text: #include <math.h>
  #include <stdlib.h>
  
  float randInF(float min, float max)
  {
      return min + ((float)rand() / (float)RAND_MAX) * abs(min - max);
  }
  
  int randInI(int min, int max)
  {
      return min + (rand() % abs(max - min));
  }
  
  unsigned int randInUI(unsigned int min, unsigned int max)
  {
      return min + ((unsigned int)rand() % (max - min));
  }
  
  float InvSqrt (float x)
  {
      float xhalf = 0.5f*x;
      int i = *(int*)&x;
      i = 0x5f3759df - (i >> 1);
      x = *(float*)&i;
      x = x*(1.5f - xhalf*x*x);
      return x;
  }
  