[Paraview] Problems with 'interpolate scalars before mapping' in v3.10
Utkarsh Ayachit
utkarsh.ayachit at kitware.com
Mon May 9 16:02:21 EDT 2011
The problem is pretty straight forward. Looks like
vtkMapper::ShallowCopy(..) does not copy the state of
InterpolateScalarsBeforeMapping. I will commit a fix for that for next
release. Until then, you'll have to manually copy ivars that you care
about.
Utkarsh
On Sun, May 8, 2011 at 10:25 AM, Nenad Vujicic <nenadus at gmail.com> wrote:
> Dear Utkarsh,
>
> I uploaded test plugin that shows my problem at
> http://alas.matf.bg.ac.rs/~mr00053/projects/PVTest.zip.
>
> After I build and load the plugin from Qt client, I load
> disk_out_ref.ex2, select "H2" for mapping scalars, check Interpolate
> Scalars on Display tab in Object inspector and go on File->Export
> (select .my file). I get 6 message boxes which report 0, 0, 0, 0, 0, 1
> (instead of 0, 0, 0, 0, 1, 1) as values for
> vtkMapper::InterpolateScalarsBeforeMapping. So, here is first
> question: "How to create multiple vtkActor objects from
> vtkCompositePolyDataMapper2's input"? I thought that vtkMyExporter.cpp
> Ln 138-162 should be fine, but uploaded sources shows different.
>
> Thanks,
> Nenad.
>
> On Fri, May 6, 2011 at 2:29 PM, Utkarsh Ayachit
> <utkarsh.ayachit at kitware.com> wrote:
>> Nenad,
>>
>> There;s nothing much different about the vtkCompositePolyDataMapper or
>> vtkPolyDataMapper as far as the state of the
>> InterpolateScalarsBeforeMapping flag goes. I cannot see how that
>> variable can return false if it is indeed set to true as you are
>> saying. Can you share the plugin?
>>
>> Utkarsh
>>
>> On Thu, May 5, 2011 at 6:03 PM, Nenad Vujicic <nenadus at gmail.com> wrote:
>>> Hello everyone,
>>>
>>> Perhaps I was a bit unclear in my previous messages. Here are more
>>> details about the problem and test case.
>>>
>>> I use ParaView v3.10.1 release sources, Visual Studio 2008 SP1, Python
>>> 2.7, OpenMPI 1.4.3 on Vista SP2. I compiled sources with standard
>>> options (just turned on BUILD_SHARED_LIBS, MPI and Python). I derived
>>> new class from vtkExporter, vtkMyExporter, and in
>>> vtkMyExporter::WriteData() I call code specified down. The problem is
>>> in QMessage line, which reports always 0, even when this flag is
>>> turned on. Same is happening with most of other parameters.
>>>
>>> I believe that learning how to decompose composite ptrActor into
>>> several actors with vtkPolyDataMapper mapper and vtkPolyData data will
>>> solve all other problems (which occur when generating texture from
>>> scalars). At the moment, I'm interested only in actors which use
>>> vtkCompositePolyDataMapper2 mappers. As input I use disk_out_ref.ex2
>>> with selected H2 (or any other channel) for mapping colors. Does
>>> anyone have any idea how this can be done? Btw, this worked perfectly
>>> under ParaView v.3.8.1 and with RenderWindow created using VTK 5.4.2
>>> (where I create vtkCompositePolyDataMapper2 and populate it manually).
>>>
>>> Thank You very much for Your help!
>>>
>>> Best regards,
>>> Nenad.
>>>
>>> --------------------
>>>
>>> 1) Get interactive renderer 'InteractiveRenderer' from
>>> vtkMyExporter::RenderWindow
>>> 2) For every actor 'ptrActor' (3D actors only) in InteractiveRenderer do:
>>>
>>> vtkCompositeDataIterator* actor_iterator;
>>> vtkCompositePolyDataMapper2* composite_mapper = NULL;
>>>
>>> // get actor's mapper
>>> vtkMapper* mapper = ptrActor->GetMapper();
>>> if(mapper == NULL)
>>> return true; // discard
>>>
>>> // get mapper's input
>>> vtkCompositeDataSet* composite_input_data =
>>> dynamic_cast<vtkCompositeDataSet*>(mapper->GetInputDataObject(0, 0));
>>> if(composite_input_data != NULL)
>>> {
>>> // get actor's composite mapper
>>> composite_mapper = dynamic_cast<vtkCompositePolyDataMapper2*>(mapper);
>>> if(composite_mapper == NULL)
>>> return false;
>>>
>>> // in case input data is composite object, get iterator for traversing
>>> actor_iterator = composite_input_data->NewIterator();
>>>
>>> // initialize iterator for traversing
>>> actor_iterator->InitTraversal();
>>> actor_iterator->GoToFirstItem();
>>> }
>>> else
>>> actor_iterator = NULL;
>>>
>>> // export all components of input actor
>>> for(;;)
>>> {
>>> vtkSmartPointer<vtkActor> actor;
>>>
>>> // if input data is composite object, create actor with
>>> current component as data, otherwise use entire actor (I do this
>>> because I need actor with vtkPolyDataMapper and vtkPolyData data for
>>> vtkScalarsToColorsPainter)
>>> if(actor_iterator != NULL)
>>> {
>>> // check if there are no more components
>>> if(actor_iterator->IsDoneWithTraversal())
>>> break;
>>>
>>> // get next component
>>> vtkDataObject* data_object = actor_iterator->GetCurrentDataObject();
>>> if(dynamic_cast<vtkPolyData*>(data_object) != NULL)
>>> {
>>> // get poly data
>>> vtkPolyData* poly_data =
>>> dynamic_cast<vtkPolyData*>(data_object);
>>>
