;----------------------------------------------------------------------- ; MODULE XPBITMAP ; Compile with Tasm. ; C callable. ; ; MODE X Source Addapted from Themie Gouthas's ; XLIB - Mode X graphics library ;----------------------------------------------------------------------- include xlib.inc include xpbitmap.inc LOCALS .code ;---------------------------------------------------------------------- ; PutObj- mask write a planar bitmap from system ram to video ram ; all zero source bitmap bytes indicate destination byte to be left unchanged ; ; PutObj(X,Y,ScrnOffs,char far * Bitmap) ;---------------------------------------------------------------------- _PutObj proc ARG X:word,Y:word,ScrnOffs:word,Bitmap:dword LOCAL BMWidth:byte,BMHeight:byte,NextLineIncr:word=LocalStk push bp mov bp,sp sub sp,LocalStk ; CREATE SPACE FOR LOCAL VARIABLES push si push di push ds cld mov ax,SCREEN_SEG mov es,ax mov ax,[Y] ; CALCULATE DEST SCREEN ROW mov bx,[_ScrnLogicalByteWidth]; BY MULT. DEST Y COORD BY SCREEN mul bx ; WIDTH THEN ADDING SCREEN OFFSET mov di,[ScrnOffs] ; STORE RESULT IN DI add di,ax mov cx,[X] ; LOAD X COORD INTO CX AND MAKE A mov dx,cx ; COPY IN DX shr dx,2 ; FIND STARTING BYTE IN DES add di,dx ; ADD TO DI GIVING SCREEN ; FIRST PIXEL'S BYTE lds si,[Bitmap] ; DS:SI -> BITMAP DATA lodsw ; AL = B.M. WIDTH (BYTES) A ; HEIGHT mov [BMHeight],ah ; SAVE SOURCE BITMAP DIMENS mov [BMWidth],al ; xor ah,ah ; NEXTLINEINCR = BYTES TO TO sub bx,ax ; OF BITMAPS NEXT ROW ON S mov [NextLineIncr],bx ; and cx,0003h ; MASK X COORD GIVING PLANE ; BITMAP PIXEL mov ah,11h ; INIT. MASK shl ah,cl ; SHIFT FOR STARTING PIXEL mov dx,SC_INDEX ; PREPARE VGA FOR CPU WRITES mov al,MAP_MASK out dx,al inc dx mov bh,4 ; SET PLANE COUNTER (BH) TO @@PlaneLoop: push di ; SAVE BITMAP'S START DEST. mov bl,[BMHeight] ; RESET ROW COUNTER (BL) mov al,ah out dx,al ; SET VGA WRITE PLANE @@RowLoop: mov cl,[BMWidth] ; RESET COLUMN COUNTER CL @@ColLoop: lodsb ; GET NEXT SOURCE BITMAP BY or al,al ; IF NOT ZERO THEN WRITE TO jz @@NoPixel ; OTHERWISE SKIP TO NEXT BY mov es:[di],al @@NoPixel: inc di loop @@ColLoop ; LOOP IF MORE COLUMNS LEFT add di,[NextLineIncr] ; MOVE TO NEXT ROW dec bl ; DECREMENT ROW COUNTER jnz @@RowLoop ; JUMP IF MORE ROWS LEFT pop di ; RESTORE BITMAPS START DES rol ah,1 ; SHIFT MASK FOR NEXT PLANE adc di,0 ; IF WRAPPED INCREMENT DEST dec bh ; DECREMENT PLANE COUNTER jnz @@PlaneLoop ; JUMP IF MORE PLANES LEFT pop ds ; RESTORE DATA SEGMENT pop di ; RESTORE REGISTERS pop si mov sp,bp ; DEALLOC LOCAL VARIABLES pop bp ret _PutObj endp ;---------------------------------------------------------------------- ; WriteObj - Write a planar bitmap from system ram to video ram ; ; Source Bitmap structure: ; ; Width:byte, Height:byte, Bitmap data (plane 0)...Bitmap data (plane 1).., ; Bitmap data (plane 2)..,Bitmap data (plane 3).. ; ;---------------------------------------------------------------------- _WriteObj proc ARG X:word,Y:word,ScrnOffs:word,Bitmap:dword LOCAL Plane:byte,BMHeight:byte,LineInc:word=LocalStk push bp mov bp,sp sub sp,LocalStk ; Create space for local variables push si push di push ds cld mov ax,SCREEN_SEG mov es,ax mov ax,[Y] ; Calculate dest screen row mov bx,[_ScrnLogicalByteWidth] ; by mult. dest Y coord by Screen mul bx ; width