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Making
Shaders
More
Physically
Plausible
Robert
R.
Lewis
Appeared in "SkiGraph" Western Computer Graphics Symposium
Appeared in Computer Graphics Forum (pp. 1-13)
TR-94-38
ABSTRACT
There is a need to develop shaders that not only "look good", but are more
physically plausible. From physical and geometric considerations, we review
the derivation of a shading equation expressing reflected radiance in terms
of incident radiance and the bidirectional reflectance distribution function
(BRDF). We then examine the connection between this equation and
conventional shaders used in computer graphics. Imposing the additional
physical constraints of energy conservation and Helmholtz reciprocity allows
us to create variations of the conventional shaders that are more physically
plausible.