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Assembly Source File | 1993-06-19 | 15.2 KB | 639 lines

PAGE 80,132 TITLE - XTASM.ASM - Assembly routines for 3D engine ;;;.286P ;============================================================================== ; COMMAND LINE ASSEMBLY ; MASM /B63 /Z /D_Mx FILENAME; ; ; WHERE Mx SPECIFIES MODEL (l OR c) FOR LARGE OR COMPACT MODELS ;============================================================================== INCLUDE ET.EQU INCLUDE ET.MAC ANGLE_30 equ 160 ANGLE_360 equ 1920 extrn _bMaps:DWORD extrn _oMaps:DWORD extrn _bdfp:DWORD extrn _PageBegin:WORD extrn _InvCosTable:DWORD extrn _InvSinTable:DWORD extrn _LongCosTable:DWORD extrn _DistanceTable:WORD extrn _AdjustTable:DWORD extrn _CenterRow:WORD extrn _MaxDistance:WORD extrn _TopColor:WORD extrn _BottomColor:WORD extrn _lowmask:BYTE extrn _Walls:WORD extrn _xRay:NEAR extrn _yRay:NEAR extrn N_LDIV@:FAR PUBLIC _graphinit PUBLIC _usepage PUBLIC _flippage PUBLIC _SetPalette PUBLIC _DrawWalls PUBLIC _DrawOneObject SC_INDEX equ 03c4h ;Sequence Controller Index CRTC_INDEX equ 03d4h ;CRT Controller Index MISC_OUTPUT equ 03c2h ;Miscellaneous Output register SCREEN_SEG equ 0a000h ;segment of display memory in mode X _TEXT segment byte public 'CODE' DGROUP group _DATA,_BSS assume cs:_TEXT,ds:DGROUP _ViewPage dw 0 ; The address of the current view page _WritePage dw 0 ; The address of the current write page PageTable dw 4 dup (0) ; Address of 4 pages ScreenWidth dw 320/4 ; The width of the screen PageSize dw 320/4*240 ; The size of each page CRTParms label word dw 00d06h ;vertical total dw 03e07h ;overflow (bit 8 of vertical counts) dw 04209h ;cell height (2 to double-scan) dw 0ea10h ;v sync start dw 0ac11h ;v sync end and protect cr0-cr7 dw 0df12h ;vertical displayed dw 00014h ;turn off dword mode dw 0e715h ;v blank start dw 00616h ;v blank end dw 0e317h ;turn on byte mode CRT_PARM_LENGTH equ (($-CRTParms)/2) _TEXT ends _DATA segment word public 'DATA' ; Index/data pairs for CRT Controller registers that differ between ; mode 13h and mode X. _d@ label byte _DATA ends _BSS segment word public 'BSS' _b@ label byte _BSS ends public _graphinit public _ViewPage,_WritePage public ScreenWidth,PageSize,PageTable _TEXT SEGMENT byte public 'CODE' ASSUME cs:_TEXT ;============================================================================== ; void graphinit(int width,int psize,int mask) ; width - width of the screen in bytes/plane (defaults to 320/4 if 0) ; psize - size of each page in bytes/plane (defaults to 320*200/4 if 0) ;============================================================================== PBEGIN _graphinit push bp mov bp,sp push si push di push ds mov ax,cs mov ds,ax mov es,ax mov bx,320/4 mov cs:[ScreenWidth],bx mov bx,320/4*240 mov cs:[PageSize],bx ; Set up the page table xor ax,ax mov bx,cs:[PageSize] lea di,cs:[PageTable] mov cx,4 init4: stosw add ax,bx loop init4 ; Now set up the graphics mode mov ax,13h int 10h ; Set 320x200x256 mov dx,3d4h mov al,13h out dx,al inc dx mov al,2dh ;Set bytes per line at 90 out dx,al mov dx,3c4h mov al,4 out dx,al inc dx in al,dx and al,0f7h ;Turn off chain4 mode out dx,al mov dx,3d4h mov al,17h out dx,al inc dx in al,dx or al,40h ;Turn on byte mode out dx,al mov dx,3d4h mov al,14h out dx,al inc dx in al,dx and al,0bfh ;Turn off double-word mode out dx,al mov dx,3dah in al,dx mov dx,3c0h mov al,30h ;Select Attribute index 10h out dx,al mov al,71h ;Turn on PCS, PPC and G/A out dx,al mov ax,SCREEN_SEG ;now clear all display memory, 8 