Path: chuka.playstation.co.uk!news
From: Chris Chadwick <xjk18@dial.pipex.com>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Sprite Z Ordering
Date: Wed, 23 Apr 1997 01:17:55 -0700
Organization: PlayStation Net Yaroze (SCEE)
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Alex Amsel wrote:
> 
> On Tue, 22 Apr 1997 03:54:33 -0700, Chris Chadwick
> <xjk18@dial.pipex.com> did quoth at me:
> 
> >Also, why are GsOT_TAGS defined as two bit-fields (unsigned p:24 and unsigned char num:8)?
> >I thought just a normal (32bit) pointer would be used - although I suspect this has something to
> >do with the three CPU logical address spaces used to map the 2MB of physical memory (maybe!?).
> 
> 24 bits for the pointer and 8 bits for the number of long words of
> data to follow (0 is allowable here, and is the number at the start of
> each gradation). The primitive data is then just linked in. Each
> primitive has a code followed by appropriate data basically. You could
> probably work them out quite quickly by doing a bit of testing. Unless
> you want to draw poly data straight off then you won't need to use
> them directly, although I did request the information was released (up
> to Sony).
> 
> >Sorry, but I had never heard of Ordering Tables until I got my Yaroze (there, I've admitted it :)
> >All the details please someone!
> 
> Ordering Tables are very standard in 3D graphics - check out various
> books for implentations and variations.
> 
> Anything by Foley et al. is always good, especially:
> 
> Computer Graphics: Principles and Practice by Foley, van Dam, Feiner
> and Hughes. ISBN 0-201-12110--7
> 
> * Alex Amsel * Into Beyond Web Design & JAVA Programming *
> * http://www.intobeyond.com  *  WWFC Utter Rubbish 1996-7*
> MM - "Steve Corica is every bit as good as that Kinkladze"

Hi Alex and thanks for the info! My last posting was probably a bit
misleading - I do understand the principle of OT's, it's just
that I wanted to know the details of how they are actually implemented.
I did *try* stepping through some code and examining memory using the
CodeWarrior debugger ( it'll be great when it's finished :-( ) but that
proved to be an exercise in futility...

I'll certainly try and get my hands on the book you mention but please
let me know if it would require me to be able to read and understand
complex algebra equations because I'm lacking a bit in that area... ahem!.

Cheers

Chris