POV-Ray : Newsgroups : povray.general : Just musing about a pattern function... Server Time: 25 Jun 2019 20:26:28 GMT
  Just musing about a pattern function... (Message 11 to 11 of 11)  
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From: Alain
Subject: Re: Just musing about a pattern function...
Date: 22 Mar 2019 20:07:09
Message: <5c95406d$1@news.povray.org>
Le 19-03-21 à 20:49, Bald Eagle a écrit :
> clipka <ano### [at] anonymousorg> wrote:
> 
>> Because then POV-Ray has to shoot secondary rays (for shadow tests, or
>> reflections and/or refractions depending on material), and decide
>> whether or not to consider that other surface for this purpose: Is it
>> /genuinely/ coincident or just extremely close?
>>
>> That's where the true can of worms is opened.
> 
> Well, yes, I didn't think that there wouldn't be a string of complications in
> the ideal implementation - but a simple "if a ray from the camera intersects
> only one object then assign the designated material, if it intersects both
> objects, then assign the designated third material (which may be the same as
> either of the previous)" would at least be useful for highlighting some overlaps
> in CSG, and could give rise to some hard-to-envision effects that might make a
> useful artistic tool.
> 
> And I suppose that part of the implementation could be an option Epsilon value
> to override the usual 1E-06 distance...
> 
> Like I said, it was just something that popped into the noggin before I even
> really woke up.
> 
> 

The problem it that it may be impossible to differentiate between «there 
is only one surface at this location» and «there are two surfaces at the 
same location».


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