[vtk-developers] vtkCellArray memory layout

[David Lonie]

On Wed, Mar 20, 2013 at 7:12 PM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

>  A backward compatible approach might use an additional offset array into
> the existing cell ids array.
>

Backwards compatibility is definitely the biggest obstacle to a change like
this. This approach would lose some of the nice features we've discussed
like super-fast VBO creation, but would be a step in the direction of
allowing a cellId-based random-access API, which is more important for my
needs at the moment. However, the memory overhead of duplicating the cell
size information may be unacceptable in some cases.

The other approach Berk proposed is to introduce an abstract class above
vtkCellArray that only uses sequential access via GetNextCell, etc, and
rewrite only selected filters to use this API, since coprocessing adapters
should be able to handle sequential access without much trouble. (As I
mentioned earlier in my reply to Will, The real thorn in my side for this
project is the array-index random access methods). This would certainly be
easier, and leave a major rewrite/redesign for a later project, perhaps one
that has the resources to update VTK away from the fixed-pipeline GL
approach.

Dave
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20130321/8bf20721/attachment.html>