POV-Ray : Newsgroups : povray.newusers : Ignorance rules! : Re: Ignorance rules! Server Time
9 Jun 2023 18:00:44 EDT (-0400)
  Re: Ignorance rules!  
From: William F Pokorny
Date: 26 Jun 2020 08:47:54
Message: <5ef5ee7a$1@news.povray.org>
On 6/26/20 1:43 AM, Thorsten wrote:
> On 24.06.2020 19:53, William F Pokorny wrote:
>> (4) - And, yep. I don't like the DBL, SNGL in our source code since 
>> v1.0. Or the PRECISE_FLOAT Christoph asked me to add to a pull request 
>> years back which then never got adopted. PRECISE_FLOAT now needs to be 
>> yanked at some point from povr and I'd like to drop DBL and SNGL too. 
>> Today you can find the bare 'foat/double' declarations in the source 
>> code depending on who wrote what. This makes it unlikely we can really 
>> ever change DBL to be anything but double, for example. Certainly not 
>> without a lot of type conversions even if, by some chance, everything 
>> works correctly.
> Except, that is not why they are there: DBL is in the source code 
> because there was a time when you could not depend on "double" actually 
> doing what you wanted it to do. A time when certain CPUs had 80 bit 
> floating point numbers, and other odd things with software emulated 
> floating-point. In this world it was essentially that the floating-point 
> representation could be changed. These days are long over, but the code 
> just happens to be so old that it still has these leftovers.

Yes, thanks. A good point.

It's easy to forget while playing with code today that those who created 
POV-Ray were working in a much tougher, unstable environment. Plus we 
now have ready access to so much more information - Wikipedia, papers, 
on line code, etc.

Bill P.

Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.