Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!spool.mu.edu!agate!mindseye!izumi
From: izumi@mindseye.berkeley.edu (Izumi Ohzawa)
Newsgroups: comp.sys.next
Subject: Re: graphics portability between ns and ns-color
Message-ID: <1991Jun5.091018.21988@agate.berkeley.edu>
Date: 5 Jun 91 09:10:18 GMT
Article-I.D.: agate.1991Jun5.091018.21988
References: <9106050533.AA20158@nextasy2.eecs.wsu.edu> <1669@toaster.SFSU.EDU>
Sender: root@agate.berkeley.edu (Charlie Root)
Organization: /etc/organization
Lines: 27

In article <1669@toaster.SFSU.EDU> eps@cs.SFSU.EDU (Eric P. Scott) writes:
>In article <9106050533.AA20158@nextasy2.eecs.wsu.edu>
>	dwatola@NEXTASY2.EECS.WSU.EDU (David Watola) writes:
>>the problem is that this background color is white on a monochrome system,
>>and black (same as the pen color, unfortunately) on a color system.  why?
>
>Your image has an alpha channel and you're not compositing it properly.
>

In last weeks demo of RenderMan for NeXT at a BaNG DeveloperSIG,
RenderMan was run on NeXTdimension and Monochrome NeXTstation
side-by-side.  It exhibited the same problem.

Now, RenderMan is by Pixar, and Pixar is where the alpha channel
was invented.

So, it is one of the following:
[1] NeXT goofed.
[2] Pixar goofed.
[3] It's a feature of NeXT alpha channel.

My guess is [3].

Izumi Ohzawa             [ 大澤五住 ]
USMail: University of California, 360 Minor Hall, Berkeley, CA 94720
Telephone: (415) 642-6440             Fax:  (415) 642-3323
Internet: izumi@violet.berkeley.edu   NeXTmail: izumi@pinoko.berkeley.edu