02/04/2003
15-462 Graphics I
22
Shininess Coefficient
•Ls is specular component of light
•r is
vector of perfect reflection of l about n
•v is
vector to viewer
• f is
angle between v and r
•Is = ks Ls cosa f
• a is
shininess coefficient
•Compute
cos f = r ¢ v
•Requires
|r| = |v| = 1
•Multiply
distance term
Higher a is
narrower