; Versioned authored lighting, RGB shading and exact occlusion traversal.
.code
InitLightingSystem PROTO
BakeMapLighting PROTO
UpdateDynamicLights PROTO
AddLightSource PROTO :DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD
SpawnExplosionLight PROTO :DWORD,:DWORD
SpawnMuzzleFlashLight PROTO :DWORD,:DWORD
CastLightRay PROTO :DWORD,:DWORD,:DWORD,:DWORD
ComputeWallLightLevel PROTO :DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD
ComputeSpriteLight PROTO :DWORD,:DWORD,:DWORD
SamplePointLighting PROTO :DWORD,:DWORD,:DWORD,:DWORD
LightCellFree PROTO :DWORD,:DWORD
RefreshLightGrid PROTO

ValidateLightingData PROC uses ebx ecx edx esi, settings:DWORD,sources:DWORD,count:DWORD
    mov esi,settings
    cmp DWORD PTR [esi],2
    ja vl_invalid
    cmp DWORD PTR [esi+4],255
    ja vl_invalid
    cmp DWORD PTR [esi+8],1
    ja vl_invalid
    cmp DWORD PTR [esi+12],32
    jb vl_invalid
    cmp DWORD PTR [esi+12],2048
    ja vl_invalid
    cmp DWORD PTR [esi+16],255
    ja vl_invalid
    cmp DWORD PTR [esi+20],1
    jb vl_invalid
    cmp DWORD PTR [esi+20],96
    ja vl_invalid
    cmp DWORD PTR [esi+24],1
    jne vl_invalid
    cmp DWORD PTR [esi+28],0
    jne vl_invalid
    cmp count,13
    ja vl_invalid
    mov ecx,count
    mov esi,sources
vl_source:
    test ecx,ecx
    jz vl_valid
    cmp [esi].LightSource.x,2048
    jae vl_invalid
    cmp [esi].LightSource.y,2048
    jae vl_invalid
    cmp [esi].LightSource.radius,1
    jb vl_invalid
    cmp [esi].LightSource.radius,2048
    ja vl_invalid
    cmp [esi].LightSource.intensity,255
    ja vl_invalid
    cmp [esi].LightSource.curIntensity,255
    ja vl_invalid
    cmp [esi].LightSource.lightType,1
    jbe vl_type_ok
    cmp [esi].LightSource.lightType,4
    jne vl_invalid
vl_type_ok:
    mov eax,[esi].LightSource.flags
    and eax,0FFFFFFF8h
    jnz vl_invalid
    test [esi].LightSource.color,0FF000000h
    jnz vl_invalid
    add esi,40
    dec ecx
    jmp vl_source
vl_valid:
    mov eax,1
    ret
vl_invalid:
    xor eax,eax
    ret
ValidateLightingData ENDP

InitLightingSystem PROC uses eax ecx edi
    mov lightingMode,0
    mov ambientLightLevel,40
    mov isFlashlightOn,1
    mov flashlightRadius,384
    mov flashlightIntensity,240
    mov flashlightConeAngle,45
    mov authoredLightCount,0
    mov lightingTick,0
    mov edi,OFFSET lightSources
    mov ecx,MAX_LIGHTS*10
    xor eax,eax
    rep stosd
    mov edi,OFFSET lightGridRGB
    mov ecx,MAP_SIZE
    mov eax,00282828h
    rep stosd
    call RefreshLightGrid
    ret
InitLightingSystem ENDP

CommitLightingData PROC uses eax ecx esi edi,settings:DWORD,sources:DWORD,count:DWORD,rgb:DWORD
    call InitLightingSystem
    mov esi,settings
    lodsd
    mov lightingMode,eax
    lodsd
    mov ambientLightLevel,eax
    lodsd
    mov isFlashlightOn,eax
    lodsd
    mov flashlightRadius,eax
    lodsd
    mov flashlightIntensity,eax
    lodsd
    mov flashlightConeAngle,eax
    mov esi,sources
    mov edi,OFFSET lightSources+40
    mov ecx,count
    mov authoredLightCount,ecx
    imul ecx,10
    rep movsd
    mov esi,rgb
    mov edi,OFFSET lightGridRGB
    mov ecx,MAP_SIZE
    rep movsd
    call RefreshLightGrid
    ret
CommitLightingData ENDP

