Message-ID: <386E810E.DDD820D@indigo.ie>
From: "B O'Donnell" <odonnllb AT indigo DOT ie>
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Subject: Blitting problem with Allegro
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Date: Sat, 01 Jan 2000 22:34:54 +0000
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

I've had a problem since I started with Allegro which is fairly trivial
but getting increasingly irritating.

When I blit to screen (640*480*256) from a bitmap, short lines of pixels
appear on the screen vertically displaced from their proper position,
and standing out against the background, though, as far as I can tell,
they also appear where they ought - anyway, though my eyes aren't that
good, I can't see any black lines in the blits.

It seems to have got worse since I grabbed another half meg of memory
for a few more sprites, but it was there when I was using  a lot less
memory.

This starts happening after a few dozen (hundreds?) of blits on the same
screen, and I've had the same results whatever programming approach I
try, ranging from munging the source bitmap to point to my graphic and
blitting, to putting every pixel in practically by hand.

I'm also getting two extra mouse cursors stuck on the screen
occasionally, which disappear simultaneously when I redraw a totally
different part of the screen.

My card is an S3 with 2 megabytes of memory, but I don't have this
problem on Linux with svgalib.

TIA
Brian O'Donnell
odonnllb AT indigo DOT ie