HPAVC/HPAVC CD-ROM.iso/3DDEMO.ZIP/3D/SOURCE/POLYLOW.ASM

Assembly Source File | 1996-07-16 | 34KB | 1,466 lines

;    Copyright (c) 1996 by Kerrigan Burgess, all rights reserved.

                .486

                ASSUME  CS:_TEXT
                ASSUME  DS:_DATA

; export Functions

                PUBLIC Line
                PUBLIC Scan_Convert_Lambert
                PUBLIC Scan_Convert_Gouraud

; export Data

                PUBLIC _MinClipX
                PUBLIC _MaxClipX
                PUBLIC _MinClipY
                PUBLIC _MaxClipY
                PUBLIC _ScreenWidth
        PUBLIC _LookPAL
                PUBLIC _X1
                PUBLIC _X2
                PUBLIC _X3
                PUBLIC _Y1
                PUBLIC _Y2
                PUBLIC _Y3
                PUBLIC _Z1
                PUBLIC _Z2
                PUBLIC _Z3
                PUBLIC _U1
                PUBLIC _V1
                PUBLIC _U2
                PUBLIC _V2
                PUBLIC _U3
                PUBLIC _V3
                PUBLIC _I1
                PUBLIC _I2
                PUBLIC _I3
                PUBLIC _A1
                PUBLIC _A2
                PUBLIC _A3
                PUBLIC _ColorIndex
                PUBLIC _TransLevel
        PUBLIC _AvgZ
        PUBLIC _RendBuffer

_DATA           SEGMENT 'DATA' USE32

; Export data
                _MinClipX     dd 0
                _MaxClipX     dd 0
                _MinClipY     dd 0
                _MaxClipY     dd 0
                _ScreenWidth  dd 0
        _LookPAL      dd 0
        _LookPALptr   dd 0
                _X1           dd 0
                _X2           dd 0
                _X3           dd 0
                _Y1           dd 0
                _Y2           dd 0
                _Y3           dd 0
                _Z1           dd 0
                _Z2           dd 0
                _Z3           dd 0
                _U1           dd 0
                _V1           dd 0
                _U2           dd 0
                _V2           dd 0
                _U3           dd 0
                _V3           dd 0
                _I1           dd 0
                _I2           dd 0
                _I3           dd 0
                _A1           dd 0
                _A2           dd 0
                _A3           dd 0
                _ColorIndex   dd 0
                _TransLevel   dd 0
        _AvgZ         dd 0
        _RendBuffer   dd 0

; Locals
                _oldx3        dd 0
        _oldy3        dd 0
        _oldi3        dd 0
        _LeftX        dd 0
        _RightX       dd 0
        _LeftI        dd 0
        _RightI       dd 0
        _MiddleI      dd 0
                _LeftDx       dd 0
                _RightDx      dd 0
        _LeftDi       dd 0
        _RightDi      dd 0
        _MiddleDi     dd 0
        _Width        dd 0
                _GENERAL      dd 0
                _color        dd 0
            _Count        dd 0
        _Temp         dd 0

_DATA           ENDS

_TEXT           SEGMENT PUBLIC 'CODE' USE32

                ; ARG Buffer-->edi color-->eax count-->ecx

Line   PROC    NEAR

         mov ah,al
         mov ebx,eax
         sal ebx,16
         or eax,ebx
         push ecx
         and ecx,0x00000003
         rep stosb
         pop ecx
         sar ecx,2
         rep stosd
         cld                   ; Direction bit must be clear on exit.
         ret

Line   ENDP

Scan_Convert_Lambert PROC NEAR

         push ebp
         push esi
         push edi

         mov eax,_X2
         cmp eax,_X1
         jne @@CheckY_L
         cmp eax,_X3
         je  @@TheEnd_L

@@CheckY_L:

         mov eax,_Y2
         cmp eax,_Y1
         jne @@CheckY2Y1_L
         cmp eax,_Y3
         je @@TheEnd_L

@@CheckY2Y1_L:

         cmp eax,_Y1
         jge @@CheckY3Y1_L
         mov edx,_X1
         mov ecx,_X2
         mov _X1,ecx         ; _X1=_X2
         mov _X2,edx         ; _X2=_X1
         mov edx,_Y1
         mov _Y2,edx         ; _Y1=_Y2
         mov _Y1,eax         ; _Y2=_Y1

@@CheckY3Y1_L:

         mov eax,_Y3
         cmp eax,_Y1
         jge @@CheckY3Y2_L
         mov ebx,_X1
         mov ecx,_X3
         mov _X1,ecx         ; _X1=_X3
         mov _X3,ebx         ; _X3=_X1
         mov ebx,_Y1
         mov _Y1,eax         ; _Y1=_Y3
         mov _Y3,ebx         ; _Y3=_Y1