then adding screen offset mov di,[ScrnOffs] ; store result in DI add di,ax mov cx,[X] ; Load X coord into CX and make a mov dx,cx ; copy in DX shr dx,2 ; Find starting byte in dest row add di,dx ; add to DI giving screen offset of ; first pixel's byte lds si,[Bitmap] ; DS:SI -> Bitmap data lodsw ; Al = B.M. width (bytes) AH = B.M. ; height UnFlipped: mov [BMHeight],ah ; Save source bitmap dimensions xor ah,ah ; LineInc = bytes to the begin. sub bx,ax ; of bitmaps next row on screen mov [LineInc],bx mov bh,al ; Self Modifying, Shame, shame shame.. and cx,0003h ; mask X coord giving plane of 1st ; bitmap pixel(zero CH coincidentally) mov ah,11h ; Init. mask for VGA plane selection shl ah,cl ; Shift for starting pixel plane mov dx,SC_INDEX ; Prepare VGA for cpu to video writes mov al,MAP_MASK out dx,al inc dx mov [Plane],4 ; Set plane counter to 4 @@PlaneLoop: push di mov bl,[BMHeight] mov al,ah out dx,al @@RowLoop: mov cl,bh shr cl,1 rep movsw ; Copy a complete row for curr plane adc cl,0 rep movsb add di,[LineInc] ; Move to next row dec bl ; decrement row counter jnz @@RowLoop ; Jump if more rows left pop di ; Restore bitmaps start dest byte rol ah,1 ; Shift mask for next plane adc di,0 ; If wrapped increment dest address dec [Plane] ; Decrement plane counter jnz @@PlaneLoop ; Jump if more planes left pop ds ; restore data segment pop di ; restore registers pop si mov sp,bp ; dealloc local variables pop bp ret _WriteObj endp ;---------------------------------------------------------------------- ; EraseObj ;---------------------------------------------------------------------- _EraseObj proc ARG X:word,Y:word,Width:byte,Height:byte,ScrnOffs:word LOCAL Plane:byte,LineInc:word=LocalStk push bp mov bp,sp sub sp,LocalStk ; Create space for local variables push si push di push ds cld mov ax,SCREEN_SEG mov es,ax mov ax,[Y] ; Calculate dest screen row mov bx,[_ScrnLogicalByteWidth] ; by mult. dest Y coord by Screen mul bx ; width then adding screen offset mov di,[ScrnOffs] ; store result in DI add di,ax mov cx,[X] ; Load X coord into CX and make a mov dx,cx ; copy in DX shr dx,2 ; Find starting byte in dest row add di,dx ; add to DI giving screen offset of ; first pixel's byte mov al, [Width] xor ah,ah ; LineInc = bytes to the begin. sub bx,ax ; of bitmaps next row on screen mov [LineInc],bx mov bh,al ; Self Modifying, Shame, shame shame.. and cx,0003h ; mask X coord giving plane of 1st ; bitmap pixel(zero CH coincidentally) mov ah,11h ; Init. mask for VGA plane selection shl ah,cl ; Shift for starting pixel plane mov dx,SC_INDEX ; Prepare VGA for cpu to video writes mov al,MAP_MASK out dx,al inc dx mov [Plane],4 ; Set plane counter to 4 @@PlaneLoop: push di mov bl,[Height] mov al,ah out dx,al @@RowLoop: mov cl,bh shr cl,1 push ax mov ax,0 rep stosw ; Copy a complete row for curr plane pop ax add di,[LineInc] ; Move to next row dec bl ; decrement row counter jnz @@RowLoop ; Jump if more rows left pop di ; Restore bitmaps start dest byte rol ah,1 ; Shift mask for next plane adc di,0 ; If wrapped increment dest address dec [Plane] ; Decrement plane counter jnz @@PlaneLoop ; Jump if more planes left pop ds ; restore data segment pop di ; restore registers pop si mov sp,bp ; dealloc local variables pop bp ret _EraseObj endp end