Newsgroups: comp.sys.sgi
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!sun1.ruf.uni-freiburg.de!ra
From: ra@sun1.ruf.uni-freiburg.de (Christoph Ramshorn)
Subject: Gouraud shading bug(?) on 4D20G under 3.3.2
Message-ID: <1991Apr17.205152.21270@sun1.ruf.uni-freiburg.de>
Organization: Rechenzentrum der Universitaet Freiburg, Deutschland
Distribution: comp
Date: Wed, 17 Apr 91 20:51:52 GMT
Lines:       25



	We recently upgraded to 3.3.2 on our 4D20G and have a problem with
Gouraud shading since: some triangles are rendered in green or magenta hues
regardless of their actual color; the edges of those triangle edges are colored
correctly, though.  Which triangles show those wrong colors depends on light
source position (infinitely distant lights used), but the effect does not seem
to follow any rule. This bug(?) is also observable the "flip (martini, x29,
etc.)" demos.

	From hinv:
	1 12 MHZ IP6 Processor
	FPU: MIPS R2010A/R3010 VLSI Floating Point Chip Revision: 1.5
	CPU: MIPS R2000A/R3000 Processor Chip Revision: 1.6
	...
	Graphics board: GR1.1 Bit-plane, Z-buffer options installed

Any bug fixes, workarounds, suggestions available? We'd really appreciate...


Christoph Ramshorn, Geologisches Institut, Albertstr.23-B
D-7800 Freiburg i.Br., West Germany
ra@trias.geologie.uni-freiburg.de
Phone +49 761 203 2408  Fax +49 761 203 2463