@@CheckY3Y2_L:

         mov eax,_Y2
         cmp eax,_Y3
         jle @@Skip1_L
         mov ebx,_X2
         mov ecx,_X3
         mov _X2,ecx         ; _X2=_X3
         mov _X3,ebx         ; _X3=_X2
         mov ebx,_Y3
         mov _Y3,eax         ; _Y3=_Y2
         mov _Y2,ebx         ; _Y2=_Y3

@@Skip1_L:

         mov eax,_Y3
         cmp eax,_MinClipY
         jl @@TheEnd_L
         mov eax,_Y1
         cmp eax,_MaxClipY
         jg @@TheEnd_L
         mov eax,_MinClipX
         mov ebx,_MaxClipX
         cmp eax,_X1
         jle @@CheckXtents_L
         cmp eax,_X2
         jle @@CheckXtents_L
         cmp eax,_X3
         jg  @@TheEnd_L

@@CheckXtents_L:

         cmp ebx,_X1
         jge @@TheStart_L
         cmp ebx,_X2
         jge @@TheStart_L
         cmp ebx,_X3
         jl  @@TheEnd_L

@@TheStart_L:                    ; now poly is in cliparea

         mov _GENERAL,0         ; reset flag
         mov edi,_RendBuffer
     mov ebx,_LookPAL
         mov ecx,_ColorIndex
         mov al,BYTE PTR [ ebx + ecx ]     ; color=Look_Pal[ _ColorIndex ]
         mov ah,al
     mov ebx,eax
     sal ebx,16
     or  eax,ebx
         mov _color,eax           ; replicate color
         mov eax,_Y2
         cmp eax,_Y1
         je  @@FLAT_TOP_L
         cmp eax,_Y3
         je  @@FLAT_BOTTOM_L
         mov _GENERAL,1           ; GENERAL=TRUE
         mov eax,_X3
         sub eax,_X1
     sal eax,16
         mov ebx,_Y3
         sub ebx,_Y1
         cdq
     idiv ebx                   ; slope = ((_X3-_X1)<<16)/(_Y3-_Y1)
         mov ebx,_Y2
         sub ebx,_Y1
     imul ebx
     sar eax,16
         add eax,_X1
         mov ebx,_X3
         mov _oldx3,ebx
         mov ebx,_Y3
         mov _oldy3,ebx
         mov _X3,eax               ; _X3=newx
         mov ebx,_Y2
         mov _Y3,ebx

@@FLAT_BOTTOM_L:

         mov eax,_X3
         cmp eax,_X2               ; if (_X3<_X2)
         jge @@Skip2_L
         mov ecx,_X2
         mov _X2,eax
         mov _X3,ecx

@@Skip2_L:
         mov ebx,_Y3
         sub ebx,_Y1
     mov eax,0x00010000    ; divide by 65536 (fixed point 16).
         cdq
     idiv ebx
         mov ebx,_X2
         sub ebx,_X1
     mov ecx,eax
     imul ebx
         mov _LeftDx,eax
     mov eax,ecx
         mov ebx,_X3
         sub ebx,_X1
     imul ebx
         mov _RightDx,eax
         mov ebx,_X1
     sal ebx,16
         mov _LeftX,ebx
     add ebx,0x00008000
         mov _RightX,ebx       ; RightX=LeftX+32768
         mov eax,_MinClipY
         cmp eax,_Y1
         jle @@Skip3_L
     cmp eax,_Y3
         jg  @@SecondHalf_L      ; the whole poly is clipped
         sub eax,_Y1
     mov ebx,eax
         imul _LeftDx
         add eax,_LeftX
         mov _LeftX,eax
     mov eax,ebx
         imul _RightDx
         add eax,_RightX
         mov _RightX,eax
     mov eax,_MinClipY
         mov _Y1,eax

@@Skip3_L:

         mov eax,_MaxClipY
         cmp eax,_Y3
         jge @@Skip4_L
     cmp eax,_Y1           ; the whole poly is clipped
         jl  @@SecondHalf_L
         mov _Y3,eax

@@Skip4_L:
         mov eax,_Y1
     mov ebx,eax
         sal eax,8
         sal ebx,6
     add eax,ebx
     add edi,eax             ; Buffer+=(_Y1<<8)+(_Y1<<6)

         jmp $+2                   ; clear prefetch queue

         mov eax,_X1
         mov ebx,_MinClipX
         mov ecx,_MaxClipX
     cmp eax,ebx               ; if (_X1>=POLY_MIN_CLIP_X && _X1<=POLY_MAX_CLIP_X && etc.
         jl  @@Clipped_L
     cmp eax,ecx
         jg  @@Clipped_L
         mov eax,_X2
     cmp eax,ebx
         jl  @@Clipped_L
     cmp eax,ecx
         jg  @@Clipped_L
         mov eax,_X3
     cmp eax,ebx
         jl  @@Clipped_L
     cmp eax,ecx
         jg  @@Clipped_L
         mov ebp,_Y3
         sub ebp,_Y1              ; edx holds count
         mov ebx,_LeftX
         mov edx,_RightX
         mov eax,_color

