[vtkusers] Re: Adding fps-info to renderer

[Martin Baumann]

Hi,

thanks for your hint! This could help me a lot!
As I need the frame per second information (that is not 1/render_time!)
I used vtkTimerLog to
do the fps calculations. I think for my case this will work:

class vtkFPSCallback : public vtkCommand
{
public:
  static vtkFPSCallback *New()
  {
    return new vtkFPSCallback;
  }

  void SetTextActor(vtkTextActor *txt)
  {
    this->TextActor = txt;
  }

  virtual void Execute(vtkObject *caller, unsigned long, void*)
  {
    static vtkTimerLog* timer = vtkTimerLog::New();
    timer->StopTimer();
    double fps = 1.0/timer->GetElapsedTime();
    timer->StartTimer();

    // output to caller object
    vtkRenderer *ren = reinterpret_cast<vtkRenderer *>(caller);
    float render_time = ren->GetLastRenderTimeInSeconds();
    sprintf(this->TextBuff,"fps %.1f\nrender-time %.4f sec", fps, render_time);
    this->TextActor->SetInput(this->TextBuff);

    // output to console
    static int i=0;
    ++i;
    cout << "Frame " << i << "\t" << "Render-Time = " << render_time << " sec"
         << "\t" << "Frame-Rate  = " << fps << " 1/sec" << endl;
  }

protected:
  vtkTextActor *TextActor;
  char TextBuff[128];
};

Regards, Martin

Goodwin Lawlor wrote:

> > Martin Baumann wrote:
>   
>> >> Hi,
>> >>
>> >> can you give me an idea of how to updated the string that contains
>> >> the framerate automatically with every new frame?
>>     
> >
> > Something like:
> >
> > class vtkFPSCallback : public vtkCommand
> > {
> > public:
> >   static vtkFPSCallback *New()
> >     { return new vtkFPSCallback; }
> >
> >   void SetTextActor(vtkTextActor *txt)
> >     {
> >     this->TextActor = txt;
> >     }
> >
> >   virtual void Execute(vtkObject *caller, unsigned long, void*)
> >     {
> >     vtkRenderer *ren = reinterpret_cast<vtkRenderer *>(caller);
> >     float fps = 1.0/ren->GetLastRenderTimeInSeconds();
> >     sprintf(this->TextBuff,"%.1f", fps);
> >     this->TextActor->SetInput(this->TextBuff);
> >     }
> > protected:
> >   vtkTextActor *TextActor;
> >   char TextBuff[128];
> > };
> >
> > //...
> > //...
> >
> >
> >   vtkFPSCallback *UpdateFPS = vtkFPSCallback::New();
> >     UpdateFPS->SetTextActor(txt);
> >     ren1->AddObserver(vtkCommand::EndEvent,UpdateFPS);
> >
> >
> >
> > hth
> >
> > Goodwin