ps.1.1
// Decl(t0,	Normal1)
// Decl(t1,	Normal2)

def c0, 1.000, 1.000, 0.500, 0.50
def c1, 0.000, 0.000, 0.250, 0.00
def c2, 0, 0, 0, 0.5
def c3, 0, 0, 0, 0.375	; 3/8

tex        t0      
tex        t1      

add_d2	r0 		,   t0    	,   t1          		;r0 = (t0+t1)/2
mad		r0		, 	r0		, 	c0		, 	c1		;r0.z*= 0.5

; Normalize (2nd order)
dp3_sat	r1     	,   r0_bx2 	,   r0_bx2      		;r1.w = n2
mul     t0.w    , 1-r1.w   	,   c2.w				;t0.w = 1/2*(1-n2)
mul		r0.w	, 1-r1.w   	, 1-r1.w				;r0.w = (1-n2)^2
mad		t0.w	,	r0.w	,	c3.w	,	t0.w	;t0.w+= 3/8*(1-n2)^2
mad		r0		, 	r0_bx2	,	t0.w	,	r0_bx2		

; Convert to [0,1] range
mad		r0		,	r0		,	c0.w	, 	c0.w