Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!mips!daver!versatc.versatec.COM!ritter
From: ritter@versatc.versatec.COM (Jack Ritter)
Newsgroups: comp.graphics
Subject: Re: World Cordinate Resolution
Summary: NOW I remember
Keywords: Accuracy, floating point VS real numbers
Message-ID: <20589@versatc.versatec.COM>
Date: 13 Apr 90 17:22:50 GMT
References: <20582@versatc.versatec.COM>
Organization: Versatec, Santa Clara, Ca. 95051
Lines: 36

In article <20582@versatc.versatec.COM>, ritter@versatc.versatec.COM (Jack Ritter) writes:
> If your're careful about over/under flow, you dont
> need all those exponent bits. What if you define
> your world space span as: -10000 to 10000, for
> example? Does this convert surplus exponent bits
> into additional accuracy bits, or does it just
> make the holes in floating-point-space bigger?
> -- 
From the responses I got, I should clarify what I
mean. I'm talking about standard floating point
arithmetic (whether HW or SW). By 'accuracy bits'
I mean the fixed length mantissa, so the 'conversion'
I refer to is only EFFECTIVE conversion.
  Anyway, before anyone waists any more time on this,
  I remember from school that accuracy is accuracy, whether
  or not you use the exponent's higher bits; the problem
  is mixing very tiny numbers with very large ones,
  which usually dousnt happen in image synthesis
  because most scenes have a 'reasonable' span of scale.
  (Of course certain calculation can always blow up if
  you're not careful, like root finding).


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