From:	ranla AT post DOT tau DOT ac DOT il (Tal Lavi)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Inevitebly slow writes in VESA?
Date:	Sat, 10 Oct 1998 01:56:09 LOCAL
Organization:	Tel-Aviv University Computation Center
Lines:	24
Message-ID:	<ranla.11.0004F5B6@post.tau.ac.il>
NNTP-Posting-Host:	slip-107.tau.ac.il
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

My ray-caster needs only to draw vertical lines in a 16bpp mode. This, 
ofcourse, makes it hard to write a dword in a time.

I have succeeded in rewriting the engine so that he'll calculate two 
vertical scan-lines at once, so they could be drawn on the screen at 
once(I have not calculated each one dependendly, stored them, at then 
drawed them, but actually calculated both simultaniusly).

I am calculating every two CONSECUTIVE veritical scan-lines at once(0&1, 2&3,
etc..), which means that every dword that is written in dword-alligned to the
beginning of the LFB.

To my disapointment, I haven't gained ALLOT more speed, rather than just 
some.

Does anyone has a clue about what could have gone wrong? according to my 
calculations, I should have gained X8 speed.
My guess(which is very improbable), is that the beginning of the LFB is 
not DWord alligned. Can this be true?

Please, don't tell me to post my code, it's much too complicated, and it 
won't do any good.

		Virge		ranla AT post DOT tau DOT ac DOT il

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