Path: chuka.playstation.co.uk!news
From: Alex Herbert <aherbert@ndirect.co.uk>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: GsGetLw - Anyone?
Date: Thu, 16 Jul 1998 18:36:03 +0000
Organization: PlayStation Net Yaroze (SCEE)
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James Russell wrote:

> Your 3D object is described in local coordinates, and must be transformed into World coordinates,
> and then finally into Screen coordinates before it can be drawn. GsGetLs creates a matrix which will
> perform these two transformations in one go. However, any lighting must be performed using the
> Local->World matrix. You set up the lighting in the GTE with the Local->World matrix.
>
> If you're not performing any lighting, then you can ignore this matrix, but if you want to perform
> lighting, then you call GsGetLws() which will return both the Local->World and the Local->Screen
> matrices. You then set the GTE's lighting parameters with the Local->World matrix (using
> GsSetLightMatrix() ), and the GTE's point transformation parameters with the Local->Screen matrix
> (using GsSetLsMatrix() ).

Ok, I get it!  But, I've just been looking at the dino demo, and that uses the Local Screen matrix in
GsSetLightMatrix(), and GsGetLw (or GsGetLws) is never called.  I am doing the same in my code and
everything looks fine, which is why I asked the original question.  However, my view is static at the
moment.  Will I see adverse effects when I move the viewpoint?  Or will the lights just move with the
view? (i.e.  Is what I'm doing making the lights relative to the view rather than the world?)

Thanks for the help guys.


Herbs