ch24p2_toonshadersilo.vs

游戏开发特殊技巧-special.effects.game.programming

vs.1.0

; ===========================================================================
;
; This vertex shader computes position, diffuse color (pass-thru), and two
; texture coordinates... one for the shade texture and one for the siloheutte
; (edge) texture.
;
; c0,c1,c2,c3		= combined world/view/proj matrix
; c4				= light position
; c5,c6,c7,c8		= world/view matrix
; c9                = constants (0.5,??,??,??)
;
; ===========================================================================


m4x4    r0,      v0,    c5           ; r0 = View space position
m3x3    r1,      v1,    c0           ; r1 = View space normal
m4x4    oPos,    v0,    c0           ; Spit out projected position


dp3     r2.x,    r0,    r0           ; Normalize r0 (position)
rsq     r2.x,    r2.x	  
mul     r0,      r0,    r2.x

dp3     r1.w,    r1,    r1           ; Normalize normal
rsq     r1.w,    r1.w
mul     r1,      r1,    r1.w

dp3     oT0.x,   r1,    c4			 ; l dot n = shade tex idx


dp3     r3.x,    r0,    -r1           ; Compute dot product
mad     oT1.x,   r3.x,  c9.x, c9.x   ; Scale to [0,1] and store as tex idx



mov     oD0,     v4					 ; diffuse color = v4 (pass-thru)