robert@464: #ifndef _PinkNoise_H
robert@464: #define _PinkNoise_H
robert@464: 
robert@464: // Technique by Larry "RidgeRat" Trammell 3/2006
robert@464: // http://home.earthlink.net/~ltrammell/tech/pinkalg.htm
robert@464: // implementation and optimization by David Lowenfels
robert@464: 
robert@464: #include <cstdlib>
robert@464: #include <ctime>
robert@464: #include <stdlib.h>
robert@464: 
robert@464: #define PINK_NOISE_NUM_STAGES 3
robert@464: 
robert@464: class PinkNoise {
robert@464: public:
robert@464:   PinkNoise() {
robert@464:   srand ( time(NULL) ); // initialize random generator
robert@464:     clear();
robert@464:   }
robert@464: 
robert@464:   void clear() {
robert@464:     for( size_t i=0; i< PINK_NOISE_NUM_STAGES; i++ )
robert@464:       state[ i ] = 0.0;
robert@464:     }
robert@464: 
robert@464:   float tick() {
robert@464:     static const float RMI2 = 2.0 / float(RAND_MAX); // + 1.0; // change for range [0,1)
robert@464:     static const float offset = A[0] + A[1] + A[2];
robert@464: 
robert@464:   // unrolled loop
robert@464:     float temp = float( rand() );
robert@464:     state[0] = P[0] * (state[0] - temp) + temp;
robert@464:     temp = float( rand() );
robert@464:     state[1] = P[1] * (state[1] - temp) + temp;
robert@464:     temp = float( rand() );
robert@464:     state[2] = P[2] * (state[2] - temp) + temp;
robert@464:     return ( A[0]*state[0] + A[1]*state[1] + A[2]*state[2] )*RMI2 - offset;
robert@464:   }
robert@464: 
robert@464: protected:
robert@464:   float state[ PINK_NOISE_NUM_STAGES ];
robert@464:   static const float A[ PINK_NOISE_NUM_STAGES ];
robert@464:   static const float P[ PINK_NOISE_NUM_STAGES ];
robert@464: };
robert@464: 
robert@464: //const float PinkNoise::A[] = { 0.02109238, 0.07113478, 0.68873558 }; // rescaled by (1+P)/(1-P)
robert@464: //const float PinkNoise::P[] = { 0.3190,  0.7756,  0.9613  };
robert@464: 
robert@464: #endif