Megapole by Red Sector Inc. [web]
;******************************************************************************* ; /\______ /\______ /\________ ; __\\\___ \_ __\\\___ \_ __\\\______ \ ; | / / | / / | _____/ \_ ; | / /____| / /____| \ | ; | \____ : _____/ : \ | ; | / \ \ | ; | / . \ . \ | ; __ _|_ / \ \ _|_ __ ; \ \\_\ \\__\ _/ : \_ : \_ /__// /_// / ; |____/_ _ :______ _ :______ _ | ; \\\____________| \\\____________| \\\____________| ; ; _______ _______ _______ _______ _______ _______ ; _\\\__ \___\\\__ \___\\\__ \___\\\_____ \___\\\_____ \___\\\__ \_ ;| /______/| / /| / /| / | / | / / ;\ | / /_| / /_| / | / | / /_ ;|\_______ : _____/ : \_____/ : / : / : \____ | ;| / . \ . \ . / . / . / | ;| / \ \ / / | ;|___ :___ :___ :___\ :___ :___/ sns | ; \\_________: \\_________: \\_________: \\_________: \\_________: \\_________| ; ; R E D S E C T O R I N C ; ; Metropole a 256 bytes intro by Baudsurfer/RSI 2015 aka olivier.poudade.free.fr ; Presented first at the Function 2015 demoscene demo party in Budapest Hungaria ; Greets Blabla Conscience Bon^2 BReWErS CODEX Flush Lineout Mandarine Onslaught ; Paranoimia Quartex Rebels Razor1911 RiOT Titan and to all assembly programmers ; rsi.untergrund.net twitter.com/red_sector_inc facebook.com/redsectorinc ircnet ; RSI asciilogo by sEnsER/BRK vidcap youtube.com/watch?v=Z8Av7Sc7yGY by Fra/MDRN ;******************************************************************************* b equ byte ; tested on xp, freedos, ms windows dos and its debug w equ word ; short form pretty-print helpers datatype specifiers org 100h ; entering ip=cs:256 just above .com psp 127-byte dta mov fs,ax ; ax=0? was pop bp before rewrite for non-zero fs seg pop bp ; bp=0 cs:[0fffeh]=ss:[sp]=0000 if not debug executed mov al,13h ; function switch to video mode 13h 320x200x256 & cls int 10h ; general video bios service for all mode 13h vga api push w 0a000h ; was les cx,[bx] es=9fffh cx=20cdh & lea ax,[di-10h] pop es ; ms-dos v6.22 or freedos not "les rr,[0]" compatible a:test bp,100h ; script idx bounds reached? bp E [0;255] i.e aam 255 jz c ; if hibyte OR rollover sign propagated to hibyte lsb xor b[c],8h ; xor mutex modify next opcode to keep idx normalized c:dec bp ; follow through and advance script idx dec bp/inc bp e:mov cx,0ffh ; cl=visibility fostrum, null ch implicit object mask g:cwd ; shorter xor dx,dx with ah<128 for div moved for agi mov si,140h ; vga vid mode 19 horizontal scanline width in pixels mov bx,cx ; bl=distance nullify bh raymarch object height limit mov ax,di ; di=beam spot absolute vga coord, no dos para fix-up not bl ; bl=distance/z axis orientation= -visibility fostrum div si ; main 3d projection returns with ax=y dx=x ; dh = x call q ; main 3d projection returns withah=(y-y0)*z ; bl = z call q ; main 3d projection returns withah=(x-x0)*z ; ah = y mov si,46ch ; 46ch=bda rtc off in zero seg plus ad hoc off buffer add bl,[fs:si] ; bl=z+=rtc word in bda advances camera, assumed fs=0 adc dh,[si] ; dh+=beam spot camera x coordinates cs/ds:46ch & rtc add ah,[si+1] ; ah+=beam spot camera y coordinates cs/ds:46dh & rtc mov al,dh ; push/pop preserve texture x>>8 texel base for later adc ch,al ; this object's implicit form xor /w building overlay and dh,bl ; dh=x bl=x i.e x+=y bh and dl used as generic params mov bh,30h ; bh=y height max of overpass, function generic param mov dl,20h ; dl=y height min of overpass, function generic param call r ; function returns if this object or building ray hit jz h ; if objects volume intersect with ray texture former push bx ; preserve prev rtc time to avoid costly seg override mov dl,10h ; dl=y height max of spaceship function generic param mov bh,14h ; bh=y height min of spaceship function generic param sub bl,[fs:si] ; bl=z+=rtc word in bda advances spaceship1 camera<-- sub bl,[fs:si] ; bl=z+=rtc word in bda advances spaceship1 camera<-- xor ch,ch ; flag differenciates between spaceship* and overpass call r ; function returns if this object or building ray hit pop bx ; restore prev rtc time also implicit ch val returned jz h ; if objects volume intersect with ray texture former mov dl,18h ; dl=y height max of spaceship function generic param mov bh,1ch ; bh=y height min of spaceship function generic param add bl,[fs:si] ; bl=z+=rtc word in bda advances spaceship2 camera--> call r ; function returns if this object or building ray hit jz h ; if objects volume intersect with ray texture former loop g ; if no object volumes intersect then continue