[vtkusers] Rendering large polydata, inconsistent frame rate

[javier.maestro at nabla-designs.es]

The code appeared a little messed up, sorry about that. I attached
the code on the ColoredPoints.cxx file. 

El 27-04-2015 09:59,
javier.maestro at nabla-designs.es escribió: 

> Hi all, 
> 
> I'm testing
VTK limits rendering a large number of points of a vtkPolyData
structure. I'm trying to determine how many points can I use so the
frame rate is fast enough for a specific application. 
> 
> As expected,
as the number of points gets bigger, the rendering takes more time and
the frame rate decreases. I expect the frame rate to decrease but I also
expect it to keep a constant value. However even though at first it
seems to be constant, sometimes the frame rate drops drastically and it
takes a while to get back to that constant rate. 
> 
> I'm using a grid
of points (128 x 400) just as an example. I get 6 FPS using the program
below (PC Intel Core 2 Duo 2GHz, 3GB RAM, Windows 7), but sometimes it
drops to 0 FPS and it stays in there for periods of 1 min. Is there any
reason for the inconsistent frame rate? 
> 
> Thanks. 
> 
> #include
<vtkVersion.h>
> #include <vtkSmartPointer.h>
> #include <vtkPoints.h>
>
#include <vtkPolyData.h>
> #include <vtkPointData.h>
> #include
<vtkCellArray.h>
> #include <vtkUnsignedCharArray.h>
> #include
<vtkPolyDataMapper.h>
> #include <vtkActor.h>
> #include
<vtkRenderWindow.h>
> #include <vtkRenderer.h>
> #include
<vtkRenderWindowInteractor.h>
> #include <vtkVertexGlyphFilter.h>
>
#include <vtkProperty.h>
> #include <vtkLookupTable.h>
> #include
<vtkFloatArray.h>
> #include <vtkPoints.h>
> #include <vtkTextActor.h>
>
#include <vtkTextProperty.h>
> #include <vtkCommand.h>
> #include
<stdio.h>
> 
> #define LINES_X 128
> #define LINES_Y 400
> 
> /** Update
callback. */
> class vtkTimerCallback : public vtkCommand{
> 
>
public:
> /** New operator. */
> static vtkTimerCallback *New(){
>
return (vtkTimerCallback *)new vtkTimerCallback;
> }
> /** Callback
timer. */ 
> virtual void Execute(vtkObject *caller,
> unsigned long
vtkNotUsed(eventId), void *vtkNotUsed(callData)){
> 
> static char
value[40];
> static int counter = 0;
> 
> vtkRenderWindowInteractor
*iren = 
> static_cast<vtkRenderWindowInteractor*>(caller);
> 
> //
Update frame counter
> textActor->SetInput(value);
>
textActor->Modified();
> sprintf(&value[0], "%d", counter ++); 
> 
> //
Just render again (data hasn't really changed)
> poly->Modified();
>
iren->Render();
> }
> 
> // Access polydata and text actor
>
vtkSmartPointer<vtkPolyData> poly;
> vtkSmartPointer<vtkTextActor>
textActor;
> };
> 
> // Cell connectivity
>
vtkSmartPointer<vtkCellArray> getCells(){
> 
>
vtkSmartPointer<vtkCellArray> mesh = 
>
vtkSmartPointer<vtkCellArray>::New();
> 
> int nx = LINES_X;
> int ny =
LINES_Y;
> for(int i=0;i<nx-1;i++){
> for(int j=0;j<ny-1;j++){
>
mesh->InsertNextCell(4);
> mesh->InsertCellPoint((0+j) + ny*i);
>
mesh->InsertCellPoint((ny+j) + ny*i);
> mesh->InsertCellPoint((ny+1+j) +
ny*i);
> mesh->InsertCellPoint((1+j)+ ny*i);
> }
> }
> return mesh;
>
}
> 
> int main(int, char *[]){
> 
> // Polydata
>
vtkSmartPointer<vtkPoints> points = 
>
vtkSmartPointer<vtkPoints>::New();
> vtkSmartPointer<vtkFloatArray>
scalars = 
> vtkSmartPointer<vtkFloatArray>::New();
>
vtkSmartPointer<vtkPolyData> poly = 
>
vtkSmartPointer<vtkPolyData>::New();
> 
> for(int a=0;a<LINES_X;a++){
>
for(int b=0;b<LINES_Y;b++){
> points->InsertNextPoint((float)a,
(float)b, 0);
> float value = (float)a/(float)LINES_X;
>
scalars->InsertNextValue(value);
> }
> } 
> poly->SetPoints(points);
>
poly->GetPointData()->SetScalars(scalars);
>
poly->SetPolys(getCells());
> 
> // Mapper
>
vtkSmartPointer<vtkPolyDataMapper> mapper =
>
vtkSmartPointer<vtkPolyDataMapper>::New();
>
mapper->SetInputData(poly);
> mapper->ScalarVisibilityOn();
>
mapper->SetScalarModeToUsePointData();
>
mapper->SetColorModeToMapScalars();
> mapper->SetScalarRange(0, 1.0);
>

> // Lookup Table
> vtkSmartPointer<vtkLookupTable> lookupTable = 
>
vtkSmartPointer<vtkLookupTable>::New();
> lookupTable->SetTableRange(0,
1.0);
> mapper->SetLookupTable(lookupTable);
>
mapper->ReleaseDataFlagOn();
> mapper->ImmediateModeRenderingOn();
> 
>
// Actor
> vtkSmartPointer<vtkActor> actor =
>
vtkSmartPointer<vtkActor>::New();
> actor->SetMapper(mapper);
> 
> //
Renderer
> vtkSmartPointer<vtkRenderer> renderer =
>
vtkSmartPointer<vtkRenderer>::New();
> vtkSmartPointer<vtkRenderWindow>
renderWindow =
> vtkSmartPointer<vtkRenderWindow>::New();
>
renderWindow->AddRenderer(renderer);
> 
> // Setup the text and add it
to the window
> vtkSmartPointer<vtkTextActor> textActor = 
>
vtkSmartPointer<vtkTextActor>::New();
>
textActor->GetTextProperty()->SetFontSize ( 24 );
>
textActor->SetPosition2 ( 10, 40 );
> renderer->AddActor2D ( textActor
);
> textActor->SetInput ( "0" );
>
textActor->GetTextProperty()->SetColor ( 1.0,0.0,0.0 );
> 
> // Add
actors
> renderer->AddActor(actor);
> renderer->AddActor(textActor);
>

> // Interactor
> vtkSmartPointer<vtkRenderWindowInteractor>
renderWindowInteractor =
>
vtkSmartPointer<vtkRenderWindowInteractor>::New();
>
renderWindowInteractor->SetRenderWindow(renderWindow);
> 
> // Render
>
renderWindow->Render();
> renderWindowInteractor->Initialize(); 
> 
> //
Sign up to receive TimerEvent (Update)
>
vtkSmartPointer<vtkTimerCallback> timerCallback = 
>
vtkSmartPointer<vtkTimerCallback>::New();
> timerCallback->poly =
poly;
> timerCallback->textActor = textActor;
>
renderWindowInteractor->AddObserver(vtkCommand::TimerEvent,
timerCallback);
> renderWindowInteractor->CreateRepeatingTimer(1);
> 
>
// Start interactor
> renderWindowInteractor->Start(); 
> 
> return
EXIT_SUCCESS;
> }
 
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