tf2/tf2_src/materialsystem/stdshaders/LightmappedGeneric_BumpmappedEnvmap_ps14.psh

; STATIC: "NORMALMAPALPHAENVMAPMASK" "0..1"
ps.1.4
;------------------------------------------------------------------------------
; Phase 1
;------------------------------------------------------------------------------
; Get the 3-vector from the normal map
texld  r0, t0
; Get environment matrix
texcrd r1.rgb, t1
texcrd r2.rgb, t2
texcrd r3.rgb, t3
; Normalize eye-ray vector through normalizer cube map
texld  r4, t4                  ; <---- CUBE MAP here!!!
;mov r0.rgba, r4

; Transform normal
dp3    r5.r, r1, r0_bx2
dp3    r5.g, r2, r0_bx2
dp3    r5.b, r3, r0_bx2
; Reflection calculatiom
dp3_x2 r3.rgb, r5, r4_bx2      ; 2(N.Eye)
mul    r3.rgb, r5, r3          ; 2N(N.Eye)
dp3    r2.rgb, r5, r5          ; N.N
mad    r2.rgb, -r4_bx2, r2, r3 ; 2N(N.Eye) - Eye(N.N)

#if NORMALMAPALPHAENVMAPMASK
; Alpha gets lost after phase marker, so store it here
mov    r5, r0.a
#endif

;------------------------------------------------------------------------------
; Phase 2
;------------------------------------------------------------------------------
; What's left over from the last phase:
; r0 - normal
; r1 - free
; r2 - vector to sample in envmap
; r3 - free
; r4 - normal
; r5 - normal map alpha (rgba)

phase

; Sample environment map
texld  r3, r2

; dot eye-vector with per-pixel normal from r0
dp3_sat	r1, v0_bx2, r0_bx2

; Result goes in output color (multiply by constant color c0)
mul    r0.rgb, r3, c0

; run Fresnel approx. on it: R0 + (1-R0) (1-cos(q))^5 in alpha channel
mul		r1.rgb, r0, r0
+mul r0.a, 1-r1.a, 1-r1.a			; squared

lrp		r0.rgb, c1, r1, r0 ; blend between color and color * color
+mul r0.a, r0.a, r0.a				; quartic

dp3		r1.rgb, r0, c3
+mul r0.a, r0.a, 1-r1.a				; quintic

lrp		r0.rgb, c2, r0, r1			; blend between color and greyscale
mad r0.a, r0.a, c6.a, c4.a			; Take Fresnel R(0) into consideration

mul r0.rgb, r0, r0.a				; multiply output color by result of fresnel calc

#if NORMALMAPALPHAENVMAPMASK
+mul r0.a, c0.a, r5.r				; Fade amount * alpha from the texture
#else
+mov r0.a, c0.a						; Just use the fade amount
#endif