POV-Ray: Newsgroups: povray.beta-test: How do we want photons { pass_through } to work?: How do we want photons { pass

POV-Ray : Newsgroups : povray.beta-test : How do we want photons { pass_through } to work? : How do we want photons { pass_through } to work?		Server Time 2 Jul 2024 10:45:01 EDT (-0400)

From: clipka
Date: 2 Apr 2010 14:42:16
Message: <4bb63a88$1@news.povray.org>

First, here's bad news:

We have a bug in photons { pass_through }.

The current implementation mechanism is (and apparently has always been) 
causing an "amplification" effect on photons. See 
http://bugs.povray.org/task/93 for an example scene.

Then, there's good news:

I located the error.

There is a piece of code in PhotonTrace::ComputeLightedTexture that 
causes pass_through objects to *both* let the photon pass unaffected 
*and* have a clone of it pass trough it with all effects - transmit & 
filter attenuation, reflection & refraction - the whole smash.

Duh!

Question is, how to fix this thing? Do we just want to suppress 
reflection & refraction but do transmit & filter attenuation? That would 
be my favorite, though according to the documentation only media-based 
attenuation should occur.

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