Path: utzoo!attcan!uunet!lll-winken!uwm.edu!zaphod.mps.ohio-state.edu!rpi!masscomp!mark
From: mark@masscomp.ccur.com (Mark Thompson)
Newsgroups: comp.graphics
Subject: Re: A-Buffer source (and plotting lots of triangles)?
Message-ID: <31667@masscomp.ccur.com>
Date: 19 Jul 90 12:13:37 GMT
References: <1990Jul16.225553.2623@maths.tcd.ie> <1264@idunno.Princeton.EDU> <104
Organization: CONCURRENT COMPUTER CORP. WESTFORD MA.
Lines: 24

Reply-To: mark@calvin.westford.ccur.com (Mark Thompson)
Organization: Concurrent Computer Corp. Westford MA.

In article <10491@odin.corp.sgi.com> robert@sgi.com writes:
>I implemented a renderer with a Reyes-like front end, and two scan
>conversion back ends:  scanline Z buffer with 4x4 or 8x8
>stochastically jittered subsamples,  an alpha buffer with 4x4 or
>8x8 masks.
>
>I never was able to fully debug the alpha buffer.
>Because of all sorts of odd boundary conditions, I occasionally
>created incorrect masks.  The Z buffer was much simpler to code (about
>1/7th the size of the alpha buffer), and worked flawlessly from the beginning.
>
>The two algorithms produced almost identical images.

I'll bet those images weren't identical when rendering piles of
overlaping partially transparent objects!
+--------------------------------------------------------------------------+
|  Mark Thompson                                                           |
|  mark@westford.ccur.com                                                  |
|  ...!{decvax,uunet}!masscomp!mark   Designing high performance graphics  |
|  (508)392-2480                      engines today for a better tomorrow. |
+------------------------------------------------------------------------- +