"And" <49341109@ntnu.edu.tw> wrote:
>
> A more subtle details is that the light_color usually not the same.
> the color of POV-Ray light_source describes the color of the illuminated object.
> the color of looks_like object describes the color of (sun) itself. The sun
> color often much brighter than the object it illuminates.

I show you the calculation:
The angular diameter of the Sun is about 1/2 degree, so the solid angle of it is
about 0.00006 steradian viewed from Earth. If the luminance of the Sun is
sun_color, than the illuminace of the sun light is sun_color*0.00006, then the
luminance of the reflect surface will be sun_color*0.00006*surface_albedo/pi, so
you should set the color of the POVRay's light_source sun_color*0.00006/pi.
On the other hand, if you set the light_source color A, than the looks_like
color will be A*pi/0.00006 ~= A*52333.

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