lugre_random.cpp

Go to the documentation of this file.

#include "lugre_prefix.h"
#include "lugre_random.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef WIN32
#define snprintf _snprintf
#endif

#define RANDOM_FLOAT_PRECISION  0xFFFFFF

unsigned int NextValue(unsigned int last){
    //printf("cRandom::NextValue(%d)\n",last);
    
    while(last < 0xFFFF){
        last = last * last + last + 1;
        //printf("last=%d\n",last);
    }
    
    static char buf[128+1];
    char *p = buf;
    snprintf(buf,128,"%d",last);
    //printf("buf=%s\n",buf);
    int len = strlen(buf);
    p += len / 4;
    *(p + len / 2 + 1) = 0;
    unsigned int v = atoi(p);
    v = v * v;
    //printf("-> %d\n",v);
    return v;
}

namespace Lugre {
    
cRandom::cRandom                        (unsigned int seed){
    miSeed = seed;
    miLast = miSeed * miSeed;
}
    
unsigned int    cRandom::GetInt     (unsigned int max){
    return GetInt(1,max);
}

unsigned int    cRandom::GetInt     (unsigned int min, unsigned int max){
    miLast = NextValue(miLast);
    return min + (miLast % (max - min + 1));
}

float           cRandom::GetFloat   (){
    return (float)GetInt(0,RANDOM_FLOAT_PRECISION) / (float)RANDOM_FLOAT_PRECISION;
}

};