1
General chat / Re: Hi
« on: August 29, 2018 »
A lot of my fascination with this stuff comes from 'wtf how did they do that in freaking assembler 30 years ago?'
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2
ASM / Re: sine generator in TASM
« on: August 21, 2018 »
Cool stuff, Rbz!
I probably have all the effect source from Hornet Archive and I've never seen a sine generator like that one. Mostly people seemed to be generating them externally and using a list of constants. There are a few that use fi[blah] commands to produce one.
Starport II (1993) had an interesting one but didn't create a table, it calculated it on the fly. SHRD was a 386 instruction, not sure it was available on the 286?
but SPII also included a sine table, so further investigation is needed
I probably have all the effect source from Hornet Archive and I've never seen a sine generator like that one. Mostly people seemed to be generating them externally and using a list of constants. There are a few that use fi[blah] commands to produce one.
Starport II (1993) had an interesting one but didn't create a table, it calculated it on the fly. SHRD was a 386 instruction, not sure it was available on the 286?
Code: [Select]
;±±±±±±±±±±±±±±±± sin/cos ±±±±±±±±±±±±±±±±
;entry: ax=angle (0..65535)
; exit: ax=muller (-127..127)
addwcos:add ax,ds:[bx] ;optimized entry for wavesets
mov ds:[bx],ax
cos: add ax,16384
sin: mov bx,ax
mov cx,bx
and cx,1023
neg cx
add cx,1023
shr bx,10
mov ah,ds:sintable[bx]
xor al,al
imul cx
push ax
push dx
mov ah,ds:sintable[bx+1]
xor al,al
neg cx
add cx,1023
imul cx
pop bx
pop cx
add ax,cx
adc dx,bx
shrd ax,dx,11
ret
but SPII also included a sine table, so further investigation is needed
Code: [Select]
sintable LABEL BYTE ;sine table (circle is 64 units)
db 0,12,24,36,48,59,70,80,89,98,105,112,117,121,124,126,127,126
db 124,121,117,112,105,98,89,80,70,59,48,36,24,12,0,-12,-24,-36
db -48,-59,-70,-80,-89,-98,-105,-112,-117,-121,-124,-126,-127
db -126,-124,-121,-117,-112,-105,-98,-89,-80,-70,-59,-48,-36
db -24,-12,0,3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51,54
db 57,59,62,65,67,70
3
ASM / Re: sine generator in TASM
« on: August 14, 2018 »
nvm the color banding. That's caused by the counter value in ah. duh
Code: [Select]
push ax
xor ah,ah
stosw
pop ax
4
ASM / sine generator in TASM
« on: August 14, 2018 »I'm working on a small plasma in TASM. It's very vanilla and not very interesting except for the sine generator. I was struggling with a big list of sine constants (originally I'd exported them from c#, double d = 32 + 32 * Math.Cos((i * 6.28) / 256)) when I came upon this generator in a prod by insomniac/matrix. But I'm not good enough at asm to tell exactly how it's working, except that wally/rage (??) was pretty darn clever. 188 bytes but I'm also getting some annoying color banding from stosw
Code: [Select]
; tasm /m2
; tlink /t
cseg segment
assume cs:cseg
org 0100h
.286
start:
mov ax,13h ; set mode 13
int 10h
push 0a000h ; stick video segment in es
pop es
mov dx,3c8h ; set color index port
xor ax,ax
out dx,al ; output color index 0
inc dx ; inc dx = 3C9h, color write port
@redup: ; Set colors 0-62, ramp up red
out dx,al ; set red to value in al
xchg al,ah ; ah is 0, so exchange it with al
out dx,al ; set green and blue = 0
out dx,al
xchg al,ah ; swap ah/al so al is again non-zero
inc al ; al +=1
cmp al,63
jne @redup
@reddn: ;set colors 63-127, ramp down red
out dx,al
xchg al,ah
out dx,al
out dx,al
xchg al,ah
dec al
jnz @reddn
@blueup: ;set colors 127-194, ramp up blue
xchg al,ah
out dx,al
out dx,al
xchg al,ah
out dx,al
inc al
cmp al,63
jne @blueup
@bluedn: ;set 194-256, ramp down blue
xchg al,ah
out dx,al
out dx,al
xchg al,ah
out dx,al
dec al
jnz @bluedn
; sin generator from argon by insomnia/matrix
; who got it from Wally/Rage, but I'm not sure
; who that was. There was a Rage demogroup
; in the amiga scene. Anyway, credit to the
; original author. My big list of sin constants
; was taking up ~200 bytes
mov cx,783Fh ; [30783]
xor si,si
sin1:
mov ax,65497
imul cx ;[2016194151]
add si,dx ; results of imul are stored in dx:ax [782C AE67, si+=30764]
add cx,si ; [783F + 782C,cx=30783+30764=61547=F06B]
mov [bx],ch ; [[bx]=F0=240]
sar byte ptr [bx],1 ; divide the value by 2, only store a byte [bx=120?]
