[vtk-developers] vtkCompositeDataPipeline::CreateInputCompositeData and multiple passes through pipelin

[Bill McGrory]

Suppose you feed a vtkCojpositeDataSet to a vtkContourfilter, and then
pass that to a vtkMultiGroupDataGeometryFilter and map it.

Now, when you render this, 
vtkCompositeDataPipeline::ExecuteData is the executive for the
vtkMultiGroupDataGeometryFilter.

the test to determine whether or not the attached pipeline is simple is
whether or not  inInfo->Get(vtkCompositeDataSet::COMPOSITE_DATA_SET())
is defined.

The first time through, it is not, and the looping for the composite
pipeline occurs as expected.

However, once the looping begins, CreateCompositeData is called, and it
will set the  inInfo->Get(vtkCompositeDataSet::COMPOSITE_DATA_SET()) to
a newly created compositedataset.

Now, if you call ExecuteData a second time, now the  COMPOSITE_DATA_SET
is defined, and doesn't occur.


Now, I suppose, I could set a flag that tells me this is a simple
pipeline when I call CreateCompositeData. But is there an algorithmic
way I can check for the existence of a simple pipeline, without adding
data to the inInfo?

Regards,
Bill
-- 
Bill McGrory