@@DoScanLine_L:

         cmp ebp,0
         je  @@SecondHalf_L
     mov esi,ebx
         sar esi,16
     push edi                 ; save old place
         add edi,esi              ; draw scanline
     mov ecx,edx
         sar ecx,16
     sub ecx,esi
     inc ecx
     push ecx          ; save ecx
     and ecx,0x00000003
         rep stosb
         pop ecx
         sar ecx,2
     rep stosd
         add ebx,_LeftDx
         add edx,_RightDx
     pop edi               ; restore old position
         add edi,_ScreenWidth
     dec ebp
         jmp @@DoScanLine_L

@@Clipped_L:

         mov eax,_color
         mov ebp,_Y3
         sub ebp,_Y1
         mov ebx,_LeftX
         mov edx,_RightX

@@DoScanLineClip_L:

     cmp ebp,0
         je  @@SecondHalf_L
         mov esi,ebx
         sar esi,16
     mov ecx,edx
         sar ecx,16
         cmp esi,_MinClipX
         jge @@Skip5_L
         cmp ecx,_MinClipX
         jl  @@Redo_L
         mov esi,_MinClipX

@@Skip5_L:

         cmp ecx,_MaxClipX
         jle @@Skip6_L
         cmp esi,_MaxClipX
         jg  @@Redo_L
         mov ecx,_MaxClipX

@@Skip6_L:

     push edi
         add edi,esi          ; draw scanline
     sub ecx,esi
     inc ecx
         mov esi,ecx          ; save ecx
     and ecx,0x00000003
     rep stosb
     mov ecx,esi
         sar ecx,2
     rep stosd
         pop edi               ; restore old position

@@Redo_L:

         add ebx,_LeftDx
         add edx,_RightDx
         add edi,_ScreenWidth  ; move to next scanline
     dec ebp
         jmp @@DoScanLineClip_L

@@SecondHalf_L:

         cmp _GENERAL,0       ; if not GENERAL Triangle goto end
         je  @@TheEnd_L
         mov eax,_X2          ; setup for bottom half
         mov _X1,eax
         mov eax,_Y2
         mov _Y1,eax
         mov eax,_X3
         mov _X2,eax
         mov eax,_oldx3
         mov _X3,eax
         mov eax,_oldy3
         mov _Y3,eax
         mov edi,_RendBuffer

@@FLAT_TOP_L:

         mov eax,_X2
         cmp eax,_X1
         jge @@Skip7_L
         mov ebx,_X1
         mov _X2,ebx
         mov _X1,eax

@@Skip7_L:

         mov ebx,_Y3
         sub ebx,_Y1
     mov eax,0x00010000         ; eax=65536
         cdq
     idiv ebx
     mov ebx,eax                ; save height
         mov ecx,_X3
         sub ecx,_X1
     imul ecx
         mov _LeftDx,eax
     mov eax,ebx           ; restore eax
         mov ecx,_X3
         sub ecx,_X2
     imul ecx
         mov _RightDx,eax
         mov eax,_X1
         sal eax,16
         mov _LeftX,eax
         mov eax,_X2
         sal eax,16
     add eax,0x00008000    ; add 0.5 to it
         mov _RightX,eax
         mov eax,_MinClipY
         cmp eax,_Y1
         jle @@Skip8_L
     cmp eax,_Y3
         jg  @@TheEnd_L          ; poly is totally clipped
         sub eax,_Y1
     mov ecx,eax
         imul _LeftDx
         add eax,_LeftX
         mov _LeftX,eax
     mov eax,ecx
         imul _RightDx
         add eax,_RightX
         mov _RightX,eax
     mov ebx,_MinClipY
         mov _Y1,ebx           ; _Y1=POLY_MIN_CLIP_Y

@@Skip8_L:

         mov eax,_MaxClipY
         cmp eax,_Y3
         jge @@Skip9_L
     cmp eax,_Y1
         jl  @@TheEnd_L
         mov _Y3,eax

@@Skip9_L:

         mov eax,_Y1
     mov ebx,eax
         sal eax,8
         sal ebx,6
     add eax,ebx
     add edi,eax            ; Buffer+=(_Y1<<8)+(_Y1<<6)

         jmp $+2                   ; clear prefetch queue

         mov eax,_X1
         mov ebx,_MinClipX
         mov ecx,_MaxClipX
     cmp eax,ebx               ; if (_X1>=POLY_MIN_CLIP_X && _X1<=POLY_MAX_CLIP_X && etc.
         jl  @@Clipped2_L
     cmp eax,ecx
         jg  @@Clipped2_L
         mov eax,_X2
     cmp eax,ebx
         jl  @@Clipped2_L
     cmp eax,ecx
         jg  @@Clipped2_L
         mov eax,_X3
     cmp eax,ebx
         jl  @@Clipped2_L
     cmp eax,ecx
         jg  @@Clipped2_L
         mov ebp,_Y3              ; Draw regular poly (no clip)
         sub ebp,_Y1              ; edx holds count
         mov ebx,_LeftX
         mov edx,_RightX
         mov eax,_color

