[vtkusers] interactor in a main loop

[Clinton Stimpson]

>
> Message: 2
> Date: Wed, 06 Oct 2004 09:45:10 +0200
> From: francesco caruso <guernika_devel at yahoo.it>
> Subject: [vtkusers] interactor in a main loop
> To: vtkusers at vtk.org
> Message-ID: <4163A286.1030508 at yahoo.it>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
> Hello
>
> In my VTK application, there is a main loop in which
> frames are grabbed continuously.
>
> I'd like add an interactor, but when I do it the main loop stops
> because interactor is waiting for an event.
>
> How can I resolve this?
>
> Thanks in advance
>

You might be able to use a timer to do the frame grabbing.  The
vtkRenderWindowInteractor classes can make timers and they work with the
interactor start method.

Or ..

Have your existing event loop control the VTK windows as well as do the
frame grabbing.

This sample was originally made to show how to do multiple graphics windows
with multiple interactors without putting each window on a separate thread,
which makes it more complicated.

Clint

============================================

#include "vtkRenderWindow.h"
#include "vtkRenderer.h"

#include "vtkActor.h"
#include "vtkPolyDataMapper.h"
#include "vtkCylinderSource.h"
#include "vtkToolkits.h"

#ifdef VTK_USE_X
#include <X11/Intrinsic.h>
#include "vtkXRenderWindowInteractor.h"
#else
#include "vtkRenderWindowInteractor.h"
#include <windows.h>
#endif

int main(int, char**)
{
#ifdef VTK_USE_X
  XtToolkitInitialize();
  // create X11 application context
  XtAppContext app_context = XtCreateApplicationContext();
#endif

  // create two renderers
  vtkRenderer* ren1 = vtkRenderer::New();
  vtkRenderer* ren2 = vtkRenderer::New();

  // create 2 windows and hook the renderers up to them
  vtkRenderWindow* win1 = vtkRenderWindow::New();
  win1->AddRenderer(ren1);
  vtkRenderWindow* win2 = vtkRenderWindow::New();
  win2->AddRenderer(ren2);

#ifdef VTK_USE_X
  // create the X11 interactors and hook our X11 stuff up to them
  vtkXRenderWindowInteractor* iren1 = vtkXRenderWindowInteractor::New();
  iren1->SetRenderWindow(win1);
  iren1->Initialize(app_context);
  vtkXRenderWindowInteractor* iren2 = vtkXRenderWindowInteractor::New();
  iren2->SetRenderWindow(win2);
  iren2->Initialize(app_context);
#else
  // create the win32 interactors
  vtkRenderWindowInteractor* iren1 = vtkRenderWindowInteractor::New();
  iren1->SetRenderWindow(win1);
  iren1->Initialize();
  vtkRenderWindowInteractor* iren2 = vtkRenderWindowInteractor::New();
  iren2->SetRenderWindow(win2);
  iren2->Initialize();
#endif

  // put something in the windows so we know we can interact with it
  vtkActor* actor = vtkActor::New();
  vtkMapper::GlobalImmediateModeRenderingOn(); // allow the same actor in
multiple renderers, but slower
  vtkPolyDataMapper* mapper = vtkPolyDataMapper::New();
  actor->SetMapper(mapper);
  vtkCylinderSource* cyl = vtkCylinderSource::New();
  mapper->SetInput(cyl->GetOutput());

  ren1->AddProp(actor);
  ren2->AddProp(actor);

  // reset the view
  ren1->ResetCamera();
  ren2->ResetCamera();


// there are more things you can do below for more advanced stuff
// (e.g. integrate console input, network sockets, etc..
// to event loop without dealing with threads)

#ifdef VTK_USE_X
  // the main X11 event loop
  XtAppMainLoop(app_context);
#else
  MSG  msg;
  int status;
  while ((status = ::GetMessage (&msg, 0, 0, 0)) != 0)
  {
    if (status == -1)
      return -1;
    ::TranslateMessage (&msg);
    ::DispatchMessage (&msg);
  }
#endif

  return 0;

}