[vtkusers] Multiple Render Windows

[Christopher.Moore at noaa.gov]

Hi Markus,

It's nice that you included the simple (complete) sample code with your 
email.  I was able to quickly compile it on my machine (VTK 4.2, Redhat 
9.0, Nvidia driver/Quadro 550) and it doesn't show the problem you are 
having.  The Sphere remains visible as the Cone actors happily spin around 
in both windows.

Are you using Mesa or hardware-accelerated OpenGL?  Seems the only 
difference between our systems is RH version, and opengl...

Best of luck,
Chris Moore - NOAA Seattle

On Tue, 24 Feb 2004 duke123 at gmx.net wrote:

> Dear VTKers,
> 
> I am a new VTK user (VTK 4.2, Redhat 7.2) and am currently experiencing a
> strange problem. I am using a Sensable Phantom device, along with VTK for
> haptic and graphic rendering. I have some medical volume data with segmented
> bones, represented as vtkVolume and a vtkActor for each segment (as polygonal
> mesh). 
> 
> In my application I want to use 2 render windows, one displaying a volume
> rendering of the volume, and the other one displaying the segmented bones,
> which are touchable by the phantom. The current phantom position is shown by a
> cursor (vtkActor).
> 
> Since volume rendering takes some time, the "volume window" needs only be
> re-rendered when the camera position has changed, whereas the "main window"
> shall be redrawn as fast as possible, since it contains the phantom cursor. 
> 
> The problem I have, is that some actors which are present in the "main
> window" disappear, as soon as the "volume window" is rendered. This problem can be
> solved by adding all actors to both windows. But I don't want to do that.
> 
> I have put together a simple example highlighting my problem (sources at the
> end of this mail). In this example, there are two cones and one sphere and
> two render windows. The first window contains only  one cone, whereas the
> other window contains a cone and the sphere. When both windows are rendered for
> the first time, all actors are drawn. If the windows are rendered again, the
> sphere disappears. If the cone is removed from the second window, so that this
> window only contains the sphere, the sphere is rendered. 
> 
> I have checked how many actors are rendered ( GetNumberOfPropsRendered() )
> and two actors are reported, although only one is visible.
> 
> I hope that this problem is because I made a stupid mistake, since I am new
> to VTK. 
> Anyways, thanks for your help.
> 
> 
> Markus
> 
> 
> Here is the example C++ code.
> 
> 
> #include "vtkSphereSource.h"
> #include "vtkConeSource.h"
> #include "vtkPolyDataMapper.h"
> #include "vtkActor.h"
> #include "vtkRenderer.h"
> #include "vtkRenderWindow.h"
> #include "vtkCamera.h"
> #include "vtkRenderWindowInteractor.h"
> #include "vtkProperty.h"
> 
> 
> void main( int argc, char *argv[] )
> {
>   
>   vtkConeSource *cone = vtkConeSource::New();
>   cone->SetHeight( 3.0 );
>   cone->SetRadius( 1.0 );
>   cone->SetResolution( 10 );  
> 	
> 
> 
>   vtkSphereSource *sphere = vtkSphereSource::New();    
>   sphere->SetRadius(5.0);
>   sphere->SetThetaResolution(20);
>   sphere->SetPhiResolution(20);
>   sphere->SetCenter(-10,0,5);
> 
>   vtkPolyDataMapper *coneMapper = vtkPolyDataMapper::New();
>   coneMapper->SetInput( cone->GetOutput() );
>   
>   vtkPolyDataMapper *sphereMapper = vtkPolyDataMapper::New();
>   sphereMapper->SetInput( sphere->GetOutput() );
>   
>    
>   
>   vtkActor *coneActor = vtkActor::New();
>   coneActor->SetMapper(coneMapper);
>   coneActor->GetProperty()->SetColor(0, 0, 1);
>   coneActor->GetProperty()->SetInterpolationToPhong();	 
>    
>   vtkActor *sphereActor = vtkActor::New();
>   sphereActor->SetMapper( sphereMapper );
>   sphereActor->SetOrigin(0,0,0);
>     
>   vtkRenderWindow *renWin = vtkRenderWindow::New();
>   vtkRenderWindow *renWin2 = vtkRenderWindow::New();
>   
>   vtkRenderer *ren1= vtkRenderer::New();
>   ren1->AddActor(coneActor ); 
>   ren1->SetBackground( 1,1,1 );  
>  
>   vtkRenderer *ren2= vtkRenderer::New(); 
>  
>    // if the following line is uncommented, it works
>   ren2->AddActor(coneActor);
>   ren2->AddActor(sphereActor);
>   ren2->SetBackground( 1,1,1 ); 
> 
>   
>   renWin->AddRenderer( ren1 );
>   renWin2->AddRenderer( ren2 );
>   
>   renWin->SetSize( 400, 300 );
>   renWin2->SetSize( 400, 300 );
>   renWin2->SetPosition(0,350);
>   
>  
>   // Loop over 360 degrees and render both windows each time.
>    
>   for (int i = 0; (i % 360) < 360; i++) {
>    
>     renWin->Render();   
>     renWin2->Render();
>     coneActor->SetOrientation(i,0,0); 
>   }
>   
> }
> 
> 
> 
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