POV-Ray : Newsgroups : povray.unofficial.patches : Image-Function different than POV-Ray? Server Time
18 Jul 2024 10:55:17 EDT (-0400)
  Image-Function different than POV-Ray? (Message 1 to 1 of 1)  
From: Tim Nikias
Subject: Image-Function different than POV-Ray?
Date: 23 Oct 2007 06:32:39
Message: <471dcdc7$1@news.povray.org>
Hey there!

I've recently acquired a MacBook Pro and have moved my files over to the 
Laptop and tried rendering there.

However, the image results were different. What I did on the PC was to 
use trace() and sample a heightfield which I generated procedurally 
using rand(), save the traced positions to disk and use them to place 
stones and/or grassblades.

Now, when loading the entire scene into MegaPOV on the Mac, I get spots 
where the heightfield is visible, even though on the PC it is not.

I'm guessing that MegaPOV handles the image-function slighty different 
than the official POV-Ray binary does. I generate it with an average of 
a couple pigments, randomly placed using rand(), but since I can rule 
out that rand() is the origin of the problem (other parts of the image 
rely on it as well and look the same as on the PC), it must either be 
how MegaPOV calculates the average, or how the image-function is converted.

For future images I'd like to know which it is. Currently, I can simple 
re-trace() the heightfield on the Mac, after all, the stones and blades 
aren't required to look EXACTLY like on the PC, but the difference might 
be more visible in other images.

On a side note: shouldn't such changes (if they are known) in behaviour 
in regard to the official sources be documented? When I look at MegaPOV 
docs, I of course see notes about other additions, but I'd otherwise 
expect MegaPOV to render an "official" Source-File just like POV-Ray 
does, not differently. Maybe that's just my oppinion and of course you 
could argue that MegaPOV, being an experimental field for POV-Patches, 
is destined to work slightly different. I'm not against that, I'm just 
wondering and interested in what the general approach is on the 
MegaPOV-Front. :-)


aka "Tim Nikias"
Homepage: <http://www.nolights.de>

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