POV-Ray : Newsgroups : povray.bugreports : Bug or Missing Feature: Image Duplicate : Re: Bug or Missing Feature: Image Duplicate Server Time
21 Oct 2021 07:34:17 EDT (-0400)
  Re: Bug or Missing Feature: Image Duplicate  
From: clipka
Date: 6 Jan 2016 18:37:32
Message: <568da53c@news.povray.org>
Am 06.01.2016 um 19:36 schrieb Sven Littkowski:
> Hi, and thanks. Yes, I know about the "+c" parameter. But usually, I see
> an unfinished image in that folder.

No you don't. Not with 3.7.

You used to see that with 3.6, because it supported progressive file
output: It simply created the output file when it started the render,
wrote the header, added data as the render progressed pixel line by
pixel line, and finally added the finishing touches to the file after
the render finished. (It should be noted that if the render aborted,
technically the output image was usually broken; it just so happens that
most image file formats are quite robust to this type of damage, and
allow the written portions of the file to be salvaged.)

In 3.7, progressive file output is no longer that easy to implement,
because render results no longer come in sequentially line by line, but
rather block by block in a somewhat random fashion. To maintain a
partially finished output image and keep it up-to-date with every
finished block, you'd have to roll back portions of the written image,
and re-write them (a feat that isn't supported by most image output
libraries), or discard the image and rewrite it from scratch (which also
has various drawbacks).


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