sl 1.0

# calculate N dot V for silhouette edges
norm r0, N
norm r1, V
dp3 s0, r0, r1
li s1, 0
li s2, 1
clamp s0, s1, s2

#now, check if (N dot V) < epsilon
li s1, 0.087155
blt s0, s1, 19

#now calculate N dot L, to do shading
norm r1, L
dp3 s0, r0, r1
clamp s0, s1, s2

#set up a fairly wide area of darkness
li s1, 0.240
blt s0, s1, 10

#shade the normal area
li s0, 0.75
mul v0, C0, s0
#liv R v0, 1

#check if we are in a specular highlight
add r0, V, L
norm r0, r0
dp3 s0, r0, N
pow s0, s0, S

#set up a fairly small area of brightness
li s1, 0.85
blt s1, s0, 1
mov v0, C0
#liv G v0, 1
jmp 2

#shade the dark area
li s1, 0.35
mul v0, C0, s1
#liv B v0, 1
ret