gearmulator

patest_leftright.c (6538B)

---

 /** @file patest_leftright.c
 	@ingroup test_src
 	@brief Play different tone sine waves that 
 		alternate between left and right channel.
 
 	The low tone should be on the left channel.
 
 	@author Ross Bencina <rossb@audiomulch.com>
 	@author Phil Burk <philburk@softsynth.com>
 */
 /*
  * $Id$
  *
  * 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.
  *
  * 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.
  */
 
 /*
  * The text above constitutes the entire PortAudio license; however, 
  * the PortAudio community also makes the following non-binding requests:
  *
  * 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. It is also 
  * requested that these non-binding requests be included along with the 
  * license above.
  */
 
 #include <stdio.h>
 #include <math.h>
 #include "portaudio.h"
 
 #define NUM_SECONDS   (8)
 #define SAMPLE_RATE   (44100)
 #define FRAMES_PER_BUFFER  (512)
 #ifndef M_PI
 #define M_PI  (3.14159265)
 #endif
 #define TABLE_SIZE   (200)
 #define BALANCE_DELTA  (0.001)
 
 typedef struct
 {
     float sine[TABLE_SIZE];
     int left_phase;
     int right_phase;
     float targetBalance; // 0.0 = left, 1.0 = right
     float currentBalance;
 } 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( const void *inputBuffer,
                            void *outputBuffer,
                            unsigned long framesPerBuffer,
                            const PaStreamCallbackTimeInfo* timeInfo,
                            PaStreamCallbackFlags statusFlags,
                            void *userData )
 {
     paTestData *data = (paTestData*)userData;
     float *out = (float*)outputBuffer;
     unsigned long i;
     int finished = 0;
     /* Prevent unused variable warnings. */
     (void) inputBuffer;
 
     for( i=0; i<framesPerBuffer; i++ )
     {
 		// Smoothly pan between left and right.
 		if( data->currentBalance < data->targetBalance )
 		{
 			data->currentBalance += BALANCE_DELTA;
 		}
 		else if( data->currentBalance > data->targetBalance )
 		{
 			data->currentBalance -= BALANCE_DELTA;
 		}
 		// Apply left/right balance.
         *out++ = data->sine[data->left_phase] * (1.0f - data->currentBalance);  /* left */
 		*out++ = data->sine[data->right_phase] * data->currentBalance;  /* 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)
 {
     PaStream *stream;
     PaStreamParameters outputParameters;
     PaError err;
     paTestData data;
     int i;    
     printf("Play different tone sine waves that alternate between left and right channel.\n");
     printf("The low tone should be on the left channel.\n");
     
     /* initialise sinusoidal wavetable */
     for( i=0; i<TABLE_SIZE; i++ )
     {
         data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
     }
     data.left_phase = data.right_phase = 0;
     data.currentBalance = 0.0;
     data.targetBalance = 0.0;
 
     err = Pa_Initialize();
     if( err != paNoError ) goto error;
 
     outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
     if (outputParameters.device == paNoDevice) {
       fprintf(stderr,"Error: No default output device.\n");
       goto error;
     }
     outputParameters.channelCount = 2;       /* stereo output */
     outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output */
     outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency;
     outputParameters.hostApiSpecificStreamInfo = NULL;
 
     err = Pa_OpenStream( &stream,
                          NULL,                  /* No input. */
                          &outputParameters,     /* As above. */
                          SAMPLE_RATE,
                          FRAMES_PER_BUFFER,
                          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 several seconds.\n");
     for( i=0; i<4; i++ )
 	{
 		printf("Hear low sound on left side.\n");
 		data.targetBalance = 0.01;
         Pa_Sleep( 1000 );
 		
 		printf("Hear high sound on right side.\n");
 		data.targetBalance = 0.99;
         Pa_Sleep( 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;
 }