[Fieldtrip] Re: [reactive] reactive-fieldtrip

[Conal Elliott]

Hi Eyal,

Thanks for the comments.  I'm replying on the FieldTrip list rather than on
reactive, since the issues are mostly FieldTrip issues.

On Tue, Nov 11, 2008 at 7:24 AM, Eyal Lotem <eyal.lotem at gmail.com> wrote:

> Hi
>
> I would also like to congratulate Conal and everyone else involved in
> the Reactive framework and libraries for the new release.  Amazing
> work!
>
> I have finally managed to do more than read about it, and actually toy
> with some Reactive programming :-)
> It seems great fun, and the learning curve is not as steep as it might
> seem at first.
>
> I mostly played with Test.hs inside the reactive-fieldtrip adapter,
> and I have encountered a few issues:
>
> A. It seems that when changing spinningG to scale according to time,
> it becomes extremely slow very quickly.


Probably because of the current algorithm for dynamic tessellation
(approximation by polygons).  As you scale up, a surface will get
tessellated more and more finely during rendering.  The tessellations are
cached in an efficient, infinite, pure data structure (a MemoTrie) as
they're computed.  Given your experience, I gather there's some tuning
required.


> B. The lplace demo itself is also extremely slow, whereas other demos
> seem to be fine/quick. It might be buggy, and not extremely slow, its
> taking so long to react that I am not sure what is happening.


All of the demos are *very* zippy on my machine, even with 10-20 spinning
torus pairs going.

Could you please give me particulars about your setup?  For instance:
cpu(s), graphics card, OS, and versions of opengl & glut.

C. Stylistic question/comment:
> The (Anim a) type (UI -> Behavior a) is a Reader
> Functor/Applicative/Monad.  I see it used as a Functor in various
> examples, but it seems that there's no use of the Applicative/Monad of
> the reader, is this intentional?
> I find it a bit awkward that it passes the "env" arg to all of the
> stuff its combining... The example even used an undefined error value
> in place of the env in some cases, suggesting that it is a burden to
> pass it around.   Why not encourage the implicit passing of the env
> everywhere via the reader Applicative?
>

Fixed now.  Thanks.

Regards,  - Conal
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