bumpmappedenvmap.psh

hl2 source code. Do not use it illegal.

ps.1.1

;------------------------------------------------------------------------------
; Environment mapping on a bumped surface
; t0 - Normalmap
; t3 - Cube environment map (*must* be a cube map!)
;
; c0 - color to multiply the results by
; Input texture coords required here are a little wonky.
; tc0.uv <- U,V into the normal map
; tc1.uvw, tc2.uvw, tc3.uvw <- 3x3 matrix transform 
;								from tangent space->env map space
; tc1.q, tc2.q, tc3.q <- eye vector in env map space
;------------------------------------------------------------------------------

; Get the 3-vector from the normal map
tex t0

; Perform matrix multiply to get a local normal bump.  Then
; reflect the eye vector through the normal and sample from 
; a cubic environment map.
texm3x3pad t1, t0_bx2
texm3x3pad t2, t0_bx2		
texm3x3vspec t3, t0_bx2

; result goes in output color (multiply by constant color c0)
mul r0, t3, c0

; The output alpha comes from the normal map.
mov r0.w, t0.a ; don't need this if we aren't alpha blending!