Subject: more on scan-line renderer & copying

From: [email-masked] (Lance Norskog)
Date: Tue, 17 Mar 92 19:37:49 PST

Now I remember what I meant!  If you're doing double-buffering,
and using a scan-line renderer, and track parts of the screen
that need to be updated, you can OR the last two update regions
together and repaint those on the T-2 buffer that you're about
to reuse.  So, you don't repaint the backbuffer completely, and
you don't copy a fixed background from somewhere.  

This only works with a fixed viewpoint.

Lance Norskog

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From: Dave Stampe-Psy+Eng <dstamp@watserv1>
Date: Wed, 18 Mar 92 00:39:21 -0500

> From [email-masked] Tue Mar 17 22:37:38 1992
> From: [email-masked] (Lance Norskog)
> To: dstamp@watserv1, rend386@sunee
> Subject: more on scan-line renderer & copying
> 

Unfortunately, this actually takes longer than just drawing once
you've done all the rest of the scanline stuff... you can use
really optimized VGA code once the scanline has produced the spans.
Or you just rewrite some of the polys w/o clearing the buffer at all
(background is just a big poly...) but tracking is kinda hard to do.
Determining the update map is the hard part...

- Dave STampe