Main Archive Specials Wiki | FAQ Links Submit Forum


Trammell Pink Noise (C++ class)

Type : pink noise generator
References : Posted by dfl at ccrma dot stanford dot edu
Code :
#ifndef _PinkNoise_H
#define _PinkNoise_H

// Technique by Larry "RidgeRat" Trammell 3/2006
// http://home.earthlink.net/~ltrammell/tech/pinkalg.htm
// implementation and optimization by David Lowenfels

#include
#include

#define PINK_NOISE_NUM_STAGES 3

class PinkNoise {
public:
PinkNoise() {
srand ( time(NULL) ); // initialize random generator
clear();
}

void clear() {
for( size_t i=0; i< PINK_NOISE_NUM_STAGES; i++ )
state[ i ] = 0.0;
}

float tick() {
static const float RMI2 = 2.0 / float(RAND_MAX); // + 1.0; // change for range [0,1)
static const float offset = A[0] + A[1] + A[2];

// unrolled loop
float temp = float( rand() );
state[0] = P[0] * (state[0] - temp) + temp;
temp = float( rand() );
state[1] = P[1] * (state[1] - temp) + temp;
temp = float( rand() );
state[2] = P[2] * (state[2] - temp) + temp;
return ( A[0]*state[0] + A[1]*state[1] + A[2]*state[2] )*RMI2 - offset;
}

protected:
float state[ PINK_NOISE_NUM_STAGES ];
static const float A[ PINK_NOISE_NUM_STAGES ];
static const float P[ PINK_NOISE_NUM_STAGES ];
};

const float PinkNoise::A[] = { 0.02109238, 0.07113478, 0.68873558 }; // rescaled by (1+P)/(1-P)
const float PinkNoise::P[] = { 0.3190, 0.7756, 0.9613 };

#endif



Comments


Added on : 09/02/07 by ltramme1476[ AT ]earthlink[ DOT ]net
Comment :
Many thanks to David Lowenfels for posting this implementation of the early experimental version. I recommend switching to the new algorithm form described in 'newpink.htm' -- better range to 9+ octaves, better accuracy to +-0.25 dB, and leveled computational loading.  So where is MY submission to the archive? Um...  well, it's coming... if he doesn't beat me to the punch again and post his code first! -- Larry Trammell (the RidgeRat)            



Add your own comment
Comments are displayed in fixed width, no HTML code allowed!
Email:

Comment:

Are you human?



Site created and maintained by Bram
Graphic design by line.out | Server sponsered by fxpansion