Right. Like I said, it was the simplest thing that would work to be able to
autobuild stuff using a Logo-like dialect. OTOH it can't really be exactly
Logo, not exactly; Logo didn't have flying turtles!

On Thu, Feb 28, 2013 at 9:59 AM, Bert Freudenberg <bert at freudenbergs.de>wrote:

>
> On 2013-02-28, at 08:38, Frank Shearar <frank.shearar at gmail.com> wrote:
>
> > On 28 February 2013 01:04, Casey Ransberger <casey.obrien.r at gmail.com>
> wrote:
> >> Vector3D is totally it. I knew I'd seen it x at y@z somewhere, which was
> in
> >> OpenQWAQ now that I think about it.
> >>
> >> Is there a canonical MC repository for this code, or should I grab an
> Cobalt
> >> image and start filing stuff out?
> >>
> >> Eeep! I'm a step closer to Logo in Minecraft :D I did the simplest thing
> >> that would work, which is something like...
> >>
> >> turtle
> >>    penDown;
> >>    turn: #west;
> >>    go: 5;
> >>    turn: #up;
> >>    go: 1;
> >>    turn: #east;
> >>    go: 5
> >>
> >> This is actually good enough to make procedurally generating relatively
> >> complex builds (e.g., a CPU) much less painful that even a map editor,
> but
> >> it doesn't feel like Logo at all. I haven't used Logo since childhood,
> but
> >> IIRC one would turn by degrees and these would be mapped onto pixel
> space. I
> >> *think* this is why I'm wanting a 3D Point, so I can map 3D points onto
> >> voxel space without reinventing the third dimension from scratch.
> >>
> >> This was a fun problem to think about: I tried to get #left and #right
> as
> >> valid params to the turn method, but wait! What does #left mean when the
> >> turtle is currently traveling up? Which has me now thinking in terms of
> >> roll/yaw/pitch. It's weird to think about.
> >
> > Yep, that makes sense, given Logo's differential-geometry-ness.
> > #left/#right are, of course, yaw: 'left a bit, up a bit, ok fly like
> > that. down a bit, right a bit.' Have you heard of the TNB frame at
> > all? The torsion/normal/binormal frame. Might help in getting yourself
> > inside the turtle.
> >
> > frank
>
> Yep. The most important thing about turtle graphics is that almost all
> turtle commands are relative to the turtle's position and direction. So
> instead of turning "west" and "east" absolutely, you should turn "left" and
> "right", and if you do 4 "up + go" in a row would have made a (square)
> looping. "Left" and "right" make total sense if you imagine being a turtle
> :)
>
> If it's just a "cursor" instead of a turtle, then using absolute
> directions would make sense. In that case "cursor goX: 5; goY: 5; goX: -5;
> goY: -5" would also draw an upright square. This might be more convenient
> in some cases, but you shouldn't call it "turtle".
>
> - Bert -
>
>
>
>


-- 
Casey Ransberger
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