RedAlert/WIN32LIB/FONT/TEXTPRNT.ASM

;
;	Command & Conquer Red Alert(tm)
;	Copyright 2025 Electronic Arts Inc.
;
;	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 3 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 <http://www.gnu.org/licenses/>.
;

;***************************************************************************
;**     C O N F I D E N T I A L --- W E S T W O O D   S T U D I O S       **
;***************************************************************************
;*                                                                         *
;*                 Project Name : 32 bit library Text Print                *
;*                                                                         *
;*                    File Name : TEXTPRNT.ASM                             *
;*                                                                         *
;*                   Programmer : Scott K. Bowen                           *
;*                                                                         *
;*                   Start Date : July 2, 1994                             *
;*                                                                         *
;*                  Last Update : July 2, 1994   [SKB]                     *
;*                                                                         *
;*-------------------------------------------------------------------------*
;* Functions:                                                              *
;*   Text_Print -- Assembly text print routine.                            *
;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - *

IDEAL
P386
MODEL USE32 FLAT



GLOBAL	FontPtr:DWORD
GLOBAL	Text_Print:NEAR

; The header of the font file looks like this:
; 	UWORD	FontLength;		0
; 	BYTE	FontCompress;		2
;	BYTE	FontDataBlocks;		3
;	UWORD	InfoBlockOffset;	4
;	UWORD	OffsetBlockOffset;	6
;	UWORD	WidthBlockOffset;	8
;	UWORD	DataBlockOffset;	10
;	UWORD	HeightOffset;		12
; For this reason the following equates have these values:
FONTINFOBLOCK		EQU	4
FONTOFFSETBLOCK		EQU	6
FONTWIDTHBLOCK		EQU	8
FONTDATABLOCK		EQU	10
FONTHEIGHTBLOCK		EQU	12

FONTINFOMAXHEIGHT	EQU	4
FONTINFOMAXWIDTH	EQU	5

LOCALS ??

	DATASEG

ColorXlat	DB	000H,001H,002H,003H,004H,005H,006H,007H
		DB	008H,009H,00AH,00BH,00CH,00DH,00EH,00FH

		DB	001H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	002H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	003H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	004H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	005H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	006H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	007H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	008H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	009H,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00AH,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00BH,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00CH,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00DH,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00EH,000H,000H,000H,000H,000H,000H,000H
		DB	000H,000H,000H,000H,000H,000H,000H,000H

		DB	00FH

	CODESEG


;***************************************************************************
;* TEXT_PRINT -- Assembly text print routine.                              *
;*                                                                         *
;*                                                                         *
;* INPUT:                                                                  *
;*                                                                         *
;* OUTPUT:                                                                 *
;*                                                                         *
;* WARNINGS:                                                               *
;*                                                                         *
;* HISTORY:                                                                *
;*   06/28/1994 SKB : Created.                                             *
;*=========================================================================*
	PROC	Text_Print C near
	USES	ebx,ecx,edx,esi,edi
	ARG	vpselector:WORD
	ARG	vpoffset:DWORD
	ARG	vpwidth:DWORD
	ARG	vpheight:DWORD
	ARG	vpxadd:DWORD
	ARG	string:DWORD
	ARG	x_pixel:DWORD
	ARG	y_pixel:DWORD
	ARG	fcolor:DWORD
	ARG	bcolor:DWORD
		
	LOCAL	infoblock:DWORD		; pointer to info block
	LOCAL	offsetblock:DWORD	; pointer to offset block  (UWORD *)
	LOCAL	widthblock:DWORD	; pointer to width block   (BYTE  *)
	LOCAL	heightblock:DWORD	; pointer to height block  (UWORD *)

	LOCAL	curline:DWORD		; pointer to first column of current row.
	LOCAL	bufferwidth:DWORD    	; width of buffer (vpwidth + Xadd)
	LOCAL	nextdraw:DWORD		; bufferwidth - width of cur character.
	LOCAL	startdraw:DWORD		; where next character will start being drawn.

	LOCAL	char:DWORD		; current character value.	

	LOCAL	maxheight:BYTE		; max height of characters in font.
	LOCAL	bottomblank:BYTE	; amount of empty space below current character.
	LOCAL	charheight:BYTE		; true height of current character.


;-------------------------------- Where to draw -----------------------------------------------
	; Set up memory location to start drawing.
	movzx	eax,[vpselector]
	mov	es,ax			; Set up selector to write to.

	mov	eax,[vpwidth]		; get the width of the viewport
	add	eax,[vpxadd]		; add amount to add to get to left edge of next line.	
	mov	[bufferwidth],eax     	; save it off for later use.

	mul	[y_pixel]		; multiply rowsize * y_pixel start.
	mov	edi,[vpoffset]		; get start of the viewport
	add	edi,eax			; add x,y position to start of vp to get starting row address.	
	mov	[curline],edi		; save 0,y address for line feed stuff.
	add	edi,[x_pixel]		; add to get starting column in starting row.
	mov	[startdraw],edi		; save it off.


