Path: utzoo!mnetor!uunet!amdahl!ames!necntc!linus!alliant!lackey
From: lackey@Alliant.COM (Stan Lackey)
Newsgroups: comp.sys.atari.8bit
Subject: Re: 3D on the 8-bits (was Re: Advan Basic)
Message-ID: <1552@alliant.Alliant.COM>
Date: 8 Apr 88 13:33:58 GMT
References: <8804052209.AA25737@ucbvax.Berkeley.EDU> <666@nunki.usc.edu>
Reply-To: lackey@alliant.UUCP (Stan Lackey)
Organization: Alliant Computer Systems, Littleton, MA
Lines: 23

In article <666@nunki.usc.edu> rjung@castor.usc.edu (Robert Jung) writes:
>
>  It was speculated on the net of whether or not 3-D glasses can be used...
>In theory, all you need is a pair of LCD glasses that can switch the lens
>and have that synchronized with two alternating images shown on the screen.
>  From a software point of view, you're probably talking about page-flipping
>the pointers to screen RAM every 1/60th of a second, and sending a signal to
>the glasses (via the joystick port?) to "switch" the glasses around
>accordingly...

You don't even need to do that.  At the end of a display list, there is a
wait-for-vertical-blank-then-jump instruction, with the jump addr normally
being the beginning of the display list.  

This allows the graphics chip to do the alternating.  You would have two 
display lists, one for each of the images,
but instead of the jump at the end of each one being back to its
top, have it point to the top of the other display list.  A DLI at the very 
end of each display list could be used to flip the LCD glasses.  

I have used this technique to get more gray levels, but the image seems a
little flickery.
-Stan