Path: chuka.playstation.co.uk!news
From: "Alex Herert" <aherbert@ndirect.co.uk>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Collision detection with rotating sprites
Date: Sat, 12 Dec 1998 13:41:01 -0000
Organization: PlayStation Net Yaroze (SCEE)
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Message-ID: <74trtj$1s7@chuka.playstation.co.uk>
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Miles Buzzing wrote in message <01be1ef5$5bfd4ba0$LocalHost@guildfoc>...
>Yes, I've had a go with some broad tests. The method I use is less accurate
>that yours, but probably faster - check a bounding square based on the
>longest axis of the sprite first and then use a more precise bounding
>sphere test (using the anti-christ of fast code - Sqrt).
>
>I like bounding spheres but there is just no quick way to calculate square
>root as far as I can see. Even with a fixed point maths routine I still
>have to perform at least 12+ iterations to get an reasonable approximation
>of sqrt. Has anyone out there found a really quick and dirty way of
>calculating it?


Yep.  Don't bother with any form of sqrt.  Just compare squared values
instead (i.e. square the value you're comparing with).  It don't get much
quicker than that! :)


Herbs