[vtkusers] elevationColoredPoints ?!

[Lucian Goron]

Hello,

I have a code that was suppose to create a set of points, to render them and
then compute the elevation-colored points as in the following example
http://www.vtk.org/Wiki/VTK/Examples/Elevation_Filter.
Unfortunately, I get a seg fault. I am relatively new to VTK and I am sure
that I miss something related to pointers and dynamic allocation...

my code is:

#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkMath.h>
#include <vtkDelaunay2D.h>
#include <vtkXMLPolyDataWriter.h>
#include <vtkLookupTable.h>
#include <vtkFloatArray.h>
#include <vtkElevationFilter.h>

using namespace std;

int main(int argc, char *argv[])
{
  //Create the geometry of a point (the coordinate)
  vtkPoints *points = vtkPoints::New();

  //Create the topology of the point (a vertex)
  vtkCellArray *vertices = vtkCellArray::New();

  int i = 0;
  int gridSize = 10;
  vtkIdType point_id[111];

  for(int x = 0; x < gridSize; x++)
  {
    for(int y = 0; y < gridSize; y++)
    {
      i++;
      point_id[i] = points->InsertNextPoint(x, y, vtkMath::Random(-0.5,
0.5));
      vertices->InsertNextCell ( i, point_id );
    }
  }

  //Create a polydata object
  vtkPolyData *p = vtkPolyData::New();
  p->SetPoints ( points );
  p->SetVerts ( vertices );

  //Create an actor and mapper
  vtkPolyDataMapper *mapper = vtkPolyDataMapper::New();
  mapper->SetInput(p);

  vtkActor *actor = vtkActor::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->SetPointSize(3);

   //Create a renderer, render window, and interactor
  vtkRenderer *renderer = vtkRenderer::New();
  vtkRenderWindow *renderWindow = vtkRenderWindow::New();
  renderWindow->AddRenderer(renderer);
  vtkRenderWindowInteractor *renderWindowInteractor =
vtkRenderWindowInteractor::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  //Add the actors to the scene
  renderer->AddActor(actor);

  //Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

  /// /// /// /// /// ///

  //triangulate the grid points
  vtkDelaunay2D *delaunay = vtkDelaunay2D::New();
  delaunay->SetInput(p);
  delaunay->Update();

  vtkElevationFilter *elevationFilter = vtkElevationFilter::New();
  elevationFilter->SetInput(p);
  //you could set these z values to the min and max z values of your data to
have a more sensibly scaled output
  elevationFilter->SetLowPoint(0.0, 0.0, -1.0);
  elevationFilter->SetHighPoint(0.0, 0.0, 1.0);
  elevationFilter->Update();

  vtkPolyData* outputPolyData =
vtkPolyData::SafeDownCast(elevationFilter->GetOutput());

  vtkFloatArray *elevation =
vtkFloatArray::SafeDownCast(outputPolyData->GetPointData()->GetArray("Elevation"));

  //create the color map
  vtkLookupTable *colorLookupTable = vtkLookupTable::New();
  colorLookupTable->SetTableRange(0, 1);
  colorLookupTable->Build();

  //generate the colors for each point based on the color map
  vtkUnsignedCharArray *colors = vtkUnsignedCharArray::New();
  colors->SetNumberOfComponents ( 3 );
  colors->SetName ( "Colors" );

  cout << "There are " << outputPolyData->GetNumberOfPoints() << " points."
<< vtkstd::endl;

  for(int i = 0; i < outputPolyData->GetNumberOfPoints(); i++)
  {
    double val = elevation->GetValue(i);
    cout << "val: " << val << vtkstd::endl;

    double dcolor[3];
    colorLookupTable->GetColor(val, dcolor);
    cout << "dcolor: " << dcolor[0] << " " << dcolor[1] << " " << dcolor[2]
<< vtkstd::endl;
    unsigned char color[3];
    for(unsigned int j = 0; j < 3; j++)
    {
      color[j] = 255 * dcolor[j]/1.0;
    }
    cout << "color: " << (int)color[0] << " " << (int)color[1] << " " <<
(int)color[2] << vtkstd::endl;

    colors->InsertNextTupleValue(color);
  }

  outputPolyData->GetPointData()->AddArray(colors);

  //write the output file
  vtkXMLPolyDataWriter *writer = vtkXMLPolyDataWriter::New();
  string outputFile = "ef.vtp";
  writer->SetFileName(outputFile.c_str());
  writer->SetInput(outputPolyData);
  writer->Write();

  return 0;
}

my gdbrun is:

#0  0xb7dca274 in vtkDataArrayTemplate<float>::GetTuple () from
/usr/local/lib/vtk-5.3/libvtkCommon.so.5.3
#1  0xb7d6cc5a in vtkPoints::GetPoint () from
/usr/local/lib/vtk-5.3/libvtkCommon.so.5.3
#2  0xb56b260a in vtkPolyData::ComputeBounds () from
/usr/local/lib/vtk-5.3/libvtkFiltering.so.5.3
#3  0xb55d356e in vtkDataSet::GetBounds () from
/usr/local/lib/vtk-5.3/libvtkFiltering.so.5.3
#4  0xb7a448ab in vtkPainterPolyDataMapper::GetBounds () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#5  0xb79921f3 in vtkActor::GetBounds () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#6  0xb7a7413f in vtkRenderer::ComputeVisiblePropBounds () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#7  0xb7a773dc in vtkRenderer::ResetCamera () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#8  0xb7a87f9e in vtkRenderWindow::DoStereoRender () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#9  0xb7a88505 in vtkRenderWindow::DoFDRender () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#10 0xb7a88aea in vtkRenderWindow::DoAARender () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#11 0xb7a891fb in vtkRenderWindow::Render () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#12 0xb7b4d02a in vtkXOpenGLRenderWindow::Render () from
/usr/local/lib/vtk-5.3/libvtkRendering.so.5.3
#13 0x0806cb75 in main ()

Can somebody help me ?
Thanks.
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