Method InsertPolygonInHash

Filters/Geometry/vtkDataSetSurfaceFilter.cxx:2465–2564

Insert a polygon into the hash. Input: an array of vertex ids the start index of the polygon in the array the end index of the polygon in the array the cellId of the polygon ------------------------------------------------------------------------------

//        the cellId of the polygon
//------------------------------------------------------------------------------
void vtkDataSetSurfaceFilter::InsertPolygonInHash(
  const vtkIdType* ids, int numPts, vtkIdType sourceId)
{
  // sanity check
  if (numPts == 0)
  {
    return;
  }
  vtkFastGeomQuad *quad, **end;

  // find the index to the smallest id
  vtkIdType offset = 0;
  for (int i = 0; i < numPts; i++)
  {
    if (ids[i] < ids[offset])
    {
      offset = i;
    }
  }

  // copy ids into ordered array with smallest id first
  vtkIdType* tab = new vtkIdType[numPts];
  for (int i = 0; i < numPts; i++)
  {
    tab[i] = ids[(offset + i) % numPts];
  }

  // Look for existing hex in the hash;
  end = this->QuadHash + tab[0];
  quad = *end;
  while (quad)
  {
    end = &(quad->Next);
    // a has to match in this bin.
    // first just check the polygon size.
    bool match = true;
    if (numPts == quad->numPts)
    {
      if (tab[0] == quad->ptArray[0])
      {
        // if the first two points match loop through forwards
        // checking all points
        if (numPts > 1 && tab[1] == quad->ptArray[1])
        {
          for (int i = 2; i < numPts; ++i)
          {
            if (tab[i] != quad->ptArray[i])
            {
              match = false;
              break;
            }
          }
        }
        else
        {
          // check if the points go in the opposite direction
          for (int i = 1; i < numPts; ++i)
          {