER,               0,              /* number of buffers, if zero then use default minimum */              paClipOff,      /* we won't output out of range samples so don't bother clipping them */              patestCallback,              &data );    if( err != paNoError ) goto error;    err = Pa_StartStream( stream );    if( err != paNoError ) goto error;/* Play an increasing number of sine waves until we hit MAX_USAGE */    do    {        data.numSines++;        Pa_Sleep( 200 );        load = Pa_GetCPULoad( stream );        printf("numSines = %d, CPU load = %f\n", data.numSines, load );        fflush( stdout );    }    while( (load < MAX_USAGE) && (data.numSines < MAX_SINES) );    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;}