[vtkusers] Quadratic cell data bug ?
John Platt
jcplatt at lineone.net
Mon Feb 21 14:17:07 EST 2005
Hi Jacques,
Try replacing
cellScalars ->SetNumberOfTuples(6);
with
cellScalars ->SetNumberOfTuples(1);
When a quadratic quad is converted to polydata by vtkDataSetMapper (a
helper class containing vtkDataSetSurfaceFilter which extracts
faces/edges for the internal instance of vtkPolyDataMapper) it is
triangulated into 6 linear triangles. Just set the number of cell tuples
equal to the number of quadratic cells and you should have no problems.
HTH
John.
-----Original Message-----
From: jacques.charreyron [mailto:jacques.charreyron at caramail.com]
Sent: 21 February 2005 15:03
To: John Platt
Subject: Re: RE: [vtkusers] Quadratic cell data bug ?
John,
Thanks for your answer,
In fact I really meant cell data and
"currentMapper->SetScalarModeToUseCellData();"
id used on purpose.
Sorry my code snippets were wrong as fas as variable names are concerned
. please read :
vtkFloatArray *cellScalars = vtkFloatArray::New();
cellScalars ->SetNumberOfComponents(1);
cellScalars ->SetNumberOfTuples(6);
cellScalars ->SetTuple1(0,10.0);
grid->GetCellData()->SetScalars(cellScalars );
instead of :
vtkFloatArray *pointScalars = vtkFloatArray::New();
pointScalars->SetNumberOfComponents(1);
pointScalars->SetNumberOfTuples(6);
pointScalars->SetTuple1(0,10.0);
grid->GetCellData()->SetScalars(pointScalars);
Yours,
Jacques
_____
> De: "John Platt" <jcplatt at lineone.net>
> A: "'jacques.charreyron'" <jacques.charreyron at caramail.com>
> Objet: RE: [vtkusers] Quadratic cell data bug ?
> Date: Mon, 21 Feb 2005 14:06:46 -0000
Hi Jacques,
On a very quick look, check
currentMapper->SetScalarModeToUseCellData();
Did you mean point data?
HTH
John.
-----Original Message-----
From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On
Behalf Of jacques.charreyron
Sent: 21 February 2005 10:25
To: vtkusers at vtk.org
Subject: [vtkusers] Quadratic cell data bug ?
Hello,
I am trying to display values on quadratic cells. In my example I have
one quadratic quad cell
I allocate only one tuple in my float array and put an arbitrary value :
vtkFloatArray *pointScalars = vtkFloatArray::New();
pointScalars->SetNumberOfComponents(1);
pointScalars->SetNumberOfTuples(6);
pointScalars->SetTuple1(0,10.0);
grid->GetCellData()->SetScalars(pointScalars);
When running this example I get this error :
ERROR: In
G:\Sandbox\Shared\common\intel_a\Api\Vtk\R4.4\Src\Common\vtkDataSet.cxx,
line 403
vtkPolyData (0x01BADF98): Cell array with 1 components, has only 0
tuples but there are 6 cells
When I allocate six tuples to put six value : ie one for each triangle
like this :
vtkFloatArray *pointScalars = vtkFloatArray::New();
pointScalars->SetNumberOfComponents(1);
pointScalars->SetNumberOfTuples(6);
pointScalars->SetTuple1(0,10.0);
pointScalars->SetTuple1(1,10.0);
pointScalars->SetTuple1(2,10.0);
pointScalars->SetTuple1(3,10.0);
pointScalars->SetTuple1(4,10.0);
pointScalars->SetTuple1(5,10.0);
grid->GetCellData()->SetScalars(pointScalars);
I get the following error :
Warning: In
G:\Sandbox\Shared\common\intel_a\Api\Vtk\R4.4\Src\Common\vtkDataSet.cxx,
line 411
vtkUnstructuredGrid (0x01B8CB00): Cell array with 1 components, has 6
tuples but there are only 1 cells
ERROR: In
G:\Sandbox\Shared\common\intel_a\Api\Vtk\R4.4\Src\Common\vtkDataSet.cxx,
line 403
vtkPolyData (0x01BADF98): Cell array with 1 components, has only 0
tuples but there are 6 cells
Any idea ?
