[vtkusers] Rendering large polydata, inconsistent frame rate

Mon Apr 27 08:30:37 EDT 2015

I'm using the lastest version of VTK (6.2). I fogot to mention that
I have tested the code in other PCs (with more RAM and better video
graphics) and I didn't see the inconsistent frame rate. That's why I
would like to know if it could be related to the limited resources of
the PC I'm currently working on. Are there any minimum requirements
depending on the operation that is to be perform in VTK? 

El 27-04-2015
14:05, Bill Lorensen escribió: 

> What version of VTK are you using. I
do not see and degradation when I
> run on my Mac with the latest VTK.
>

> On Mon, Apr 27, 2015 at 7:11 AM, <javier.maestro at nabla-designs.es>
wrote:
> 
>> 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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