@@DoScanLine2_L:

     cmp ebp,0
         je  @@TheEnd_L
     mov esi,ebx
         sar esi,16
     push edi                 ; save old position
     add edi,esi
     mov ecx,edx
         sar ecx,16
     sub ecx,esi
     inc ecx
     push ecx          ; save ecx
     and ecx,0x00000003
         rep stosb
         pop ecx
         sar ecx,2
     rep stosd
         add ebx,_LeftDx
         add edx,_RightDx
     pop edi               ; restore old position
         add edi,_ScreenWidth
     dec ebp
         jmp @@DoScanLine2_L

@@Clipped2_L:

         mov eax,_color
         mov ebp,_Y3
         sub ebp,_Y1
         mov ebx,_LeftX
         mov edx,_RightX

@@DoScanLineClip2_L:

     cmp ebp,0
         je  @@TheEnd_L
         mov esi,ebx
         sar esi,16
     mov ecx,edx
         sar ecx,16
         cmp esi,_MinClipX
         jge @@Skip10_L
         cmp ecx,_MinClipX
         jl  @@Redo2_L
         mov esi,_MinClipX

@@Skip10_L:

         cmp ecx,_MaxClipX
         jle @@Skip11_L
         cmp esi,_MaxClipX
         jg  @@Redo2_L
         mov ecx,_MaxClipX

@@Skip11_L:

     push edi             ; save old position
         add edi,esi
     sub ecx,esi
     inc ecx
         mov esi,ecx          ; save ecx
     and ecx,0x00000003
     rep stosb
     mov ecx,esi
         sar ecx,2
     rep stosd
         pop edi               ; restore saved position

@@Redo2_L:

         add ebx,_LeftDx
         add edx,_RightDx
         add edi,_ScreenWidth
     dec ebp
         jmp @@DoScanLineClip2_L

@@TheEnd_L:

     pop  edi
         pop  esi
         pop  ebp

     cld
     ret

Scan_Convert_Lambert ENDP

Scan_Convert_Gouraud PROC NEAR

         push ebp
         push esi
         push edi

         mov eax,_X2
         cmp eax,_X1
         jne @@CheckY_G
         cmp eax,_X3
     je  @@TheEnd_G

@@CheckY_G:

         mov eax,_Y2
         cmp eax,_Y1
         jne @@CheckY2Y1_G
         cmp eax,_Y3
     je @@TheEnd_G

@@CheckY2Y1_G:

         cmp eax,_Y1
         jge @@CheckY3Y1_G
         mov edx,_X1
         mov ecx,_X2
         mov _X1,ecx         ; _X1=_X2
         mov _X2,edx         ; _X2=_X1
         mov edx,_Y1
         mov _Y2,edx         ; _Y1=_Y2
         mov _Y1,eax         ; _Y2=_Y1
     mov eax,_I1
     mov ebx,_I2
     mov _I2,eax         ; _I2=_I1
     mov _I1,ebx         ; _I1=_I2

@@CheckY3Y1_G:

         mov eax,_Y3
         cmp eax,_Y1
         jge @@CheckY3Y2_G
         mov ebx,_X1
         mov ecx,_X3
         mov _X1,ecx         ; _X1=_X3
         mov _X3,ebx         ; _X3=_X1
         mov ebx,_Y1
         mov _Y1,eax         ; _Y1=_Y3
         mov _Y3,ebx         ; _Y3=_Y1
         mov eax,_I1
     mov ebx,_I3
     mov _I3,eax         ; _I3=_I1
     mov _I1,ebx         ; _I1=_I3

@@CheckY3Y2_G:

         mov eax,_Y2
         cmp eax,_Y3
         jle @@Skip1_G
         mov ebx,_X2
         mov ecx,_X3
         mov _X2,ecx         ; _X2=_X3
         mov _X3,ebx         ; _X3=_X2
         mov ebx,_Y3
         mov _Y3,eax         ; _Y3=_Y2
         mov _Y2,ebx         ; _Y2=_Y3
         mov eax,_I2
     mov ebx,_I3
     mov _I2,ebx         ; _I2=_I3
     mov _I3,eax         ; _I3=_I2

@@Skip1_G:

         mov eax,_Y3
         cmp eax,_MinClipY
         jl @@TheEnd_G
         mov eax,_Y1
         cmp eax,_MaxClipY
     jg @@TheEnd_G
         mov eax,_MinClipX
         mov ebx,_MaxClipX
         cmp eax,_X1
         jle @@CheckXtents_G
         cmp eax,_X2
         jle @@CheckXtents_G
         cmp eax,_X3
     jg  @@TheEnd_G

