[vtkusers] vtkBoxWidget GetPlane Function Bug ?

[Eric E. Monson]

I think this should work:

/ Get the planes
m_BoxWidget->GetPlanes(m_Planes);

// Access by index
m_Planes->GetPlane(0, m_PlaneMinX);
m_Planes->GetPlane(1, m_PlaneMaxX);

Since this way you're creating a separate instance of vtkPlane in which to put each result.

-Eric


On Aug 9, 2010, at 9:29 AM, naresh wrote:

> Dear Eric
> 
> You are right . I am sorry for saying radom data rather i should say it returns same data as last one.  I tried to debug it and check the two pointer of vtkPlane . In stack both become same at last. So i think it points same address .
> 
> So what would be the solution  do i copy the value assining to new address everytime ?
> 
> 
> 
> 
> ----- Original Message ----- From: "Eric E. Monson" <emonson at cs.duke.edu>
> To: "naresh" <naresh at winner.co.in>
> Cc: <vtkusers at vtk.org>
> Sent: Monday, August 09, 2010 6:51 PM
> Subject: Re: [vtkusers] vtkBoxWidget GetPlane Function Bug ?
> 
> 
> Hey Naresh,
> 
> I don't know if this is your problem, but the documentation for vtkPlanes (and looking at the source code) says that GetPlane(int i) will always return a pointer to the same vtkPlane object (internal to vtkBoxWidget):
> 
> http://www.vtk.org/doc/nightly/html/classvtkPlanes.html
> 
> "Create and return a pointer to a vtkPlane object at the ith position. Asking for a plane outside the allowable range returns NULL. This method always returns the same object. Use GetPlane(int i, vtkPlane plane) instead"
> 
> So, I would try using the other GetPlane method to make sure you are getting different planes each time.
> 
> This shouldn't give you random data, though, so maybe something just isn't initialized by the time you are accessing it... Did you follow the examples for vtkBoxWidget for initializing everything? (something like this from Examples and Tests in http://www.vtk.org/doc/nightly/html/classvtkBoxWidget.html)
> 
> vtkBoxWidget *boxWidget = vtkBoxWidget::New();
> boxWidget->SetInteractor(iren);
> boxWidget->SetPlaceFactor(1.25);
> boxWidget->SetProp3D(actor);
> (or, boxWidget->SetInput(filter->GetOutput()); )
> boxWidget->PlaceWidget();
> vtkMyCallback *callback = vtkMyCallback::New();
> boxWidget->AddObserver(vtkCommand::InteractionEvent, callback);
> boxWidget->On();
> 
> Hope this helps,
> -Eric
> 
> ------------------------------------------------------
> Eric E Monson
> Duke Visualization Technology Group
> 
> 
> On Aug 9, 2010, at 8:53 AM, naresh wrote:
> 
>> Hi
>> 
>> I have problem with vtkBoxwidget->GetPlane function. It returns the radom data of normal values. Is these bug or i am doing anything wrong ?
>> 
>> Here is code of it. I tried to debug it . In first time and second time values changes as radomly in normal value.
>> 
>> 
>> for(int i=0; i<2; i++)
>> {
>> // Get the planes
>> m_BoxWidget->GetPlanes(m_Planes);
>> 
>> // Access by index
>> m_PlaneMinX = m_Planes->GetPlane(0);
>> m_PlaneMaxX = m_Planes->GetPlane(1);
>> }
>> 
>> 
>> 
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