From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Which is faster? Allegro or Sandmann's LFB
Date:	Mon, 30 Dec 1996 20:23:55 +0000
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Message-ID:	<csZE8NBbTCyyEwhh@talula.demon.co.uk>
References:	<59s2q3$84l AT nuscc DOT nus DOT sg>
	<19961226 DOT 230751 DOT 4975 DOT 3 DOT chambersb AT juno DOT com> <59v0p0$g3j AT nuscc DOT nus DOT sg>
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[Uzi Suicide] writes:
>I ported this to Allegro, using BITMAP *dbuffer, and putpixel to this
>dbuffer, etc.
>
>The result I got was 17fps using my own vbe 2.0 lib, and 7fps using
>Allegro.

There are a couple of things I'd like to point out with regard to that
result. While I won't dispute that highly specialised graphics code will
almost always be faster than a generic lib like Allegro, I don't think
your test was showing Allegro at it's best. Calling putpixel() is very
inefficient for anything more than a single pixel, since it has all the
overhead of a function call, clipping, checking for xor and patterned
draw modes, etc. The _putpixel() function cuts out most of this, but
still has the overhead of supporting bank switching for non-lfb svga
cards. If all you are doing is plotting single pixels to a memory
buffer, try a direct write with dbuffer->line[y][x] = color. If there is
still much difference between that and your code, please send me your
code so I can see where I'm going wrong! :-)

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Ghoti: 'gh' as in 'enough', 'o' as in 'women', and 'ti' as in 'nation'.
 */

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