@@CheckXtents_G:

         cmp ebx,_X1
         jge @@TheStart_G
         cmp ebx,_X2
         jge @@TheStart_G
         cmp ebx,_X3
     jl  @@TheEnd_G

@@TheStart_G:                     ; now poly is in cliparea

         mov _GENERAL,0         ; reset flag
         mov edi,_RendBuffer

         mov esi,_LookPAL
     add esi,_ColorIndex      ; LookPAL[ _ColorIndex + (MiddleI>>16) ]

         mov eax,_Y2
         cmp eax,_Y1
     je  @@FLAT_TOP_G
         cmp eax,_Y3
         je  @@FLAT_BOTTOM_G
         mov _GENERAL,1           ; GENERAL=TRUE
         mov eax,0x00010000       ; 65536
     cdq
         mov ebx,_Y3
         sub ebx,_Y1
     div ebx
         mov ebp,eax              ; save height
         mov ebx,_x3
     sub ebx,_x1
     imul ebx
         mov ebx,_Y2
         sub ebx,_Y1
     imul ebx
     sar eax,16
         add eax,_X1              ; newx
         mov ebx,_X3
         mov _oldx3,ebx
         mov ebx,_Y3
         mov _oldy3,ebx
     mov ebx,_I3
     mov _oldi3,ebx
         mov _X3,eax               ; _X3=newx
         mov eax,_Y2
     sub eax,_Y1
     imul _I3
     mov ebx,eax
     mov eax,_Y3
     sub eax,_Y2
     imul _I1
     add eax,ebx
     imul ebp                   ; multiply by height
     sar eax,16                 ; holds newi
         mov _I3,eax                ; _I3=newi
     mov ebx,_Y2               ; _Y3=_Y2
         mov _Y3,ebx

@@FLAT_BOTTOM_G:

         mov eax,_X3
         cmp eax,_X2               ; if (_X3<_X2)
         jge @@Skip2_G
         mov ecx,_X2
         mov _X2,eax
         mov _X3,ecx
     mov eax,_I3
     mov ebx,_I2
     mov _I3,ebx
     mov _I2,eax

@@Skip2_G:

         mov ebx,_Y2
         sub ebx,_Y1
     mov eax,0x00010000    ; divide by 65536 (fixed point 16).
         cdq
     idiv ebx
     mov ecx,eax           ; save height
         mov eax,_X2
         sub eax,_X1
     imul ecx
         mov _LeftDx,eax
         mov eax,_X3
         sub eax,_X1
     imul ecx
         mov _RightDx,eax

         mov ebx,_X1
     sal ebx,16
         mov _LeftX,ebx
     add ebx,0x00008000
         mov _RightX,ebx       ; RightX=LeftX+32768

         mov eax,_I1
     sal eax,16
     mov _LeftI,eax
     mov _RightI,eax

     mov eax,_I2
     sub eax,_I1
     imul ecx
     mov _leftDi,eax
     mov eax,_I3
     sub eax,_I1
     imul ecx
     mov _RightDi,eax
     mov _MiddleDi,0

         mov eax,_MinClipY     ; if (_Y1 < POLY_MIN_CLIP_Y)
         cmp eax,_Y1
         jle @@Skip3_G
       cmp eax,_Y3
       jg  @@SecondHalf_G      ; the whole poly is clipped
             sub eax,_Y1
         mov ebx,eax           ; save ydiff
             imul _LeftDx
             add _LeftX,eax
         mov eax,ebx
             imul _RightDx
             add _RightX,eax

             mov eax,ebx
         imul _LeftDi
         add _LeftI,eax
             mov eax,ebx
         imul _RightDi
         add _RightI,eax

         mov eax,_RightI
         sub eax,_LeftI
             cdq
         mov ebx,_RightX
         sub ebx,_LeftX
         sar ebx,16             ; get whole number
         inc ebx                ; to avoid divide by 0
         idiv ebx
         mov _MiddleDi,eax

         mov eax,_MinClipY
             mov _Y1,eax

@@Skip3_G:

         mov eax,_MaxClipY
         cmp eax,_Y3
         jge @@Skip4_G
     cmp eax,_Y1           ; the whole poly is clipped
     jl  @@TheEnd_G

         mov _Y3,eax

@@Skip4_G:

         mov eax,_Y1             ; optimized for 320x200
     mov ebx,eax
         sal eax,8
         sal ebx,6
     add eax,ebx
     add edi,eax             ; Buffer+=(_Y1<<8)+(_Y1<<6)

         jmp $+2                 ; clear prefetch queue

         mov eax,_X1
         mov ebx,_MinClipX
         mov ecx,_MaxClipX
     cmp eax,ebx               ; if (_X1>=POLY_MIN_CLIP_X && _X1<=POLY_MAX_CLIP_X && etc.
     jl  @@Clipped_G
     cmp eax,ecx
     jg  @@Clipped_G
         mov eax,_X2
     cmp eax,ebx
     jl  @@Clipped_G
     cmp eax,ecx
     jg  @@Clipped_G
         mov eax,_X3
     cmp eax,ebx
     jl  @@Clipped_G
     cmp eax,ecx
     jg  @@Clipped_G

         mov ebp,_Y3
         sub ebp,_Y1              ; count
         mov _Count,ebp

         mov eax,_LeftX
         mov edx,_RightX
     mov ebx,_LeftI
     mov ecx,_RightI

     push eax                 ; need regs ( Crappy Intel )
     push edx
     push edi                 ; save old place

         shr eax,16
         add edi,eax              ; mov to required point
         shr edx,16
     sub edx,eax
     inc edx
     mov ebp,edx
     mov eax,edi              ; read in edi into active cache
         mov eax,_LeftI           ; start at left end

