Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!iuvax!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!sunb3!mcooper
From: mcooper@sunb3.cs.uiuc.edu
Newsgroups: comp.graphics
Subject: one plane lighting..
Message-ID: <23900011@sunb3>
Date: 24 Aug 90 19:29:00 GMT
Lines: 29
Nf-ID: #N:sunb3:23900011:000:1008
Nf-From: sunb3.cs.uiuc.edu!mcooper    Aug 24 14:29:00 1990


An interesting problems here.  One I've never encountered before.  Using 
an SGI PI, I was adding lighting to some code.  What appears to be happening is 
that the machine itself is ignoring (or setting to zero) any Z component of
any light.  

	Which is to say, if I specify a light as 

	front[] = {POSITION, 1.0, 0.0, 1.0, 0.0, LMNULL};

the machine treats it as:

	front[] = {POSITION, 1.0, 0.0, 0.0, 0.0, LMNULL};


You can see how this might get irrtating.  It IGNORES the default light!
Any light I put at any location outside the Z plain gets projected back
to it!


Any suggestions?


+-------------------------------------+----------------------------------------+
|  "When the going gets weird,        |                                        |
|              the weird turn pro."   |  Marc Cooper	mcooper@cs.uiuc.edu    |
|		  		      |  University of Illinois, C-U	       |
|		 -Hunter S. Thompson  |					       |
+-------------------------------------+----------------------------------------+