LightCellFree PROC uses edx,x:DWORD,y:DWORD
    cmp x,32
    jae lcf_no
    cmp y,32
    jae lcf_no
    mov eax,y
    shl eax,5
    add eax,x
    movzx eax,BYTE PTR [gameMap+eax]
    cmp eax,0
    je lcf_yes
    cmp eax,6
    je lcf_yes
    cmp eax,10
    je lcf_yes
lcf_no:
    xor eax,eax
    ret
lcf_yes:
    mov eax,1
    ret
LightCellFree ENDP

; Supercover traversal: test both sides when crossing an exact grid corner.
CastLightRay PROC uses ebx ecx edx esi edi,x1:DWORD,y1:DWORD,x2:DWORD,y2:DWORD
    LOCAL cellX:DWORD,cellY:DWORD,ex:DWORD,ey:DWORD,deltaX:DWORD,deltaY:DWORD,sx:DWORD,sy:DWORD,nx:DWORD,ny:DWORD,axv:DWORD
    mov eax,x1
    or eax,y1
    or eax,x2
    or eax,y2
    test eax,0FFFFF800h
    jnz lr_blocked
    mov eax,x1
    shr eax,6
    mov cellX,eax
    mov eax,y1
    shr eax,6
    mov cellY,eax
    mov eax,x2
    shr eax,6
    mov ex,eax
    mov eax,y2
    shr eax,6
    mov ey,eax
    mov sx,1
    mov eax,x2
    sub eax,x1
    jns lr_dx
    neg eax
    mov sx,-1
lr_dx:
    mov deltaX,eax
    mov sy,1
    mov eax,y2
    sub eax,y1
    jns lr_dy
    neg eax
    mov sy,-1
lr_dy:
    mov deltaY,eax
    mov eax,cellX
    shl eax,6
    cmp sx,1
    jne lr_nx_neg
    add eax,64
    sub eax,x1
    jmp lr_nx
lr_nx_neg:
    neg eax
    add eax,x1
lr_nx:
    mov nx,eax
    mov eax,cellY
    shl eax,6
    cmp sy,1
    jne lr_ny_neg
    add eax,64
    sub eax,y1
    jmp lr_ny
lr_ny_neg:
    neg eax
    add eax,y1
lr_ny:
    mov ny,eax
    mov edi,65
lr_step:
    mov eax,cellX
    cmp eax,ex
    jne lr_cross
    mov eax,cellY
    cmp eax,ey
    je lr_end
lr_cross:
    mov eax,3FFFFFFFh
    cmp deltaX,0
    je lr_a
    mov eax,nx
    imul eax,deltaY
lr_a:
    mov axv,eax
    mov eax,3FFFFFFFh
    cmp deltaY,0
    je lr_b
    mov eax,ny
    imul eax,deltaX
lr_b:
    cmp axv,eax
    jb lr_x
    ja lr_y
    mov eax,cellX
    add eax,sx
    invoke LightCellFree,eax,cellY
    test eax,eax
    jz lr_blocked
    mov eax,cellY
    add eax,sy
    invoke LightCellFree,cellX,eax
    test eax,eax
    jz lr_blocked
    mov eax,sx
    add cellX,eax
    add nx,64
lr_y:
    mov eax,sy
    add cellY,eax
    add ny,64
    jmp lr_test
lr_x:
    mov eax,sx
    add cellX,eax
    add nx,64
lr_test:
    invoke LightCellFree,cellX,cellY
    test eax,eax
    jz lr_blocked
    dec edi
    jnz lr_step
lr_blocked:
    xor eax,eax
    ret
lr_end:
    invoke LightCellFree,cellX,cellY
    ret
CastLightRay ENDP

