cannam@124: /** @file paex_pink.c
cannam@124: 	@ingroup examples_src
cannam@124: 	@brief Generate Pink Noise using Gardner method.
cannam@124: 
cannam@124: 	Optimization suggested by James McCartney uses a tree
cannam@124: 	to select which random value to replace.
cannam@124: <pre>
cannam@124: 	x x x x x x x x x x x x x x x x 
cannam@124: 	x   x   x   x   x   x   x   x   
cannam@124: 	x       x       x       x       
cannam@124: 	 x               x               
cannam@124: 	   x   
cannam@124: </pre>                            
cannam@124: 	Tree is generated by counting trailing zeros in an increasing index.
cannam@124: 	When the index is zero, no random number is selected.
cannam@124: 
cannam@124: 	@author Phil Burk  http://www.softsynth.com
cannam@124: */
cannam@124: /*
cannam@124:  * $Id: paex_pink.c 1752 2011-09-08 03:21:55Z philburk $
cannam@124:  *
cannam@124:  * This program uses the PortAudio Portable Audio Library.
cannam@124:  * For more information see: http://www.portaudio.com
cannam@124:  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
cannam@124:  *
cannam@124:  * Permission is hereby granted, free of charge, to any person obtaining
cannam@124:  * a copy of this software and associated documentation files
cannam@124:  * (the "Software"), to deal in the Software without restriction,
cannam@124:  * including without limitation the rights to use, copy, modify, merge,
cannam@124:  * publish, distribute, sublicense, and/or sell copies of the Software,
cannam@124:  * and to permit persons to whom the Software is furnished to do so,
cannam@124:  * subject to the following conditions:
cannam@124:  *
cannam@124:  * The above copyright notice and this permission notice shall be
cannam@124:  * included in all copies or substantial portions of the Software.
cannam@124:  *
cannam@124:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@124:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@124:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
cannam@124:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
cannam@124:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@124:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@124:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@124:  */
cannam@124: 
cannam@124: /*
cannam@124:  * The text above constitutes the entire PortAudio license; however, 
cannam@124:  * the PortAudio community also makes the following non-binding requests:
cannam@124:  *
cannam@124:  * Any person wishing to distribute modifications to the Software is
cannam@124:  * requested to send the modifications to the original developer so that
cannam@124:  * they can be incorporated into the canonical version. It is also 
cannam@124:  * requested that these non-binding requests be included along with the 
cannam@124:  * license above.
cannam@124:  */
cannam@124: 
cannam@124: #include <stdio.h>
cannam@124: #include <math.h>
cannam@124: #include "portaudio.h"
cannam@124: 
cannam@124: #define PINK_MAX_RANDOM_ROWS   (30)
cannam@124: #define PINK_RANDOM_BITS       (24)
cannam@124: #define PINK_RANDOM_SHIFT      ((sizeof(long)*8)-PINK_RANDOM_BITS)
cannam@124: 
cannam@124: typedef struct
cannam@124: {
cannam@124:     long      pink_Rows[PINK_MAX_RANDOM_ROWS];
cannam@124:     long      pink_RunningSum;   /* Used to optimize summing of generators. */
cannam@124:     int       pink_Index;        /* Incremented each sample. */
cannam@124:     int       pink_IndexMask;    /* Index wrapped by ANDing with this mask. */
cannam@124:     float     pink_Scalar;       /* Used to scale within range of -1.0 to +1.0 */
cannam@124: }
cannam@124: PinkNoise;
cannam@124: 
cannam@124: /* Prototypes */
cannam@124: static unsigned long GenerateRandomNumber( void );
cannam@124: void InitializePinkNoise( PinkNoise *pink, int numRows );
cannam@124: float GeneratePinkNoise( PinkNoise *pink );
cannam@124: 
cannam@124: /************************************************************/
