qcsrc/lib/random.qc

   1 #include "random.qh"
   2
   3 void RandomSelection_Init()
   4 {
   5         RandomSelection_totalweight = 0;
   6         RandomSelection_chosen_ent = NULL;
   7         RandomSelection_chosen_float = 0;
   8         RandomSelection_chosen_string = string_null;
   9         RandomSelection_best_priority = -1;
  10 }
  11
  12 void RandomSelection_Add(entity e, float f, string s, vector v, float weight, float priority)
  13 {
  14         if (priority > RandomSelection_best_priority)
  15         {
  16                 RandomSelection_best_priority = priority;
  17                 RandomSelection_chosen_ent = e;
  18                 RandomSelection_chosen_float = f;
  19                 RandomSelection_chosen_string = s;
  20                 RandomSelection_chosen_vec = v;
  21                 RandomSelection_totalweight = weight;
  22         }
  23         else if (priority == RandomSelection_best_priority)
  24         {
  25                 RandomSelection_totalweight += weight;
  26                 if (random() * RandomSelection_totalweight <= weight)
  27                 {
  28                         RandomSelection_chosen_ent = e;
  29                         RandomSelection_chosen_float = f;
  30                         RandomSelection_chosen_string = s;
  31                         RandomSelection_chosen_vec = v;
  32                 }
  33         }
  34 }
  35
  36 float DistributeEvenly_amount;
  37 float DistributeEvenly_totalweight;
  38
  39 void DistributeEvenly_Init(float amount, float totalweight)
  40 {
  41         if (DistributeEvenly_amount)
  42         {
  43                 LOG_TRACE("DistributeEvenly_Init: UNFINISHED DISTRIBUTION (", ftos(DistributeEvenly_amount), " for ", ftos(DistributeEvenly_totalweight), " left!)");
  44         }
  45         if (totalweight == 0) DistributeEvenly_amount = 0;
  46         else DistributeEvenly_amount = amount;
  47         DistributeEvenly_totalweight = totalweight;
  48 }
  49
  50 float DistributeEvenly_Get(float weight)
  51 {
  52         float f;
  53         if (weight <= 0) return 0;
  54         f = floor(0.5 + DistributeEvenly_amount * weight / DistributeEvenly_totalweight);
  55         DistributeEvenly_totalweight -= weight;
  56         DistributeEvenly_amount -= f;
  57         return f;
  58 }
  59
  60 float DistributeEvenly_GetRandomized(float weight)
  61 {
  62         float f;
  63         if (weight <= 0) return 0;
  64         f = floor(random() + DistributeEvenly_amount * weight / DistributeEvenly_totalweight);
  65         DistributeEvenly_totalweight -= weight;
  66         DistributeEvenly_amount -= f;
  67         return f;
  68 }
  69
  70 // from the GNU Scientific Library
  71 float gsl_ran_gaussian_lastvalue;
  72 float gsl_ran_gaussian_lastvalue_set;
  73 float gsl_ran_gaussian(float sigma)
  74 {
  75         if (gsl_ran_gaussian_lastvalue_set)
  76         {
  77                 gsl_ran_gaussian_lastvalue_set = 0;
  78                 return sigma * gsl_ran_gaussian_lastvalue;
  79         }
  80         else
  81         {
  82                 float a = random() * 2 * M_PI;
  83                 float b = sqrt(-2 * log(random()));
  84                 gsl_ran_gaussian_lastvalue = cos(a) * b;
  85                 gsl_ran_gaussian_lastvalue_set = 1;
  86                 return sigma * sin(a) * b;
  87         }
  88 }
  89
  90 // prandom - PREDICTABLE random number generator (not seeded yet)
  91
  92 #ifdef USE_PRANDOM
  93         float prandom_seed;
  94         float prandom()
  95         {
  96                 float c;
  97                 c = crc16(false, strcat(ftos(prandom_seed), ftos(prandom_seed + M_PI)));
  98                 prandom_seed = c;
  99
 100         #ifdef USE_PRANDOM_DEBUG
 101                         LOG_TRACE("RANDOM -> ", ftos(c));
 102         #endif
 103
 104                 return c / 65536;  // in [0..1[
 105         }
 106
 107         vector prandomvec()
 108         {
 109                 vector v;
 110
 111                 do
 112                 {
 113                         v.x = prandom();
 114                         v.y = prandom();
 115                         v.z = prandom();
 116                 }
 117                 while (v * v > 1);
 118
 119                 return v;
 120         }
 121
 122         void psrandom(float seed)
 123         {
 124                 prandom_seed = seed;
 125         #ifdef USE_PRANDOM_DEBUG
 126                         LOG_TRACE("SRANDOM ", ftos(seed));
 127         #endif
 128         }
 129
 130         #ifdef USE_PRANDOM_DEBUG
 131                 void prandom_debug()
 132                 {
 133                         LOG_TRACE("Current random seed = ", ftos(prandom_seed));
 134                 }
 135         #endif
 136 #endif