#qwe_asd

[zezah]

Fast inverse square root

code tag: float Q_rsqrt( float number ) { long i; float x2, y; const float threehalfs = 1.5F; x2 = number * 0.5F; y = number; i = * ( long * ) &y; // evil floating point bit level hacking i = 0x5f3759df - ( i >> 1 ); // what the fuck? y = * ( float * ) &i; y = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration // y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removed return y; } https://highlight.hohli.com/index.php:

float Q_rsqrt( float number )

{

  long i;

  float x2, y;

  const float threehalfs = 1.5F;

   x2 = number * 0.5F;

  y  = number;

  i  = * ( long * ) &y;                       // evil floating point bit level hacking

  i  = 0x5f3759df - ( i >> 1 );               // what the fuck? 

  y  = * ( float * ) &i;

  y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration

//  y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

   return y;

}