pixels mov es,ax ; at a time sub di,di ;point ES:DI to display memory sub ax,ax ;clear to zero-value pixels mov cx,8000h ;# of words in display memory rep stosw ;clear all of display memory pop ds pop di ;restore C register vars pop si pop bp ;restore caller's stack frame ret _graphinit endp ;============================================================================== ; void SetVGAmode(void); ;============================================================================== PBEGIN _SetVGAmode push bp mov ax,13h int 10h ; Set 320x200x256 pop bp ret _SetVGAmode endp ;============================================================================== ; void usepage(int page) ;============================================================================== UPnum equ [bp+ABASE] PBEGIN _usepage push bp mov bp,sp mov bx,UPnum and bx,3 shl bx,1 mov ax,cs:PageTable[bx] mov cs:[_WritePage],ax pop bp ret _usepage endp ;============================================================================== ; void flippage() ; ; NOTE: Some lines have been commented out for test purposes. If you experience ; flicker when the page flips, un-comment the lines waiting for vertical ; retrace. ;============================================================================== PBEGIN _flippage mov cx,cs:[_ViewPage] xchg cx,cs:[_WritePage] mov cs:[_ViewPage],cx ; An ISR will set the VGA at the next retrace mov bh,0dH mov bl,cl mov dx,3dah Ret1: ;;;; in al,dx ;;;; test al,1 ;;;; jnz Ret1 ; Wait for display enable ; cli mov al,0ch mov ah,ch mov dx,3d4h out dx,ax ; set the displayed offset (high) ; inc al ; mov ah,cl ;;; mov ax,bx ;;; out dx,ax ; set the displayed offset (low) ; sti ;; mov dx,3dah Ret2: ;; in al,dx ;; test al,8 ;; jz Ret2 ; Wait for the video card to use the address just set ret _flippage endp ;============================================================================== ; void SetPalette(unsigned char far *PalBuf); ;============================================================================== SPbuf equ [bp+ABASE] PBEGIN _SetPalette push bp mov bp,sp push ds push si lds si,dword ptr SPbuf mov cx,256 xor bx,bx cld mov dx,3C8H sp010: mov al,bl out dx,al inc dx lodsb out dx,al lodsb out dx,al lodsb out dx,al dec dx inc bx loop sp010 pop si pop ds pop bp ret _SetPalette endp ;============================================================================== ; void DrawWalls(void); ;============================================================================== Y2 equ [bp-2] AVLOW equ [bp-4] AVHI equ [bp-6] VCOL equ [bp-8] BOFFLOW equ [bp-10] BOFFHI equ [bp-12] sColor equ [bp-14] fColor equ [bp-16] PBEGIN _DrawWalls push bp mov bp,sp sub sp,18 push ds push si push di mov dx,3c4H mov ax,0F02H out dx,ax ;Select map mask and all planes mov bx,word ptr DGROUP:_MaxDistance ; Get max distance to wall shl bx,1 ; Make a word index mov ax,word ptr DGROUP:_DistanceTable[bx] ;Look up actual height cmp ax,200 ; Full screen height? jae drw000 ; Yes, nothing to fill in and ax,0FFFEH ; Strip any odd values mov bx,ax ; Save height mov si,ax ; Again save height shr bx,1 ; Get Height / 2 mov dx,100 ; Pick up our center row sub dx,bx ; and sub ht/2 mov bx,dx ; Save new value mov ax,90 imul dx mov bx,ax mov ax,90 imul si mov si,ax ; mov cl,6 ; Get ready to mult by 80 ; shl bx,cl ; first mult by 64 ; shl si,cl ; also mult the original ht ; mov cl,4 ; No do a mult by 16 ; shl dx,cl ; to top layer ; shl ax,cl ; and initial height ; add bx,dx ; Add x64 and x16 for x80 ; add si,ax ; do same with height mov ax,0A000H mov es,ax