LightDistance PROC uses ebx edx,deltaX:DWORD,deltaY:DWORD
    mov eax,deltaX
    cdq
    xor eax,edx
    sub eax,edx
    mov ebx,eax
    mov eax,deltaY
    cdq
    xor eax,edx
    sub eax,edx
    cmp eax,ebx
    jae ld_max
    xchg eax,ebx
ld_max:
    lea ebx,[ebx+ebx*2]
    shr ebx,3
    add eax,ebx
    ret
LightDistance ENDP

AddLightColor PROC uses eax ebx ecx edx,color:DWORD,amount:DWORD
    mov ebx,255
    mov eax,color
    and eax,255
    imul eax,amount
    xor edx,edx
    div ebx
    add lightAccumB,eax
    mov eax,color
    shr eax,8
    and eax,255
    imul eax,amount
    xor edx,edx
    div ebx
    add lightAccumG,eax
    mov eax,color
    shr eax,16
    and eax,255
    imul eax,amount
    xor edx,edx
    div ebx
    add lightAccumR,eax
    ret
AddLightColor ENDP

PointLightAmount PROC uses ebx ecx edx esi,source:DWORD,x:DWORD,y:DWORD
    LOCAL distance:DWORD
    mov esi,source
    mov eax,x
    sub eax,[esi].LightSource.x
    mov ecx,y
    sub ecx,[esi].LightSource.y
    invoke LightDistance,eax,ecx
    mov distance,eax
    cmp eax,[esi].LightSource.radius
    jae pla_zero
    test [esi].LightSource.flags,LIGHT_FLAG_SHADOWS
    jz pla_visible
    invoke CastLightRay,[esi].LightSource.x,[esi].LightSource.y,x,y
    test eax,eax
    jz pla_zero
pla_visible:
    mov eax,[esi].LightSource.radius
    sub eax,distance
    imul eax,[esi].LightSource.curIntensity
    xor edx,edx
    div [esi].LightSource.radius
    ret
pla_zero:
    xor eax,eax
    ret
PointLightAmount ENDP

RefreshLightGrid PROC uses eax ebx ecx edx esi edi
    mov esi,OFFSET lightGridRGB
    mov edi,OFFSET lightGrid
    mov ecx,MAP_SIZE
rlg_loop:
    lodsd
    mov edx,eax
    and eax,255
    mov ebx,edx
    shr ebx,8
    and ebx,255
    add eax,ebx
    shr edx,16
    and edx,255
    add eax,edx
    xor edx,edx
    mov ebx,3
    div ebx
    stosb
    loop rlg_loop
    ret
RefreshLightGrid ENDP

PackBakedRGB PROC uses ebx edx
    mov eax,lightAccumR
    cmp eax,255
    jbe @F
    mov eax,255
@@:
    shl eax,16
    mov ebx,eax
    mov eax,lightAccumG
    cmp eax,255
    jbe @F
    mov eax,255
@@:
    shl eax,8
    or ebx,eax
    mov eax,lightAccumB
    cmp eax,255
    jbe @F
    mov eax,255
@@:
    or eax,ebx
    ret
PackBakedRGB ENDP

AccumulateBakedCell PROC uses eax ebx ecx edx,x:DWORD,y:DWORD,weight:DWORD
    invoke LightCellFree,x,y
    test eax,eax
    jz abc_done
    mov eax,y
    shl eax,5
    add eax,x
    mov edx,[lightGridRGB+eax*4]
    mov eax,edx
    and eax,255
    imul eax,weight
    add lightAccumB,eax
    mov eax,edx
    shr eax,8
    and eax,255
    imul eax,weight
    add lightAccumG,eax
    shr edx,16
    imul edx,weight
    add lightAccumR,edx
    mov eax,weight
    add lightWeight,eax
abc_done:
    ret
AccumulateBakedCell ENDP

