Path: chuka.playstation.co.uk!news
From: Tom <tm7130@bristol.ac.uk>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: texture mapping
Date: Mon, 12 Apr 1999 23:52:41 +0100
Organization: PlayStation Net Yaroze (SCEE)
Lines: 29
Message-ID: <37127939.211A@bristol.ac.uk>
References: <7et0hi$j5q2@scea>
NNTP-Posting-Host: p02-puffback-gui.tch.virgin.net
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 2.02E-VN006  (Win95; I)

Owes Beck wrote:
> 
> hey,
>  i have this problem of when i convert a dxf to rsd,  it seems that each
> face of the polygon is broken into 2 triangles, so when i try to put a
> texture on a single face it comes out messed up because it warpes to the 2
> triangles.  is there anyway to simply make a face of the polygon its
> original shape without breaking it to triangles?
> 
> Thanks!

If you're using dxf2rsd then add the quadrangulate (is that a word?) option. I use 
'-quad2 5' myself as this gives a pretty good result. If you're talking about 
warping of a texture in a quad polygon then I'm afraid that there's not much you can 
do about this.

The problem is that the Playstation doesn't do perspective correct texture mapping, 
instead relying on a crude (but speedy) linear interpolation routine (I remember 
writing one for the Acorn years ago). To get around this you tell the Playstation to 
use automatic polygon subdivision (set some of the bits in the attribute part of a 
GsDOBJ structure) which minimises the problem but that's about the best you can do.

I've probably got the wrong end of the stick entirely but I hope I've been of some 
help.


Cheers,

	Tom