TonyB skrev i meldingen <380b0b0f@news.povray.org>...
>Is it like an image map? What is it really on the inside of UVPOVs little
>brain? Is it 3D, is it 2D? Where does it come from? What is a photon map
>exactly? (Don't worry about speaking some C, I can read it.)
>
>Thanks in advance for your replies.
>
>

I don't know if this really belongs here, but anyway. Short Answer: You can
read the documentation of uvpov, a file called photons.htm.

Longer:
A photon map is created by shooting imaginary photons from the light source
and see how they interact with objects in the scene. Usually, povray uses
*backward* raytracing, following photons the wrong way. But them you cannot
simulate caustics or light reflecting around corners et.c. Therefore, photon
mapping shoots rays the other way, thus making an approximation of what it
might look like in the real world. Forward ray-tracing is a very
time-consuming process, and photon mapping requires a lot of memory.

Summary: Photon mapping is a hybrid of backwards and forwards raytracing,
simulating some of the light cast in the "correct" direction.

Anyone?

Simen.

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