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 ♥♥♥♥?
       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;
}