mov di,cs:_WritePage ;get start of buffer mov ax,ds:_TopColor mov ah,al shr bx,1 ;only fill words mov cx,bx ;get amount to fill in rep stosw add di,si ;then skip amount of wall mov ax,ds:_BottomColor mov ah,al mov cx,bx rep stosw drw000: xor bx,bx ;Initial loop/plane counter drw010: push bx ;save loop/plane counter mov VCOL,bx ;Set beginning video column mov dx,3c5H mov al,byte ptr DGROUP:_lowmask[bx] out dx,al ;select mask to write to mov si,offset _Walls ; Point to wall array shl bx,1 shl bx,1 shl bx,1 ;x 8 for correct wall structure add si,bx mov cx,80 ;Number of walls to display drw020: push ds ;save data segment push si ;save wall pointer push cx ;save wall count lodsw ;Get bitmap number xchg ax,bx ;use bx as the index shl bx,1 shl bx,1 ;dword index into bitmap table mov di,word ptr DGROUP:_bMaps[bx] ;offset to bitmap mov es,word ptr DGROUP:_bMaps[bx+2] ;segment of bitmap lodsw ;get bitmap column to display mov cl,6 shl ax,cl ;x64 to get correct row add di,ax ;and add to bitmap offset lodsw ;get bitmap distance shl ax,1 ; Make word index for table lookup mov si,ax ;save distance mov bx,word ptr DGROUP:_DistanceTable[si] ;get height of bitmap mov cx,100 mov ax,bx ; Pick up the height shr ax,1 ; Divide by two sub cx,ax ; And subtract from center for Y1 mov ax,cx ; Start with Y1 add ax,bx ; and add height to it for Y2 cmp ax,199 ; Don't let Y2 go beyond screen height jle short drw030 mov ax,199 ; Else force it to screen height drw030: mov Y2,ax ;save y2 shl si,1 ; Turn object distance into dword index mov ax,word ptr DGROUP:_AdjustTable[si+2] mov dx,word ptr DGROUP:_AdjustTable[si] mov AVHI,ax ; Get (64 * 65536) / height mov AVLOW,dx xchg si,di ;si now points to bitmap mov di,VCOL ; Video column to display at sar di,1 ; Divide by 4 to get correct planar col sar di,1 ; Divide by 4 to get correct planar col add di,word ptr cs:_WritePage ; Add in page offset mov ax,es ; Pick up segment to bitmap mov ds,ax ; now ds:si points to bitmap mov ax,0A000H ; Video segment mov es,ax ; now es:di points to screen mov word ptr BOFFLOW,0 ; Initialize the current bitmap offset mov word ptr BOFFHI,0 cmp cx,word ptr Y2 ; is Y1 > Y2? jge short drw090 ; Yes, get on out or cx,cx ; Y1 <= 0? jle drw050 ; Yes, no sky color needed ; mov ax,cx ; Get copy of Y1 ; mov bx,cx ; and another copy ; mov cl,6 ; shl ax,cl ; do a mult 64 ; add di,ax ; and add to video offset ; mov cl,4 ; mov ax,bx ; get original Y1 ; shl ax,cl ; do a mult 16 ; add di,ax ; and add to video for a mult 80 ; xchg cx,bx ; restore original Y1 mov ax,90 imul cx add di,ax drw050: mov bx,89 ; Offset to next video row mov dx,AVLOW ; Hold onto lsb of adjustment mov ax,AVHI ; Pick up msb of bitmap adjustment ;------------------------------------------------------------------------------ ; Here is where the actual bitmap is transferred to the screen. Better ; optimization could be done by precalculating the adjustment factor instead ; of looping until Y1 >= 0. This has not been tried so I don't know if the ; speed would make it worth it.... ;------------------------------------------------------------------------------ drw060: or cx,cx ; Is Y1 still < 0 ? jl short drw070 ; Yes, don't start drawing yet movsb ;Move bitmap to video dec si add di,bx ;next row of video drw070: add word ptr BOFFLOW,dx ; Add lsb to current offset adc si,ax ; Use msb to get next bitmap location inc cx ; Next y1 cmp cx,word ptr Y2 ; Beyond Y2 yet? jl short drw060 ; Nope, keep looping drw090: pop cx ;get wall count pop si ;recover structure pointer pop ds