;-------------------------------- Create block pointers ----------------------------------------
	; Get the pointer to the font.
	; We could check for NULL but why waste the time.
	; It is up to programmer to make sure it is set.
	mov	esi,[FontPtr]		; Get the font pointer

	; Set up some pointers to the different memory blocks.
	; esi (FontPtr) is added to each to get the true address of each block.
	; Many registers are used for P5 optimizations.
	; ebx is used for InfoBlock which is then used in the next section.
	movzx	eax,[WORD PTR esi+FONTOFFSETBLOCK]	; get offset to offset block
	movzx	ebx,[WORD PTR esi+FONTINFOBLOCK]      	; get offset to info block (must be ebx for height test)
	movzx	ecx,[WORD PTR esi+FONTWIDTHBLOCK] 	; get offset to width block
	movzx	edx,[WORD PTR esi+FONTHEIGHTBLOCK]	; get offset to height block

	add	eax,esi				; add offset of FontPtr to offset block  
	add	ebx,esi				; add offset of FontPtr to info block 
	add	ecx,esi				; add offset of FontPtr to width block
	add	edx,esi				; add offset of FontPtr to height block

	mov	[offsetblock],eax		; save offset to offset block
	mov	[infoblock],ebx			; save offset to info block
	mov	[widthblock],ecx   		; save offset to width block
	mov	[heightblock],edx		; save offset to height block

;------------------------------------------ Test for fit ----------------------------------------------
	; Test to make sure the height of the max character will fit on this line
	; and and not fall out of the viewport.
	; remember we set ebx to FONTINFOBLOCK above.
	movzx	eax,[BYTE PTR ebx + FONTINFOMAXHEIGHT]; get the max height in font.
	mov	[maxheight],al			; save it for later use.
	add	eax,[y_pixel]			; add current y_value.
	cmp	eax,[vpheight]			; are we over the edge?
	jg	??overflow			; if so, we're outa here.

	mov	[y_pixel],eax			; save for next line feed. y value for next line.

	cld					; Make sure we are always forward copying.

;------------------------ Set palette foreground and background ----------------------------------
	mov	eax,[fcolor]		; foreground color
	mov	[ColorXlat+1],al
	mov	[ColorXlat+16],al

	mov	eax,[bcolor]		; background color
	mov	[ColorXlat],al

;-------------------------------------------------------------------------------------------------
;----------------------------------------- Main loop ----------------------------------------------
	; Now we go into the main loop of reading each character in the string and doing
	; something with it.
??next_char:
	; while (*string++)
	xor	eax,eax				; zero out since we will just load al.	
	mov	esi,[string]			; get address on next character.	
	lodsb					; load the character into al.
	test	eax,0FFH			; test to see if character is a NULL
	jz	??done				; character is NULL, get outa here.

	mov	edi,[startdraw]			; Load the starting address.

	mov	[string],esi			; save index into string. (incremented by lodsb)	
	
	cmp	eax,13				; is the character a line feed?
	je	??line_feed			; if so, go to special case.

	mov	[char],eax			; save the character off for later reference.
	mov	ebx,eax				; save it in ebx for later use also.

	add	eax,[widthblock]		; figure address of width of character.
	mov	ecx,[x_pixel]			; get current x_pixel.
	movzx	edx,[BYTE PTR eax]	 	; get the width of the character in dl.
	add	ecx,edx				; add width of char to current x_pixel.
	add	[startdraw],edx			; save start draw for next character.

	cmp	ecx,[vpwidth]			; is the pixel greater then the vp width?
	jg	??force_line_feed		; if so, force a line feed.

	mov	[x_pixel],ecx			; save value of start of next character.
	mov	ecx,[bufferwidth]		; get amount to next y same x (one row down)
	sub	ecx,edx				; take the current width off.
	mov	[nextdraw],ecx			; save it to add to edi when done with a row.

	; At this point we got the character. It is now time to find out specifics
	; about drawing the darn thing.
	; ebx = char so they can be used as an indexes.
	; edx = width of character for loop later.

	; get offset of data for character into esi.
	shl	ebx,1				; mult by 2 to later use as a WORD index.
	mov	esi,[offsetblock]		; get pointer to begining of offset block.
	add	esi,ebx				; index into offset block.	
	movzx	esi,[WORD PTR esi]		; get true offset into data block from FontPtr.
	add	esi,[FontPtr]			; Now add FontPtr address to get true address.

	; Get top and bottom blank sizes and the true height of the character.
	add	ebx,[heightblock]		; point ebx to element in height array.
	mov	al,[ebx+1]			; load the data height into dl.
	mov	cl,[ebx]			; load the first data row into cl.
	mov	bl,[maxheight]			; get the max height of characters.
	mov	[charheight],al			; get number of rows with data.
	add	al,cl				; add the two heights.
	sub	bl,al				; subract topblank + char height from maxheight.
	mov	[bottomblank],bl		; save off the number of blank rows on the bottom.
	; leaving this section:
	; dl is still the width of the character.
	; cl is the height of the top blank area.

	mov	ebx,OFFSET ColorXlat		; setup ebx for xlat commands.
	mov	dh,dl				; save the width of the character to restore each loop.

	cmp	cl,0				; is there any blank rows on top?
	jz	??draw_char			; if not go and draw the real character.

	xor	eax,eax				; get color 0 for background.
	xlat	[ebx]				; get translated color into al
	test	al,al				; is it transparent black
	jnz	??loop_top			; if not go and write the color

;----------------------------------------- skip Top blank area ----------------------------------------
	; this case, the top is transparrent, but we need to increase our dest pointer to correct row.
	movzx	eax,cl				; get number of rows into eax;
	mov	ecx,edx				; save width since edx will be destroyed by mul.
	mul	[bufferwidth]			; multiply that by the width of the buffer.
	mov	edx,ecx				; restore the width
	add	edi,eax				; update the pointer.	
	jmp	short ??draw_char		; now go draw the character.

