Warp wrote:
>  The only defect of area_light is that it only affects shadow testing and
>nothing more. This means that diffuse and specular lighting will still be
>the one of a point light. (I'm not saying this is a good thing; it's just
>the way it's currently implemented.)
>  It might be possible to take into account the area_light settings when
>calculating diffuse and specular lighting. Perhaps someone will try a
>patch in the near future?

I would love to give a try...
All that I miss is couple of hints.

Follow me a bit and tell me if I'm heading wrong:

1. Povray shoots a single ray toward an area light to determine light color
(emission?) and multiple rays to determine blocking?

If I'm correct, this means that povray attenuates the color of the light
multiplying it by the blocking factor?
 Something like:
L = Lmax x (fraction of area light blocked)

this also means that only one light vector is taken into account when
calculating the lighting at the surface?

Browsing the sources seems to support this theory....
If I'm correct, the Diffuse function gets called in order to gather light
from sources, it calls do_light, which calls block_area_light.
block_area_light calculates the shadow fraction, using multiple rays.
However Diffuse_One_Light (called from Diffuse) uses the original light
vector only.

It seems to me that two avenues are open:
1. Use a single-ray to sample both color and shadow, leading to the need of
many pixel samples
2. Use a specialized version of Diffuse_One_Light which uses each one of the
shadow rays to calculate lighting

Comments?

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