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Assembly Source File | 1993-12-24 | 11.3 KB | 314 lines

; Realtime Bitmap Rotation Routine ; Handles approx. 0.5 million pixels / second on a 386 ; by Soeren Holstebroe (seap) ; no group but available if you are interested. (code / algorithms + music) ; ; Last edited: 10/10-1993 ; ; I would really appreciate if you would send some of your own source-codes ; or/and anything you use this piece of code in or/and any improvement of ; this routine. ; Note: This is freeware. You may do with this code whatever you want, but ; hey! please leave a greeting in your program. You greet me, I greet you. ; If any problems turn up or if you want to exchange more sources or if you ; just want to say "Hi! nice/lame piece of code you have made" or if you ; actually used this piece of asm, please write. ; ; Write to: ; Internet: seap@diku.dk ; Fidonet : 2:230/159.16 ; Snailnet: Hjortekærbakken 1 ; 2800 Lyngby ; Denmark ; NB! Don't write to the snailnet address too long after release-date. .286 cseg segment assume cs:cseg;ds:dseg org 0100h ; stak start: jmp main oldmode DB ? opengfx: mov ah,0fh int 10h mov oldmode,al mov ah,0h mov al,13h int 10h ret closegfx: mov ah,0h mov al,oldmode int 10h ret makemulstab: xor di,di xor ax,ax mov cx,(iwidth*iheight) mulsloop: mov mulstab [di],ax add ax,iwidth inc di inc di loop mulsloop ret retrace: mov dx,3dah ; wait for vertical retrace ventl: in al,dx and al,8 jz ventl venth: in al,dx and al,8 jne venth ret tempX dw 0 tempY dw 0 cosvx dw 0 sinvx dw 0 cosvy dw 0 sinvy dw 0 cosv dw 0 sinv dw 0 rotate proc near mov bp,angle ; bp = rotation-angle mov ax,cos[bp] ; get cos(bp) and sin(bp) (for speed) mov cosv,ax mov ax,sin[bp] mov sinv,ax mov cx,iheight ; image-iheight mov bx,(-(iheight/2)); bx = -iheight/2 mov di,0 ; pre-calc all multiplications mov ax,-(iwidth/2) imul cosv mov cosvx,ax ; cosvx = cos v * X mov ax,-(iwidth/2) imul sinv mov sinvx,ax ; sinvx = sin v * X mov ax,-(iheight/2) imul cosv mov cosvy,ax ; cosvy = cos v * Y mov ax,-(iheight/2) imul sinv mov sinvy,ax ; sinvy = sin v * Y @ry: push cx mov cx,iwidth ; image iwidth ; dx = sin v * Y + cos v * X mov dx,sinvy add dx,cosvx ; dx = cos v * Y - sin v * X mov si,cosvy sub si,sinvx add dx,(iwidth/2)*256 add si,(iheight/2)*256 @rx: ; Xo = sin v * Y + cos v * X ; Yo = cos v * Y - sin v * X cmp dx,(iwidth)*256 ; check if x is within source jae blackout cmp si,(iwidth)*256 ; the same for y jae blackout ; Get-pixel ; calculate source-image offset getpixel: mov bx,si ; y = y/128 (fixed point) xchg bh,bl xor bh,bh add bx,bx mov ax,mulstab[bx] ; get y offset xor bx,bx ; x = x/256 (fixed point) mov bl,dh add bx,ax ; si = source = iwidth * Yo + Xo mov al,ds:image2[bx] ; al = pixel color ; change the above line if ; you want another image. ; Remember to change iwidth and ; iheight as well jmp plot_pixel blackout: mov al,0 ; black pixel plot_pixel: mov es:[di],al ; display pixel inc di ; next dest. pixel ; NOTE!!!! ; This will run faster ; if two colors are computed ; before the video-card is ; being accesed. ; When two colors are computed ; you can use a word-write ; instead of the byte-write. ; If you own a 386 DX, you can ; even wait until you have ; computed 4 colors before you ; acces the video-ram. ; I have made byte-writes ; to make it more compatible, but... ; Well, please mail me any ; improvements. ; update tempX add dx,cosv ; bx = sin v * Y + cos v * X ; update tempY sub si,sinv ; si = cos v * Y - sin v * X loop @jrx ; update screen coord add di,(320-iwidth) ; next dest. line ; update sinvy & cosvy mov ax,cosv add cosvy,ax mov ax,sinv add sinvy,ax pop cx loop @jry ret @jrx: jmp @rx @jry: jmp @ry rotate endp main: mov ah,0ch ; kill keyboard buffer mov al,-1 int 21h call opengfx ; open mode 13 ; precalculate image-y-offsets call makemulstab push cs pop ds mov ax,0a000h mov es,ax mloop: call rotate add angle,2 and angle,1feh ; Angle goes from 0 to 256 degree. Remember to double ; the offset. (for wordsize). call retrace mov ah,1 ; check if kb-buffer is empty int 16h jz mloop ; nope, loop again call closegfx mov ah,4ch ; return to dos int 21h mulstab DW (iwidth*iheight) DUP(?) angle dw 0 iwidth = 100 iheight = 100 ; test-pattern nr. 1 image1 db 0,0,0,0,12,14,15,16,17,18,0,0,0,0,0,0 db 0,0,0,11,13,19,0,0,0,20,21,22,0,0,0,0 db 0,0,9,10,0,0,0,0,0,0,23,24,0,0,0,0 db 0,0,8,0,0,0,0,0,0,0,0,25,0,0,0,0 db 0,0,7,6,0,0,0,0,0,0,0,26,27,0,0,0 db 0,0,0,5,4,0,0,0,0,0,0,28,29,0,0,0 db 0,0,0,0,3,2,1,0,0,0,0,30,31,0,0,0 db 0,0,0,0,0,0,0,0,0,0,32,33,0,0,0,0 db 0,0,0,0,0,0,0,0,0,34,35,36,0,0,0,0 db 0,0,0,0,0,0,0,0,37,38,39,0,0,0,0,0 db 0,0,0,0,0,0,0,40,41,42,43,0,0,0,0,0 db 0,0,0,0,0,0,44,45,46,47,0,0,0,0,0,0 db 0,0,0,0,48,49,50,51,52,0,0,0,0,0,0,0 db 0,0,0,53,54,55,56,57,0,0,0,0,0,0,0,0 db 0,0,58,59,60,61,62,63,0,0,0,0,0,0,0,0 db 0,64,65,66,67,68,69,70,71,0,0,0,0,0,0,0 ; test-pattern nr. 2 (compiles a bit slow) image2 label byte rept (100*25) db 0,0,0,40 endm ; precalculated sin/cos table ; table-size: 256+64=320 sin DW 00000h,00006h,0000ch,00012h,00018h,0001fh,00025h,0002bh DW 00031h,00037h,0003dh,00044h,0004ah,0004fh,00055h,0005bh DW 00061h,00067h,0006dh,00072h,00078h,0007dh,00083h,00088h DW 0008dh,00092h,00097h,0009ch,000a1h,000a6h,000abh,000afh DW 000b4h,000b8h,000bch,000c1h,000c5h,000c9h,000cch,000d0h DW 000d4h,000d7h,000dah,000ddh,000e0h,000e3h,000e6h,000e9h DW 000ebh,000edh,000f0h,000f2h,000f4h,000f5h,000f7h,000f8h DW 000fah,000fbh,000fch,000fdh,000fdh,000feh,000feh,000feh cos DW 000ffh,000feh,000feh,000feh,000fdh,000fdh,000fch,000fbh DW 000fah,000f8h,000f7h,000f5h,000f4h,000f2h,000f0h,000edh DW 000ebh,000e9h,000e6h,000e3h,000e0h,000ddh,000dah,000d7h DW 000d4h,000d0h,000cch,000c9h,000c5h,000c1h,000bch,000b8h DW 000b4h,000afh,000abh,000a6h,000a1h,0009ch,00097h,00092h DW 0008dh,00088h,00083h,0007dh,00078h,00072h,0006dh,00067h DW 00061h,0005bh,00055h,0004fh,0004ah,00044h,0003dh,00037h DW 00031h,0002bh,00025h,0001fh,00018h,00012h,0000ch,00006h DW 00000h,0fffah,0fff4h,0ffeeh,0ffe8h,0ffe1h,0ffdbh,0ffd5h DW 0ffcfh,0ffc9h,0ffc3h,0ffbch,0ffb6h,0ffb1h,0ffabh,0ffa5h DW 0ff9fh,0ff99h,0ff93h,0ff8eh,0ff88h,0ff83h,0ff7dh,0ff78h DW 0ff73h,0ff6eh,0ff69h,0ff64h,0ff5fh,0ff5ah,0ff55h,0ff51h DW 0ff4ch,0ff48h,0ff44h,0ff3fh,0ff3bh,0ff37h,0ff34h,0ff30h DW 0ff2ch,0ff29h,0ff26h,0ff23h,0ff20h,0ff1dh,0ff1ah,0ff17h DW 0ff15h,0ff13h,0ff10h,0ff0eh,0ff0ch,0ff0bh,0ff09h,0ff08h DW 0ff06h,0ff05h,0ff04h,0ff03h,0ff03h,0ff02h,0ff02h,0ff02h DW 0ff02h,0ff02h,0ff02h,0ff02h,0ff03h,0ff03h,0ff04h,0ff05h DW 0ff06h,0ff08h,0ff09h,0ff0bh,0ff0ch,0ff0eh,0ff10h,0ff13h DW 0ff15h,0ff17h,0ff1ah,0ff1dh,0ff20h,0ff23h,0ff26h,0ff29h DW 0ff2ch,0ff30h,0ff34h,0ff37h,0ff3bh,0ff3fh,0ff44h,0ff48h DW 0ff4ch,0ff51h,0ff55h,0ff5ah,0ff5fh,0ff64h,0ff69h,0ff6eh DW 0ff73h,0ff78h,0ff7dh,0ff83h,0ff88h,0ff8eh,0ff93h,0ff99h DW 0ff9fh,0ffa5h,0ffabh,0ffb1h,0ffb6h,0ffbch,0ffc3h,0ffc9h DW 0ffcfh,0ffd5h,0ffdbh,0ffe1h,0ffe8h,0ffeeh,0fff4h,0fffah DW 00000h,00006h,0000ch,00012h,00018h,0001fh,00025h,0002bh DW 00031h,00037h,0003dh,00044h,0004ah,0004fh,00055h,0005bh DW 00061h,00067h,0006dh,00072h,00078h,0007dh,00083h,00088h DW 0008dh,00092h,00097h,0009ch,000a1h,000a6h,000abh,000afh DW 000b4h,000b8h,000bch,000c1h,000c5h,000c9h,000cch,000d0h DW 000d4h,000d7h,000dah,000ddh,000e0h,000e3h,000e6h,000e9h DW 000ebh,000edh,000f0h,000f2h,000f4h,000f5h,000f7h,000f8h DW 000fah,000fbh,000fch,000fdh,000fdh,000feh,000feh,000feh cseg ends END start ; seap was here before you :)