>>> // create new temporary poly data mapper
>>> vtkSmartPointer<vtkPolyDataMapper> poly_data_mapper =
>>> vtkSmartPointer<vtkPolyDataMapper>::New();
>>>
>>> // copy mapper's parameters
>>> poly_data_mapper->ShallowCopy(composite_mapper);
>>>
>>> // set mapper's input
>>> poly_data_mapper->SetInput(poly_data);
>>>
>>> // create new actor
>>> actor = vtkSmartPointer<vtkActor>::New();
>>>
>>> // copy actor parameters
>>> actor->ShallowCopy(ptrActor);
>>>
>>> // set actor's mapper
>>> actor->SetMapper(poly_data_mapper);
>>> }
>>> else
>>> {
>>> return false;
>>> }
>>> }
>>> else
>>> actor = ptrActor;
>>>
>>> // report some actor's property
>>> QMessageBox::about(NULL, "",
>>> QString::number(ptrActor->GetMapper()->GetInterpolateScalarsBeforeMapping()));
>>>
>>> // perform transformation from scalars to texture using
>>> vtkScalarsToColorsPainter class
>>>
>>> // extract data from ptrActor (I use previously generated
>>> texture instead of colors / scalars)
>>>
>>> // write to my custom format
>>>
>>> // if input is not composite, break the loop
>>> if(composite_input_data == NULL)
>>> break;
>>>
>>> // set iterator on next item
>>> if(actor_iterator != NULL)
>>> actor_iterator->GoToNextItem();
>>> }
>>>
>>>
>>> ----------------------------------------------------------------------------------------------------
>>>
>>> On Wed, May 4, 2011 at 3:04 PM, Utkarsh Ayachit
>>> <utkarsh.ayachit at kitware.com> wrote:
>>>> Nenad,
>>>>
>>>> I am not sure I understand where this code is being put. You say it's
>>>> an exporter? Meaning it exports to something like a vrml/x3d file? But
>>>> that doesn't seem right since you say you are using the
>>>> PolyDataMapper.
>>>>
>>>> What is this plugin trying to achieve?
>>>>
>>>> Utkarsh
>>>>
>>>> On Wed, May 4, 2011 at 8:31 AM, Nenad Vujicic <nenadus at gmail.com> wrote:
>>>>> Hello everyone,
>>>>>
>>>>> I'm having some problems with porting my ParaView exporter plug-in to
>>>>> v3.10, because ParaView started using vtkCompositeDataSet internally
>>>>> instead of keeping components merged. The problem is in performing
>>>>> transformation of scalars to texture using vtkScalarsToColorsPainter
>>>>> class. Here is approximately my code (questions come after
>>>>> pseudo-code):
>>>>>
>>>>> for every actor in currently active renderer:
>>>>> for every component of composite data object (I retrieve
>>>>> vtkDataObject* with vtkCompositeDataIterator::GetCurrentDataObject()
>>>>> call)
>>>>>
>>>>> // prepare new actor which defines component
>>>>> dynamic cast vtkDataObject* data_object to vtkPolyData* poly_data;
>>>>> create new vtkPolyDataMapper* pdm;
>>>>> pdm->ShallowCopy(composite_mapper);
>>>>> pdm->SetInput(poly_data);
>>>>> allocate new actor and do actor->ShallowCopy(ptrActor) //
>>>>> ptrActor) is selected actor from currently active renderer - line 1
>>>>> actor->SetMapper(pdm);
>>>>>
>>>>> // perform converting from scalars to texture
>>>>> ConvertScalarsToColors(actor);
>>>>>
>>>>> Routine ConvertScalarsToColors(vtkActor*) is defined in following way:
>>>>>
>>>>> L1 get actor's poly_data and mapper references,
>>>>> L2 create s2c - instance of MyVtkScalarsToColorsPainter (derived from
>>>>> vtkScalarsToColorsPainter for allowing setting its protected
>>>>> attributes),
>>>>> L3 initialize s2c parameters from mapper and poly_data
>>>>> L4 if s2c->CanUseTextureMapForColoring(poly_data) returns true,
>>>>> s2c->PrepareForRendering(), get texture and texture coordinates and
>>>>> sets them to passed actor
>>>>>
>>>>> Q1: First problem is in L3 when setting s2c parameters. Original
>>>>> mapper has turned on InterpolateScalarsBeforeMapping flag, but new one
>>>>> doesn't have it. How to safely copy properties of
>>>>> vtkCompositePolyDataMapper2 to vtkPolyDataMapper or I shouldn't do it?
>>>>>
>>>>> Q2: Even if I override above problem by turning on manually
>>>>> InterpolateScalarsBeforeMapping, I get very bad texture on output. It
>>>>> looks like scalars were not interpolated before mapping, sometimes
>>>>> even more distorted..
>>>>>
>>>>> The same code works with v3.8 perfectly. I also tried to apply
>>>>> vtkCompositeDataGeometryFilter to composite data object and to apply
>>>>> ConvertScalarsToColors() to result (even without creating new actor),
>>>>> but without success. Strange thing is that when I try this with
>>>>> manually created VTK scene (out of ParaView) it works perfectly and
>>>>> texture looks great!
>>>>>
>>>>> I would appreciate any help!
>>>>>
>>>>> Best regards,
>>>>> Nenad.
>>>>> _______________________________________________
>>>>> Powered by www.kitware.com
>>>>>
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>>>>>
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>>>>>
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>>>>>
>>>>
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>>
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