Chris@4: /** @file paex_pink.c
Chris@4: 	@ingroup examples_src
Chris@4: 	@brief Generate Pink Noise using Gardner method.
Chris@4: 
Chris@4: 	Optimization suggested by James McCartney uses a tree
Chris@4: 	to select which random value to replace.
Chris@4: <pre>
Chris@4: 	x x x x x x x x x x x x x x x x 
Chris@4: 	x   x   x   x   x   x   x   x   
Chris@4: 	x       x       x       x       
Chris@4: 	 x               x               
Chris@4: 	   x   
Chris@4: </pre>                            
Chris@4: 	Tree is generated by counting trailing zeros in an increasing index.
Chris@4: 	When the index is zero, no random number is selected.
Chris@4: 
Chris@4: 	@author Phil Burk  http://www.softsynth.com
Chris@4: */
Chris@4: /*
Chris@4:  * $Id: paex_pink.c 1752 2011-09-08 03:21:55Z philburk $
Chris@4:  *
Chris@4:  * This program uses the PortAudio Portable Audio Library.
Chris@4:  * For more information see: http://www.portaudio.com
Chris@4:  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
Chris@4:  *
Chris@4:  * Permission is hereby granted, free of charge, to any person obtaining
Chris@4:  * a copy of this software and associated documentation files
Chris@4:  * (the "Software"), to deal in the Software without restriction,
Chris@4:  * including without limitation the rights to use, copy, modify, merge,
Chris@4:  * publish, distribute, sublicense, and/or sell copies of the Software,
Chris@4:  * and to permit persons to whom the Software is furnished to do so,
Chris@4:  * subject to the following conditions:
Chris@4:  *
Chris@4:  * The above copyright notice and this permission notice shall be
Chris@4:  * included in all copies or substantial portions of the Software.
Chris@4:  *
Chris@4:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@4:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@4:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
Chris@4:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
Chris@4:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@4:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@4:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@4:  */
Chris@4: 
Chris@4: /*
Chris@4:  * The text above constitutes the entire PortAudio license; however, 
Chris@4:  * the PortAudio community also makes the following non-binding requests:
Chris@4:  *
Chris@4:  * Any person wishing to distribute modifications to the Software is
Chris@4:  * requested to send the modifications to the original developer so that
Chris@4:  * they can be incorporated into the canonical version. It is also 
Chris@4:  * requested that these non-binding requests be included along with the 
Chris@4:  * license above.
Chris@4:  */
Chris@4: 
Chris@4: #include <stdio.h>
Chris@4: #include <math.h>
Chris@4: #include "portaudio.h"
Chris@4: 
Chris@4: #define PINK_MAX_RANDOM_ROWS   (30)
Chris@4: #define PINK_RANDOM_BITS       (24)
Chris@4: #define PINK_RANDOM_SHIFT      ((sizeof(long)*8)-PINK_RANDOM_BITS)
Chris@4: 
Chris@4: typedef struct
Chris@4: {
Chris@4:     long      pink_Rows[PINK_MAX_RANDOM_ROWS];
Chris@4:     long      pink_RunningSum;   /* Used to optimize summing of generators. */
Chris@4:     int       pink_Index;        /* Incremented each sample. */
Chris@4:     int       pink_IndexMask;    /* Index wrapped by ANDing with this mask. */
Chris@4:     float     pink_Scalar;       /* Used to scale within range of -1.0 to +1.0 */
Chris@4: }
Chris@4: PinkNoise;
Chris@4: 
Chris@4: /* Prototypes */
Chris@4: static unsigned long GenerateRandomNumber( void );
Chris@4: void InitializePinkNoise( PinkNoise *pink, int numRows );
Chris@4: float GeneratePinkNoise( PinkNoise *pink );
Chris@4: 
Chris@4: /************************************************************/
