[vtkusers] vtkRenderWindowInteractor with custom render loop

[Sankhesh Jhaveri]

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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