EnigmA Amiga Run 1997 July/EnigmA AMIGA RUN 20 (1997)(G.R. Edizioni)(IT)[!][issue 1997-07 & 08][EAR-CD IV].iso/lightwave/lwmlist/94.lightwave-09/000445_owner-lightwave-l _Thu Sep 15 16:04:09 1994.msg

Internet Message Format | 1994-10-01 | 2KB

Return-Path: <owner-lightwave-l>
Received: by mail.netcom.com (8.6.9/Netcom)     id PAA10689; Thu, 15 Sep 1994 15:35:29 -0700
Received: from nova.unix.portal.com by mail.netcom.com (8.6.9/Netcom)     id PAA10631; Thu, 15 Sep 1994 15:35:16 -0700
From: [e-mail]
Received: from hobo.corp.portal.com (hobo.online.portal.com [156.151.5.5]) by nova.unix.portal.com (8.6.7/8.6.5) with ESMTP id PAA24699 for <[e-mail]>; Thu, 15 Sep 1994 15:35:25 -0700
Received: from localhost (pccop@localhost) by hobo.corp.portal.com (8.6.4/1.64) id PAA02890 for [e-mail]; Thu, 15 Sep 1994 15:35:23 -0700
To: [e-mail]
Subject: Re: Antialiasing
Lines: 17
Date: Thu, 15 Sep 94 15:35:23 PDT
Message-ID: <[e-mail]>
X-Origin: The Portal System (TM)
Sender: [e-mail]
Precedence: bulk
Reply-To: [e-mail]

>Stuart's explanation is the clearest (and most difficult).  But now I'm
>wondering whether the threshold test is based on the green level, which
>is what the manual says, or on something more like luminence, which is
>what Stuart hinted at.

   I wondered the same thing, so I did a quick experiment. I made a single
square polygon, made it 0,0,255 blue, put it at 45 degrees, and rendered
with low anti-aliasing. The adaptive sampler found the edge between the
blue poly and the black background with no problem. Same thing if the
object is red. I checked, and the rendered image of the object was 0 green
in both cases, so if green was the only thing being checked, the 0 green
of the object should not have read as different from the 0 green of the
background. Seems that it is really checking some sort of combined
luminance value, not just green.

     <ELF> - Eric J Fleischer,MD - Dr Gandalf
     [e-mail]