Don’t you just love getting email from your friends.  I am sure that as you read this you may think about past jokes and humerous anecdotes received.

I don’t get many like that, this is what I got from a friend of mine today,

How bout this for a fast invsqrt…

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;

Explanation given here (not for the faint of heartr)

You have to see the explanation and Steve’s right its not for the faint of heart.

So any XNA peeps who stumble along here might you be interested.