170 lines
4.8 KiB
NASM
170 lines
4.8 KiB
NASM
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.386
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.MODEL small
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SKIPPRIMITIVES = 0 ; set to 1 to skip unwound drawing
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INCLUDE viewsize.inc
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INCLUDE macros.inc
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SCREEN = 0a0000h
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SCREENWIDTH = 320
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PEL_WRITE_ADR = 03c8h
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PEL_DATA = 03c9h
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.DATA
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EXTRN viewbuffer:WORD
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EXTRN viewLocation:DWORD
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EXTRN windowWidth:DWORD
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EXTRN windowHeight:DWORD
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.CODE
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;=========================================================================
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;= VI_DrawMaskedPicToBuffer =
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;= =
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;= C prototype: =
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;= void VI_DrawMaskedPicToBuffer (int x, int y, pic_t *pic) =
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;=========================================================================
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@Proc VI_DrawMaskedPicToBuffer, <eax,ebx,ecx,edx,esi,edi>, <<x,DWORD>,<y,DWORD>,<pic,DWORD>>
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mov edi,OFFSET viewbuffer
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mov esi,[pic] ; si -> pic
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;----- Set up y and height
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xor ecx,ecx
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mov cx,[esi+2] ; get height (row count) of image
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mov eax,[y] ; get row location
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sub ax,[esi+6] ; subtract orgy
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;----- Adjust for y < 0
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or eax,eax ; is y < 0 ?
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jnl short @@findheight ; if not, go to height adjust
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add ecx,eax ; if so, add y to height (h -= (-y))
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xor eax,eax ; y = 0
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;----- Check for bitmap going off the bottom edge
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@@findheight:
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push eax ; save y
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add eax,ecx ; bottom row of image
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cmp eax,windowHeight
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pop eax ; restore y
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jle short @@heightok ; if not, get on with it
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mov ecx,windowHeight
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sub ecx,eax ; h = bottom - y
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@@heightok:
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;;;; set es:edi to di+(eax*MAX_VIEW_WIDTH)
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mov ebx,windowWidth
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mul ebx ; oh no, not a mul!
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add edi,eax ; move down Viewbuffer to proper row
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;----- Set up x and width
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mov edx,[x] ; get column location
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sub dx,[esi+4] ; subtract orgx
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mov bx,[esi] ; get width (col count) of image
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;----- Set up esi to pic->data
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add esi,8
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;----- Adjust for x < 0
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or edx,edx ; is x < 0:
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jnl short @@findwidth ; if not, go to width adjust
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add ebx,edx ; if so, add x to width (w -= (-x))
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;----- Check for bitmap going off the right edge
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@@findwidth:
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push edx ; save x
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add edx,ebx ; rightmost col of image
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cmp edx,windowWidth ; is (w+x) > right ?
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pop edx ; restore x
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jle short @@widthok ; if not, get on with it
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mov ebx,windowWidth ; if so,
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sub ebx,edx ; w = right - x
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@@widthok:
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;----- Set up edi to point to Veiwbuffer[x,y]
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add edi,edx
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mov edx,windowWidth ; set eax to pixels in viewbuffer
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sub edx,ebx ; to right of our image
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@@rowloop:
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push ecx ; save height (row count)
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;------ Copy this row (masked) to Viewbuffer
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mov ecx,ebx ; get width (col count) of image
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shr ecx,2
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@@colloop: ; for each pixel in row
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; lodsb ; get the pixel
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; test al,al ; check for zero (mask)
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; jnz short @@putit ; if not zero, put it in Viewbuffer
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; inc di ; otherwise, increment Viewbuffer ptr
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lodsd
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test eax,eax
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jnz short @@try1
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add edi,4
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loop @@colloop
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jmp short @@rowdone
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@@try1:
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test al,al
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jz short @@try2
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mov [es:edi],al
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@@try2:
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inc edi
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shr eax,8
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test al,al
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jz short @@try3
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mov [es:edi],al
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@@try3:
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inc edi
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shr eax,8
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test al,al
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jz short @@try4
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mov [es:edi],al
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@@try4:
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inc edi
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shr eax,8
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test al,al
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jz short @@next4
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mov [es:edi],al
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@@next4:
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inc edi
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loop @@colloop ; and go to next pixel
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; jmp short @@rowdone ; we must be done with this row
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;@@putit: ; put the pixel in Viewbuffer
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; stosb ; go ahead, put it there
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; loop @@colloop ; go to the next pixel
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@@rowdone: ; this row is finished
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;------
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pop ecx ; restore height (row count)
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add edi,edx ; increment Viewbuffer to next row
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loop @@rowloop ; go to the next row
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@exitp <eax,ebx,ecx,edx,esi,edi>
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ENDP
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END
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