text: /*
   * $Id: patest_sine.c,v 1.3 2003-03-02 08:01:43 dmazzoni Exp $
   * patest_sine.c
   * Play a sine wave using the Portable Audio api for several seconds.
   *
   * 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 NUM_SECONDS   (10)
  #define SAMPLE_RATE   (44100)
  #define AMPLITUDE     (0.9)
  #define FRAMES_PER_BUFFER  (64)
  #define OUTPUT_DEVICE Pa_GetDefaultOutputDeviceID()
  //#define OUTPUT_DEVICE (2)
  
  #ifndef M_PI
  #define M_PI  (3.14159265)
  #endif
  
  #define TABLE_SIZE   (200)
  typedef struct
  {
      float sine[TABLE_SIZE];
      int left_phase;
      int 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 )
  {
      paTestData *data = (paTestData*)userData;
      float *out = (float*)outputBuffer;
      unsigned long i;
      int finished = 0;
      (void) outTime; /* Prevent unused variable warnings. */
      (void) inputBuffer;
      for( i=0; i<framesPerBuffer; i++ )
      {
          *out++ = data->sine[data->left_phase];  /* left */
          *out++ = data->sine[data->right_phase];  /* right */
          data->left_phase += 1;
          if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
          data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
          if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
      }
      return finished;
  }
  
  /*******************************************************************/
  int main(void);
  int main(void)
  {
      PortAudioStream *stream;
      PaError err;
      paTestData data;
      int i;
      printf("PortAudio Test: output sine wave. SR = %d, BufSize = %d, devID = %d\n",
      	SAMPLE_RATE, FRAMES_PER_BUFFER, OUTPUT_DEVICE);
      /* initialise sinusoidal wavetable */
      for( i=0; i<TABLE_SIZE; i++ )
      {
          data.sine[i] = (float) (AMPLITUDE * sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. ));
      }
      data.left_phase = data.right_phase = 0;
      err = Pa_Initialize();
      if( err != paNoError ) goto error;
      err = Pa_OpenStream(
                &stream,
                paNoDevice,/* default input device */
                0,              /* no input */
                paFloat32,  /* 32 bit floating point input */
                NULL,
                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;
      printf("Play for %d seconds.\n", NUM_SECONDS ); fflush(stdout);
      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;
  }
  