From: eglebbk AT phys DOT uva DOT nl (Evert Glebbeek)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Using (page-flipping) to speed up a program
Date: Wed, 05 Jul 2000 16:14:09 GMT
Organization: Physics student, University of Amsterdam
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Newsgroup: comp.os.msdos.djgpp
 From: Damian Yerrick <Bullcr_pd_yerrick AT hotmail DOT comRemoveBullcr_p>
 On Tue, 04 Jul 2000 18:50:27 GMT

>Or switch to VESA modes.  But do all video cards support 16-bit color
>in 320x240?  Or are they designed for Windows business applications?
IIRC, 320x240 16 bit requires the VB/AF driver set. I think it also
works under Windows using DirectX, but I'm not sure.
>RLE sprites _are_ clipped.  Compiled sprites are not guaranteed to be
>clipped or even to be supported on some platforms.
You're right. I thought I didn't use RLE sprites because they can't be
clipped; I don't use them because they can't be flipped.
>screen is undefined if you use create_video_bitmap().
Oh? I can't find reference to this in the Allegro docs and I can't
deduce it from the source either, so this is new to me.
Or do you mean that `screen' isn't nescessarily pointing to the page
currently being displayed? If so, I knew that already... :)
>What you should do in this case is save `screen' in your init code and
>then assign `screen' to whatever page is showing on screen.
I do that already:

page1 = screen;
page2 = create_video_bitmap (SCREEN_W, SCREEN_H);

so I'll just have to do something like
screen = the_active_page;
after a show_video_bitmap()? I'll give it a try. Thanks.

Evert Glebbeek.