Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: shade@dragonshadow.com (Scott Cartier)
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Using same model with multiple textures and CLUTs
Date: Tue, 02 Nov 1999 19:39:07 GMT
Organization: SCEA News Server
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Here's the situation.  I have a model upon which I map a single 4-bit
texture.  I want to be able to have several of these objects on the
screen at the same time, each with a different texture.  Also, to
increase variety, I want to be able to have multiple CLUTs for each
texture.

So my program should conceivably display the same model using textures
A and B, and if I have two models using texture A I want to be able to
have them use CLUTs X and Y.

I want to do this with a minimum of per frame computation.  Meaning I
want to set up as much as possible beforehand to reduce the work each
frame.

What is the best way to do this?

With sprites it's easy since there are fields in the GsSPRITE
structure to allow you to point to different textures/CLUTs.  However,
with TMDs the texture/CLUT information is stored in each polygon of
the model.  So I get the feeling that the only way to use multiple
textures/CLUTs (without having multiple copies of the model) is to
traverse the TMD, altering each polygon to point to the texture/CLUT
it needs.  This has to be done for each object, and since this needs
to be done every frame, it eats into computation time.

Does anyone know a way to get around this?

Scott