surface matte
param	float	Ka		1
param	float	Kd		1
local	normal	Nf	0 0 0
initcode 1
	return
code
	return_area
	pushv	I 
	pushv	N 
	normalize
	faceforward
	popv	Nf 
	cpCC	Os Oi 
	pushv	Nf 
	diffuse
	mulFv	Kd 
	ambient
	mulFv	Ka 
	addcc
	pushc	Cs 
	mulC	Os 
	mulcc
	popc	Ci 
	return