Comments on: Converting a Number to 4 bytes and vice versa

By: Danny Miller

Danny Miller — Wed, 07 May 2008 16:49:29 +0000

Great post. I was searching Google as I was trying this method when I read about it somewhere else. Glad to see that someone has tried it out and tested it against flash’s built in sqrt… Maybe Adobe should adopt this method when they upgrade.

By: michael

michael — Sun, 14 Oct 2007 17:30:01 +0000

i have also tried to implement the inverse square root func by using a bytearray to map a float to an integer:

public function invSqrt(x:Number):Number { var xhalf:Number = .5 * x;


    var t:ByteArray = new ByteArray();

    t.writeFloat(x);

    t.position = 0;
    var i:int = t.readInt();

    i = 0x5f3759df - ( i >> 1);
    t.position = 0;

    t.writeInt(i);

    t.position = 0;

    x = t.readFloat();

x = x * (1.5 - xhalf * x * x); return x; }

works perfectly, but of course it’s much slower than a simple Math.sqrt() call.

By: joa

joa — Tue, 02 Oct 2007 10:00:19 +0000

I did not. Thank you Mario :)

By: Mario Klingemann

Mario Klingemann — Mon, 01 Oct 2007 19:01:37 +0000

When you write “can not shift because flash doesnt like it…” – did you already try the unsigned bitwise shift ( >>> )?