BakeMapLighting PROC uses ebx ecx edx esi edi
    LOCAL index:DWORD,x:DWORD,y:DWORD
    mov index,0
bl_cell:
    mov eax,index
    and eax,31
    mov x,eax
    mov eax,index
    shr eax,5
    mov y,eax
    mov eax,ambientLightLevel
    mov lightAccumR,eax
    mov lightAccumG,eax
    mov lightAccumB,eax
    invoke LightCellFree,x,y
    test eax,eax
    jz bl_store
    mov eax,x
    shl eax,6
    add eax,32
    mov x,eax
    mov eax,y
    shl eax,6
    add eax,32
    mov y,eax
    mov esi,OFFSET lightSources+40
    mov edi,13
bl_source:
    test [esi].LightSource.flags,LIGHT_FLAG_ACTIVE
    jz bl_next_source
    cmp [esi].LightSource.lightType,LIGHT_TYPE_STATIC
    jne bl_next_source
    mov eax,[esi].LightSource.intensity
    push [esi].LightSource.curIntensity
    mov [esi].LightSource.curIntensity,eax
    invoke PointLightAmount,esi,x,y
    pop [esi].LightSource.curIntensity
    invoke AddLightColor,[esi].LightSource.color,eax
bl_next_source:
    add esi,40
    dec edi
    jnz bl_source
bl_store:
    call PackBakedRGB
    mov ebx,index
    mov [lightGridRGB+ebx*4],eax
    inc index
    cmp index,MAP_SIZE
    jb bl_cell
    ; Smooth out of place, without averaging through wall cells.
    mov index,0
bl_smooth:
    mov ebx,index
    mov eax,[lightGridRGB+ebx*4]
    mov [lightSmoothRGB+ebx*4],eax
    mov eax,ebx
    and eax,31
    mov x,eax
    shr ebx,5
    mov y,ebx
    invoke LightCellFree,x,y
    test eax,eax
    jz bl_next_smooth
    mov lightAccumR,0
    mov lightAccumG,0
    mov lightAccumB,0
    mov lightWeight,0
    invoke AccumulateBakedCell,x,y,2
    mov eax,x
    dec eax
    invoke AccumulateBakedCell,eax,y,1
    mov eax,x
    inc eax
    invoke AccumulateBakedCell,eax,y,1
    mov eax,y
    dec eax
    invoke AccumulateBakedCell,x,eax,1
    mov eax,y
    inc eax
    invoke AccumulateBakedCell,x,eax,1
    mov eax,lightAccumR
    xor edx,edx
    div lightWeight
    mov lightAccumR,eax
    mov eax,lightAccumG
    xor edx,edx
    div lightWeight
    mov lightAccumG,eax
    mov eax,lightAccumB
    xor edx,edx
    div lightWeight
    mov lightAccumB,eax
    call PackBakedRGB
    mov ebx,index
    mov [lightSmoothRGB+ebx*4],eax
bl_next_smooth:
    inc index
    cmp index,MAP_SIZE
    jb bl_smooth
    mov esi,OFFSET lightSmoothRGB
    mov edi,OFFSET lightGridRGB
    mov ecx,MAP_SIZE
    rep movsd
    call RefreshLightGrid
    ret
BakeMapLighting ENDP

