Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!pasteur!ames!sgi!thant@horus.SGI.COM
From: thant@horus.SGI.COM (Thant Tessman)
Newsgroups: comp.sys.sgi
Subject: Re: (none)
Summary: Colored and lit surfaces
Keywords: SGI
Message-ID: <26217@sgi.SGI.COM>
Date: 6 Feb 89 15:55:43 GMT
References: <27497@bu-cs.BU.EDU> <603@cs-spool.calgary.UUCP>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 34

In article <603@cs-spool.calgary.UUCP>, paquette@cpsc.ucalgary.ca (Trevor Paquette) writes:
> In article <27497@bu-cs.BU.EDU>, tjh@bu-cs.BU.EDU (Tim Hall) writes:
> > We recently got a (Demo model) Personal Iris 4D that has a 32 bit frame
> > buffer and a Z-buffer.  I would like to create a 3-D surface mesh that
> > has a different color at each vertex and is shaded by some lighting model
> > I've defined using lmdef.
> > 
[Stuff deleted.]
> > 
> > So is it the case that interpolation of color and shading are mutually
> > exclusive?
> > 
> > Thanks
> >     Tim Hall
> > Please reply to
> > tjh@dolphin.bu.edu
> 
>   You got it.. I had the same problem as well. 
[Stuff deleted.]
> 
> ==============================================================================
> Trevor Paquette/GraphicsLand, Calgary, Alberta
> UUCP: uunet!{ubc-cs,utai,alberta}!calgary!paquette       ICBM:51 03 N/114 05 W
>                  Luminous beings we are, not this crude matter


The way I've colored a lit surface is by re-lmdef'ing the ambient and diffuse
properties of the current material for each vertex.  You don't have to rebind
the material.  I did this on a GT but it should work fine on a PI as well.

Thant Tessman (thant@sgi.com)

P.S.  There will probably be an even faster and easier way to do this in a 
future software release.