[vtkusers] Re : Using OpenGl with VTK

[Mohammed Amine SAHTARI]

Thank you very much Utkarsh.


I am tring to implement your solution but I have some problems.

1) I create vtkMyDerivedProp.h and vtkMyDerivedProp.cxx

 I subclass vtkProp :
       - I copy the class code of vtkProp3D (.h and .c files)
       - I replace all the words :
               vtkProp3D *by* *vtkMyDerivedProp *and Prop3D by *
MyDerivedProp*
       - I include *"vtkGl.h"* in vtkMyDerivedProp.h
       - I add RenderOpaqueGeometry() in vtkMyDerivedProp.h like this :
               *virtual int RenderOpaqueGeometry(vtkViewPort* )
               {*

*             glBegin (GL_LINES);

             glVertex2f (-2.5, 2.5);

             glVertex2f (2.5, -2.5);

             glEnd ();*

*               }*

2) In my program :

 - I include and instantiate vtkMyDerivedProp :

    *  **# include "vtkMyDerivedProp.h"
      vtkMyDerivedProp *MyDerivedProp;*

-         I use  vtkMyDerivedProp :

*     vtkRenderer  *renderer = vtkRenderer  ::New();*

*      vtkMyDerivedProp-> RenderOpaqueGeometry(renderer);*

*      renderer->AddProp(vtkMyDerivedProp);*


*Problem *: vtkMyDerivedProp is used without been defined!

*Question 1 :* How can I define it ?   (vtkMyDerivedProp::New()  doesn't
work)

*Question 2 :*  RenderOpaqueGeometry has vtkViewPort* in input but doesn't
use it. Is it a problem ?

How can I fix this?

Looking forward to hear from you soon,

Amine**






2008/8/14 Utkarsh Ayachit <utkarsh.ayachit at kitware.com>

iren->Start() results in repeated calls to renWin->Render() on interaction.
> This will clear whatever you had drawn. A better approach is to subclass
> vtkProp(or one of it's subclasses) and put your rendering code in
> RenderOpaqueGeometry() / RenderTranslucentPolygonalGeometry()/
> RenderOverlay() etc. depending upon what pass you want it to be rendered and
> then add the prop to the renderer. That way every time the renderer
> re-renders, your code will be executed.
>
>
> Utkarsh
>
> Mohammed Amine SAHTARI wrote:
>
>>
>> I want to add an OpenGl code in an application of VTK.
>>
>> For this purpose, I try to draw lines using commands OpenGL.:
>>
>> *1) I add this on the top of the program :*
>>
>> #include <GL/gl.h>
>> *2) I place my OpenGL commands after renWin->Render() but before
>> iren->Start()** :  *
>>
>>
>> renWin->Render();
>>
>>    glBegin (GL_LINES);
>>       glVertex2f (-2.5, 2.5);
>>       glVertex2f (2.5, -2.5);
>>     glEnd ();
>>
>> iren->Start();
>>
>>
>> *But it doesn't appears.*
>>
>> did I miss something ? How can I do this work ?
>> Looking forward to hear from you soon,
>>
>> Amine
>>
>>
>>
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