[PD] note data record / playback

[David Powers]

Okay, I did try to go through most of your tutorial, but for some
reason the post below seems much clearer. Just what I needed, thanks.

Hopefully I can make more sense of things from here.

~David

On 9/12/06, Frank Barknecht <fbar at footils.org> wrote:
> Hallo,
> David Powers hat gesagt: // David Powers wrote:
>
> > I'm sure that's true, but I'm I had problems understanding the
> > existing data structure tutorials. Just the definition of the term
> > "scalar" confused me, for starters. It's not even entirely clear, from
> > the tutorials, that structures might be useful, if you don't care
> > about the graphic part. For some reason, the struct in C makes much
> > more sense. Probably it's just some new terminology that I don't
> > recognize.
>
> hm, did you read this:
> http://puredata.info/community/projects/convention04/lectures/tk-barknecht/tut.tgz
>
> It's trying to explain all this stuff in very small steps, and
> reportedly people seem to get along with it quite well. There also is
> a pdf on puredata.info, but I don't have URL availabl atm. Check the
> archives.
>
> Regarding the sequencer-example: I admit it's not documented, but it's
> kind of too advanced anyways if you didn't yet do or understand the
> basics tutorial.
>
> But to give a broad overview: In your array-based approach you have
> different arrays for different needs: One to store time stamps,
> another to store note value etc.
>
> timestamp [table ts]: t0 t1 t2 ... tn
> notes [table note]:   n0 n1 n2 ... nn
> ...
>
> A data structure in Pd is similar to this, but it's like one column of
> all these tables crammed into one single "thing":
>
> [struct ds float ts float note]
>
>       ts note
>       |  |
> ds 0: t0 n0 ...
> ds 1: t1 n1 ...
> ds 2: t2 n2 ...
> ...
> ds n: tn nn ...
>
>
> You then use the [set] and [get] objects to access or change these
> fields:
>
>
>  1028
>  |      60      pointer
>  |      |       |
>  [set ds ts note]
>
>  pointer
>  |
>  [get ds ts note]
>  |      |
>  |      60
>  1028
>
>
> The "pointer" in the graphic above is used to select a data structure
> instance to work on with get or set. You may think of the pointer as
> equivalent to the number you would use to index all the tables from
> your table-based approach:
>
>  [struct ds float ts float note] <=>  [table ts], [table note]
>  pointer                         <=>  [f]: index from 0, 1, 2, ... ,n
>  get                             <=>  tabread
>  set                             <=>  tabwrite
>  "next"                          <=>  increment index: [+ 1]
>  "traverse pd-data"              <=>  reset index to 0 and "set table"
>                                       message for tabwrite/-read
>
> Whereas with tables you have lots of tables to store data, with data
> structures, you have one definition (struct ...) and then one or more
> subpatches to hold the actual data.
>
> So data structures can be seen as an extension of [table]. In fact,
> they even share part of their implementation AFAIK. A [table] in Pd is
> just a special kind of data structure that's predefined.
>
> Ciao
> --
>  Frank Barknecht                 _ ______footils.org_ __goto10.org__
>
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