UpdateDynamicLights PROC uses eax ebx ecx edx esi
    inc lightingTick
    mov esi,OFFSET lightSources+40
    mov ecx,1
udl_next:
    test [esi].LightSource.flags,LIGHT_FLAG_ACTIVE
    jz udl_skip
    cmp [esi].LightSource.lightType,LIGHT_TYPE_BURST
    je udl_burst
    mov eax,[esi].LightSource.intensity
    cmp [esi].LightSource.lightType,LIGHT_TYPE_STATIC
    je udl_store
    cmp [esi].LightSource.lightType,LIGHT_TYPE_PULSE
    jne udl_flicker
    mov edx,lightingTick
    shl edx,2
    add edx,ecx
    and edx,511
    mov ebx,[tableSin+edx*4]
    sar ebx,1
    add ebx,98304
    imul eax,ebx
    sar eax,17
udl_flicker:
    test [esi].LightSource.flags,LIGHT_FLAG_FLICKER
    jz udl_store
    mov edx,lightingTick
    shr edx,2
    imul edx,1103515245
    imul ebx,ecx,12345
    add edx,ebx
    shr edx,16
    and edx,15
    sub edx,7
    add eax,edx
    cmp eax,0
    jge @F
    xor eax,eax
@@:
    cmp eax,255
    jle udl_store
    mov eax,255
    jmp udl_store
udl_burst:
    mov eax,[esi].LightSource.curIntensity
    sub eax,[esi].LightSource.decaySpeed
    jg udl_store
    xor eax,eax
    mov [esi].LightSource.flags,0
udl_store:
    mov [esi].LightSource.curIntensity,eax
udl_skip:
    add esi,40
    inc ecx
    cmp ecx,16
    jb udl_next
    ret
UpdateDynamicLights ENDP

SamplePointLighting PROC uses ebx ecx edx esi edi,x:DWORD,y:DWORD,distance:DWORD,side:DWORD
    LOCAL forward:DWORD,lateral:DWORD,beam:DWORD,atten:DWORD,fog:DWORD
    LOCAL originX:DWORD,originY:DWORD,originAngle:DWORD
    ; Camera-attached flashlight. Cinematics never move the gameplay body, but
    ; use the same lighting origin as the editor's camera-only preview packet.
    mov eax,playerX
    mov originX,eax
    mov eax,playerY
    mov originY,eax
    mov eax,playerAngle
    mov originAngle,eax
    cmp isCutsceneActive,0
    je spl_origin_ready
    mov eax,csCameraX
    mov originX,eax
    mov eax,csCameraY
    mov originY,eax
    mov eax,csCameraAngle
    mov originAngle,eax
spl_origin_ready:
    mov eax,256
    mov lightRed,eax
    mov lightGreen,eax
    mov lightBlue,eax
    cmp lightingMode,0
    je spl_done
    mov eax,x
    sar eax,6
    and eax,31
    mov edx,y
    sar edx,6
    and edx,31
    shl edx,5
    add eax,edx
    mov eax,[lightGridRGB+eax*4]
    mov edx,eax
    and eax,255
    mov lightAccumB,eax
    mov eax,edx
    shr eax,8
    and eax,255
    mov lightAccumG,eax
    shr edx,16
    mov lightAccumR,edx
    cmp lightingMode,2
    jne spl_fog
    mov esi,OFFSET lightSources+40
    mov edi,15
spl_source:
    test [esi].LightSource.flags,LIGHT_FLAG_ACTIVE
    jz spl_next
    cmp [esi].LightSource.lightType,LIGHT_TYPE_STATIC
    je spl_next
    cmp [esi].LightSource.radius,0
    jle spl_next
    invoke PointLightAmount,esi,x,y
    invoke AddLightColor,[esi].LightSource.color,eax
spl_next:
    add esi,40
    dec edi
    jnz spl_source
    cmp isFlashlightOn,0
    je spl_fog
    mov eax,x
    sub eax,originX
    mov ebx,y
    sub ebx,originY
    invoke LightDistance,eax,ebx
    cmp eax,flashlightRadius
    jae spl_fog
    mov edx,flashlightRadius
    sub edx,eax
    mov eax,edx
    imul eax,flashlightIntensity
    xor edx,edx
    div flashlightRadius
    mov atten,eax
    mov ecx,originAngle
    and ecx,511
    mov eax,x
    sub eax,originX
    imul [tableCos+ecx*4]
    shrd eax,edx,16
    mov forward,eax
    mov eax,y
    sub eax,originY
    imul [tableSin+ecx*4]
    shrd eax,edx,16
    add forward,eax
    cmp forward,0
    jle spl_fog
    mov eax,y
    sub eax,originY
    imul [tableCos+ecx*4]
    shrd eax,edx,16
    mov lateral,eax
    mov eax,x
    sub eax,originX
    imul [tableSin+ecx*4]
    shrd eax,edx,16
    sub lateral,eax
    mov ecx,flashlightConeAngle
    mov eax,forward
    imul [tableSin+ecx*4]
    idiv DWORD PTR [tableCos+ecx*4]
    mov beam,eax
    test eax,eax
    jle spl_fog
    mov eax,lateral
    cdq
    xor eax,edx
    sub eax,edx
    cmp eax,beam
    jae spl_fog
    mov ebx,beam
    sub ebx,eax
    mov eax,ebx
    imul eax,atten
    xor edx,edx
    div beam
    mov atten,eax
    invoke CastLightRay,originX,originY,x,y
    test eax,eax
    jz spl_fog
    invoke AddLightColor,00FFFFFFh,atten
spl_fog:
    mov fog,256
    mov eax,distance
    cmp eax,280
    jle spl_side
    cmp eax,720
    jb spl_partial
    mov fog,32
    jmp spl_side
spl_partial:
    sub eax,280
    imul eax,224
    xor edx,edx
    mov ebx,440
    div ebx
    sub fog,eax
spl_side:
    cmp side,1
    jne spl_coeff
    mov eax,fog
    imul eax,192
    shr eax,8
    mov fog,eax
spl_coeff:
    mov eax,lightAccumR
    cmp eax,256
    jbe @F
    mov eax,256
@@:
    imul eax,fog
    shr eax,8
    mov lightRed,eax
    mov eax,lightAccumG
    cmp eax,256
    jbe @F
    mov eax,256
@@:
    imul eax,fog
    shr eax,8
    mov lightGreen,eax
    mov eax,lightAccumB
    cmp eax,256
    jbe @F
    mov eax,256
@@:
    imul eax,fog
    shr eax,8
    mov lightBlue,eax
spl_done:
    mov eax,lightRed
    cmp eax,lightGreen
    jae @F
    mov eax,lightGreen
@@:
    cmp eax,lightBlue
    jae @F
    mov eax,lightBlue
@@:
    ret
SamplePointLighting ENDP

