[vtkusers] VTK Point Cloud

[Luca Pallozzi Lavorante]

Valerie,
you have to create a vtkpolyData instance. I have a function that reads a
XYZ ASCII file (whose name you pass as argument) and creates the polydata
(actually, inside the polydata, instances od vtkPoints and vtkCellArray are
used). Once you have the polydata, you´ll proceed with visualization using
the vtkPolyData -> vtkPolyDataMapper -> vtkActor pipeline

Here is the function.

   Luca


vtkPolyData *xyzreader (char *name) {

        double x[3];
        FILE *f;
        char LINE[256];


        if ( (f = fopen(name, "r")) == NULL ) {
          fprintf (stderr, "Error while opening file %s!\n", name);
          return NULL;
        }
       vtkPoints *points = vtkPoints::New();
       vtkPolyData *poly = vtkPolyData::New();
       vtkCellArray *conn = vtkCellArray::New();

       // Create geometry of point cloud
       while ( fgets(LINE, 256, f) != NULL ) {

          if (sscanf(LINE, "%lf %lf %lf", &x[0], &x[1], &x[2]) != 3) {
            fprintf (stderr, "I/O Error!\n");
            fclose (f);
            return NULL;
          }
          points->InsertNextPoint(x);
     } // End of while loop

     // Create topology of point cloud. This is necessary!
     for (int i = 0; i < points->GetNumberOfPoints(); i++)
          conn->InsertNextCell(1, &i);

     poly->SetPoints(points);
     poly->SetVerts(conn);
     points->Delete();
     conn->Delete();

     fclose (f);
     return poly;
 }
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