dec bx
cmp bx,16383
jne sin1
; inc bx ; BX points to the sine/cos-values [comment by insomnia but this step isn't needed and saves a byte]
mov si,bx ; move it to SI since I need BX
main:
;------- main program ------------
xor di,di ; Reset vga position
mov cl,[p_pos1] ; stick plasma position values into ch,cl
mov ch,[p_pos2]
mov ah,200 ; 200 rows in mode 13
Y_LOOP:
push ax ; ax is also our x counter, so save
; the y vals to test later
mov dl,[p_pos3] ; the other position values in dh,dl
mov dh,[p_pos4] ; now the plasma position vals are in cx/dx
mov ah,160 ; X counter. since we're using stosw we only have to loop 320/2 times
X_LOOP:
xor al,al ; al holds the color, so clear it
; x = SinTable[p_pos1] + SinTable[p_pos2] + SinTable[p_pos3] + SinTable[p_pos4]
mov bl,dl ; mov p_pos3 into bl
add al,si[bx] ; x += Sin[p_pos3]
mov bl,dh ; mov p_pos4 into bl
add al,si[bx] ; x += Sin[p_pos4]
mov bl,cl ; mov p_pos1 into bl
add al,si[bx] ; x += Sin[p_pos1]
mov bl,ch ; mov p_pos2 into bl
add al,si[bx] ; x += Sin[p_pos2]
; push cx ; save the position vals
; mov cx,4 ; write 4 pixels at a time
; rep stosb ; put pixel cx times in es:di, advancing the screen pointer
; pop cx ; restore position vals
stosw ; stosw is smaller than that noise
add dl,2 ; add movement var to p_pos3
add dh,1 ; add movement var to p_pos4
dec ah ; decrement the x counter
jnz X_LOOP ; test for 0
add cl,2 ; add movement var to p_pos1
add ch,3 ; add movement var to p_pos2
pop ax ; restore the y counter
dec ah ; Next vertical line
jnz Y_LOOP ; test for 0
add [p_pos1],2 ; add some vals to the position vars
add [p_pos2],3 ; speed up/slow down the plasma
sub [p_pos3],1
add [p_pos4],4
jmp main ; do it all again
p_pos1 db 0
p_pos2 db 0
p_pos3 db 0
p_pos4 db 0
; SinTable db 64,63,63,63,63,63,63,63,63,63
; db 63,62,62,62,62,61,61,61,60,60
; db 60,59,59,59,58,58,57,57,56,56
; db 55,55,54,54,53,52,52,51,51,50
; db 49,49,48,47,47,46,45,44,44,43
; db 42,42,41,40,39,39,38,37,36,35
; db 35,34,33,32,32,31,30,29,28,28
; db 27,26,25,25,24,23,22,21,21,20
; db 19,19,18,17,16,16,15,14,14,13
; db 12,12,11,11,10,9,9,8,8,7
; db 7,6,6,5,5,4,4,4,3,3
; db 3,2,2,2,1,1,1,1,0,0
; db 0,0,0,0,0,0,0,0,0,0
; db 0,0,0,0,0,0,0,0,0,1
; db 1,1,1,2,2,2,3,3,3,4
; db 4,4,5,5,6,6,7,7,8,8
; db 9,9,10,11,11,12,12,13,14,14
; db 15,16,16,17,18,18,19,20,21,21
; db 22,23,24,24,25,26,27,28,28,29
; db 30,31,31,32,33,34,35,35,36,37
; db 38,38,39,40,41,41,42,43,44,44
; db 45,46,47,47,48,49,49,50,50,51
; db 52,52,53,54,54,55,55,56,56,57
; db 57,58,58,58,59,59,60,60,60,61
; db 61,61,62,62,62,62,63,63,63,63
; db 63,63,63,63,63,63
cseg ends
End Start
5
General chat / Re: What are you working on at the moment?
