[vtkusers] Filtered polydata

[Nil Goyette]

Hi all,

My last mesage was probably not seen because it appeared on the ML 
several hours after I sent it. Anyone? It would be nice to have a some 
general advices before starting this project. Thank you.

Nil

Le 2018-05-09 à 10:00, Nil Goyette a écrit :
> Hi all,
>
> We decided to port our old vtk application to vtk8 and I have some 
> questions concerning the jump to OpenGL2+. We load a streamlines file 
> (tck/trk/fib/vtk), which is simply a list of lines in 3D [1], to view 
> it with an image, compute some stats on it, etc. This is already 
> working well, thanks to the MITK framework.
>
> The problem is that we need to filter the streamlines when the user 
> moves a selection box. It needs to be real-time, even with million(s) 
> of streamlines. By 'filter', I simply mean that the user won't see all 
> the data, but the data still should be in memory. Last time I simply 
> created my own mapper, extending vtkPolyDataMapper, looping over a 
> shared QSet containing the indices I wanted to draw. It was kind of a 
> hack but it was super fast because there was no data duplication, only 
> the qset was modified.
>
> vtk changed a lot so I prefer asking before coding anything. Is there 
> a standard way to filter a huge polydata in real-time? If not, I 
> started studying OpenGL2/vtkOpenGLPolyDataMapper.cxx and I have some 
> questions about the best way to draw only the lines I want, probably 
> concerning glDrawRangeElements and Primitives.IBO.
>
> Nil Goyette
>
> [1] https://i.imgur.com/krzBvJV.png
>
>
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