Method InsertTriInHash

Filters/Geometry/vtkDataSetRegionSurfaceFilter.cxx:963–1034

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//------------------------------------------------------------------------------
void vtkDataSetRegionSurfaceFilter::InsertTriInHash(
  vtkIdType a, vtkIdType b, vtkIdType c, vtkIdType sourceId, vtkIdType faceId)
{
  int tmp;
  vtkFastGeomQuad *quad, **end;

  // Reorder to get smallest id in a.
  if (b < a && b < c)
  {
    tmp = a;
    a = b;
    b = c;
    c = tmp;
  }
  else if (c < a && c < b)
  {
    tmp = a;
    a = c;
    c = b;
    b = tmp;
  }
  // We can't put the second smnallest in b because it might change the order
  // of the vertices in the final triangle.

  // Look for existing tri in the hash;
  end = this->QuadHash + a;
  quad = *end;
  vtkIdType regionId = -1;
  if (this->RegionArray)
  {
    regionId = this->RegionArray->GetValue(sourceId);
  }
  while (quad)
  {
    end = &(quad->Next);
    const vtkIdType* quadsRegionId = (quad->ptArray + quad->numPts);
    // a has to match in this bin.
    if (quad->numPts == 3)
    {
      if (((b == quad->ptArray[1] && c == quad->ptArray[2]) ||
            (b == quad->ptArray[2] && c == quad->ptArray[1])) &&
        (regionId == -1 ||
          regionId == *quadsRegionId)) // internal cells, but on a material interface
      {
        // We have a match.
        quad->SourceId = -1;
        // That is all we need to do. Hide any tri shared by two or more cells (that also are from
        // same region)
        return;
      }
    }
    quad = *end;
  }

  // Create a new quad and add it to the hash.
  quad = this->NewFastGeomQuad(5);
  quad->Next = nullptr;
  quad->SourceId = sourceId;