Path: utzoo!news-server.csri.toronto.edu!rutgers!usc!jarthur!nntp-server.caltech.edu!nyet
From: nyet@nntp-server.caltech.edu (prof. n liu)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Paradise VGA: Two video pages?
Message-ID: <1991Mar12.215005.1383@nntp-server.caltech.edu>
Date: 12 Mar 91 21:50:05 GMT
References: <1991Mar6.101436.1@vortex.rti.org>
Organization: California Institute of Technology, Pasadena
Lines: 33


efricha@vortex.rti.org (Eric F. Richards) writes:


>	I have a question regarding paging using the Paradise VGA
>Professional video card.

>	I am trying to create two separate read/write pages so that 
>I can rapidly switch between two mode 12h (640X480 16 color) images.  
>This support is provided in Microsoft C 5.1 for video modes of lower
>resolution by the _setvisualpage and _setactivepage functions.  I want 
>to be able to write to the non-visible page and then make that page the 
>visual one so it looks like the picture was drawn instantly.  This action 
>would be repeated for several images to give a "motion picture" effect.

>	Can this be done?  How?  Please don't skip details since
>I have never tried this before.

>	Please send replies to richarde@eglin.af.mil -- I'll summarize
>if there is enough (or any :-)) interest.

Actually, I am interested too, since mode 12h is a standard VGA mode
This standard also sets the available pages to, guess what, 1 page.
Is there some reason why there is no support for more pages in VGA modes
for SVGA cards with adequate memory? Hell, paradise found reason not to have
a 800x600x256 mode on its 512k cards. Weird.

I take it as a sign that most games (note: animation extensive) only use
320x200x(16 or 256, two pages) or 640x400x16(EGA, two pages).

nye

respond to: nyet@cobalt.cco.caltech.edu