Path: utzoo!attcan!uunet!snorkelwacker!usc!sdsu!crash!pnet01!wade
From: wade@pnet01.cts.com (Wade Bickel)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 3D-graphics
Message-ID: <734@crash.cts.com>
Date: 19 Nov 89 08:16:05 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 40

PKONTKANEN@cc.helsinki.fi writes:
>
>		I am going to make a program, which uses filled 3D vector
>	graphics with hidden-surface removal. Normal methods - transform and
>        rotation matrices - aren't fast enough for my purposes. I have planned
>	to build a whole city with vector graphics. Can anybody recommend
>	any good books about this subject? Does someboby know better ways
>	to calculate the necessary transformations and rotations?
>		I haven't yet decided what kind of graphics routine to use.
>	It should make possible to move anywhere in arbitrary 3D-world in
>	real time. Does anybody have good ideas how to do this?
>
>					Petri Kontkanen
>
>				                               

          No can do!  If you want to move in arbitrary 3-Space your going to
have to do the algebra.  If nothing in your 3-D world moves you can cut some
big corners, but if the viewpoint is to be able to move to any point and
look in any direction you have to do the math.
          Try developing a fixed point integer system if you want to strive
for speed.  ie:  maintain the fractional part of your coords in the lower ?
bits (2 is good), and use the higher bits to store the whole part of your
numbers.  Note that if you do this, you must shift of excess fractional bits
after a multiply, or shift them in befor a divide.  Note also that it is
possible to use different radix's (positions of the "decimal" point) together,
as long as your program knows what the radix of the results must be, and
provides the proper shifting.
 
          As far as a good text, try Foley & VanDam's (not sure of the
spelling) "Fundimentals of Interactive Computer Graphics", or Newman and
Sproull's "Principals of Interactive Computer Graphics" (McGraw Hill).
 
                                                         Good Luck,
 
                                                                Wade.

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