; Seven Kingdoms: Ancient Adversaries
;
; Copyright 1997,1998 Enlight Software Ltd.
;
; This program is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program. If not, see .
;
;Filename : IB_ATD.ASM
;Description : Blt a bitmap to the display surface buffer
; with decompression, transparency handling
INCLUDE IMGFUN.inc
INCLUDE COLCODE.inc
.CODE
;----------- BEGIN OF FUNCTION IMGbltAreaTransDecompress ------
;
; Put a compressed bitmap on image buffer.
; It does handle color key transparency.
;
; Syntax : IMGbltAreaTransDecompress( imageBuf, pitch, x, y, bitmapBuf,
; x1, y1, x2, y2)
;
; char *imageBuf - the pointer to the display surface buffer
; int pitch - pitch of the display surface buffer
; int x,y - where to put the image on the surface buffer
; char *bitmapPtr - the pointer to the bitmap buffer
; int x1,y1,x2,y2 - clipping window from left, top of the bitmap
;
; the area to be blit to the screen is called clip window
; the width of clip window is stored in clipWindow
;
; ESI and AH points to a point in the bitmap data
; if ESI points to a compression key (i.e. F8-FF),
; AH refer to how many of points are passed.
; i.e. [esi] = F8 21, AH may to 0 to 20
;
; SeekForward function move the (ESI,AH) pointer
; to forward ECX points (decompressed)
;
; ESI and AH are positioned to the top left hand corner of clip window
; and move right, and then downward
;
; After the cursor moved right, it checks for three cases:
; 1. non-transparent data
; 2. transparent data, but do not pass the right of the clip window
; 3. transparent data, and will pass the right of the clip window
;
; for case 1, blit the point and move one point right. If the right
; side of the clip window is passed, position EDI and (ESI,AH) to the
; left side of the clip window on next line.
;
; for case 2, simply move the EDI and (ESI,AH) forward by the run-length
; count
;
; for case 3, skip EDI and (ESI,AH) to the left side of the clip window
; on the next line
;
;-------------------------------------------------
;
; Format of the bitmap data :
;
; width
; height
; bitmap image
;
;-------------------------------------------------
PUBLIC IMGbltAreaTransDecompress
SeekForward PROTO STDCALL ; see IB_ATRD.ASM
IMGbltAreaTransDecompress PROC imageBuf,pitch,x,y,bitmapPtr,x1,y1,x2,y2
LOCAL clipWidth:DWORD, bitmapWidth:DWORD, bitmapHeight:DWORD
LOCAL tempESI:DWORD
STARTPROC
MOV EAX, imageBuf ; store the address of the image buffer to a variable
MOV image_buf, EAX
;------ get the bitmap width and height -----;
MOV AX , DS
MOV ES , AX
MOV ESI, bitmapPtr
;------ calculate destination on the video memory ----;
CALC_ADDR_2 EDI, x, y, x1, y1,pitch ; Get the address to the destination buffer
;------ calculate clipWidth - no. of points ploted on each row --;
XOR EAX, EAX
LODSW ; get bitmap width
MOV bitmapWidth, EAX
MOV EAX, x2
SUB EAX, x1
INC EAX
MOV clipWidth, EAX
;----- calculate number of rows to be ploted on the screen
LODSW ; get bitmap height
MOV bitmapHeight, EAX
MOV ECX, EAX
MOV ECX, y2
SUB ECX, y1
; INC ECX ; leave last line less to @@last_line
; last line is handled separately to avoid seekForward
JC @@end ; if negative, skip the procedure
; ----- position ESI to the first point to draw -------
; AH contain the bytes remained in decompression
; position to row y1 and column x1
PUSH ECX
; ECX = y1 * bitmapWidth + x1
MOV EAX, y1
MUL bitmapWidth
ADD EAX, x1 ; DROP EDX
MOV ECX, EAX
MOV AH,0
CALL SeekForward
POP ECX ; ECX is now the height of clipping window
JECXZ @@lastLine
@@loopY: ; --------- start of each line ------------
PUSH ECX
MOV ECX, clipWidth
@@loopX:
; -------- start of each point -----------
LODSB
JUMP_IF_TRANS al, @@clipCompress1
@@nonTrans:
; ------- non-transparent data -----------
; 00-F7, simply blit the point on video memory
STOSB
; ------- test end of line ----------------
; (pass the right of clipping window)
LOOP @@loopX
ADD EDI, pitch
SUB EDI, clipWidth
; ------- seek source(ESI) to next line -----
MOV ECX, bitmapWidth
SUB ECX, clipWidth
MOV AH,0
CALL SeekForward
JMP @@endloopY
ALIGN 4
@@clipCompress1:
; ------ transparent data -------------
MOV tempESI, ESI ; save ESI
; note: run-length is now in [ESI]-AH
JUMP_IF_NOT_MANY_TRANS al, @@clipCompress1a
LODSB ; load the run-length count
ENCODE_FEW_TRANS_CODE al
@@clipCompress1a:
MOV DL,AL
DECODE_FEW_TRANS_CODE dl
SUB DL,AH
MOVZX DX,DL
CMP ECX, EDX
JBE @@clipCompress2
; ECX > EDX
; meaning the run-length is still within clip window
ADD EDI, EDX ; skip the number of points
SUB ECX, EDX
MOV AH,0
JMP @@loopX
ALIGN 4
@@clipCompress2:
; ------- run-length is outside clip window --------
; EDI seek the the start of the next line
; EDI += ECX - clipWidth + pitch
ADD EDI, pitch
SUB ECX, clipWidth
ADD EDI, ECX
; find out the no. of byte to call SeekForward
; to seek the left side of clip window of next line
; ECX = (ECX - clipWidth) + bitmapWidth
ADD ECX, bitmapWidth
MOV ESI, tempESI ; restore ESI to compresion key (f8-ff)
DEC ESI
CALL SeekForward
@@endloopY: POP ECX
LOOP @@loopY
;------- similarly blit the last line -------;
@@lastLine:
MOV ECX, clipWidth
@@lastLoopX:
LODSB
JUMP_IF_TRANS al, @@lastClipCompress1
@@lastNonTrans:
STOSB
; --------- test end of line ----------
LOOP @@lastLoopX
JMP @@endLast
ALIGN 4
@@lastClipCompress1:
; note: run-length is now in AH not [ESI]
JUMP_IF_NOT_MANY_TRANS al, @@lastClipCompress1a
; F8
LODSB
ENCODE_FEW_TRANS_CODE al
@@lastClipCompress1a:
MOV DL,AL
DECODE_FEW_TRANS_CODE al
SUB DL,AH
MOVZX DX,DL
CMP ECX, EDX
JBE @@endLast
; ECX > EDX
; meaning the run-length is still within clip window
ADD EDI, EDX ; skip the number of points
SUB ECX, EDX
MOV AH,0
JMP @@lastLoopX
ALIGN 4
@@endLast:
@@end: ENDPROC
IMGbltAreaTransDecompress ENDP
;----------- END OF FUNCTION IMGbltAreaTransRemapDecompress ----------
END