Atari 8-bit "Archimedes Spiral" demo - Found again!
Sometimes you stumble upon what you were looking for by accident ...
When I was 9 or 10 years old, I didn't have a modem, much less access to the Internet. The few computer magazines I had, I read over and over - and would have to type in games from program listings. I remembered typing in a BASIC program full of complicated math I didn't understand. The resulting program would take hours to run, but produced an impressive 3-D wireframe image. (With hidden line removal!)
I had a bit of luck a year later, and posted my findings here on LiveJournal.
Today I was reading through some .PDFs of old Atari magazines, not even thinking of this, when lo-and-behold, there was the article. Hazzoo-huzzah! It turned out not to be MACE Journal or Compute, but a 1982 issue of ANALOG Computing - #7, the one with the awesome Blade-Runner inspired cover art. Many thanks to Charles Bachand, and editor Lee Pappas for the article!
I wonder if Charles is reachable... and if he remembers where he got the code for the demo... The image I found before (in a Commodore ad) appears in Compute! issue 12 from May 1981 ... the ad is from Micro Technology Unlimited ... and that same issue has a screen-dump utility by that company's employee, Martin J. Cohen, Ph.D. who is the author of their Keyword Graphics Package. Hmm! (Neat: in that issue he thanks Gregory Yob for help in part of his code!)
Those with too much time on their hands are encouraged to look at the issue on Internet Archive - A.N.A.L.O.G. Computing magazine, issue 7 (1982) pp60-61. (Thanks to Brewster Kahle, Jason Scott, and others for their work there!)
A.N.A.L.O.G. Computing magazine, issue 7 (1982) pp60-61
by Charles Bachand
HATS OFF TO ATARI!!
This article contains a graphics program called "Archimedes Spiral". The program, although quite short, takes nearly three hours to run! This is definitely not a quick demo. (To produce the transparent version of the spiral, delete line 240.)(It still looks like a hat to me. Ed.)
100 REM ARCHIMEDES SPIRAL 110 REM 120 REM ANALOG MAGAZINE 130 REM 140 GRAPHICS 8+16:SETCOLOR 2,0,0 150 XP=144:XR=4.71238905:XF=XR/XP 160 FOR ZI=-64 TO 64 170 ZT=ZI*2.25:ZS=ZT*ZT 180 XL=INT(SQR(20736-ZS)+0.5) 190 FOR XI=0-XL TO XL 200 XT=SQR(XI*XI+ZS)*XF 210 YY=(SIN(XT)+SIN(XT*3)*0.4)*56 220 X1=XI+ZI+160:Y1=90-YY+ZI 230 TRAP 250:COLOR 1:PLOT X1,Y1 240 COLOR 0:PLOT X1,Y1+1:DRAWTO X1,191 250 NEXT XI:NEXT ZI 260 GOTO 260
It would be so much simpler if you could hand out a hardcopy of the graphics to demonstrate your prowess with the computer. Your friends will be doing cartwheels and going hazoo-huzzah over your printing expertise. (Hazoo-huzzah?! Ed.)
(Ed. Note: No one here at A.N.A.L.O.G is responsihle for Charlie's state of mind when he writes these non-tutorials. Just thought you people would like to know.)