gistfile1.txt

#include <vtkCellData.h>
#include <vtkSmartPointer.h>
#include <vtkStructuredGrid.h>
#include <vtkUnsignedIntArray.h>
#include <vtkXMLStructuredGridWriter.h>

void Grid3D() {
  // Create a grid
  vtkSmartPointer<vtkStructuredGrid> structuredGrid =
      vtkSmartPointer<vtkStructuredGrid>::New();

  vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();

  // Create a vtkUnsignedCharArray container and store the colors in it
  vtkSmartPointer<vtkUnsignedIntArray> labels =
      vtkSmartPointer<vtkUnsignedIntArray>::New();
  labels->SetName("Labels");
  labels->SetNumberOfComponents(1);

  unsigned int voxelsPerDimension = 2;
  unsigned int counter = 0;
  // The grid is created as points (the corners of voxels), so we need n+1
  // points per dimension
  for (unsigned int k = 0; k < voxelsPerDimension + 1; k++) {
    for (unsigned int j = 0; j < voxelsPerDimension + 1; j++) {
      for (unsigned int i = 0; i < voxelsPerDimension + 1; i++) {
        points->InsertNextPoint(i, j, k);
      }
    }
  }

  // raster scan label voxels
  unsigned int voxelCounter = 0;
  for (unsigned int k = 0; k < voxelsPerDimension; k++) {
    for (unsigned int j = 0; j < voxelsPerDimension; j++) {
      for (unsigned int i = 0; i < voxelsPerDimension; i++) {
        labels->InsertNextValue(voxelCounter);

        voxelCounter++;
      }
    }
  }

  structuredGrid->GetCellData()->SetScalars(labels);

  // Specify the dimensions of the grid (again, in their points)
  structuredGrid->SetDimensions(voxelsPerDimension + 1, voxelsPerDimension + 1,
                                voxelsPerDimension + 1);

  structuredGrid->SetPoints(points);

  structuredGrid->BlankPoint(0);
  structuredGrid->Modified();

  vtkSmartPointer<vtkXMLStructuredGridWriter> structuredGridWriter =
      vtkXMLStructuredGridWriter::New();
  structuredGridWriter->SetInputData(structuredGrid);
  structuredGridWriter->SetFileName("grid.vts");
  structuredGridWriter->Write();
}

int main(int, char *[]) {

  Grid3D();

  return EXIT_SUCCESS;
}