cannam@124: /* Calculate pseudo-random 32 bit number based on linear congruential method. */
cannam@124: static unsigned long GenerateRandomNumber( void )
cannam@124: {
cannam@124:     /* Change this seed for different random sequences. */
cannam@124:     static unsigned long randSeed = 22222;
cannam@124:     randSeed = (randSeed * 196314165) + 907633515;
cannam@124:     return randSeed;
cannam@124: }
cannam@124: 
cannam@124: /************************************************************/
cannam@124: /* Setup PinkNoise structure for N rows of generators. */
cannam@124: void InitializePinkNoise( PinkNoise *pink, int numRows )
cannam@124: {
cannam@124:     int i;
cannam@124:     long pmax;
cannam@124:     pink->pink_Index = 0;
cannam@124:     pink->pink_IndexMask = (1<<numRows) - 1;
cannam@124:     /* Calculate maximum possible signed random value. Extra 1 for white noise always added. */
cannam@124:     pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1));
cannam@124:     pink->pink_Scalar = 1.0f / pmax;
cannam@124:     /* Initialize rows. */
cannam@124:     for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0;
cannam@124:     pink->pink_RunningSum = 0;
cannam@124: }
cannam@124: 
cannam@124: #define PINK_MEASURE
cannam@124: #ifdef PINK_MEASURE
cannam@124: float pinkMax = -999.0;
cannam@124: float pinkMin =  999.0;
cannam@124: #endif
cannam@124: 
cannam@124: /* Generate Pink noise values between -1.0 and +1.0 */
cannam@124: float GeneratePinkNoise( PinkNoise *pink )
cannam@124: {
cannam@124:     long newRandom;
cannam@124:     long sum;
cannam@124:     float output;
cannam@124:     /* Increment and mask index. */
cannam@124:     pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask;
cannam@124:     /* If index is zero, don't update any random values. */
cannam@124:     if( pink->pink_Index != 0 )
cannam@124:     {
cannam@124:         /* Determine how many trailing zeros in PinkIndex. */
cannam@124:         /* This algorithm will hang if n==0 so test first. */
cannam@124:         int numZeros = 0;
cannam@124:         int n = pink->pink_Index;
cannam@124:         while( (n & 1) == 0 )
cannam@124:         {
cannam@124:             n = n >> 1;
cannam@124:             numZeros++;
cannam@124:         }
cannam@124:         /* Replace the indexed ROWS random value.
cannam@124:          * Subtract and add back to RunningSum instead of adding all the random
cannam@124:          * values together. Only one changes each time.
cannam@124:          */
cannam@124:         pink->pink_RunningSum -= pink->pink_Rows[numZeros];
cannam@124:         newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
cannam@124:         pink->pink_RunningSum += newRandom;
cannam@124:         pink->pink_Rows[numZeros] = newRandom;
cannam@124:     }
cannam@124: 
cannam@124:     /* Add extra white noise value. */
cannam@124:     newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
cannam@124:     sum = pink->pink_RunningSum + newRandom;
cannam@124:     /* Scale to range of -1.0 to 0.9999. */
cannam@124:     output = pink->pink_Scalar * sum;
cannam@124: #ifdef PINK_MEASURE
cannam@124:     /* Check Min/Max */
cannam@124:     if( output > pinkMax ) pinkMax = output;
cannam@124:     else if( output < pinkMin ) pinkMin = output;
cannam@124: #endif
cannam@124:     return output;
cannam@124: }
cannam@124: 
cannam@124: /*******************************************************************/
cannam@124: #define PINK_TEST
cannam@124: #ifdef PINK_TEST
cannam@124: 
cannam@124: /* Context for callback routine. */
cannam@124: typedef struct
cannam@124: {
cannam@124:     PinkNoise   leftPink;
cannam@124:     PinkNoise   rightPink;
cannam@124:     unsigned int sampsToGo;
cannam@124: }
cannam@124: paTestData;
cannam@124: 
cannam@124: /* This routine will be called by the PortAudio engine when audio is needed.
cannam@124: ** It may called at interrupt level on some machines so don't do anything
cannam@124: ** that could mess up the system like calling malloc() or free().
