GLOW

THE BOX'S MAIN HELP:

This function generates a glow, 
which falls off at the edges of the object.

DIR (input):

This must be a vector.  The default is the incidence vector.

NORM (input):

This must be a point.  The default is the surface normal.

ATT (input):

This must be a float.  The default is 2.0.
This is the attenuation of the glow off the sides of the object.

GLO (input):

This must be a color.  The default is WHITE.
This is the color of the glow.

OUT (output):

This function returns a glow,
which falls off at the edges of the object.