« on: August 06, 2018 »
I'm working on small code in Turbo Assembler with a simple plasma lol. I was sucking pretty hard with a big list of sine constants until I happened on a sin generator in an old prod by insomniac/matrix. But he got it from wally/rage (?? the old amiga group?) and I need to examine it in turbo debugger, because I haven't got a clue how it's working. Comments by insomniac.
Code: [Select]
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
; CALCULATE SINE/COS - VALUES (Wally/Rage)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
mov cx,783Fh ; don't ask me, I just use it..
xor si,si
plc1: mov ax,65497
imul cx
add si,dx
add cx,si
mov [bx],ch
sar byte ptr [bx],1
dec bx
cmp bx,16383
jne plc1
inc bx ; BX points to the sine/cos-values
6
General chat / Re: Hi
« on: April 07, 2018 »
Welcome! There's a reason some of us aren't putting our age on here lol
8
General coding questions / Re: voxel waves
« on: April 07, 2018 »
wow, I actually understood that! I don't know that I'm smart enough to reproduce it, but I have a better sense of what the code's doing. Karma coming your way! =:D
9
General coding questions / Re: voxel waves
« on: April 05, 2018 »
Attached. I haven't seen it done a lot, and in the case of insolit dust's code it would probably make more sense if you'd done a lot of stuff similarly complex. Future crew's source is illegible lol
10
General coding questions / voxel waves
« on: April 04, 2018 »
Does anyone know of or have an example of this effect, the one that future crew had in second reality? The only example I've been able to find is by Insolit Dust who used to post here, but it's difficult to read and has enough hardcoded values that I can't really tell what it's trying to do. Any language should be okay, but it's more difficult for me to deconstruct an xy location if the video is addressed like unsigned char *b = DBuf + (a << 
+ (a << 6) + i;
snippet from insolit dust, he posted a link to his site here so I hope this is okay!
+ (a << 6) + i;snippet from insolit dust, he posted a link to his site here so I hope this is okay!
Code: [Select]
void Line(int x0, int y0, int x1, int y1, int hy, int s)
{
register int i;
int sx, sy;
int c,y,h,u0,v0,u1,v1,a,b,h0,h1,h2,h3;
sx = (x1 - x0) / 320;
sy = (y1 - y0) / 320;
for (i = 0; i < 320; i++)
{
u0 = (x0 >> 16) & 0xFF;
a = (x0 >> 8) & 255;
v0 = ((y0 >> 8) & 0xFF00);
b = (y0 >> 8) & 255;
u1 = (u0 + 1) & 0xFF;
v1 = (v0 + 256) & 0xFF00;
h0 = HMap[u0 + v0];
h2 = HMap[u0 + v1];
h1 = HMap[u1 + v0];
h3 = HMap[u1 + v1];
h0 = (h0 << 8) + a * (h1 - h0);
h2 = (h2 << 8) + a * (h3 - h2);
h = ((h0 << 8) + b * (h2 - h0)) >> 16;
h0 = CMap[u0 + v0];
h2 = CMap[u0 + v1];
h1 = CMap[u1 + v0];
h3 = CMap[u1 + v1];
h0 = (h0 << 8) + a * (h1 - h0);
h2 = (h2 << 8) + a * (h3 - h2);
c = ((h0 << 8) + b * (h2 - h0));
y = (((h - hy) * s) >> 11) + (240 / 2);
if (y < (a = LastY[i]))
{
unsigned char *b = DBuf + (a << 8) + (a << 6) + i;
int sc,cc;
if (LastC[i] == -1)
LastC[i] = c;
sc = (c - LastC[i]) / (a - y);
cc = LastC[i];
if (a > 240 - 1)
{
b -= (a - (240 - 1)) * 320;
cc += (a - (240 - 1)) * sc;
a = 240 - 1;
}
if (y < 0)
y = 0;
while (y < a)
{
*b = cc >> 18;
cc += sc;
b -= 320;
a--;
}
LastY[i] = y;
}
LastC[i] = c;
x0 += sx;
y0 += sy;
}
}
11
General chat / Re: Hello there!!
