[vtkusers] Algorithm base class question

[Amy Squillacote]

Benjamin Schindler wrote:
> Hi
>
> Thanks for the very quick response. The problem I have behind is, that
> upon calling GetOutput on the Algorithm, I get a: 
>
> vtkStreamingDemandDrivenPipeline (0x910fbb0): Algorithm
> vtkSPHSliceFilter(0x91e0650) returned failure for request:
> vtkInformation (0x914b438)
>   Debug: Off
>   Modified Time: 1918
>   Reference Count: 1
>   Registered Events: (none)
>   Request: REQUEST_DATA_OBJECT
>   ALGORITHM_AFTER_FORWARD: 1
>   FORWARD_DIRECTION: 0
>   FROM_OUTPUT_PORT: 0
>
> I guessed, that since vtkPointSetAlgorithm (according to the docs) takes
> same input as output. I assumed this is the case even if you override
> FillInputPortInformation. So switching over to vtkPointSetAlgorithm did
>   

No, the whole point of overriding FillInputPortInformation is to change 
the type of input an algorithm expects.

> not solve my problems. I attached the source of the filter, but I'm not
> sure it helps, because I put a breakpoint on every function in the
> source file and never hit any before getting the error
> Any ideas?
>
> Thanks
> Benjamin
>
> On Mon, 2008-10-27 at 10:28 -0500, Amy Squillacote wrote:
>   
>> Hi Benjamin,
>>
>> You could create a vtkPointSetAlgorithm and override its 
>> FillInputPortInformation method so that it takes a vtkMultiBlockDataSet 
>> rather than a vtkPointSetAlgorithm. Take a look at how this method is 
>> overridden in VTK/Graphics/vtkThreshold.cxx.
>>
>> - Amy
>>
>> Benjamin Schindler wrote:
>>     
>>> Hi
>>>
>>> I'm writing for testing a filter that takes a MultiBlockDataSet and
>>> outputs a PointSet. What base-class is most suitable for this kind of
>>> filter? I looked at PointSetAlgorithm, but the doc says it must also
>>> take a PointSet as input... 
>>>
>>> Thanks
>>> Benjamin
>>>
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>>>   
>>>       

-- 
Amy Squillacote                    Phone: (256) 726-4839
Computer Scientist                 Fax: (256) 726-4806
CFD Research Corporation           Web: http://www.cfdrc.com
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