[vtkusers] vtkRenderWindowInteractor with custom render loop

[Elaine Jiang]

Hi Sankhesh,

Yes, I want users to be able to interact with the VTK objects with a VR
wand. I can test whether the wand works by temporarily using keyboard
buttons to zoom, pan, rotate, and select the VTK objects. I would need to
use a vtkRenderWindowInteractor in this case, right?

Thanks,
Elaine

On Mon, Aug 21, 2017 at 1:28 PM, Sankhesh Jhaveri <
sankhesh.jhaveri at kitware.com> wrote:

> Hi Elaine,
>
> By using the ExternalVTKWidget and all the vtkExternal* classes, you get
> interaction by default. The external widget ensures that the VTK camera is
> synchronized with the VR camera. Is there some special kind of interaction
> that you are looking for?
>
> Sankhesh
> ​
>
> On Mon, Aug 21, 2017 at 12:27 PM elainejiang8 <elainejiang8 at gmail.com>
> wrote:
>
>> Hi all,
>>
>> I'm writing a program that integrates vtk with an external VR program.
>> This
>> requires that I use the VR program's render loop instead of vtk's.
>> However,
>> I'm hoping to still be able to use vtkRenderWindowInteractor as it will
>> make
>> interacting with vtk objects much easier. I saw a post on stackoverflow
>> that
>> said that I could just call vtkRenderWindowInteractor::Initialize() for
>> the
>> interactor to become enabled, but when I call the function, I can't seem
>> to
>> interact with the vtk objects. Does anyone have any insight into this
>> issue?
>> I'll attach my initialization and render functions below:
>>
>> void initialize() {
>>     vtkNew<vtkExternalOpenGLRenderWindow> renWin;
>>     externalVTKWidget->SetRenderWindow(renWin.GetPointer());
>>     renWin->AddRenderer(ren);
>>
>>     /**********************************************************/
>>
>>     std::string files[7] = {"../data/cco-ascii.vtk",
>> "../data/newjets-ascii.vtk", "../data/fekcorr-ascii.vtk",
>> "../data/newar-ascii.vtk", "../data/newhetg-ascii.vtk",
>> "../data/newopt-ascii.vtk", "../data/newsi-ascii.vtk"};
>>
>>     for(int i = 0; i < NUM_ACTORS; i++) {
>>         vtkSmartPointer<vtkPolyDataReader> reader =
>>         vtkSmartPointer<vtkPolyDataReader>::New();
>>         reader->SetFileName(files[i].c_str());
>>         reader->Update();
>>         vtkSmartPointer<vtkPolyData> inputPolyData = reader->GetOutput();
>>
>>         // Merge duplicate points, and/or remove unused points and/or
>> remove
>> degenerate cells
>>         vtkSmartPointer<vtkCleanPolyData> clean =
>>         vtkSmartPointer<vtkCleanPolyData>::New();
>>         clean->SetInputData(inputPolyData);
>>
>>         vtkSmartPointer<vtkSmoothPolyDataFilter> smoothFilter =
>>         vtkSmartPointer<vtkSmoothPolyDataFilter>::New();
>>         smoothFilter->SetInputConnection(clean->GetOutputPort());
>>         smoothFilter->SetNumberOfIterations(15);
>>         smoothFilter->SetRelaxationFactor(0.1);
>>         smoothFilter->FeatureEdgeSmoothingOff();
>>         smoothFilter->BoundarySmoothingOn();
>>         smoothFilter->Update();
>>
>>         // Update normals on newly smoothed polydata
>>         vtkSmartPointer<vtkPolyDataNormals> normals =
>> vtkSmartPointer<vtkPolyDataNormals>::New();
>>         normals->SetInputConnection(smoothFilter->GetOutputPort());
>>         normals->ComputePointNormalsOn();
>>         normals->ComputeCellNormalsOn();
>>         normals->Update();
>>
>>         vtkSmartPointer<vtkPolyDataMapper> mapper =
>>         vtkSmartPointer<vtkPolyDataMapper>::New();
>>         mapper->SetInputConnection(normals->GetOutputPort());
>>         mapper->ScalarVisibilityOff();
>>
>>         vtkSmartPointer<vtkActor> actor =
>>         vtkSmartPointer<vtkActor>::New();
>>         actor->SetMapper(mapper);
>>         actor->GetProperty()->SetInterpolationToFlat();
>>         actor->GetProperty()->SetOpacity(0.8);
>>
>>         ren->AddActor(actor);
>>         actors.push_back(actor);
>>     }
>>
>>     /**********************************************************/
>>
>>     // Set the custom type to use for interaction.
>>     vtkSmartPointer<MouseInteractorHighLightActor> style =
>>     vtkSmartPointer<MouseInteractorHighLightActor>::New();
>>     style->SetDefaultRenderer(ren);
>>
>>     interactor->SetRenderWindow(renWin.GetPointer());
>>     interactor->SetInteractorStyle(style);
>>
>>     /**********************************************************/
>>
>>     ren->SetBackground(0.87, 0.88, 0.91);
>>     ren->ResetCamera();
>>     *interactor->Initialize();*
>>
>>     vtkOpenGLCamera *camera = (vtkOpenGLCamera *)ren->GetActiveCamera();
>>     // camera default position set at (4.68744, 2.67252, 360.229)
>>     camera->SetPosition(4, 2, 360);
>>     camera->SetViewUp(0,1,0); // controls "up" direction for camera
>> }
>>
>>
>> void display() {
>>     // Enable depth testing. Demonstrates OpenGL context being managed by
>> external
>>     // application i.e. GLUT in this case.
>>     glEnable(GL_DEPTH_TEST);
>>
>>     // Buffers being managed by external application i.e. GLUT in this
>> case.
>>     glClearColor(0.87f, 0.88f, 0.91f, 1.0f); // Set background color to
>> gray
>> and opaque
>>     glClearDepth(1.0f);
>>     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the color
>> buffer
>>
>>     glFlush();  // Render now
>>
>>     glEnable(GL_LIGHTING);
>>     glEnable(GL_LIGHT0);
>>
>>     //interactor->Render();
>>     externalVTKWidget->GetRenderWindow()->Render();
>>     glutSwapBuffers();
>> }
>>
>> Thanks,
>> Elaine
>>
>>
>>
>> --
>> View this message in context: http://vtk.1045678.n5.nabble.
>> com/vtkRenderWindowInteractor-with-custom-render-loop-tp5744540.html
>> Sent from the VTK - Users mailing list archive at Nabble.com.
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> --
> Sankhesh Jhaveri *Sr. Research & Development Engineer* | Kitware
> <http://www.kitware.com/> | (518) 881-4417
> ​
>
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