[vtk-developers] Re: significant slow-down (6x) ofvtkPiecewiseFunction::GetValue() with new pipeline

[Lisa Avila]

Perhaps we need a "safe" GetValue (which does the update), and a fast one 
that can be used after calling Update first. This is an easy change (except 
for deciding on method names!) and would fix these problems. Of course 
GetValue was not implemented efficiently (unless someone has changed it) so 
that itself should be improved if folks are relying on it for more than 
just querying a few values....

Lisa




At 11:47 AM 11/28/2004, Charl P. Botha wrote:
>Hi there Dean,
>
>On Sun, 28 Nov 2004 10:39:42 -0500, Dean Inglis <dean.inglis at camris.ca> wrote:
> > this is also the likely root of the slowdown seen with tests and
> > examples using vtkSplineWidget, that I noted in a previous post:
> > http://public.kitware.com/pipermail/vtk-developers/2004-October/002936.html
> >
> > vtkSpline relies on vtkPiecewiseFunction for most of its work.
> > Hopefully someone working on the new pipeline can sort this out soon....
>
>I was reminded of your posts to the mailing list when I was tracking
>this down, but I wasn't sure that there was a link, so I thought it
>prudent not to voice my suspicions in that regard.
>I also hope that there's a way to get around the speed hit, as some of
>my code is also heavily dependent on vtkPiecewiseFunction::GetValue()
>calls.
>
>Regards,
>Charl
>
>--
>charl p. botha http://cpbotha.net/ http://visualisation.tudelft.nl/
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