;----------------------------------------- fill Top blank area ----------------------------------------
	; edi was set a long time ago.
	; al is the translated color
??loop_top:
	stosb					; store the value
	dec	dh				; decrement our width.
	jnz	??loop_top			; if more width, continue on.

	add	edi,[nextdraw]			; add amount for entire row.

	dec	cl				; decrement or row count
	mov	dh,dl				; restore width in dh for loop.
	jz	??draw_char			; we are done here, go draw the character.
	jmp	short ??loop_top		; go back to top of loop.


;----------------------------------------- Draw character ----------------------------------------------
??draw_char:
	movzx	ecx,[charheight]		; get the height of character to count down rows.
	test	ecx,ecx				; is there any data? (blank would not have any)
	jz	??next_char			; if no data, go on to next character.	

??while_data:
	lodsb					; get byte value from font data
	mov	ah,al				; save hinibble
	and	eax,0F00FH	       		; mask of low nibble in al hi nibble in ah.
	xlat	[ebx]				; get new color

	test	al,al				; is it a transparent?
	jz	short ??skiplo			; skip over write
	mov	[es:edi],al			; write it out
??skiplo:
	inc	edi
	dec	dh				; decrement our width.
	jz	short ??nextrow			; check if done with width of char

	mov	al,ah				; restore to get
	; test the time difference between looking up in a large table when shr al,4 is not done as
	; compared to using only a 16 byte table when using the shr al,4
	;shr	al,4				; shift the hi nibble down to low nibble
	xlat	[ebx]				; get new color

	test	al,al				; is it a transparent?
	jz	short ??skiphi			; skip over write
	mov	[es:edi],al			; write it out
??skiphi:
	
	inc	edi
	dec	dh				; decrement our width.
	jnz	short ??while_data		; check if done with width of char

??nextrow:
	add	edi,[nextdraw]			; go to next line.
	dec	ecx				; decrement the number of rows to go
	mov	dh,dl				; restore our column count for row.
	jnz	??while_data			; more data for character.

	; Now it is time to setup for clearing out the bottom of the character.
	movzx	ecx,[bottomblank]		; get amount on bottom that is blank
	cmp	ecx,0				; if there is no blank bottom...
	jz	??next_char			; then skip to go to next character

	xor	eax,eax				; get color 0 for background.
	xlat	[ebx]				; get translated color into al
	test	al,al				; is it transparent black
	jz	??next_char			; skip the top black section to let the background through

	mov	dh,dl				; restore width in dh for loop.

;----------------------------------------- Blank below character -----------------------------------
??loop_bottom:
	stosb					; store the value
	dec	dh				; decrement our width.
	jnz	??loop_bottom			; if more width, continue on.

	add	edi,[nextdraw]			; add amount for entire row.

	mov	dh,dl				; restore width in dh for loop.
	dec	cl				; decrement or row count
	jz	??next_char			; we are done here, go to the next character.
	jmp	short ??loop_bottom		; go back to top of loop.

;----------------------------------- end of next_char (main) loop ------------------------------------
;-------------------------------------------------------------------------------------------------


;----------------------------------- special case line feeds ----------------------------------------

??force_line_feed:	
	; decrement pointer *string so that it will be back at same character
	; when it goes through the loop.
	mov	eax,[string]			; get string pointer.
	dec	eax				; decrement it to point to previos char
	mov	[string],eax			; save it back off.
	; Now go into the line feed code.....

??line_feed:
	mov	edx,[y_pixel]			; get the current y pixel value.
	movzx	ecx,[maxheight]			; get max height for later use.
	add	edx,ecx				; add max height to y_pixel
	cmp	edx,[vpheight]			; are we over the edge?
	jg	??overflow			; if so, we are outa here.

	mov	eax,[bufferwidth]      		; get bytes to next line.
	mov	edi,[curline]			; get start of current line.	
	mul	ecx				; mult max height * next line.	

	add	edi,eax				; add adjustment to current line.
	add	[y_pixel],ecx			; increment to our next y position.
	mov	[curline],edi			; save it off for next line_feed.
	mov	[startdraw],edi			; save it off so we know where to draw next char.w

	mov	[x_pixel],0			; zero out x_pixel

	jmp	??next_char

??overflow:
	mov	[startdraw],0			; Indicate that there is no valid next pos.
??done:
	mov	eax,[startdraw]			; return this so calling routine
	ret					; can figure out where to draw next.
		
	ENDP	Text_Print



;***********************************************************

	END