This function returns a color.
The color is the sum of the contributions of all the light sources
on the surface multiplied by the co-efficient and the surface color.
OUT = CS * Kd * phong(faceforward(normalize(NN),II),II,exp).
refer to page 316 in the RenderMan Companion.

Must be a float.  Defaults to 1.0.
This is the co-efficient for the phong function.
It controls the intensity of the returned color.
For best results Ks should range from [0,1].
refer to page 316 in the RenderMan Companion.

Must be a color.  This is the surface color.
It tints the color returned from the phong function.
refer to page 316 in the RenderMan Companion.

Must be a normal.  The default is the surface normal, N.
This is the normal of the surface point to be shaded, P.
If the surface point P has been changed, calculatenormal(P)
should be used to recalculate N before shading.
refer to page 316 in the RenderMan Companion.

Must be a  point.  The default is incidence vector, I.
refer to page 316 in the RenderMan Companion.

Must be a float.
It is the exponent which determines the falloff rate of the highlights.
The larger the exponent, the shinier the surface appears.
refer to page 316 in the RenderMan Companion.

This function returns a color.
The color is the sum of the contributions of all the light sources
on the surface multiplied by the co-efficient and the highlight color.
OUT = CS * Ks * phong(faceforward(normalize(N),I),normalize(-I),exp);
refer to page 316 in the RenderMan Companion.