Sender: bukinm AT SunKEDR30 DOT inp DOT nsk DOT su
To: djgpp AT delorie DOT com
Subject: Re: Allegro and blitting to screen
References: <6onnuh$12p$2 AT oravannahka DOT Helsinki DOT FI>
	<199807212300450430 DOT 00099FEB AT pogwizd DOT tcs DOT uni DOT wroc DOT pl>
From: M DOT A DOT Bukin AT inp DOT nsk DOT su
Date: 22 Jul 1998 10:54:12 +0700
In-Reply-To: "Pawel Kowalski"'s message of Tue, 21 Jul 1998 23:00:45 +0200
Message-ID: <p6tsojuilqz.fsf@SunKEDR30.inp.nsk.su>
Lines: 18
Precedence: bulk

"Pawel Kowalski" <pk AT tcs DOT uni DOT wroc DOT pl> writes:

> I tried Allegro demo to find out what's faster: page flipping of double buffer.
> I was almost sure that the firtst technique is ~1/4 faster. Well, ...:
> 640x480x8       DB - 106fps, PF - 59fps
> 800x600x8       DB - 66fps, PF - 60fps
> 1024x768x8      DB - 39fps, PF - 60fps
> Why PF fps is always the same?

  For smooth animation page-flipping waits for vertical retrace before
switching pages.  When using double-buffering there is no vsync, otherwise
you may see both old and new frames if the whole screen can not be copied
during vertical retrace.

> I tried removing vsync_in() from 
> vesa_scroll(int, int) (djgpp/vesa.c) but with no effect...

  Remove vsync() call in demo game not in library sources.