Chris@4: /* Calculate pseudo-random 32 bit number based on linear congruential method. */
Chris@4: static unsigned long GenerateRandomNumber( void )
Chris@4: {
Chris@4:     /* Change this seed for different random sequences. */
Chris@4:     static unsigned long randSeed = 22222;
Chris@4:     randSeed = (randSeed * 196314165) + 907633515;
Chris@4:     return randSeed;
Chris@4: }
Chris@4: 
Chris@4: /************************************************************/
Chris@4: /* Setup PinkNoise structure for N rows of generators. */
Chris@4: void InitializePinkNoise( PinkNoise *pink, int numRows )
Chris@4: {
Chris@4:     int i;
Chris@4:     long pmax;
Chris@4:     pink->pink_Index = 0;
Chris@4:     pink->pink_IndexMask = (1<<numRows) - 1;
Chris@4:     /* Calculate maximum possible signed random value. Extra 1 for white noise always added. */
Chris@4:     pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1));
Chris@4:     pink->pink_Scalar = 1.0f / pmax;
Chris@4:     /* Initialize rows. */
Chris@4:     for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0;
Chris@4:     pink->pink_RunningSum = 0;
Chris@4: }
Chris@4: 
Chris@4: #define PINK_MEASURE
Chris@4: #ifdef PINK_MEASURE
Chris@4: float pinkMax = -999.0;
Chris@4: float pinkMin =  999.0;
Chris@4: #endif
Chris@4: 
Chris@4: /* Generate Pink noise values between -1.0 and +1.0 */
Chris@4: float GeneratePinkNoise( PinkNoise *pink )
Chris@4: {
Chris@4:     long newRandom;
Chris@4:     long sum;
Chris@4:     float output;
Chris@4:     /* Increment and mask index. */
Chris@4:     pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask;
Chris@4:     /* If index is zero, don't update any random values. */
Chris@4:     if( pink->pink_Index != 0 )
Chris@4:     {
Chris@4:         /* Determine how many trailing zeros in PinkIndex. */
Chris@4:         /* This algorithm will hang if n==0 so test first. */
Chris@4:         int numZeros = 0;
Chris@4:         int n = pink->pink_Index;
Chris@4:         while( (n & 1) == 0 )
Chris@4:         {
Chris@4:             n = n >> 1;
Chris@4:             numZeros++;
Chris@4:         }
Chris@4:         /* Replace the indexed ROWS random value.
Chris@4:          * Subtract and add back to RunningSum instead of adding all the random
Chris@4:          * values together. Only one changes each time.
Chris@4:          */
Chris@4:         pink->pink_RunningSum -= pink->pink_Rows[numZeros];
Chris@4:         newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
Chris@4:         pink->pink_RunningSum += newRandom;
Chris@4:         pink->pink_Rows[numZeros] = newRandom;
Chris@4:     }
Chris@4: 
Chris@4:     /* Add extra white noise value. */
Chris@4:     newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;
Chris@4:     sum = pink->pink_RunningSum + newRandom;
Chris@4:     /* Scale to range of -1.0 to 0.9999. */
Chris@4:     output = pink->pink_Scalar * sum;
Chris@4: #ifdef PINK_MEASURE
Chris@4:     /* Check Min/Max */
Chris@4:     if( output > pinkMax ) pinkMax = output;
Chris@4:     else if( output < pinkMin ) pinkMin = output;
Chris@4: #endif
Chris@4:     return output;
Chris@4: }
Chris@4: 
Chris@4: /*******************************************************************/
Chris@4: #define PINK_TEST
Chris@4: #ifdef PINK_TEST
Chris@4: 
Chris@4: /* Context for callback routine. */
Chris@4: typedef struct
Chris@4: {
Chris@4:     PinkNoise   leftPink;
Chris@4:     PinkNoise   rightPink;
Chris@4:     unsigned int sampsToGo;
Chris@4: }
Chris@4: paTestData;
Chris@4: 
Chris@4: /* This routine will be called by the PortAudio engine when audio is needed.
Chris@4: ** It may called at interrupt level on some machines so don't do anything
Chris@4: ** that could mess up the system like calling malloc() or free().
