"Bald Eagle" <cre### [at] netscapenet> wrote:
> "jr" <cre### [at] gmailcom> wrote:
> > phew, and I'm floundering.. :-( cannot see how you've arrived at the data in
> > 'CircleArray' elements 6 + 8/9.
> An initial circle array should have everything defined with _All or _Both to
> render a starting image to starting picking tangents and arcs.
ah, that is multi-pass.
> > (part of the confusion is that calculations and representation are so
> > intertwined, like when you use a colour ([n]) to select a tangent. and what
> > is special about the order of indices in 'TangentList'?)
> All of the calculations should be nice and neat and tidy in the upper part of
> the scene file. BezierArcs and analyticalTangents
they are, and I've abstracted the "do work" macros in an .inc. still 700+ lines
remaining after. :-)
> The TangentList array takes the [named] numerical values that you use to select
> the colored tangent lines and "converts"/indexes that to which tangents in the
> AnalyticalTangent macro output array they correspond to.
in other words, the values index the 'LastTangent' + 'CurrentTangent' arrays?
> > choice of tangents and which part of
> > circumference to draw should be derived.
> I had this idea in mind - but it's never going to be quite that simple, and the
> logic involved in doing that ---- it's going to be challenging. I had started
> to look into serpentine belt design software to see if I could deivine some
> rules or see some code ---- but that is a LONG tangent [sic] that I thought best
> not to pursue. "Get the PRISM rendered." was the goal - and that took a mighty
> Well, you'd have to flowchart it out and see what happens. What happens if the
> circles aren't laid out in the array just like that? What happens if they
> overlap or one is inside the other (just by mistake). How do you determine
> which tangent is the "outside" one - to give you the intended, desired "convex
> hull" truncated/rounded triangle that we're talking about? That seemed like an
> unnecessary mountain to climb over.
from my (obviously) naive point of view, I thought re overlap, the circles are
in a plane and overlap can be calculated given centres and radii are known. in
a macro, that would be part of checking the arguments beforehand. wrt
determining which tangent, it should be selected from the combination of
respective directions and centres; I assume that one can deal in "quadrants" and
perhaps use some pre-calculated lookup table?
I suspect the climbing over is worth it though, given the existing "toolbox" of
macros. you've done most of the sweat-work, now it's more (re)organising code
and writing "wrappers".
> > ...
> > and one more question, a prism made using just two circles, will that be doable
> > (wrt comment above 'ArrayIsLinear')?
> That was the idea. I put that in there when considering just that - but I don't
> know if I tested that out and saw if it worked properly or not.
> Got some residual holiday / RL stuff to get out of the way and hopefully I willl
> have a block of uninterrupted time and enough of an energy spurt to make another
> meaningful contribution to this.
> I would also like to see what Leroy has come up with - I'm not sure if his stuff
> only runs under Windows or what...
yeah, he posted a "teaser" (ie some core (array) missing). I think it's an
..inc, anyway, too will have a look in the next few days or so.
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