Hi James,That's a very interesting piece of info too. Is it a standalone 3rd party re-implementation of 16-bit NTVDM driver? I mean can I also run arbitrary 16 bit software like COM files with it or am I still restricted only to 16-bit VB stuff?
If it's standalone than it's a great bonus to every "modern" (read "castrated") version of Windows past XP and Vista.
But thanks for making us aware anyway.
@Jochen:This:
; P L a 256-byte intro by Rrrola - final version
; \ / \ rrrola@gmail.com
; U S http://rrrola.wz.cz
; greets to everyone who came to Riverwash 2009
;%define BLOWUP 86 ; "ambient occlusion" strength (default 86: -1 byte)
MAXSTEPSHIFT equ 6 ; shading strength (>=6 unless BLOWUP defined)
MAXITERS equ 26
BASECOLOR equ -34
%define BLOCKS ; render 4x1 blocks (for slower machines, +3 bytes)
org 100h ; assume ah=bx=0 cx=255 sp=di=-2 si=100h
mov al,13h ;<(byte)[100h]>>8 = 0.6875
push bx ; (word)[100h]>>16 = 0.0769
mov dx,3C8h ; (float)[100h] = -0.0008052
int 10h
;palette - 4 gradients of 32 shades
P mov al,bl ;<set al on 1st pass, then each red and green
Q test bl,cl ; parity: eooooeoeoeee eooooeoeoeee ...
jpe E ; index: #0gb1gb2gb3g b4gb5gb6gb7g ...
imul al
shr ax,7
E imul bl
mov al,ah
out dx,al
mov dl,0c9h
loop P
mov cl,3
dec bx
jnz Q
push 09FCEh ;<aligns with the screen ;-)
pop es
mov bh,56h ; xyz addressing trick from neon_station
; vecNN = (words){[5600h+N] [5656h+N] [56ACh+N]}
;frame loop - prepare constants
;ax=key bx=5600h bp=dx=0 cx=3 si=100h di=-2 sp=-4 word[5700h]=T
M fninit ; {} = fpu stack
add word[bx+si],byte 88 ; T++
fild word[bx+si] ;=14.00564 * 2pi
fsincos ; {s=sin(T*0.00564) c=cos(T*0.00564)}
fdiv st1,st0 ; {s t=cotg(T*0.00564)}
fild word[bx+si]
fmul dword[si]
fsin
fimul word[si] ; {r>>16=0.0769*sin(T*-0.0708) s t}
pop edx ;=9B6C0000... just get rid of it
push es
push bp ;dword[-4]=9FCE0000h
;pixel loop
;x = word[-3] ~ -0.5..0.5 (+= 0.003125 each column)
;y = word[-2] ~ -0.4..0.4 (+= 0.00390625 each row)
X
%ifdef BLOCKS
test bp,cx ; 4x1 blocks: keep last color?
jnz D
%endif
pusha ;[-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 ]
; di si bp sp bx dx cx ax yyyy
; FEFF0001adr FCFF005600000300col ..xxxx
;fisheye projection: z = C-x*x-y*y
mov [bx],bx ;=0.33594
Z mov ax,[di]
fild word[di]
imul ax
sub [bx],dx
dec di
jpo Z ;di=-4
fild word[bx] ; {z>>16=0.33594-x*x-y*y x y r s t}
;advance x and y for next pixel (low word)
%ifdef BLOCKS
add word[di],3334h
%else
add dword[di],0000CCCDh
%endif
;rotate direction vector
R fmul st4 ; {sz x y r s t}
fld st0
fmul st6 ; {cz sz x y r s t}
fxch st2
fmul st5
fsub st2,st0; {sx sz cz-sx y r s t}
fmul st6
faddp st1,st0; {cx+sz cz-sx y r s t}
fxch st2 ; {y cz-sx cx+sz r s t}
inc di
jpo R
dec di ;di=-2 ; {X Y Z r s t}
;advance x and y for next pixel (high word)
%ifdef BLOCKS
adc word[di],cx
%endif
;store ray origin and direction vector
imul dx,[bx+si],byte 10;=0.0134*T
S
fistp word[bx+di] ; d>>16 = v-2 = {X, Y, Z}
;fistp dword[bx+di] ;<slower, but fixes corners (+3 bytes)
;sar dword[bx+di],1
mov [bx],dx
add dh,[si] ; o>>16 = v0 = 0.0134*T + {0, 0.6875, 0.375}
add bl,bh
jnc S ;bl=2 ; {r s t}
