Difference between revisions of "VTK/Examples/Cxx/PolyData/DeleteCells"

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== Delete a cell from vtkPolyData  ==
 
== Delete a cell from vtkPolyData  ==
This example demonstrates how to delete a cell from a vtkPolyData. This is a three-step process: first, build upward-links from points to cells; second, mark cells for deletion; third, delete the marked cells. The first step is necessary to create a data structure suitable for efficient delete operations. Creating this data structure is also expensive, so it is only carried out before operations that need it, e.g. those that require changes to the topology.
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This example demonstrates how to delete a cell from a vtkPolyData. This is a three-step process: first, build upward-links from points to cells; second, mark cells for deletion; third, delete the marked cells. The first step is necessary to create a data structure suitable for efficient delete operations. Creating this data structure is computationally expensive, so it is only carried out before operations that need it, e.g. those that require changes to the topology.
  
 
==DeleteCells.cxx==
 
==DeleteCells.cxx==

Revision as of 17:27, 29 January 2011

Delete a cell from vtkPolyData

This example demonstrates how to delete a cell from a vtkPolyData. This is a three-step process: first, build upward-links from points to cells; second, mark cells for deletion; third, delete the marked cells. The first step is necessary to create a data structure suitable for efficient delete operations. Creating this data structure is computationally expensive, so it is only carried out before operations that need it, e.g. those that require changes to the topology.

DeleteCells.cxx

#include <vtkActor.h>
#include <vtkCellArray.h>
#include <vtkLine.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartPointer.h>
 
int main(int, char *[])
{
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(0,0,0);
  points->InsertNextPoint(1,0,0);
  points->InsertNextPoint(1,1,0);
  points->InsertNextPoint(0,1,0);
 
  vtkSmartPointer<vtkLine> line0 = 
    vtkSmartPointer<vtkLine>::New();
  line0->GetPointIds()->SetId(0, 0);
  line0->GetPointIds()->SetId(1, 1);
 
  vtkSmartPointer<vtkLine> line1 = 
    vtkSmartPointer<vtkLine>::New();
  line1->GetPointIds()->SetId(0, 1);
  line1->GetPointIds()->SetId(1, 2);
 
  vtkSmartPointer<vtkLine> line2 = 
    vtkSmartPointer<vtkLine>::New();
  line2->GetPointIds()->SetId(0, 2);
  line2->GetPointIds()->SetId(1, 3);
 
  vtkSmartPointer<vtkCellArray> lines =
    vtkSmartPointer<vtkCellArray>::New();
  lines->InsertNextCell(line0);
  lines->InsertNextCell(line1);
  lines->InsertNextCell(line2);
 
  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);
  polydata->SetLines(lines);

  // Tell the polydata to build 'upward' links from points to cells.
  polydata->BuildLinks();
  // Mark a cell as deleted.
  polydata->DeleteCell(1);
  // Remove the marked cell.
  polydata->RemoveDeletedCells();

  // Visualize
  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(polydata->GetProducerPort());
 
  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
 
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
      vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);
  renderer->AddActor(actor);
 
  renderWindow->Render();
  renderWindowInteractor->Start();
 
  return EXIT_SUCCESS;
}

CMakeLists.txt

PROJECT(FilledContours)
CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
 
FIND_PACKAGE(VTK REQUIRED)
INCLUDE(${VTK_USE_FILE})
 
ADD_EXECUTABLE(DeleteCells DeleteCells.cxx)
TARGET_LINK_LIBRARIES(DeleteCells vtkHybrid)