Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!pacbell.com!ames!sgi!shinobu!odin!bennett
From: bennett@sgi.com (Jim Bennett)
Newsgroups: comp.sys.sgi
Subject: Re: Color mapping problems on the 4D/25TG
Message-ID: <1991Jan2.200729.5620@odin.corp.sgi.com>
Date: 2 Jan 91 20:07:29 GMT
References: <136@tachyon.UUCP>
Sender: news@odin.corp.sgi.com (Net News)
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 23

In article <136@tachyon.UUCP> roger@tachyon.UUCP (Roger Cordes) writes:
>
>    We have a color-map-related problem when our code is executed on the
>4D/25TG: in color map mode, a line drawn using a single color index will
>exhibit a rainbow effect, as though indices in the color map outside the range
>of those we use are being accessed. Obvious possible causes have been
>investigated (bit shift w.r.t current writemask, drawmodes, single/double
>buffer state, onemap vs. multimap, argument/value type checking and
>consistency) and eliminated. The code executes as expected on non-Turbo
>workstations:
>	color(col);
>	move(x1,y1,z1);
>	draw(x2,y2,z2);
>    This line is supposed to be a single color, and shows up as an
>interpolation between entries in another part of the color map.

You need a shademodel(FLAT) on the 4D/25TG to disable color interpolation.

>      | Roger L. Cordes, Jr.        |  Stephen Dedalus Incorporated    |
>      | ...!mcnc!rti!tachyon!roger  |  1150 SE Maynard Road, Suite 100 |
>      | (919) 467-7072              |  Cary, North Carolina  27511     |

Jim Bennett			(bennett@esd.sgi.com)