;intersect ray with scene, count number of bounding volume misses
cwd ; dx = hit(-1|0): grainy rendering
mov ah,-MAXITERS ; ah = iters(-MAXITERS..0), al = hue(0..3)
;cwd ;<for smooth rendering with bands
%ifdef BLOWUP
mov cx,BLOWUP*256+MAXSTEPSHIFT; cl = stepshift(0..MAXSTEPSHIFT)
%else
adc cx,bx ;=86*256 + 6 ;-)
%endif
call I
sub ah,cl
aad 4 ;ah=0
add al,MAXITERS*4+BASECOLOR
mov [di-4],ax ; pushed ax = color = (iters-stepshift)*4 + hue
popa
;draw pixel
D
%ifdef BLOCKS
mov [es:bp+si],al
inc bp
%else
inc bp
mov [es:bp+si],al
%endif
jnz X ; 65536 pixels
;next frame: fall through on esc - ah=word[sp]=0
in al,60h
dec ax
jnz M ;<assume no one presses ESC after 1 frame ;)
;raycasting using unbounded binary search
;start with the smallest step size
;v-2 = d = {dx, dy, dz}
;v0 = o = current {x, y, z} mod 1
;last probe was inside: halve step and go back
; outside: double step and go forward
I mov bl,0 ;bl=0
A mov bp,[bx+di] ; hit ? (o -= d>>stepshift) : (o += d>>stepshift)
sar bp,cl
xor bp,dx
add [bx],bp
add bl,bh
jnc A ;bl=2
salc ;al=FFh
fist word[bx+si] ; word[5702h] = r
;bounding volumes: "blow up" the scene by the current step size
push cx
shr cx,cl
add ch,37 ; cx = hitlimit = 0.1445 + (BLOWUP >> stepshift+8)
;inside test
;hue=[0,1]
;green octahedra: (|x|+|y|+|z|)/2 - 0.1445 + r < blowup
;orange octahedra: (|x+0.5|+|y+0.5|+|z+0.5|)/2 - 0.1445 - r < blowup
O mov dx,[bx+si] ; dx = [r,-r]
neg word[bx+si]
C imul bp,ax,32768 ; bp = [0.5, 0] - v0.xyz
sub bp,[bx+di]
jns T
neg bp
T shr bp,1
add dx,bp ; v2 = |signed(bp)|/2
mov [bx],bp
add bl,bh
jnc C ;bl=4 ; dx = sum(v2) + [r,-r]
cmp dx,cx ; if (dx < hitlimit) hit!
inc ax ;al=0,ah++
jc H
mov bl,2 ;bl=2
jpe O ;al=1 ; repeat if al==0
;hue=[2,3]
;bars: (||x|-|z|| + ||y|-|x|| + ||z|-|y||)/2 - 0.0676 < blowup
;bolts: (||x|-|z|| + ||y|-|x|| + ||z|-|y||)/2 - 0.1445 < blowup
sub dx,[bx+si]
inc ax ;al=2
;sub dx,bx ;<simple bolt movement: sum(v2)-2*r-0.3359
sub dx,[bx+si] ;<precise bolt movement: sum(v2)-3*r-0.375
sub dh,60h ; (+3 bytes)
imul dx,byte 13 ; if (|sum(v2)-3*r-0.375| < 0.03846)
mov dx,[si] ; dx = extra_width = 0.0769, hue = 2
jo B ; else
inc ax ;al=3 ; dx = extra_width = 0, hue = 3
cwd
B sub bp,[bx] ; bp = v2.zxy - v2.xyz
jns L
neg bp
L add dx,bp
mov bp,[bx]
add bl,bh
jnc B ;bl=4 ; dx = sum(|signed(bp)|) + extra_width
cmp dx,cx ; if (dx < hitlimit) hit!
;adjust step size according to the hit result
H pop cx ;cf=hit
sbb dx,dx ; dx = hit?-1:0
cmc
sbb cl,dl ; if (hit) stepshift++
adc cl,dl ; else if (stepshift > 0) stepshift--
;more probes?
cmp cl,MAXSTEPSHIFT
jae F ; if (stepshift >= maxstepshift) break
add ah,dl ; iters++, if (hit) iters--
jne I ; if (iters >= maxiters) break
F retcompiles to a 256 byte (not
Kilo... nor
Mega... but
Byte!) long COM file that's able to display an animated perspective of moving 3D objects with proper lighting and penumbra shadows! Hard if not impossible to beat, isn't it?
The snapshot below is a windowed C simulation of the same. I'm able to enjoy the original COM file under full screen XP -- something which you can't do, under your "top-notch" ugly monster of an OS called Windows 10.
