In article <38b609b4@news.povray.org>, "TonyB" 
<ben### [at] panamac-comnet> wrote:

> My concept of patterned lightsources would look like this:
> 
> light_source {Pos 1}
> sphere {0,1 pigment {Blah with filter in some places} scale .0001 
> translate
> Pos}
> 
> This would make the sphere dissapear with antialiasing, and would 
> "pattern" the lightsource, right?

Not quite...that would give the same result as my method would if it 
used a pigment(*) that was the same color along the z axis using the 
use_depth_for_z option. Or if you used a radial pattern centered over 
the light_source(or any other pattern which goes outward from a point 
but doesn't change with distance) with that option turned off.

With use_depth_for_z off, the color of the light at a point would depend 
on the color of the pigment at that point. With it on, it would depend 
on the starting angle *and the distance the light has travelled*. You 
could use a gradient z pattern and turn use_depth_for_z on, and get an 
approximation of the wave behavior of light. The angle on the x and y 
axis's(axii?) would be used for the x and y values, and the distance the 
light has travelled to the evaluation point would be used for z. This 
should be doeable, even with photon mapping.


(*)Another thing I forgot, a pigment would be useable as the color for 
this light, just the pigment keyword would be unnecessary.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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