[Paraview] Write a reader plugin

[Xunlei Wu]

Hi David and All,

I still have trouble seeing any updates in ParaView (ParaView Git built from source with VS2008 and Qt 4.6.3 on Windows 7 64bit) after loading a GRIB2 file. For simiplicity, I have created a skeleton version of my GRIB2 reader. I have only implemented RequestInformation() with some fabricated WHOLE_EXTENT() data. I have successfully built such reader as a plugin .dll (Windows) and loaded it into ParaView through Tool -> Manage Plugins. After you load a grib2 file also attached, RequestInformation() is called and WHOLE_EXTENT() has been updated. However, I do not see such change in "Object Inspector" -> "Information" panel.
I am not sure what I did wrong. And is there anything special I need to do when build ParaView from source? FYI, "BUILD_SHARED_LIB" is on.
Would you please help me? Thank you very much.

Best,
x

-----Original Message-----
From: Xunlei Wu 
Sent: Friday, January 21, 2011 12:10 PM
To: David Doria
Cc: paraview at paraview.org
Subject: RE: Write a reader plugin

Hi All,
Do you have any suggestions? Thanks a lot.
Best,
xunlei

-----Original Message-----
From: Xunlei Wu 
Sent: Saturday, January 15, 2011 5:44 PM
To: 'David Doria'
Cc: 'paraview at paraview.org'
Subject: Write a reader plugin

Hi David and all,
I am writing a reader plugin for ParaView. A test program without the VTK wrapping approves that I can get all the header (metadata) and grid data correctly. However, when I following the examples posted in http://www.vtk.org/Wiki/ParaView/Examples/Plugins/Reader
http://www.kitware.com/products/html/WritingAParaViewReaderPlug-in.html
and vtkStructuredGridReader.h/.cxx

I got confused. Shall I subclass vtkStructuredGridAlgorithm or vtkStructuredGridReader? What are the differences? With minor differences in the code, i.e. defining char* FileName, I have both scenarios built fine. 

Let's say, we are subclassing vtkStructuredGridAlgorithm for now on. After I populate values as the following

int vtkGRIB2Reader::RequestInformation(vtkInformation* vtkNotUsed(request), 								vtkInformationVector** vtkNotUsed(inputVector),							vtkInformationVector *outputVector)
{
	...
	vtkInformation* outInfo = outputVector->GetInformationObject(0);
	
	outInfo->Set(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),	ext, 6);
	outInfo->Set(vtkDataObject::SPACING(),	this->Spacing, 3);
	outInfo->Set(vtkDataObject::ORIGIN(), 	this->Origin, 3);	

	return 1;
}

In ParaView Object Inspector / Information widget, I did not see any update in all the fields except Statistics / Type: Structured (Curvilinear) Grid. Would you please help me? Did I populate outInof in the wrong place? Thanks a lot.

Best,
xunlei

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