This function returns a color.
The color is the sum of the specular reflection for all light sources
multiplied by the co-efficient Ks and the highlight color HI.
OUT = HI * Ks * specular(faceforward(normalize(NN),II),normalize(-II),rgh).
refer to page 317 in the RenderMan Companion.

Must be a float.  Defaults to 1.0.
This is the co-efficient for the specular function.
It controls the intensity of the returned color.
For best results Ks should range from [0,1].
refer to page 317 in the RenderMan Companion.

This must be a color.  Default is white.
This is the color of the highlight on the surface.
It tints the color returned from the specular function.
refer to page 317 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 NN before shading.
refer to page 317 in the RenderMan Companion.

This must be a vector.  The default is the incidence vector, I.
refer to page 317 in the RenderMan Companion.

Must be a float.
This determines the roughness or shininess of the surface,
by controling the falloff rate of the specular highlights.
refer to page 317 in the RenderMan Companion.

This function returns a color.  
The color is the sum of the specular reflection for all light sources
multiplied by the co-efficient Ks and the highlight color HI.
OUT = HI * Ks * specular(faceforward(normalize(N),II),normalize(-II),rgh).
refer to page 317 in the RenderMan Companion.