POV-Ray : Newsgroups : povray.general : Focal Blur banding? : Re: Focal Blur banding? Server Time
30 Nov 2022 05:30:14 EST (-0500)
  Re: Focal Blur banding?  
From: jr
Date: 3 Nov 2022 08:20:00
Message: <web.6363b1305fe6b371c0ce110b6cde94f1@news.povray.org>
hi,

"Shinzo" <zza### [at] gmxde> wrote:
> ...
> My guess is that POVRay calculates the lense sample positions just once for the
> whole image instead of resampling the lens positions for every pixel.

it's open source, so no guessing needed.  ;-)


> If that is the case you might want to change that as it is really sad to see
> those artefacts from Scanline renderers of the 80ties in a real raytracer.
>
> BTW.: Have you thought about changing the RandomNumberGenerator? It seems that
> sometimes in special cases there appear sampling artefacts (Hyperplane
> artefacts) that seem to come from an Linear Congruential Generator (LCG). If
> POVRay uses an LCG-Generator you should think about exchanging it to an
> LCG/XORSHIFT combination or at least to a generator that uses a combination of
> linear-generation and non-linear-generation.

more (unnecessary :-)) guess-work.  I've no idea of POV-Ray's "innards" but am
sure that if you were to post one or more patches providing (measurable)
improvement(s), they'd be looked at + considered.


regards, jr.


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