@@DoScanLine_G:

         cmp _Count,0
     je  @@Cleanup_G

@@DoInnerScanLine_G:

         cmp ebp,0                  ; inner for loop
     je  @@DoUpdateData_G

       mov edx,eax              ; get MiddleI
         sar edx,16               ; get whole part
       mov dl,BYTE PTR [ esi+edx ]
           mov [edi],dl
       inc edi
           add eax,_MiddleDi;
       dec ebp
     jmp @@DoInnerScanLine_G

@@DoUpdateData_G:

           add ebx,_LeftDi
       add ecx,_RightDi
           pop edi
       pop edx
       pop eax
       add eax,_LeftDx
       add edx,_RightDx
       add edi,_ScreenWidth
       push eax
       push edx
       push edi                 ; save old place
       shr eax,16               ; get whole part
           add edi,eax              ; move buffer into postion
           shr edx,16
       sub edx,eax
       inc edx
       mov ebp,edx              ; holds horiz count
       mov eax,ecx
       sub eax,ebx
       cdq
         idiv ebp
           mov _MiddleDi,eax
       mov eax,ebx              ; Start MiddleI from LeftI
           mov edx,edi              ; get buffer in active cache
       dec _Count
         jmp @@DoScanLine_G

@@Clipped_G:

         mov ebp,_Y3
         sub ebp,_Y1
     mov _Count,ebp

         mov eax,_LeftX
         mov edx,_RightX
     mov ebx,_LeftI
     mov _MiddleI,ebx         ; start MiddleI at LeftI
     mov ecx,_RightI

     push eax
     push edx
     push edi                 ; save old place

@@DoScanLineClip_G:

     cmp _Count,0
     je  @@Cleanup_G

          sar eax,16               ; ClipLeftX
          sar edx,16               ; ClipRightX

      cmp eax,_MinClipX
      jge @@Skip6_G
            cmp edx,_MinClipX
            jge @@Skip5_G
              pop edi
          pop edx
                pop eax
          add eax,_LeftDx
          add edx,_RightDx
          add edi,_ScreenWidth
          push eax
          push edx
          push edi
          add ebx,_LeftDi
          add ecx,_RightDi
          dec _Count
         jmp @@DoScanLineClip_G

@@Skip5_G:

     mov ebp,edx       ; will be obliterated by imul
     sub eax,_MinClipX
     neg eax
     imul _MiddleDi
     add eax,ebx       ; Add LeftI
     mov _MiddleI,eax
     mov eax,_MinClipX
     mov edx,ebp       ; restore ClipRightX

@@Skip6_G:

     cmp edx,_MaxClipX
     jle @@Skip8_G
           cmp eax,_MaxClipX
       jle @@Skip7_G
             pop edi
         pop edx
               pop eax
         add eax,_LeftDx
         add edx,_RightDx
         add edi,_ScreenWidth
         push eax
         push edx
         push edi
             add ebx,_LeftDi
             add ecx,_RightDi
             dec _Count
         jmp @@DoScanLineClip_G

@@Skip7_G:

         mov edx,_MaxClipX

@@Skip8_G:

         add edi,eax              ; mov to required point
     sub edx,eax
     inc edx
     mov ebp,edx              ; horiz count
     mov eax,edi              ; read in edi into active cache
         mov eax,_MiddleI

@@DoInnerScanLineClip_G:

         cmp ebp,0                  ; inner for loop
     je  @@DoUpdateDataClip_G
       mov edx,eax              ; get MiddleI
         sar edx,16               ; get whole part
           mov dl,BYTE PTR [ esi+edx ]
           mov [edi],dl
        inc edi
           add eax,_MiddleDi;
       dec ebp
     jmp @@DoInnerScanLineClip_G

@@DoUpdateDataClip_G:

           add ebx,_LeftDi
       add ecx,_RightDi
           pop edi
       pop edx
       pop eax
       add eax,_LeftDx
       add edx,_RightDx
       add edi,_ScreenWidth
       push eax
       push edx
       push edi                 ; save old place
           mov ebp,eax
       mov _Temp,edx
           sub edx,eax
       sar edx,16
       inc edx
       mov _Width,edx
       mov eax,ecx
       sub eax,ebx
           cdq
       idiv _Width
           mov _MiddleDi,eax
       mov _MiddleI,ebx              ; Start MiddleI from LeftI
           mov eax,ebp                   ; restore LeftX, RightX
       mov edx,_Temp
       dec _Count
         jmp @@DoScanLineClip_G

