From:	"jakub" <marushka AT ozemail DOT com DOT au>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Allegro demo ship flickers
Date:	Tue, 21 Jul 1998 21:20:29 +1000
Organization:	OzEmail Ltd.
Lines:	35
Message-ID:	<6p1tdc$vir$1@reader1.reader.news.ozemail.net>
NNTP-Posting-Host:	slsdn3p22.ozemail.com.au
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Hi,

When I run the allegro demo game, choosing autodetect 640x480, the ship
flickers. I don't know if this is the right word for it. I can see 2 ships
on top of each other slightly apart, it seems as if I am seeing the last
position of the sprite. This happens when I hold down the left or right
arrow keys to move the ship.

In page flipping mode I get about 37fps, the 'ghosting' effect is most
noticeable here.
Double buffering gives me about 41fps, the effect is still there if only
slightly better.
Dirty rectangles seems to be the best, 220fps, the effect is almost gone,
however the ship still is not completely 'smooth' its a touch jerky. I mean
jerky in its display.

Is this normal?

I have a Pentium Pro 200, 32meg ram, Graphic Blaster MA202 (standard 2meg
card).

I've been trying to write a little space invaders type game using page
flipping, I only have a little blue rectangle sprite for the ship, and have
managed to make it shoot. However it is very flickery or whatever you want
to call it, the bullet is very smooth. But moving the ship, causes this
jerky, ghosting effect.




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