; All weather uses visual time and stable seeds, never gameplay RNG.
BlendCityWeatherPixel3D PROC uses ebx esi edi px:DWORD,py:DWORD,tint:DWORD,opacity:DWORD
    cmp px,640
    jae weather_pixel_done
    cmp py,480
    jae weather_pixel_done
    mov esi,py
    imul esi,640
    add esi,px
    mov ebx,screenBuffer[esi*4]
    mov edi,256
    sub edi,opacity
    movzx eax,bl
    imul eax,edi
    mov ecx,tint
    and ecx,255
    imul ecx,opacity
    add eax,ecx
    shr eax,8
    mov edx,eax
    movzx eax,bh
    imul eax,edi
    mov ecx,tint
    shr ecx,8
    and ecx,255
    imul ecx,opacity
    add eax,ecx
    shr eax,8
    shl eax,8
    or edx,eax
    shr ebx,16
    and ebx,255
    imul ebx,edi
    mov eax,tint
    shr eax,16
    and eax,255
    imul eax,opacity
    add eax,ebx
    shr eax,8
    shl eax,16
    or eax,edx
    mov screenBuffer[esi*4],eax
weather_pixel_done:
    ret
BlendCityWeatherPixel3D ENDP

DrawCityRain3D PROC uses ebx esi edi
    local layer:DWORD,px:DWORD,py:DWORD,lengthPx:DWORD,opacity:DWORD
    local radius:DWORD,alpha:DWORD,rowStart:DWORD,age:DWORD,groundDepth:DWORD
    mov layer,0
rain_layer:
    mov eax,layer
    imul eax,3
    add eax,4
    mov lengthPx,eax
    mov eax,layer
    imul eax,28
    add eax,50
    mov opacity,eax
    xor esi,esi
rain_drop:
    mov eax,layer
    imul eax,3
    add eax,3
    imul eax,cityClock3D
    imul ecx,esi,829
    add eax,ecx
    xor edx,edx
    mov ecx,7680
    div ecx
    shr edx,4
    mov py,edx
    imul eax,esi,137
    imul ebx,layer,211
    add eax,ebx
    mov ecx,cityClock3D
    shr ecx,6
    sub eax,ecx
    and eax,1023
    imul eax,640
    shr eax,10
    mov px,eax
    xor edi,edi
rain_streak:
    mov eax,edi
    shr eax,2
    mov ebx,px
    sub ebx,eax
    mov ecx,py
    add ecx,edi
    invoke BlendCityWeatherPixel3D,ebx,ecx,00B2C5CDh,opacity
    inc edi
    cmp edi,lengthPx
    jb rain_streak
    inc esi
    cmp esi,36
    jb rain_drop
    inc layer
    cmp layer,3
    jb rain_layer
    mov eax,viewHorizon3D
    add eax,50
    cmp eax,310
    jge @F
    mov eax,310
@@:
    cmp eax,450
    jge rain_done
    mov rowStart,eax
    xor esi,esi
rain_splash:
    imul eax,esi,97
    add eax,cityClock3D
    xor edx,edx
    mov ecx,800
    div ecx
    cmp edx,250
    jae rain_splash_next
    mov age,edx
    imul eax,esi,71
    add eax,43
    xor edx,edx
    mov ecx,600
    div ecx
    add edx,20
    mov px,edx
    imul eax,esi,37
    xor edx,edx
    mov ecx,468
    sub ecx,rowStart
    div ecx
    add edx,rowStart
    mov py,edx
    sub edx,viewHorizon3D
    mov eax,viewEye3D
    imul eax,480
    cdq
    mov ecx,py
    sub ecx,viewHorizon3D
    idiv ecx
    sub eax,1024
    mov groundDepth,eax
    mov ecx,py
    imul ecx,640
    add ecx,px
    mov eax,groundDepth
    cmp cityDepthBuffer3D[ecx*4],eax
    jl rain_splash_next
    mov eax,age
    xor edx,edx
    mov ecx,40
    div ecx
    inc eax
    mov radius,eax
    mov eax,250
    sub eax,age
    imul eax,100
    xor edx,edx
    mov ecx,250
    div ecx
    mov alpha,eax
    mov ebx,px
    sub ebx,radius
    invoke BlendCityWeatherPixel3D,ebx,py,00C5C6AEh,alpha
    mov ebx,px
    add ebx,radius
    invoke BlendCityWeatherPixel3D,ebx,py,00C5C6AEh,alpha
    mov eax,radius
    shr eax,1
    mov edi,py
    sub edi,eax
    invoke BlendCityWeatherPixel3D,px,edi,00C5C6AEh,alpha
    mov eax,radius
    shr eax,1
    mov edi,py
    add edi,eax
    invoke BlendCityWeatherPixel3D,px,edi,00C5C6AEh,alpha
rain_splash_next:
    inc esi
    cmp esi,24
    jb rain_splash
rain_done:
    ret
DrawCityRain3D ENDP