Here is a code snippet to reproduce the behaviour :
#include <vtkActor.h>
#include <vtkCellType.h>
#include <vtkDataSetMapper.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkPoints.h>
#include <vtkProperty.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkUnstructuredGrid.h>
#include <vtkWindowToImageFilter.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkActor2D.h>
#include <vtkLabeledDataMapper.h>
#include <vtkLookupTable.h>
#include <vtkFloatArray.h>
#include <vtkPointData.h>
#include <vtkMath.h>
#include <vtkScalarBarWidget.h>
#include <vtkScalarBarActor.h>
#include <vtkLookupTable.h>
#include <vtkTexture.h>
#include <vtkStructuredPoints.h>
#include <vtkBandedPolyDataContourFilter.h>
#include <vtkGeometryFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkCellData.h>
int main( int argc, char *argv[] )
{
vtkPoints *points = vtkPoints::New();
points->SetNumberOfPoints(8);
points->SetPoint(0, 0, 0, 0);
points->SetPoint(1, 1, 0, 0);
points->SetPoint(2, 1, 1, 0);
points->SetPoint(3, 0, 1, 0);
points->SetPoint(4, 0.5, 0, 0);
points->SetPoint(5, 1, 0.5, 0);
points->SetPoint(6, 0.5, 1, 0);
points->SetPoint(7, 0, 0.5, 0);
vtkIdType pointIds[8];
pointIds[0] = 0;
pointIds[1] = 1;
pointIds[2] = 2;
pointIds[3] = 3;
pointIds[4] = 4;
pointIds[5] = 5;
pointIds[6] = 6;
pointIds[7] = 7;
//--------------
// Quad grid
//--------------
vtkUnstructuredGrid* grid = vtkUnstructuredGrid::New();
grid->Allocate(1);
grid->SetPoints(points);
grid->InsertNextCell(VTK_QUADRATIC_QUAD,8,pointIds);
// Point data (scalars)
vtkFloatArray *pointScalars = vtkFloatArray::New();
pointScalars->SetNumberOfComponents(1);
pointScalars->SetNumberOfTuples(6);
pointScalars->SetTuple1(0,10.0);
grid->GetCellData()->SetScalars(pointScalars);
// Lookup :
vtkLookupTable *lookupTable = vtkLookupTable::New();
lookupTable->SetNumberOfColors(10);
lookupTable->SetTableRange(0.0,1.0);
lookupTable->Build();
// Scalar bar actor
vtkScalarBarWidget *scalarBarWidget=vtkScalarBarWidget::New();
vtkScalarBarActor *scalarBarActor = vtkScalarBarActor::New();
scalarBarActor->SetLookupTable(lookupTable);
scalarBarWidget->SetScalarBarActor(scalarBarActor);
scalarBarActor->SetMaximumNumberOfColors(10);
// Mapper
vtkDataSetMapper *currentMapper=vtkDataSetMapper::New();
currentMapper->SetInput(grid);
currentMapper->ScalarVisibilityOff();
currentMapper->SetLookupTable(lookupTable);
currentMapper->SetInterpolateScalarsBeforeMapping(1);
currentMapper->SetScalarModeToUseCellData();
// Actor
vtkActor *quadActor = vtkActor::New();
quadActor->SetMapper(currentMapper);
//--------------
// Visualization
//--------------
// Renderer
vtkRenderer *renderer= vtkRenderer::New();
renderer->SetLightFollowCamera(true);
renderer->SetBackground(0.6,0.7,0.9);
renderer->AddActor(quadActor);
renderer->AddActor(scalarBarActor);
// RenderWindow
vtkRenderWindow *renderWindow = vtkRenderWindow::New();
renderWindow->AddRenderer(renderer);
renderWindow->SetSize(300,300);
// Interactor
vtkRenderWindowInteractor *interactor =
vtkRenderWindowInteractor::New();
interactor->SetRenderWindow(renderWindow);
// Interactor style
vtkInteractorStyleTrackballCamera *interactorStyle =
vtkInteractorStyleTrackballCamera::New();
interactor->SetInteractorStyle(interactorStyle);
// Event loop
interactor->Initialize();
interactor->Start();
return 0;
}
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