vtk-m/vtkm/cont/RegularConnectivity.h

#ifndef vtk_m_cont_RegularConnectivity_h
#define vtk_m_cont_RegularConnectivity_h

#include <vtkm/cont/TopologyType.h>
#include <vtkm/Extent.h>
#include <vtkm/CellType.h>
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/Field.h>
#include <vtkm/cont/DynamicArrayHandle.h>
#include <vtkm/cont/DeviceAdapterAlgorithm.h>

namespace vtkm {
namespace cont {

template<vtkm::IdComponent> class RegularStructure;

//1 D specialization.
template<>
class RegularStructure<1>
{
public:
  void SetNodeDimension(int node_i, int, int)
  {
      cellDims.Min[0] = nodeDims.Min[0] = 0;
      cellDims.Max[0] = node_i-1;
      nodeDims.Max[0] = node_i;
  }
  vtkm::Id GetNumberOfElements() const {return cellDims.Max[0];}
  vtkm::Id GetNumberOfIndices(vtkm::Id) const {return 2;}
  vtkm::Id GetElementShapeType(vtkm::Id) const {return VTKM_LINE;}

  void GetNodesOfCells(vtkm::Id index, vtkm::Vec<vtkm::Id,2> &ids) const
  {
      ids[0] = index;
      ids[1] = ids[0] + 1;
  }
    
private:
    Extent<1> cellDims;
    Extent<1> nodeDims;
};

//2 D specialization.
template<>
class RegularStructure<2>
{
public:
  void SetNodeDimension(int node_i, int node_j, int)
  {
      cellDims.Min[0] = cellDims.Min[1] = 0;
      nodeDims.Min[0] = nodeDims.Min[1] = 0;
      cellDims.Max[0] = node_i-1;
      nodeDims.Max[0] = node_i;
      cellDims.Max[1] = node_j-1;
      nodeDims.Max[1] = node_j;
  }
  vtkm::Id GetNumberOfElements() const {return cellDims.Max[0]*cellDims.Max[1];}
  vtkm::Id GetNumberOfIndices(vtkm::Id) const {return 4;}
  vtkm::Id GetElementShapeType(vtkm::Id) const {return VTKM_PIXEL;}

  void GetNodesOfCells(vtkm::Id index, vtkm::Vec<vtkm::Id,4> &ids) const
  {
      int i = index % cellDims.Max[0];
      int j = index / cellDims.Max[0];

      ids[0] = j*nodeDims.Max[0] + i;
      ids[1] = ids[0] + 1;
      ids[2] = ids[0] + nodeDims.Max[0];
      ids[3] = ids[2] + 1;
  }
    
private:
    Extent<2> cellDims;
    Extent<2> nodeDims;
};

//3 D specialization.
template<>
class RegularStructure<3>
{
public:
  void SetNodeDimension(int node_i, int node_j, int node_k)
  {
      cellDims.Min[0] = cellDims.Min[1] = cellDims.Min[2] = 0;
      nodeDims.Min[0] = nodeDims.Min[1] = nodeDims.Min[2] = 0;
      cellDims.Max[0] = node_i-1;
      nodeDims.Max[0] = node_i;
      cellDims.Max[1] = node_j-1;
      nodeDims.Max[1] = node_j;
      cellDims.Max[2] = node_k-1;
      nodeDims.Max[2] = node_k;
  }
  vtkm::Id GetNumberOfElements() const {return cellDims.Max[0]*cellDims.Max[1]*cellDims.Max[2];}
  vtkm::Id GetNumberOfIndices(vtkm::Id) const {return 8;}
  vtkm::Id GetElementShapeType(vtkm::Id) const {return VTKM_VOXEL;}

  void GetNodesOfCells(vtkm::Id index, vtkm::Vec<vtkm::Id,2> &ids) const
  {
      int cellDims01 = cellDims.Max[0] * cellDims.Max[1];
      int k = index / cellDims01;
      int indexij = index % cellDims01;
      int j = indexij / cellDims.Max[0];
      int i = indexij % cellDims.Max[0];

      ids[0] = (k * nodeDims.Max[1] + j) * nodeDims.Max[0] + i;
      ids[1] = ids[0] + 1;
      ids[2] = ids[0] + nodeDims.Max[0];
      ids[3] = ids[2] + 1;
      ids[4] = ids[0] + nodeDims.Max[0]*nodeDims.Max[1];
      ids[5] = ids[4] + 1;
      ids[6] = ids[4] + nodeDims.Max[0];
      ids[7] = ids[6] + 1;
  }
    
private:
    Extent<3> cellDims;
    Extent<3> nodeDims;
};

template<vtkm::IdComponent Dimension>
class RegularConnectivity
{
public:
  void SetNodeDimension(int node_i, int node_j=0, int node_k=0)
  {
     rs.SetNodeDimension(node_i, node_j, node_k);
  }

  vtkm::Id GetNumberOfElements() const {return rs.GetNumberOfElements();}
  vtkm::Id GetNumberOfIndices(vtkm::Id) const {return rs.GetNumberOfIndices();}
  vtkm::Id GetElementShapeType(vtkm::Id) const {return rs.GetElementShapeType();}

  template <vtkm::IdComponent ItemTupleLength, vtkm::cont::TopologyType Topology>
  void GetIndices(vtkm::Id index, vtkm::Vec<vtkm::Id,ItemTupleLength> &ids)
  {
      return rs.GetNodesOfCells(index, ids);
  }
private:
  RegularStructure<Dimension> rs;
};

//TODO:
//Add specialized 1D and 2D versions.
    
}
} // namespace vtkm::cont

#endif //vtk_m_cont_RegularConnectivity_h