add si,32 ;Wall structure size * 4 add word ptr VCOL,4 ;next video column to display at dec cx jz drw100 jmp drw020 ;next wall to display drw100: pop bx ;recover loop/plane counter inc bx cmp bx,4 ;all 4 planes? je drwDone jmp drw010 drwDone: mov dx,3c5H mov al,0FFH ;Enable all planes again out dx,al pop di pop si pop ds mov sp,bp pop bp ret _DrawWalls endp ;============================================================================== ; +4 +6 +8 +10 +12 ; void DrawOneObject(int ObjNum,int ObjCol,int ObjDist,int VidCol,int PageNum); ;============================================================================== PBEGIN _DrawOneObject push bp mov bp,sp sub sp,20 push si push di push ds mov cx,word ptr [bp+10] ; Video column and cx,3 ; Only need lower three bits mov ah,11h rol ah,cl mov al,2 mov dx,3c4h out dx,ax mov bx,word ptr [bp+8] ; Get the distance to the bitmap shl bx,1 ; Make word index for table lookup mov si,bx ; Save index for now mov bx,word ptr DGROUP:_DistanceTable[bx] dob010: mov cx,100 mov ax,bx ; Pick up the height shr ax,1 ; Divide by two sub cx,ax ; And subtract from center for Y1 mov di,cx ; Start with Y1 add di,bx ; and add height to it for Y2 cmp di,199 ; Don't let Y2 go beyond screen height jle short dob020 mov di,199 ; Else force it to screen height dob020: mov word ptr [bp-2],di ;save y2 shl si,1 ; Turn object distance into dword index mov ax,word ptr DGROUP:_AdjustTable[si+2] mov dx,word ptr DGROUP:_AdjustTable[si] mov word ptr [bp-14],ax ; Get (64 * 65536) / height mov word ptr [bp-16],dx mov bx,word ptr [bp+4] ; Bitmap number to display shl bx,1 ; dword index shl bx,1 ; dword index mov ax,word ptr DGROUP:_oMaps[bx+2] mov dx,word ptr DGROUP:_oMaps[bx] mov bx,word ptr [bp+6] ; Bitmap column to display shl bx,1 shl bx,1 shl bx,1 shl bx,1 shl bx,1 shl bx,1 ; x 64 to get correct bitmap row add dx,bx ; then add to start of bitmap mov word ptr [bp-6],ax mov word ptr [bp-8],dx mov di,word ptr [bp+10] ; Video column to display at sar di,1 ; Divide by 4 to get correct planar col sar di,1 ; Divide by 4 to get correct planar col mov bx,word ptr [bp+12] ; Page number to display at shl bx,1 ; Make a word index add di,word ptr DGROUP:_PageBegin[bx] ;Pick up actual offset mov ax,0A000H ; Video segment mov es,ax mov word ptr [bp-18],0 ; Initialize the current bitmap offset mov word ptr [bp-20],0 or cx,cx ; Is Y1 > 0 ? jle short dob030 ; Nope, start above video ; xchg si,cx ; hold onto original value ; mov ax,si ; get Y1 coordinate ; mov cl,6 ; mult by 64 ; shl ax,cl ; mov dx,si ; get back Y1 ; mov cl,4 ; shl dx,cl ; mult by 16 ; add ax,dx ; now add to Y1 * 64 to get Y1 * 80 ; add di,ax ; and add to start of video ; xchg cx,si ; get back original Y1 mov ax,90 imul cx add di,ax dob030: cmp cx,word ptr [bp-2] ; is Y1 > Y2? jge short dob090 ; Yes, get on out mov bx,90 ;Amount to next row of video lds si,dword ptr [bp-8] ;Get image buffer mov dx,word ptr [bp-16] ; Hold onto lsb of adjustment dob040: or cx,cx ; Is Y1 still < 0 ? jl short dob080 ; Yes, don't start drawing yet lodsb dec si or al,al ;Transparent color? jz dob050 ;Yes, don't write it to video mov byte ptr es:[di],al ;place character in video dob050: add di,bx ;next row of video dob080: mov ax,word ptr [bp-14] ; Pick up msb of bitmap adjustment add word ptr [bp-20],dx ; and add to current offset adc si,ax ; Keep the msb correct inc cx ; Next y1 cmp cx,word ptr [bp-2] ; Beyond Y2 yet? jl short dob040 ; Nope, keep looping dob090: pop ds pop di pop si mov sp,bp pop bp ret _DrawOneObject endp _TEXT ENDS END