POV-Ray : Newsgroups : povray.pov4.discussion.general : New camera, or new camera docs illustrations. : Re: New camera, or new camera docs illustrations. Server Time
21 Apr 2024 08:19:59 EDT (-0400)
  Re: New camera, or new camera docs illustrations.  
From: Warp
Date: 27 May 2009 14:30:04
Message: <4a1d86ac@news.povray.org>
clipka <nomail@nomail> wrote:
> Me, I cast my vote for the default-to-square-pixels approach.

  Why? You can *already* do that with the current POV-Ray. There's no need
to add anything new to get the behavior.

> >   Have you taken into account that someone rendering someone else's scene
> > using an aspect ratio different than what the original author intended
> > might end up with an image which either clips out parts of the original
> > image or, worse, shows undermodeled parts which were not meant to be seen?

> This argument is a bit short-sighted: The same could be said about rendering an
> image at a much higher resolution than originally intended by the author -
> which may get you "undermodeled" parts *everywhere*.

  There is a big difference between rendering at higher resolution and
outright clipping big parts of the image out, or adding big parts which
weren't intended to be seen.

> Furthermore, an author cannot pass on his scene's source code and at the same
> hide those undermodeled parts from curious eyes - just a few changes to the
> camera block will reveal them anyway.

  You would have to intentionally tamper with the scene file in order to
destroy the image composition. With an automatic square-pixel assumption
the tampering would be inadverted.

> Even so, as some previous poster mentioned, a possible solution to this issue
> would be to allow the scene author to specify (in the camera settings) how to
> deal with non-matching aspect ratios, by choosing between (e.g.)

>   a) adjust horizontal field of view to fit
>   b) adjust vertical field of view to fit
>   c) enlarge field of view to fit
>   d) reduce field of view to fit
>   e) distort to fit
>   f) enforce aspect ratio

  All of those can be already done with the current version of POV-Ray.

> If complemented with command-line / ini options to explicitly specify a pixel
> aspect ratio, I guess we'd have all aspect ratio issues solved.

  In fact, that can also be done currently, albeit indirectly. You can use
the 'Declare' command-line option to pass values to the scene file. You
can create a camera definition which sets its aspect ratio according to
such an identifier.

                                                          - Warp

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