Path: chuka.playstation.co.uk!news
From: Alex Herbert <aherbert@ndirect.co.uk>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: GsLinkObject4 Confusion - On to GsSortObject4
Date: Mon, 31 Aug 1998 19:52:39 +0000
Organization: PlayStation Net Yaroze (SCEE)
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Gerrit Goossen wrote:

> Actually, that was the answer I was *hoping* for!
>
> Just to offer a different point of view: For what I'm trying to do, that
> setup would be *extremely* inefficent.
>
> In a project I've been working on for a while now, I maintain a single
> large model of the game-world and dynamically build a TMD with a subset
> of the large model's primitives at runtime. This would not be possible
> if:
>
> 1) Every vertex in the original world model were rotated every frame.
> Which, furhtermore, would use *lots* more RAM, because the libs would
> have to maintain a separate copy of the rotated vertex array (to avoid
> nasty fixed-point rounding errors.)

It would only need to keep the rotated vertices until all the primitives for that
object are sorted.  I don't see how fixed-point rounding errors come into it.

> 2) I had to rebuild a the vertex array everytime I create a mini-model
> from the big one.

I'm sure it would be faster to do that than rotate each vertex numerous times.

> >Ho hum...  I need direct GTE access and the ability to sort 2D primitives, and I
> >need it NOW!

> I actually spent quite a bit of time trying to access the GTE with
> inline ASM in CW, but for some reason CW doesn't want to let me do it! I
> wonder if this is also a problem with GCC, although it doesn't really
> matter since I'm on a Mac anyway...

I wasn't that serious when I said that, as I do want my stuff to stand a chance of
getting on a demo disc.  I'm just disappointed that the only way to draw polys is
with the inefficient GsSortObject4().  I was just in one of my big headed "I could
have done it better myself" moods. :)

Herbs