VTK: Rotate actor programmatically while vtkRenderWindowInteractor is active

Question

I'm trying to rotate a vtkActor using vtkActor::RotateZ and then calling vtkRenderWindow::Render. It works fine (it rotates the actor) but I can't move, resize, or even focus the window.

I suspected this was caused due to something not catching operating system events, so I added a vtkRenderWindowInteractor to the mix. Now I can move, resize and focus the window, but the actor is not rotating anymore.

I've isolated the code in the snippet below, comment line 43 to see both effects:

renderWindowInteractor->Start();

I'm compiling VTK 6.2 with mingw-w64 (GCC 4.9.1), running in Windows 8.1. I've uploaded the code in this repo with a small CMake setup so you can test it easily.

Thanks for your help!

---

constexpr float planeWidth = 200.0f;
constexpr float planeHeight = 100.0f;

int main()
{
    auto renderer = vtkRenderer::New();

    // Create render window
    auto renWin = vtkRenderWindow::New();
    renWin->AddRenderer(renderer);
    renWin->SetSize(600,600);

    // Create a plane
    auto texturedPlane = vtkActor::New();
    auto plane = vtkPlaneSource::New();
    plane->SetOrigin(0, planeHeight, 0);
    plane->SetPoint1(planeWidth, planeHeight, 0);
    plane->SetPoint2(0, 0, 0);

    auto planeMapper = vtkPolyDataMapper::New();
    planeMapper->SetInputConnection(plane->GetOutputPort());
    texturedPlane->SetMapper(planeMapper);
    texturedPlane->SetOrigin(planeWidth / 2, planeHeight, 0);

    renderer->AddActor(texturedPlane);
    renderer->ResetCamera();

    // Create a RenderWindowInteractor
    auto renderWindowInteractor = vtkRenderWindowInteractor::New();
    renderWindowInteractor->SetRenderWindow(renWin);
    renderWindowInteractor->Start(); // <-- Comment this line!

    // Render
    float rot = 0.0f;
    while(true)
    {
        texturedPlane->SetOrientation(0,0,0);
        texturedPlane->RotateZ(rot++);

        renWin->Render();
    }
}

---

Solved using asdfasdf's solution: (Code in this repo)

constexpr float planeWidth = 200.0f;
constexpr float planeHeight = 100.0f;
vtkActor * texturedPlane;
vtkRenderWindowInteractor * renderWindowInteractor;
vtkRenderWindow * renWin;
float rot = 0.0f;

class RotateCommand : public vtkCommand
{
public:
    vtkTypeMacro(RotateCommand, vtkCommand);

    static RotateCommand * New()
    {
        return new RotateCommand;
    }

    void Execute(vtkObject * vtkNotUsed(caller),
                 unsigned long vtkNotUsed(eventId), 
                 void * vtkNotUsed(callData))
    {
        texturedPlane->SetOrientation(0,0,0);
        texturedPlane->RotateZ(rot++);

        renWin->Render();
    }
};

int main()
{
    auto renderer = vtkRenderer::New();

    // Create render window
    renWin = vtkRenderWindow::New();
    renWin->AddRenderer(renderer);
    renWin->SetSize(600,600);

    // Create a plane
    texturedPlane = vtkActor::New();
    auto plane = vtkPlaneSource::New();
    plane->SetOrigin(0, planeHeight, 0);
    plane->SetPoint1(planeWidth, planeHeight, 0);
    plane->SetPoint2(0, 0, 0);

    auto planeMapper = vtkPolyDataMapper::New();
    planeMapper->SetInputConnection(plane->GetOutputPort());
    texturedPlane->SetMapper(planeMapper);
    texturedPlane->SetOrigin(planeWidth / 2, planeHeight, 0);

    renderer->AddActor(texturedPlane);

    renderer->ResetCamera();

    // Create a RenderWindowInteractor
    renderWindowInteractor = vtkRenderWindowInteractor::New();
    renderWindowInteractor->SetRenderWindow(renWin);
    renderWindowInteractor->Initialize();
    renderWindowInteractor->CreateRepeatingTimer(1);
    RotateCommand * rotateCallback =  RotateCommand::New();
    renderWindowInteractor->AddObserver(vtkCommand::TimerEvent, rotateCallback );

    renderWindowInteractor->Start();
}

Answer 1

Hack to get around part of the problem.

vtkRenderWindowInteractor * renderWindowInteractor;
constexpr float planeWidth = 200.0f;
constexpr float planeHeight = 100.0f;

class CommandSubclass2 : public vtkCommand
{
  public:
    vtkTypeMacro(CommandSubclass2, vtkCommand);

    static CommandSubclass2 *New()
    {
        return new CommandSubclass2;
    }

    void Execute(vtkObject *vtkNotUsed(caller), unsigned long vtkNotUsed(eventId), 
                    void *vtkNotUsed(callData))
    {
        std::cout << "timer callback" << std::endl;
        renderWindowInteractor->ExitCallback();
    }
};

int main()
{
    auto renderer = vtkRenderer::New();

    // Create render window
    auto renWin = vtkRenderWindow::New();
    renWin->AddRenderer(renderer);
    renWin->SetSize(600,600);

    // Create a plane
    auto texturedPlane = vtkActor::New();
    auto plane = vtkPlaneSource::New();
    plane->SetOrigin(0, planeHeight, 0);
    plane->SetPoint1(planeWidth, planeHeight, 0);
    plane->SetPoint2(0, 0, 0);

    auto planeMapper = vtkPolyDataMapper::New();
    planeMapper->SetInputConnection(plane->GetOutputPort());
    texturedPlane->SetMapper(planeMapper);
    texturedPlane->SetOrigin(planeWidth / 2, planeHeight, 0);

    renderer->AddActor(texturedPlane);
    renderer->ResetCamera();

    // Create a RenderWindowInteractor
    renderWindowInteractor = vtkRenderWindowInteractor::New();
    renderWindowInteractor->SetRenderWindow(renWin);

    renderWindowInteractor->Initialize();
    renderWindowInteractor->CreateRepeatingTimer(1);

    vtkSmartPointer<CommandSubclass2> timerCallback =  vtkSmartPointer<CommandSubclass2>::New();
    renderWindowInteractor->AddObserver ( vtkCommand::TimerEvent, timerCallback );


    // Render
    float rot = 0.0f;
    while(true)
    {
        renderWindowInteractor->Start(); // <-- Comment this line!
        texturedPlane->SetOrientation(0,0,0);
        texturedPlane->RotateZ(rot++);           
        renWin->Render();
    }
}

I'm sorry if I didn't give you any other reply, but since this solution is quite bad, I was waiting for someone else to find a better solution, but it seems that no one answered you, so here is what I would do.

You can pretty much guess what it does. Each 1 ms after starting the interaction, a callback is called that will stop the interaction, and do a rotation.