[vtkusers] raw buffer access in Tcl

[David.Pont at ForestResearch.co.nz]

Hi Charl,
   re my earlier statement, I did not mean to imply Python or Tcl are not
solid. What I meant is actually addressed in VISSION, I really like the
'metaclass' concept, although I had in mind a way of generating this kind
of wrapper automatically for vtk in the same fashion as the language
wrappers are done, not manually as done in VISSION (I think).
This meta layer would be the information manipulated by the pipeline
editor. If other key functionality (network management/editing/persistence
etc) were added, a uniform interface to vtk pipeline editing could be
produced. This could be used from C++, but in theory at least, also be
wrapped to be used from the other supported languages?
This could allow multiple editors to be developed, developers working in
their favourite languages. If the uniform interface was adhered to (and
extended as necessary) editor A could load a pipeline built by editor B...
So this was what I had in mind when I suggested a 'solid foundation', a
uniform interface to pipeline editing, rather than relying on the features
of specific languages.
Of course it may be more efficient to do as you suggest, leverage the
features of one of those languages and spend the programming effort making
a pipeline editor, rather than an
automatically-generated-uniform-interface-to-a-pipeline-editor.

   so I am looking forward to seeing RPD...

PS: you mentioned that VISSION was not publicly available but the way the
C++ introspection was done is.... Does this mean the C++ interpreter (CINT)
or is some of the VISSION functionality built on top of this actually
available? I could see no reference to anything publicly available from
VISSION. VISSION seems to include some very useful features (on the fly
interpretation, C++ scripting, pipeline type checking etc) as part of the
'introspection stuff' that looks very good.

  regards, Dave.




|--------+--------------------------------->
|        |          "Charl P. Botha"       |
|        |          <c.p.botha at ewi.tudelft.|
|        |          nl>                    |
|        |          Sent by:               |
|        |          vtkusers-admin at public.k|
|        |          itware.com             |
|        |                                 |
|        |                                 |
|        |          17/06/2003 19:49       |
|        |                                 |
|--------+--------------------------------->
  >------------------------------------------------------------------------------------------------------------|
  |                                                                                                            |
  |      To:     VTK Users List <vtkusers at public.kitware.com>                                                  |
  |      cc:                                                                                                   |
  |      Subject:     Re: [vtkusers] raw buffer access in Tcl                                                  |
  >------------------------------------------------------------------------------------------------------------|




On Fri, 2003-06-13 at 02:21, David.Pont at ForestResearch.co.nz wrote:
> I have thought for a while that if the vtk build process can
auto-generate
> wrappers for other languages then why not for C++. This would give
> 'introspection' capabilities which would be very useful to make a vtk
> pipeline editor...

I would like to add my 2 cents.  I have not seen RPD yet, but one of the
better examples of a VTK pipeline editor is the VISSION system[1] by
Alex Telea[2].  It blows most other network editors out of the water, as
wrapping VTK represents only a single case study for VISSION.  The
system has been used to wrap other large C++ toolkits as well.

Alex solved the introspection issue in an entirely generic (and
therefore universally applicable) fashion by making use of a C++
interpreter and Alex's metaclass concept.

The only disadvantage of VISSION is that it's not publically available.
:)  However, the way in which the C++ introspection problem was solved
is available and has been proven to work exceedingly well.

Personally, I would just do it via Python a la vtkPipeline (by Prabhu,
based on work by Paul for Tcl), but then that's me. :)

[1] http://www.win.tue.nl/~alext/ALEX/PAPERS/papers.html (search for
keyword VISSION, there are at least 4 articles)
[2] http://www.win.tue.nl/~alext/

Best regards,
Charl

--
charl p. botha http://cpbotha.net/ http://visualisation.tudelft.nl/
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