Path: chuka.playstation.co.uk!news
From: yaroze@theburrow.co.uk (Barry & Robert Swan)
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: Environment Mapping
Date: Sun, 28 Mar 1999 01:42:39 GMT
Organization: PlayStation Net Yaroze (SCEE)
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On Sat, 27 Mar 1999 15:10:32 +0000, Harvey Cotton <hc054@mdx.ac.uk>
wrote:

>Can anyone help me with implementing environment mapping? I asked this
>a while back and I got some help, but I've still been unsuccessful.
>I've tried looking this topic up on the net, but found nowt. I know
>the basics of the technique but I don't fully understand how you
>go about applying a texture around an object. Any help with this would
>be greatly appreciated.
>
>Also, can anyone recommend any good 3d books? I'm looking for a graphics
>book that covers engines and effects (featuring environment mapping
>amongst other things) and something with a bit of C code in as well.
>I will be using the book for research.
>-- 
>Cheers   |  E-mail: hc054@mdx.ac.uk
>Harvey   |  ICQ: 4269478
>

hmm, I havent done this but just doing mapping around one axis is
pretty simplistic. as long as you know how to alter the uvs of a tmd
during runtime, then (lets asusme the Y plane mapping) calc angle
between viewing angle and vertex normal (after model rotation etc,
etc) This angle will most likely be between 0-ONE (if calcs using PS
units which it should). this value then needs to be mapped to fit in a
texture, ie lets use a nice 256 wide one, and then alter the u coords
for any poly that uses that vertex accordingly. The v pos could be set
beforehand and not need changing (if only doing one plane env mapping)
otherwise you would repeat same thing to alter v coords. 

Of course, you need to do this on a vertex by vertex process, which I
assume could be quite timeconsuming if you were to do lotsa polys etc,
etc