A bit of 40 years ago I was introduced to Logo and turtle graphics - I didn’t care much for Logo but the Turtle Graphics really interested me - so I wrote my own Turtle Graphics interpreter… In (Applesoft) BASIC, as we did back then…
And when 12 or so years later I wanted to write my own “ideal” BASIC, I incorporated Turtle commands into the language…
And so, for your amusement I made a little video of that old Apple II system and my new system running a few very simple Turtle graphics demos…
That’s rather lovely! I’m amazed at how fast your parser was in AppleSoft BASIC: speedy it isn’t. If you ever feel the urge to share the Apple II program, I’d be happy to upload a disk image to Internet Archive so people could play with it in the browser …
As for useful, I’ve used the output from Python’s turtle module and from UCBLogo to drive laser cutters. I think MMBasic for various micro-controller boards includes turtle graphics, if anyone feels the need to trundle a virtual turtle
I’ll need to investigate how to get it off an Apple floppy and onto something else (other than printing it to a serial port!) I think ADT is the software to use there though…
I have a raycasting demo in BASIC which achieves about 10-12fps on a Pi 1B - it’s fast enough to write a ‘Wolfenstein’ type game on a modern PC… With tweaks, DOOM written in BASIC?
Ah. now I have a lasercutter … and back then I did make it output to a pen plotter via serial and the code for that is still there… How hard can it be …
Although I’ve always wanted to make a ‘real’ turtle… One day!
Just a little addition to this… Some time back (1st April, 2022 to be precise) there was (as there usually is) an April Fool edition of the XKCD comic:
This was an audio transcript of a rather long LOGO program featuring Turtle Graphics to draw a picture in a sort of “Bob Ross” style.
The audio was eventually transcribed back into a LOGO program and other folks ran it and it was good.
So in a fit of idleness and “how hard can it be” (Something I’ll get engraved on my gravestone) I re-coded it in my BASIC…
I used an editor (vim) to do some global search/replaces then got bored with that, so wrote another BASIC program to generate a BASIC program with all the turtle graphics commands suitably changed to my dialect.
Nice! UCBLogo (which has recently gone back into active maintenance, so there are likely working versions available for your non-retro computer of choice) runs the saved workspace from theinternetftw/xkcd2601: Transcription of xkcd 2601 to runnable logo code in about the same time as your video on my system.
In terms of time … I slowed the generation down by forcing a screen update (it’s double-buffered) on every little line segment drawn. If I remove the update then it completes in about 100 milliseconds and the picture appears almost instantly…
Which isn’t too bad as I added in a scale factor to every turtle move and segment drawn to make it fit nicely into a 1280x1024 window. The code looks like:
t$ = "We start with a vision in our hearts and we put it on canvas."
proc scrollText (t$)
proc cubic (scale * -469,scale * 424,scale * -458,scale * 416,scale * -456,scale * 389)
penUp
moveTo (scale * -471, scale * 400)
penDown
tangle = 87
move (scale * 14)
penUp
and so on…
(Also note, as I’m sure you’ve seen - “cubic” is recursive too) I also had to add 2 new keywords into my system to read-back the turtle X & Y positions for the cubic function to work).
I tried to “get into” Logo (back then, and now) but it just isn’t “sticking” in these old grey cells, so will consider it read only for now…
