Date: Fri, 30 Aug 1996 04:10:32 -0700 (PDT)
From: Samuel Vincent <svincent AT cs DOT sonoma DOT edu>
To: Mike Marcelais <michmarc AT microsoft DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: Allegro and Win95 time-slicing problem ?
In-Reply-To: <01bb95d8$5e3ab180$ba27379d@michmarc2>
Message-ID: <Pine.GSO.3.94.960830040810.17959B-100000@zippy>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On 29 Aug 1996, Mike Marcelais wrote:

> stwand07 AT uctvms DOT uct DOT ac DOT za wrote in article
> <1996Aug29 DOT 185755 AT uctvms DOT uct DOT ac DOT za>...

[snip]

> My guess?  Windows cannot maintain an offscreen SVGA video area, so when a
> request comes in to Windows to draw onto an SVGA screen that someone program
> owns that isn't in the foreground, Windows pauses until the screen is in the
> foreground.  Hence, your simulation runs until it tries to draw on the
> graphics screen which causes the program to halt until it returns to the
> foreground.
> 
> solution: Draw to an offscreen buffer and not the screen.

Wow, an interesting solution.  Unfortunately, his would also have the side
affect that the user would never see anything, ever with the program in
the foreground, unless the programmer copied the offscreen buffer to the
display memory at some point.  At that instant he/she would have the same
exact problem as before.

-Sam