[vtkusers] vtkTrivialProducer strange behavior

[Brad King]

Carlos Scheidegger wrote:
> I'm trying to use vtkTrivialProducer in one application and I'm getting 
> unexpected behavior. Apparently, there cannot be more than one 
> vtkTrivialProducer pointing to the same vtkDataObject? I'm attaching a 
> python script that exercises the path. This is what happens when I run it:
[snip]
> The code will try to create two renderers and show the same dataset in 
> both, using vtkTrivialProducers to feed the mapper. Is this the expected 
> behavior? I can work around it, but I'm just wondering whether it's a 
> bug or not. (I guess it's high time I learned some serious VTK internals)

Allowing only one vtkTrivialProducer per vtkDataObject is the intended 
behavior.  It is just like any other source.  The output of 
vtkSphereSource or vtkXMLPolyDataReader is produced by the corresponding 
source.  Since stand-alone data objects have no producer they create a 
vtkTrivialProducer when a producer is needed, such as when connecting 
the data object as input to another filter.

Crashing when this rule is violated is not intended behavior, though. 
Please submit a bug report here:

http://www.vtk.org/Bug

and include the python script you posted that reproduces the bug.

Thanks,
-Brad