Date   : Wed, 08 Mar 2006 10:54:28 -0000
From   : "David Hunt" <dm.hunt@...>
Subject: Re: Warning: Sad case on list!

> Heh. Use 16 of them to do the fractal calculations, with the beebs on
> RS-nnn to front the graphics. ;-b'

I think that's a great idea, get the mainframes/minis talking to the Beebs
over serial sending VDU commands. Then all you need to do is get the Beebs
into serial input mode and you're away.

You could have banks of Beebs driven by different mainframe/mini computers.
If you drew blocks on each Beeb at 1280x1024 (160x256 Mode 2) and then
tunnelled down, so you then have four blocks of 640x512 and then sixteen
blocks of 320x256 etc. so you see a Mandelbrot set gradually "come into
focus" The mainframe/mini would either calculate and cache so the "focus"
would be linear, or draw the blocks as they are calculated. Depends on how
fast the mainframe/mini is. People want to see an image built up but
conversely don't want to wait more than 5-10 minutes.

   10 MODE2:VDU23;8202;0;0;0;
   20 *FX9
   30 AR=-2:AI=-1.25:S=2.5:D=S/1280
   40 FORE%=1024TO128STEP-128
   50   C%=E%DIV32:D%=E%DIV16
   60   FORY%=0TO1024STEPC%
   70     FORX%=0TO1280STEPD%
   80       CR=X%*D+AR:CI=Y%*D+AI:ZR=CR:ZI=CI:I%=0
   90       REPEAT
  100         A=ZR^2:B=ZI^2:L=SQR(A+B):ZI=2*ZR*ZI+CI:ZR=A-B+CR:I%=I%+1
  110       UNTIL L>2 OR I%>15
  120       GCOL0,I%
  130
IFC%=4THENPLOT69,X%,Y%ELSEMOVEX%,Y%:MOVEX%+D%,Y%:PLOT85,X%,Y%+C%:MOVEX%+D%,Y
%:MOVEX%+D%,Y%+C%:PLOT85,X%,Y%+C%
  140     NEXT
  150   NEXT
  160 NEXT

Just knocked this up to show you what I mean. Runs in less than a second on
BBC Basic for Windows... Will take eons on a real Beeb, a lot less time on
an Arc or something with a bit more poke than a Beeb.

Dave ;)