Message-ID:	<386A9193.124D022D@ozemail.com.au>
From:	QarnoS <qarnos AT ozemail DOT com DOT au>
Organization:	Anti-Conservation Foundation of Australia
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Very fast allegro blitting
Lines:	40
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X-Trace:	ozemail.com.au 946508021 210.84.138.60 (Thu, 30 Dec 1999 09:53:41 EST)
NNTP-Posting-Date:	Thu, 30 Dec 1999 09:53:41 EST
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Date:	Thu, 30 Dec 1999 09:56:20 +1100
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Hi all!

It seems that the allegro blit function is the bottleneck in my current
project, so I'm trying to create a faster allegro blit for a memory ->
screen bitmap in 640x480x256 resolution. Since I know what the bitmap
types are, and the resolution, I should be able to cut back on the
overhead of checking bitmap type, etc. This is what I have, so far, but
it crashes with no useful traceback info.

Firstly, this is the function call I'm trying to emulate (buffer is a
620x440x256 memory bitmap):

blit(buffer, screen, 0, 0, 10, 10, 620, 440);

Here's the code:

void fast_blit(BITMAP * buffer) {
     bmp_select(screen);
     for (int y = 10; y < 450; y++) {
         unsigned long address = bmp_write_line(screen, y) + 10;
         memcpy((void *)(address), buffer->line[y], 620);
         }
     bmp_unwrite_line(screen);
     }


Thanks in advance.

-- QarnoS

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