Method InsertQuadInHash

Filters/Geometry/vtkDataSetSurfaceFilter.cxx:2336–2401

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void vtkDataSetSurfaceFilter::InsertQuadInHash(
  vtkIdType a, vtkIdType b, vtkIdType c, vtkIdType d, vtkIdType sourceId)
{
  vtkIdType tmp;
  vtkFastGeomQuad *quad, **end;

  // Reorder to get smallest id in a.
  if (b < a && b < c && b < d)
  {
    tmp = a;
    a = b;
    b = c;
    c = d;
    d = tmp;
  }
  else if (c < a && c < b && c < d)
  {
    tmp = a;
    a = c;
    c = tmp;
    tmp = b;
    b = d;
    d = tmp;
  }
  else if (d < a && d < b && d < c)
  {
    tmp = a;
    a = d;
    d = c;
    c = b;
    b = tmp;
  }

  // Look for existing quad in the hash;
  end = this->QuadHash + a;
  quad = *end;
  while (quad)
  {
    end = &(quad->Next);
    // a has to match in this bin.
    // c should be independent of point order.
    if (quad->numPts == 4 && c == quad->ptArray[2])
    {
      // Check both orders for b and d.
      if ((b == quad->ptArray[1] && d == quad->ptArray[3]) ||
        (b == quad->ptArray[3] && d == quad->ptArray[1]))
      {
        // We have a match.
        quad->SourceId = -1;
        // That is all we need to do.  Hide any quad shared by two or more cells.
        return;
      }
    }
    quad = *end;
  }

  // Create a new quad and add it to the hash.
  quad = this->NewFastGeomQuad(4);