« on: January 02, 2018 »
Nice to see some new faces! I'm also a fan of amiga demos, pretty much all I do are in that style
12
Challenges & Competitions / [Summer 2017] Summer of Love BBS
« on: June 19, 2017 »
Boogop's amazing summer demo! Loaded with ancient crusty effects you've seen a gorillion times before! Absolutely no new ground broken whatsoever!
Kludged up in Freebasic, Tinyptc_ext by RBZ, FMod for music (could have used Tinyptc_ext++ herp derp), FPS limiter by RBRAZ, FFNT_Lib by Deleter. Music is d3.mod by Necros. Is there anything in here by me?!
Kludged up in Freebasic, Tinyptc_ext by RBZ, FMod for music (could have used Tinyptc_ext++ herp derp), FPS limiter by RBRAZ, FFNT_Lib by Deleter. Music is d3.mod by Necros. Is there anything in here by me?!
14
General chat / Re: Ideas for a new DBF compo
« on: April 26, 2017 »
Ditto! Some summer theme sounds like a winnah
16
C / C++ /C# / Re: [C#/GDI+] Xor Texture Tunnel (aka Fake 3D)
« on: April 11, 2017 »
Got a little more speed out of it. I love c# but eventually we run into the limitations of the language 
Code: [Select]
FastBitmap a = new FastBitmap(myTexture);
FastBitmap b = new FastBitmap(myBitmap);
for (int x = 0; x < bmp.Width; x++)
{
fixed (int* pDistance = &distanceTable[x, 0])
{
fixed (int* pAngle = &angleTable[x, 0])
{
for (int y = 0; y < bmp.Height; y++)
{
int xp = *(pDistance + y);
int xx = (xp + shiftX) % 128;
int ap = *(pAngle + y);
int yy = (ap + shiftY) % 128;
Color c = a.GetPixel(xx, yy);
b.SetPixel(x, y, c);
}
}
}
}
17
C / C++ /C# / Re: [C#/GDI+] Xor Texture Tunnel (aka Fake 3D)
« on: April 11, 2017 »
Note: much discussion on bounds checking exists and unless you read the IL it's not easy to tell what the compiler is doing.
18
C / C++ /C# / Re: [C#/GDI+] Xor Texture Tunnel (aka Fake 3D)
« on: April 11, 2017 »
Glad to see some c#! All my contest entries so far have been in c#.
Two items jump out at me
1. Multi-dimension arrays. The compiler has to do bounds checks on those and it will tool your performance.
2. Getpixel. Even with fastbitmap these are bad. They make flame effects problematic in this language.
I can't tell what size your picturebox is but using gdi 640x480 is going to be about the limit. I find 350x350 or thereabouts works pretty good but above that starts really slowing down.
The game in c# is all about optimization. When I've done contest entries I sh1t you not the last couple months are spent optimizing.
Two items jump out at me
1. Multi-dimension arrays. The compiler has to do bounds checks on those and it will tool your performance.
2. Getpixel. Even with fastbitmap these are bad. They make flame effects problematic in this language.
I can't tell what size your picturebox is but using gdi 640x480 is going to be about the limit. I find 350x350 or thereabouts works pretty good but above that starts really slowing down.
The game in c# is all about optimization. When I've done contest entries I sh1t you not the last couple months are spent optimizing.
19
C / C++ /C# / Re: [C#] SineWaveScroller w/Bitmap Font Support
« on: March 01, 2017 »
Nice to see work in c#! I've gotten a lot of mileage out of it and have done all my DBF compo entries in it. I use the FastBitmap class which allows direct pixel-pushing to the graphics object, which in my thirst for punishment I enjoy.
20
Freebasic / Re: 13 * 13 Sin Scroll font in binary
« on: February 09, 2017 »
Sorry to necro this thread but this is way cool! I was looking at the unenviable task of writing my own when I found this. I think it will do just fine!
mad props!
mad props!