@@Cleanup_G:

         pop edi
     pop edx
     pop eax

@@SecondHalf_G:

         cmp _GENERAL,0       ; if not GENERAL Triangle goto end
     je  @@TheEnd_G

         mov eax,_X2          ; setup for bottom half
         mov _X1,eax
         mov eax,_Y2
         mov _Y1,eax
     mov eax,_I2
     mov _I1,eax

         mov eax,_X3
         mov _X2,eax
     mov eax,_I3
     mov _I2,eax

         mov eax,_oldx3
         mov _X3,eax
         mov eax,_oldy3
         mov _Y3,eax
     mov eax,_oldi3
     mov _I3,eax

         mov edi,_RendBuffer

@@FLAT_TOP_G:

         mov eax,_X2
         cmp eax,_X1
         jge @@Skip9_G
         mov ebx,_X1
         mov _X2,ebx
         mov _X1,eax
     mov eax,_I2
     mov ebx,_I1
     mov _I2,ebx
     mov _I1,eax

@@Skip9_G:

         mov ebx,_Y3
         sub ebx,_Y1
     mov eax,0x00010000         ; eax=65536
         cdq
     idiv ebx
     mov ebx,eax                ; save height
         mov eax,_X3
         sub eax,_X1
     imul ebx
         mov _LeftDx,eax
         mov eax,_X3
         sub eax,_X2
     imul ebx
         mov _RightDx,eax

         mov eax,_X1
         sal eax,16
         mov _LeftX,eax
         mov eax,_X2
         sal eax,16
     add eax,0x00008000    ; add 0.5 to it
         mov _RightX,eax

         mov eax,_I1
     sal eax,16
     mov _LeftI,eax
     mov eax,_I2
     sal eax,16
     mov _RightI,eax

         mov eax,_I3
     sub eax,_I1
     imul ebx              ; multiply times height
     mov _LeftDi,eax
     mov eax,_I3
     sub eax,_I2
     imul ebx
     mov _RightDi,eax
     mov eax,_RightI
     sub eax,_LeftI
     cdq
     mov ebx,_RightX
     sub ebx,_LeftX
     sar ebx,16
     inc ebx
     idiv ebx
     mov _MiddleDi,eax

         mov ebx,_MinClipY
         cmp ebx,_Y1
         jle @@Skip10_G
     cmp ebx,_Y3
     jg  @@TheEnd_G           ; poly is totally clipped
         sub ebx,_Y1              ; ydiff
     mov eax,ebx
         imul _LeftDx
         add _LeftX,eax
     mov eax,ebx
         imul _RightDx
         add _RightX,eax

     mov eax,ebx
     imul _LeftDi
     add _LeftI,eax
     mov eax,ebx
     imul _RightDi
     add _RightI,eax

         mov eax,_RightI
     sub eax,_LeftI
     cdq
     mov ebx,_RightX
     sub ebx,_LeftX
     sar ebx,16
     inc ebx
     idiv ebx
     mov _MiddleDi,eax

     mov ebx,_MinClipY
         mov _Y1,ebx           ; _Y1=POLY_MIN_CLIP_Y

@@Skip10_G:

         mov eax,_MaxClipY
         cmp eax,_Y3
         jge @@Skip11_G
     cmp eax,_Y1
     jl  @@TheEnd_G

         mov _Y3,eax

@@Skip11_G:

         mov eax,_Y1
     mov ebx,eax
         sal eax,8
         sal ebx,6
     add eax,ebx
     add edi,eax            ; Buffer+=(_Y1<<8)+(_Y1<<6)

         jmp $+2                   ; clear prefetch queue

         mov eax,_X1
         mov ebx,_MinClipX
         mov ecx,_MaxClipX
     cmp eax,ebx               ; if (_X1>=POLY_MIN_CLIP_X && _X1<=POLY_MAX_CLIP_X && etc.
     jl  @@Clipped2_G
     cmp eax,ecx
     jg  @@Clipped2_G
         mov eax,_X2
     cmp eax,ebx
     jl  @@Clipped2_G
     cmp eax,ecx
     jg  @@Clipped2_G
         mov eax,_X3
     cmp eax,ebx
     jl  @@Clipped2_G
     cmp eax,ecx
     jg  @@Clipped2_G

         mov ebp,_Y3
         sub ebp,_Y1              ; count
         mov _Count,ebp

         mov eax,_LeftX
         mov edx,_RightX
     mov ebx,_LeftI
     mov ecx,_RightI

     push eax
     push edx
     push edi                 ; save old place

         shr eax,16
         add edi,eax              ; mov to required point
         shr edx,16
     sub edx,eax
     inc edx
     mov ebp,edx
     mov eax,edi              ; read in edi into active cache
         mov eax,_LeftI           ; start at left end