z rays h:xchg ax,dx ; texture subroutine - clone ray collision height val cmp dh,40h ; test if this ray collision height val is exactly 64 jz l ; process as scenery bottom floor, al=depth was saved pushf ; ax disposed of in z-buffer order override data flow pop ax ; subroutine marked eflags /w bit10 df=spaceship true sahf ; convert this object's bit10 df to pf for conditions jp k ; if z-ray collided with a spaceship object then exit test cl,cl ; else test if ray collision exited on loop condition jz i ; if distance=0=>no scenery intersection=open horizon inc dh ; test if this ray collision height=top=255=sky limit jnz j ; else ray hit other scenery building/overpass object i:mov al,0ffh ; is sky so apply old b/w film rear projection effect jmp m ; with brightest standard vga palette grayscale color j:and al,bl ; is building/overpass process texel window step #1/3 xor al,dh ; is building/overpass process texel window step #2/3 xor dl,bl ; is building/overpass process texel bricks step #1/2 and dl,dh ; is building/overpass process texel bricks step #2/2 shl al,02h ; is building/overpass process texel window step #3/3 and dl,01h ; test for building/overpass window or bricks texture cmovnz ax,cx ; if window texel then color val=distance 586+ opcode mov ah,0ffh ; colour for window or bricks of building or overpass sub ah,al ; is dynamic for windows and static for all other obj k:mov al,ah ; thunk for building/overpass/window/bricks/spaceship jmp m ; proceed to last step of grayscale color normalizing l:not ah ; floor grey bicolor flat-shaded for building shadows and al,ah ; floor color multiplexes shadow depth=k*(255-height) m:cld ; common thunk nullifies next spaceship=true obj flag aam 12h ; normalize with dithering add overlap ah=color/18+00 mov al,16 ; normalize with dithering add overlap ah=color/18+16 aad 1 ; dithering normalized and prepare for next frame cwd test di,di ; test for all pixels plotted overrunning vga segment jp o ; preserve zf flag and test if absolute beam position inc ax ; parity even augmenting lighting for odd meta-pixels o:stosb ; write screen pixel & advance absolute beam position jnz e ; if dst idx then continue automatic vga wrap-up fill mov w[si],3711h ; post-assigns camera fixed value coordinates (17,55) mov w[fs:si-1ch],1701h ; bda mem vid page 0 title curs position col=1 row=24 mov ah,9 ; dos 1+ write $ terminated string to standard output mov dx,p ; hardcoded 24h terminated ascii string of demo title int 21h ; general ms-dos api /w function 9 print ds:dx string jmp a ; process next demo frame (sorry no escape sequence!) q:xchg ax,dx ; 3-axis rotations require 2-axis ah=dh=x dh=(y-y0)*z sub ax,bp ; translate to demo script idx arbitrary origin bp,bp imul ax,bx ; project abcsisses/ordinates ah=(x-x0)*z dh=(y-y0)*z add ax,67fh ; translate back to ~center=k*sqr(2) arbitrary fix-up ret ; --------------------------->return to caller (0c3h) r:push ax ; isosurface discrimination preserve building overlay test bl,40h ; is it time~depth (i.e z+rtc) displaying an overpass jnz v ; if not then process default buildings intersections cmp ah,bh ; is y height>min of spaceship/overpass generic param jnc v ; if not then process default buildings intersections cmp ah,dl ; is y height<max of spaceship/overpass generic param jc v ; if not then process default buildings intersections test bl,78h ; is spaceship/overpass 120<z depth<128 static params jnz u ; if not then process modified building intersections test ch,ch ; flag differenciates between spaceship* and overpass jnz t ; if overpass then proceed to translate it vertically test al,78h ; is spaceship only objects 120<x width<128 in static jnz u ; if not then process modified building intersections std ; is spaceship and visible so set df flag accordingly t:add ah,18h ; translate spaceship/overpass objects vertically +24 u:xor ah,ch ; this object's implicit form xor /w building overlay v:test dh,10h ; alternate scene vertical irregularity every step 16 jnz x ; i.e : _||_||_||_||_||_||_||_||_||_||_||_||_||_||_|| add dh,al ; reduce scene horizontally = strech scene vertically x:or ah,dh ; induce scene horizontal "y-colinear" irregularities sahf ; implicit isosurface volume x AND y AND z AND 64=64? pop ax ; isosurface discrimination preserve building overlay ret ; --------------------------->return to caller (0c3h) p db "megapole$" ; hardcoded 24h terminated ascii string of demo title
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