andrewm@0: #ifndef _PinkNoise_H
andrewm@0: #define _PinkNoise_H
andrewm@0: 
andrewm@0: // Technique by Larry "RidgeRat" Trammell 3/2006
andrewm@0: // http://home.earthlink.net/~ltrammell/tech/pinkalg.htm
andrewm@0: // implementation and optimization by David Lowenfels
andrewm@0: 
andrewm@0: #include <cstdlib>
andrewm@0: #include <ctime>
andrewm@0: #include <stdlib.h>
andrewm@0: 
andrewm@0: #define PINK_NOISE_NUM_STAGES 3
andrewm@0: 
andrewm@0: class PinkNoise {
andrewm@0: public:
andrewm@0:   PinkNoise() {
andrewm@0:   srand ( time(NULL) ); // initialize random generator
andrewm@0:     clear();
andrewm@0:   }
andrewm@0: 
andrewm@0:   void clear() {
andrewm@0:     for( size_t i=0; i< PINK_NOISE_NUM_STAGES; i++ )
andrewm@0:       state[ i ] = 0.0;
andrewm@0:     }
andrewm@0: 
andrewm@0:   float tick() {
andrewm@0:     static const float RMI2 = 2.0 / float(RAND_MAX); // + 1.0; // change for range [0,1)
andrewm@0:     static const float offset = A[0] + A[1] + A[2];
andrewm@0: 
andrewm@0:   // unrolled loop
andrewm@0:     float temp = float( rand() );
andrewm@0:     state[0] = P[0] * (state[0] - temp) + temp;
andrewm@0:     temp = float( rand() );
andrewm@0:     state[1] = P[1] * (state[1] - temp) + temp;
andrewm@0:     temp = float( rand() );
andrewm@0:     state[2] = P[2] * (state[2] - temp) + temp;
andrewm@0:     return ( A[0]*state[0] + A[1]*state[1] + A[2]*state[2] )*RMI2 - offset;
andrewm@0:   }
andrewm@0: 
andrewm@0: protected:
andrewm@0:   float state[ PINK_NOISE_NUM_STAGES ];
andrewm@0:   static const float A[ PINK_NOISE_NUM_STAGES ];
andrewm@0:   static const float P[ PINK_NOISE_NUM_STAGES ];
andrewm@0: };
andrewm@0: 
andrewm@0: //const float PinkNoise::A[] = { 0.02109238, 0.07113478, 0.68873558 }; // rescaled by (1+P)/(1-P)
andrewm@0: //const float PinkNoise::P[] = { 0.3190,  0.7756,  0.9613  };
andrewm@0: 
andrewm@0: #endif