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From: haitex@pnet01.cts.com (Wade Bickel)
Newsgroups: comp.sys.amiga
Subject: Re: Questions about 3-D glasses.
Message-ID: <2467@crash.cts.com>
Date: 2 Feb 88 09:56:07 GMT
Sender: news@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 118


ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) writes:
[ > = Leo,  >> = my earlier posting. >>> = Ranjit Bhatnager) ]
>
>>	     Multi-tasking is stopped here because if another task tries to
>>	take the screen this server (VBlank) will try to take it back.  [ ... ]
>
>	There is no, repeat, NO excuse for disabling multitasking for this
>application.
>

	I'm not "disabling" multi-tasking, and if the user wishes to bring a
     task forward, I can deal with that.  The problem occures if some unknown
     task takes the console.  Short of examining the EXEC lists prior to 
     a screen flip, which I may try to do, I can see no reasonable way around
     this.  I could go to an interlace screen but this would cause problems
     should people which to pop back to CLI, which would then be in interlace.

>>> 	+ use a normal interlace screen, and write left-eye pictures on even
>>> 	lines and right-eye pictures on odd lines.  [ ... ]
>>
>>	      This is out of the question for a number of reasons (some of
>>	 which you point out.  In particular, it messes up the vertical 
>>	 orientation of things just a bit, and of course the drawing functions
>>	 are non-functional.
>>
>	They ARE???  Gee, I guess my 'box' program is working by black magic
>then....
>
	Thanks Leo, I guess it is worth a bit more experimentation.  I've seen	
      your box demo.  Have you seen mine?  I have a program which spins 3-D
      objects (wire frames, soon filled polygons) in 3-space with parallax.
      Just how calculation intesive are your real-time demo's?  We are also
      working on a game which uses tabulated data as opposed to calculated
      perspectives, which is how I suspect your 'box' program works (which
      I have, by the way).

>
>>	There comes a point of diminishing returns for trying to support
>>these features.  [ ... ]
>
>	On the other hand, if you don't support multitasking or Intuition,
>you're going to get flamed to a crisp on the Net and elsewhere for it.
>

	Do people on the Net buy games?  I suppose some do.  I don't intend
      to use intuition simply because I don't need it.  Eventually I may re-
      consider, but for now the graphics system works well enough.  Most
      multi-tasking applications will work, but some user attention may be
      required. 

>	I've written a number of programs utilizing our 3D technology.  The
>most esoteric I've gotten is to use raw ViewPorts and pingpong between them
>using an interrupt routine.  This in no way impedes multitasking; you
>simply can't bring the workbench to the front in this case.
>
	How do you keep your interrupt routine from interfereing with other
      tasks which might also want to claim the sceen?

>	I've written a program that bounces a ball around in a 3D box.  It
>uses an Intuition screen that can be dragged, and uses standard graphics
>calls.
>
>	I've written a 3D viewer for Videoscape 3D objects.  It uses
>Intuition screens, windows, gadgets, layers, and standard graphics calls.
>If the application demanded it, I could have used menus, too.  It multitasks.
>It works.
>
>	Mind you, you have to pull some coordinated tricks, but it's
>doable.

	Care to be a bit more enlightening?

>
>	We'll be using the Sega glasses, but I'm very interested to see
>yours.  Ours should be out Real Soon Now.
>
>	See you on the shelves....			:-)
>

	Good.  Our glasses are much better than the Sega glasses.  We had
      looked at buying 4 different types of glasses, including the Sega
      glasses and decided on the ones we're releasing because they're better.

	If you'd like a pair let me know.  I can (probably) send you a pair
      for free.      
      
>	(Consider this article the friendly posting that it is.  I'm not
>attacking you.  I'm sure you do stuff we don't.)
>

	On the contrary Leo, because of your posting, I will re-examine the
      possiblity of using interlace screens again.  When I did this before
      I had much less Amiga experiance than I now do, so I may have a bit 
      better luck this time.  Clearly if I can do this then supporting both
      intuition and Multi-tasking becomes trivial.  Any clues as to how you
      use the draw() function to draw lines into only half an interlace 
      screen?

	Leo, when you say "We" do you mean UmiCorp or someone else?  As
      I understood it you'd taken the "activision" (??) contract to convert
      some programs.  Are these 3-D?

	Also, I heard a rumor that Nintendo's 3-D glasses products were to
      be indefinitly delayed, particularly due to a lack of good software.
      Have you or anyone else heard anything along these lines?


							Thanks,


								Wade.



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