[Fluxus] type polling of scene graph

[David Griffiths]

Hi Kassen,

Strange this has never been implemented, as it's been in the c++ level
for years. I just added it to git:

(define p (build-particles 100))

(display (with-primitive p (primitive-type-name)))(newline)

cheers,

dave

On Sat, 2011-01-08 at 23:14 +0100, Kassen wrote:
> Dear list,
> 
> 
> Is there any way to poll a scene-graph id for it's type? What I mean
> is that when I know that the scene-graph contains a primitive foo that
> might be either a model loaded from a .obj file or a "particles", I'd
> like to do something like;
> 
> 
> (type foo) -> "particles"
> 
> 
> or 
> 
> 
> (particles? foo) -> #t
> 
> 
> If not are there other who would see this as useful or should I keep
> track of it myself? If so, would such use be in balance to how hard a
> implementation would be to do? Right now it seems to me that Racket
> structures all and inherently have functions like "(string? bar)" and
> "(number? baz)" yet our scene-graph lacks those.
> 
> 
> In fact, in the above examples (number? foo) returns #t, which is
> fair, as it *is* a number, literally speaking, but this does seem
> counter-intuitive in the context of the scene-graph where we'd like to
> treat it as a a "particles" (or a poly, or a ribbon, or a locator
> or....). Then again, if I dig that deep I might be causing more
> trouble than it's worth, and while new features could be imagined we'd
> lose the ability to iterate over the scene-graph, unless that too
> would become accessible as a list. There might be
> more unforeseen consequences.
> 
> 
> Yours,
> Kas.