Transform luminosity (Watt) to be usable in shader

Question

I'm studying the color and the Luminosity of Stars. I'm trying to figure how to transform information of Luminosity i perceive at a given distance to something usable into a shader. For instance , Given the Radius and temperature of a star, with inversed square law on Distance(meters) i obtain the perceived luminosity of a star in Watt (brut force, without any scattering). For sample, the luminosity I obtain for the Sun ON Earth is about 1361W and a RGB color about

w=1361    
r=255 g=245 b=242

Astronomical and physics are quite OK, but how to transform this values into usable shader formulas or values? best practices ? samples ?

I guess i will simply take the aboves value as Light reference an normalize the intensity(1361) to be 1 on each rgb componemt value. I' ll keep you posted.

Answer 1

One formula that you can play around with is the inverse square law for light fall-off at a given distance. In a virtualisation the inverse square law can often give a light that just seems a bit too bright and keen.

A brighter way to work out the fall-off in light intensity is this watering down of the formula:

NewIntensity = Original Intensity
               ------------------------------
               K1 + K2Distance + K2Distance^2

where K1, K2, and K3 are constants we can attune to give the best results. This tends to give a better looking model.