On Tue, 7 Dec 1999 19:10:16 -0500, "TonyB"
<ben### [at] panamaphoenixnet> wrote:

>>...and virtual light sources, global ilumination maps
>
>??? Explain how triangles make this possible.

For a virtual light source approach to rendering caustics, there are
three step:

1. Find the mirror image of each light source in the plane of each
triangle of the object(s) that will generate the caustics. This is
done only once, after parsing is done and before rendering.

2. For each point you want to calculate the caustics for, see how many
of those virtual light sources are visible through their respective
triengles, i.e. if the ray from the point in question to the virtual
source passes through the triangle

3. Sum up and do a weighted average of the results

One of the papers I read about radiosity and using a global
ilumination map described a similar approach. I don't recall specifics
but basically the approach was to build the illumination map of an
object using UV mapping and global ambient lighting was then done
similar to environment mapping.

Another very good use of fully tesselated objects is relatively easy
collision detection.


Peter Popov
pet### [at] usanet
ICQ: 15002700

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