Grayger » Pyglet http://www.grayger.com In the pursuit of effectiveness Fri, 03 Sep 2010 14:52:11 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 Bit Hacks http://www.grayger.com/python-eng/bit-hacks/ http://www.grayger.com/python-eng/bit-hacks/#comments Wed, 04 Nov 2009 08:39:06 +0000 grayger http://www.grayger.com/wp/?p=169 I found a short code from pyglet source code. 


def _is_pow2(v):
    # http://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2
    return (v & (v - 1)) == 0

At a glance, I can understand how it works, but I have never devised it!
It is from “Bit Hacks” by Sean Eron Anderson. They are not only beautiful but very useful in graphics libraries.

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