ComputeWallLightLevel PROC uses ebx ecx edx,screenX:DWORD,mapX:DWORD,mapY:DWORD,sideHit:DWORD,stepX:DWORD,stepY:DWORD,rawDist:DWORD,perpWallDist:DWORD,rayAngle:DWORD,rayDirX:DWORD,rayDirY:DWORD
    LOCAL x:DWORD,y:DWORD
    mov eax,rawDist
    imul rayDirX
    shrd eax,edx,24
    add eax,viewX
    mov x,eax
    mov eax,rawDist
    imul rayDirY
    shrd eax,edx,24
    add eax,viewY
    mov y,eax
    cmp sideHit,0
    jne cwl_y
    mov eax,mapX
    shl eax,6
    cmp stepX,0
    jg @F
    add eax,64
@@:
    sub eax,stepX
    mov x,eax
    jmp cwl_ready
cwl_y:
    mov eax,mapY
    shl eax,6
    cmp stepY,0
    jg @F
    add eax,64
@@:
    sub eax,stepY
    mov y,eax
cwl_ready:
    invoke SamplePointLighting,x,y,perpWallDist,sideHit
    ret
ComputeWallLightLevel ENDP

ComputeSpriteLight PROC sprX:DWORD,sprY:DWORD,sprDist:DWORD
    invoke SamplePointLighting,sprX,sprY,sprDist,0
    ret
ComputeSpriteLight ENDP

ShadeLightPixel PROC uses eax ebx
    mov eax,edx
    and eax,255
    imul eax,lightBlue
    shr eax,8
    mov ebx,eax
    mov eax,edx
    shr eax,8
    and eax,255
    imul eax,lightGreen
    shr eax,8
    shl eax,8
    or ebx,eax
    mov eax,edx
    shr eax,16
    and eax,255
    imul eax,lightRed
    shr eax,8
    shl eax,16
    or eax,ebx
    mov edx,eax
    ret
ShadeLightPixel ENDP