From: "DigitalFX" <digifx AT concentric DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Elusive 640x480 mode
Date: Wed, 29 Oct 1997 21:26:50 -0500
Organization: Concentric Internet Services
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References: <34566CDE DOT 6DA4 AT gatech DOT campus DOT mci DOT net>
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To: djgpp AT delorie DOT com
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>I have a question. I use a background bitmap, a bitmap for my player's
>ship, bullets, and asteroids.  I was trying to blit all of the necessary
>bitmaps to a double buffer (after blitting the background, of
>course)...and then after waiting for vsync()....I then attempted to blit
>the entire 640x480 double buffer to the screen.
>
>This seems slow and I had alot of difficulty with it....should it be
>this hard to blit a 640x480 buffer onto the screen? How fast should it
>be? Can you have an extremely FAST game with this technique even though
>you are drawing about 25 objects on the screen (most of them being 70x70
>pixels)??????


Take a look around the web and newsgroups for a technique called 'dirty
rectangles'
It is used in Allegros' demo program (an option, at least) and there USED to
be tutors at www.egerter.com but I'm not sure if they are still there. They
also have morphing and texture mapping/polygon tutors there.