LoadPoly.h

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#ifndef __smoab_detail_LoadPoly_h
#define __smoab_detail_LoadPoly_h

#include "SimpleMoab.h"
#include "LinearCellConnectivity.h"

#include 
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#include 

namespace smoab
{
namespace detail
{

    //basic class that given a range of moab cells will convert them to a
    //vtk poly data. If given any high order cells will do a simple linearization
    //of the cells
    class LoadPoly
    {
        moab::Interface* Interface;
        smoab::detail::LinearCellConnectivity CellConn;
        smoab::Range Points;

      public:
        //----------------------------------------------------------------------------
        //warning cells input to constructor is held by reference
        LoadPoly( const smoab::Range& cells, const smoab::Interface& interface )
            : Interface( interface.Moab ), CellConn( cells, interface.Moab ), Points()
        {
        }

        const smoab::Range& moabPoints() const
        {
            return this->Points;
        }

        //----------------------------------------------------------------------------
        //todo: have support for using only a subsection of the input cells
        void fill( vtkPolyData* dataSet )
        {
            //now that CellConn has all the cells properly stored, lets fixup
            //the ids so that they start at zero and keep the same logical ordering
            //as before.
            vtkIdType numCells, connLen;
            this->CellConn.compactIds( numCells, connLen );
            this->addGridsTopology( dataSet, numCells, connLen );
            this->addCoordinates( dataSet );
        }

      private:
        //----------------------------------------------------------------------------
        void addCoordinates( vtkPointSet* grid )
        {
            //this is sorta of hackish as moabPoints is only valid
            //after compactIds has been called
            this->CellConn.moabPoints( this->Points );

            //since the smoab::range are always unique and sorted
            //we can use the more efficient coords_iterate
            //call in moab, which returns moab internal allocated memory
            vtkNew< vtkPoints > newPoints;
            newPoints->SetDataTypeToDouble();
            newPoints->SetNumberOfPoints( this->Points.size() );

            //need a pointer to the allocated vtkPoints memory so that we
            //don't need to use an extra copy and we can bypass all vtk's check
            //on out of bounds
            double* rawPoints = static_cast< double* >( newPoints->GetVoidPointer( 0 ) );
            this->Interface->get_coords( this->Points, rawPoints );

            grid->SetPoints( newPoints.GetPointer() );
        }

        //----------------------------------------------------------------------------
        void addGridsTopology( vtkPolyData* data, vtkIdType numCells, vtkIdType numConnectivity ) const
        {
            //correct the connectivity size to account for the vtk padding
            const vtkIdType vtkConnectivity = numCells + numConnectivity;

            vtkNew< vtkIdTypeArray > cellArray;
            cellArray->SetNumberOfValues( vtkConnectivity );

            vtkIdType* rawArray = static_cast< vtkIdType* >( cellArray->GetVoidPointer( 0 ) );
            this->CellConn.copyToVtkCellInfo( rawArray );

            vtkNew< vtkCellArray > cells;
            cells->SetCells( numCells, cellArray.GetPointer() );

            data->SetPolys( cells.GetPointer() );
        }
    };

}  // namespace detail
}  // namespace smoab

#endif  // __smoab_detail_LoadPoly_h