cannam@124: */
cannam@124: static int patestCallback(const void*                     inputBuffer,
cannam@124:                           void*                           outputBuffer,
cannam@124:                           unsigned long                   framesPerBuffer,
cannam@124: 			              const PaStreamCallbackTimeInfo* timeInfo,
cannam@124: 			              PaStreamCallbackFlags           statusFlags,
cannam@124:                           void*                           userData)
cannam@124: {
cannam@124:     int finished;
cannam@124:     int i;
cannam@124:     int numFrames;
cannam@124:     paTestData *data = (paTestData*)userData;
cannam@124:     float *out = (float*)outputBuffer;
cannam@124:     (void) inputBuffer; /* Prevent "unused variable" warnings. */
cannam@124: 
cannam@124:     /* Are we almost at end. */
cannam@124:     if( data->sampsToGo < framesPerBuffer )
cannam@124:     {
cannam@124:         numFrames = data->sampsToGo;
cannam@124:         finished = 1;
cannam@124:     }
cannam@124:     else
cannam@124:     {
cannam@124:         numFrames = framesPerBuffer;
cannam@124:         finished = 0;
cannam@124:     }
cannam@124:     for( i=0; i<numFrames; i++ )
cannam@124:     {
cannam@124:         *out++ = GeneratePinkNoise( &data->leftPink );
cannam@124:         *out++ = GeneratePinkNoise( &data->rightPink );
cannam@124:     }
cannam@124:     data->sampsToGo -= numFrames;
cannam@124:     return finished;
cannam@124: }
cannam@124: 
cannam@124: /*******************************************************************/
cannam@124: int main(void);
cannam@124: int main(void)
cannam@124: {
cannam@124:     PaStream*           stream;
cannam@124:     PaError             err;
cannam@124:     paTestData          data;
cannam@124:     PaStreamParameters  outputParameters;
cannam@124:     int                 totalSamps;
cannam@124:     static const double SR  = 44100.0;
cannam@124:     static const int    FPB = 2048; /* Frames per buffer: 46 ms buffers. */
cannam@124:     
cannam@124:     /* Initialize two pink noise signals with different numbers of rows. */
cannam@124:     InitializePinkNoise( &data.leftPink,  12 );
cannam@124:     InitializePinkNoise( &data.rightPink, 16 );
cannam@124: 
cannam@124:     /* Look at a few values. */
cannam@124:     {
cannam@124:         int i;
cannam@124:         float pink;
cannam@124:         for( i=0; i<20; i++ )
cannam@124:         {
cannam@124:             pink = GeneratePinkNoise( &data.leftPink );
cannam@124:             printf("Pink = %f\n", pink );
cannam@124:         }
cannam@124:     }
cannam@124: 
cannam@124:     data.sampsToGo = totalSamps = (int)(60.0 * SR);   /* Play a whole minute. */
cannam@124:     err = Pa_Initialize();
cannam@124:     if( err != paNoError ) goto error;
cannam@124: 
cannam@124:     /* Open a stereo PortAudio stream so we can hear the result. */
cannam@124:     outputParameters.device = Pa_GetDefaultOutputDevice(); /* Take the default output device. */
cannam@124:     if (outputParameters.device == paNoDevice) {
cannam@124:       fprintf(stderr,"Error: No default output device.\n");
cannam@124:       goto error;
cannam@124:     }
cannam@124:     outputParameters.channelCount = 2;                     /* Stereo output, most likely supported. */
cannam@124:     outputParameters.hostApiSpecificStreamInfo = NULL;
cannam@124:     outputParameters.sampleFormat = paFloat32;             /* 32 bit floating point output. */
cannam@124:     outputParameters.suggestedLatency =
cannam@124:                      Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;
cannam@124:     err = Pa_OpenStream(&stream,
cannam@124:                         NULL,                              /* No input. */
cannam@124:                         &outputParameters,
cannam@124:                         SR,                                /* Sample rate. */
cannam@124:                         FPB,                               /* Frames per buffer. */
cannam@124:                         paClipOff, /* we won't output out of range samples so don't bother clipping them */
cannam@124:                         patestCallback,
cannam@124:                         &data);
cannam@124:     if( err != paNoError ) goto error;
cannam@124: 
cannam@124:     err = Pa_StartStream( stream );
cannam@124:     if( err != paNoError ) goto error;
cannam@124: 
cannam@124:     printf("Stereo pink noise for one minute...\n");
cannam@124: 
cannam@124:     while( ( err = Pa_IsStreamActive( stream ) ) == 1 ) Pa_Sleep(100);
cannam@124:     if( err < 0 ) goto error;
cannam@124: 
cannam@124:     err = Pa_CloseStream( stream );
cannam@124:     if( err != paNoError ) goto error;
cannam@124: #ifdef PINK_MEASURE
cannam@124:     printf("Pink min = %f, max = %f\n", pinkMin, pinkMax );
cannam@124: #endif
cannam@124:     Pa_Terminate();
cannam@124:     return 0;
cannam@124: error:
cannam@124:     Pa_Terminate();
cannam@124:     fprintf( stderr, "An error occured while using the portaudio stream\n" );
cannam@124:     fprintf( stderr, "Error number: %d\n", err );
cannam@124:     fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
cannam@124:     return 0;
cannam@124: }
cannam@124: #endif /* PINK_TEST */