@@DoScanLine2_G:

         cmp _Count,0
     je  @@Cleanup2_G

@@DoInnerScanLine2_G:

         cmp ebp,0                  ; inner for loop
     je  @@DoUpdateData2_G

       mov edx,eax              ; get MiddleI
         sar edx,16               ; get whole part
           mov dl,BYTE PTR [ esi+edx ]
           mov [edi],dl
        inc edi
           add eax,_MiddleDi;
       dec ebp
     jmp @@DoInnerScanLine2_G

@@DoUpdateData2_G:

           add ebx,_LeftDi
       add ecx,_RightDi
           pop edi
       pop edx
       pop eax
       add eax,_LeftDx
       add edx,_RightDx
       add edi,_ScreenWidth
       push eax
       push edx
       push edi                 ; save old place
       shr eax,16               ; get whole part
           add edi,eax              ; move buffer into postion
           shr edx,16
       sub edx,eax
       inc edx
       mov ebp,edx              ; holds horiz count
       mov eax,ecx
       sub eax,ebx
       cdq
         idiv ebp
           mov _MiddleDi,eax
       mov eax,ebx              ; Start MiddleI from LeftI
           mov edx,edi              ; get buffer in active cache
       dec _Count

         jmp @@DoScanLine2_G

@@Clipped2_G:

         mov ebp,_Y3
         sub ebp,_Y1
     mov _Count,ebp

         mov eax,_LeftX
         mov edx,_RightX
     mov ebx,_LeftI
     mov _MiddleI,ebx         ; start MiddleI at LeftI
     mov ecx,_RightI

     push eax
     push edx
     push edi                 ; save old place

@@DoScanLineClip2_G:

     cmp _Count,0
     je  @@Cleanup2_G

          sar eax,16               ; ClipLeftX
          sar edx,16               ; ClipRightX

      cmp eax,_MinClipX
      jge @@Skip13_G
            cmp edx,_MinClipX
            jge @@Skip12_G
              pop edi
          pop edx
                pop eax
          add eax,_LeftDx
          add edx,_RightDx
          add edi,_ScreenWidth
          push eax
          push edx
          push edi
          add ebx,_LeftDi
          add ecx,_RightDi
          dec _Count
         jmp @@DoScanLineClip2_G

@@Skip12_G:

         mov ebp,edx       ; save edx
     sub eax,_MinClipX
     neg eax
     imul _MiddleDi
     add eax,ebx       ; Add LeftI
     mov _MiddleI,eax
     mov eax,_MinClipX
     mov edx,ebp

@@Skip13_G:

     cmp edx,_MaxClipX
     jle @@Skip15_G
           cmp eax,_MaxClipX
       jle @@Skip14_G
             pop edi
         pop edx
               pop eax
         add eax,_LeftDx
         add edx,_RightDx
         add edi,_ScreenWidth
         push eax
         push edx
         push edi
             add ebx,_LeftDi
             add ecx,_RightDi
             dec _Count
         jmp @@DoScanLineClip2_G

@@Skip14_G:

         mov edx,_MaxClipX

@@Skip15_G:

         add edi,eax              ; mov to required point
     sub edx,eax
     inc edx
     mov ebp,edx              ; horiz count
     mov eax,edi              ; read in edi into active cache
         mov eax,_MiddleI

@@DoInnerScanLineClip2_G:

         cmp ebp,0                  ; inner for loop
     je  @@DoUpdateDataClip2_G
       mov edx,eax              ; get MiddleI
         sar edx,16               ; get whole part
           mov dl,BYTE PTR [ esi+edx ]
           mov [edi],dl
        inc edi
           add eax,_MiddleDi;
       dec ebp
     jmp @@DoInnerScanLineClip2_G

@@DoUpdateDataClip2_G:

           add ebx,_LeftDi
       add ecx,_RightDi
           pop edi
       pop edx
       pop eax
       add eax,_LeftDx
       add edx,_RightDx
       add edi,_ScreenWidth
       push eax
       push edx
       push edi                 ; save old place
           mov ebp,eax
       mov _Temp,edx
           sub edx,eax
       sar edx,16
       inc edx
       mov _Width,edx
       mov eax,ecx
       sub eax,ebx
           cdq
       idiv _Width
           mov _MiddleDi,eax
       mov _MiddleI,ebx              ; Start MiddleI from LeftI
           mov eax,ebp                   ; restore LeftX, RightX
       mov edx,_Temp
       dec _Count
         jmp @@DoScanLineClip2_G

@@Cleanup2_G:

         pop edi            ; pop regs that have been previously pushed.
     pop edx
     pop eax

@@TheEnd_G:

         pop  edi
         pop  esi
         pop  ebp

     cld
     ret
Scan_Convert_Gouraud ENDP

_TEXT            ENDS

END