// This file is distributed under a BSD license. See LICENSE.txt for details.

ps.2.0
// material 2.0: light pass (pixel shader)

// flag data layout, constants
flags
	Flags
	_pad[7]
	
	TexFlags[4]
	TexScale[4]
	
	LgtFlags[4]
	LgtScale[4]
	
	SRT1[9]
	SRT2[5]
	ColC[4]
	
	TexUsed[4]
	LgtUsed[4]
	SrcScale[4]
	SrcScale2[4]
	LgtType
endflags

alias   cDiffuse = c0
alias   cSpecular = c1
def     c2,1,0,0,0

// textures and samplers
alias   tTex = t0, sTex = s0, sBump = s1
alias   tAtten = t1
alias   tL = t2
alias   tH = t3
alias   vColor = v0

dcl     tTex.xyzw
dcl     tAtten.xyz
dcl     tL.xyz
dcl_2d  sTex

if Flags[3] // vertex color
  dcl     vColor
endif  

if Flags[0] // specular
  imov    i1,4
  dcl     tH.xyz
else
  imov    i1,3
endif

imov  i2,i1
imov  i3,0
for i=0..1 // bump maps
  if LgtUsed[i][0]
    dcl     t0+i2.xy
    dcl_2d  sBump+i3
    iadd    i2,1
    iadd    i3,1
  endif
endfor

// normal
temp    cDiff,cSpec,L,N0,N
temp    specMap

vmov    N0,c2
imov    i2,i1
imov    i3,0

for i=0..1 // bump maps
  if LgtUsed[i][0]
    temp    map
  
    // load texture
    texld   map,t0+i2,sBump+i3
    
    // accumulate
    if i3 == 0
      vmov    N0,map
      vmov    specMap,map
    else
      add     N0,N0,map
    endif

    // increment steps
    iadd    i2,1
    iadd    i3,1
    free    map
  endif
endfor

// renomalize normal if necessary
if i3 > 1
  nrm   N,N0
elif Flags[5]
  nrm   N,N0
else
  vmov  N,N0
endif

// diffuse
nrm     L.xyz,tL
dp3_sat cDiff.r,L,N
mul     cDiff.rgb,cDiffuse,cDiff.r

// specular
if Flags[0]
  temp    H
  
  nrm     H.xyz,tH
  dp3_sat cSpec.r,H,N
  pow     cSpec.r,cSpec.r,cSpecular.a
  mul     cSpec.rgb,cSpecular,cSpec.r
  
  if Flags[7]
    mul     cSpec.rgb,specMap.a,cSpec
  endif
endif

// material
temp    cTex,color
texldp  cTex,tTex,sTex

if Flags[0] // specular used?
  mad     color.rgb,cTex,cDiff,cSpec
else
  mul     color.rgb,cTex,cDiff
endif

// attenuation: *(1-r^2)
dp3_sat color.a,tAtten,tAtten
mad_sat color.rgb,color,-color.a,color

if Flags[3] // vertex color
  mul   color,color,vColor
endif

mov     oC0,color