Chris@4: */
Chris@4: static int patestCallback(const void*                     inputBuffer,
Chris@4:                           void*                           outputBuffer,
Chris@4:                           unsigned long                   framesPerBuffer,
Chris@4: 			              const PaStreamCallbackTimeInfo* timeInfo,
Chris@4: 			              PaStreamCallbackFlags           statusFlags,
Chris@4:                           void*                           userData)
Chris@4: {
Chris@4:     int finished;
Chris@4:     int i;
Chris@4:     int numFrames;
Chris@4:     paTestData *data = (paTestData*)userData;
Chris@4:     float *out = (float*)outputBuffer;
Chris@4:     (void) inputBuffer; /* Prevent "unused variable" warnings. */
Chris@4: 
Chris@4:     /* Are we almost at end. */
Chris@4:     if( data->sampsToGo < framesPerBuffer )
Chris@4:     {
Chris@4:         numFrames = data->sampsToGo;
Chris@4:         finished = 1;
Chris@4:     }
Chris@4:     else
Chris@4:     {
Chris@4:         numFrames = framesPerBuffer;
Chris@4:         finished = 0;
Chris@4:     }
Chris@4:     for( i=0; i<numFrames; i++ )
Chris@4:     {
Chris@4:         *out++ = GeneratePinkNoise( &data->leftPink );
Chris@4:         *out++ = GeneratePinkNoise( &data->rightPink );
Chris@4:     }
Chris@4:     data->sampsToGo -= numFrames;
Chris@4:     return finished;
Chris@4: }
Chris@4: 
Chris@4: /*******************************************************************/
Chris@4: int main(void);
Chris@4: int main(void)
Chris@4: {
Chris@4:     PaStream*           stream;
Chris@4:     PaError             err;
Chris@4:     paTestData          data;
Chris@4:     PaStreamParameters  outputParameters;
Chris@4:     int                 totalSamps;
Chris@4:     static const double SR  = 44100.0;
Chris@4:     static const int    FPB = 2048; /* Frames per buffer: 46 ms buffers. */
Chris@4:     
Chris@4:     /* Initialize two pink noise signals with different numbers of rows. */
Chris@4:     InitializePinkNoise( &data.leftPink,  12 );
Chris@4:     InitializePinkNoise( &data.rightPink, 16 );
Chris@4: 
Chris@4:     /* Look at a few values. */
Chris@4:     {
Chris@4:         int i;
Chris@4:         float pink;
Chris@4:         for( i=0; i<20; i++ )
Chris@4:         {
Chris@4:             pink = GeneratePinkNoise( &data.leftPink );
Chris@4:             printf("Pink = %f\n", pink );
Chris@4:         }
Chris@4:     }
Chris@4: 
Chris@4:     data.sampsToGo = totalSamps = (int)(60.0 * SR);   /* Play a whole minute. */
Chris@4:     err = Pa_Initialize();
Chris@4:     if( err != paNoError ) goto error;
Chris@4: 
Chris@4:     /* Open a stereo PortAudio stream so we can hear the result. */
Chris@4:     outputParameters.device = Pa_GetDefaultOutputDevice(); /* Take the default output device. */
Chris@4:     if (outputParameters.device == paNoDevice) {
Chris@4:       fprintf(stderr,"Error: No default output device.\n");
Chris@4:       goto error;
Chris@4:     }
Chris@4:     outputParameters.channelCount = 2;                     /* Stereo output, most likely supported. */
Chris@4:     outputParameters.hostApiSpecificStreamInfo = NULL;
Chris@4:     outputParameters.sampleFormat = paFloat32;             /* 32 bit floating point output. */
Chris@4:     outputParameters.suggestedLatency =
Chris@4:                      Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;
Chris@4:     err = Pa_OpenStream(&stream,
Chris@4:                         NULL,                              /* No input. */
Chris@4:                         &outputParameters,
Chris@4:                         SR,                                /* Sample rate. */
Chris@4:                         FPB,                               /* Frames per buffer. */
Chris@4:                         paClipOff, /* we won't output out of range samples so don't bother clipping them */
Chris@4:                         patestCallback,
Chris@4:                         &data);
Chris@4:     if( err != paNoError ) goto error;
Chris@4: 
Chris@4:     err = Pa_StartStream( stream );
Chris@4:     if( err != paNoError ) goto error;
Chris@4: 
Chris@4:     printf("Stereo pink noise for one minute...\n");
Chris@4: 
Chris@4:     while( ( err = Pa_IsStreamActive( stream ) ) == 1 ) Pa_Sleep(100);
Chris@4:     if( err < 0 ) goto error;
Chris@4: 
Chris@4:     err = Pa_CloseStream( stream );
Chris@4:     if( err != paNoError ) goto error;
Chris@4: #ifdef PINK_MEASURE
Chris@4:     printf("Pink min = %f, max = %f\n", pinkMin, pinkMax );
Chris@4: #endif
Chris@4:     Pa_Terminate();
Chris@4:     return 0;
Chris@4: error:
Chris@4:     Pa_Terminate();
Chris@4:     fprintf( stderr, "An error occured while using the portaudio stream\n" );
Chris@4:     fprintf( stderr, "Error number: %d\n", err );
Chris@4:     fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
Chris@4:     return 0;
Chris@4: }
Chris@4: #endif /* PINK_TEST */