source: GTP/trunk/App/Demos/Illum/Hierarchical Systems Demo [OpenGL]/RESOURCES/include/random.h @ 852

#include "includes.h"
#pragma once

double UnitRandom ();    
double RangeRandom (double fLow, double fHigh); 
double SymmetricRandom ();

class Halton
{
        float value;
        float inv_base;

public:
        Halton(long i,int base)
        {
                Number(i,base);
        }

        void Number(long i,int base)
        {
                float f=inv_base=1.0/base;
                value=0.0;
                while(i>0)
                {
                        value+=f*(double)(i%base);
                        i/=base;
                        f*=inv_base;
                }
        }
        void Next()
        {
                float r=1.0-value-0.0000001;
                if(inv_base<r)
                        value+=inv_base;
                else
                {
                        float h=inv_base,hh;
                        do{hh=h;h*=inv_base;}while(h>=r);
                        value+=hh+h-1.0;
                }
        }
        float Get(){return value;}
        float Random(){
                float n=Get();
                n=2*n-1;
                Next();
                return n;}
};