From: leathm AT solwarra DOT gbrmpa DOT gov DOT au (Leath Muller)
Message-Id: <199704040234.MAA22528@solwarra.gbrmpa.gov.au>
Subject: Re: Allegro 3D : Sorting Polygons
To: ellman AT xs4all DOT nl
Date: Fri, 4 Apr 1997 12:34:27 +1000 (EST)
Cc: djgpp AT delorie DOT com
In-Reply-To: <5i1541$h1q$1@news0.xs4all.nl> from "ellman@xs4all.nl" at Apr 3, 97 08:49:05 pm
Content-Type: text

> >Painting the items back-to-front.  All you have to do is order
> >the things to be drawn by distance and draw everything.  If
> >there are lots of overlaps, this gets wasteful, since you end
> >up drawing lots of pixels multiple times.  But it's easy to
> >code.
 
> Actually, that's depth sorting. The painter's algorithm is to convert all the
> polygons into a set of polygons that consist of only what is to be displayed.
> It eliminates any hidden polygons, and breaks up any partially-hidden polygons.

No, thats wrong. Painters basically sorts the polygons from furtherest to
nearest and draws them. Overdraw aplenty. Its called painters because it is
just like a painter painting a picture. He paints on top of paint he has
already drawn... the depth sorting occurs because you have to depth sort
the polygons to be able to paint the furtherest to nearest polygons. It
doesn't removed hidden polygons at all........
 
I have never seen a painters algorithm that has what you say it does...

Leathal.