/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkQuadraticLinearQuad.h,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkQuadraticLinearQuad - cell represents a quadratic-linear, 6-node isoparametric quad
// .SECTION Description
// vtkQuadraticQuad is a concrete implementation of vtkNonLinearCell to
// represent a two-dimensional, 6-node isoparametric quadratic-linear quadrilateral
// element. The interpolation is the standard finite element, quadratic-linear
// isoparametric shape function. The cell includes a mid-edge node for two
// of the four edges. The ordering of the six points defining
// the cell are point ids (0-3,4-5) where ids 0-3 define the four corner
// vertices of the quad; ids 4-7 define the midedge nodes (0,1) and (2,3) .
//
// .SECTION See Also
// vtkQuadraticEdge vtkQuadraticTriangle vtkQuadraticTetra vtkQuadraticQuad
// vtkQuadraticHexahedron vtkQuadraticWedge vtkQuadraticPyramid
//
// .SECTION Thanks
// Thanks to Soeren Gebbert  who developed this class and
// integrated it into VTK 5.0.

#ifndef __vtkQuadraticLinearQuad_h
#define __vtkQuadraticLinearQuad_h

#include "vtkNonLinearCell.h"

class vtkQuadraticEdge;
class vtkLine;
class vtkQuad;
class vtkDoubleArray;

class VTK_FILTERING_EXPORT vtkQuadraticLinearQuad : public vtkNonLinearCell
{
public:
  static vtkQuadraticLinearQuad *New();
  vtkTypeRevisionMacro(vtkQuadraticLinearQuad, vtkNonLinearCell);
  void PrintSelf(ostream & os, vtkIndent indent);

  // Description:
  // Implement the vtkCell API. See the vtkCell API for descriptions
  // of these methods.
  int GetCellType () { return VTK_QUADRATIC_LINEAR_QUAD; };
  int GetCellDimension () { return 2; }
  int GetNumberOfEdges () { return 4; }
  int GetNumberOfFaces () { return 0; }
  vtkCell *GetEdge (int);
  vtkCell *GetFace (int) { return 0; }

  int CellBoundary (int subId, double pcoords[3], vtkIdList * pts);
  void Contour (double value, vtkDataArray * cellScalars,
    vtkPointLocator * locator, vtkCellArray * verts,
    vtkCellArray * lines, vtkCellArray * polys,
    vtkPointData * inPd, vtkPointData * outPd, vtkCellData * inCd,
    vtkIdType cellId, vtkCellData * outCd);
  int EvaluatePosition (double x[3], double *closestPoint,
    int &subId, double pcoords[3], double &dist2, double *weights);
  void EvaluateLocation (int &subId, double pcoords[3], double x[3],
    double *weights);
  int Triangulate (int index, vtkIdList * ptIds, vtkPoints * pts);
  void Derivatives (int subId, double pcoords[3], double *values, int dim,
    double *derivs);
  virtual double *GetParametricCoords ();

  // Description:
  // Clip this quadratic linear quad using scalar value provided. Like
  // contouring, except that it cuts the quad to produce linear triangles.
  void Clip (double value, vtkDataArray * cellScalars,
       vtkPointLocator * locator, vtkCellArray * polys,
       vtkPointData * inPd, vtkPointData * outPd,
       vtkCellData * inCd, vtkIdType cellId, vtkCellData * outCd,
       int insideOut);

  // Description:
  // Line-edge intersection. Intersection has to occur within [0,1] parametric
  // coordinates and with specified tolerance.
  int IntersectWithLine (double p1[3], double p2[3], double tol, double &t,
    double x[3], double pcoords[3], int &subId);

  // Description:
  // Return the center of the pyramid in parametric coordinates.
  int GetParametricCenter(double pcoords[3]);

  // Description:
  // @deprecated Replaced by vtkQuadraticLinearQuad::InterpolateFunctions as of VTK 5.2
  static void InterpolationFunctions (double pcoords[3], double weights[6]);
  // Description:
  // @deprecated Replaced by vtkQuadraticLinearQuad::InterpolateDerivs as of VTK 5.2
  static void InterpolationDerivs (double pcoords[3], double derivs[12]);
  // Description:
  // Compute the interpolation functions/derivatives
  // (aka shape functions/derivatives)
  virtual void InterpolateFunctions (double pcoords[3], double weights[6])
    {
    vtkQuadraticLinearQuad::InterpolationFunctions(pcoords,weights);
    }
  virtual void InterpolateDerivs (double pcoords[3], double derivs[12])
    {
    vtkQuadraticLinearQuad::InterpolationDerivs(pcoords,derivs);
    }
  // Description:
  // Return the ids of the vertices defining edge (`edgeId`).
  // Ids are related to the cell, not to the dataset.
  static int *GetEdgeArray(int edgeId);

protected:
  vtkQuadraticLinearQuad ();
  ~vtkQuadraticLinearQuad ();

  vtkQuadraticEdge *Edge;
  vtkLine *LinEdge;
  vtkQuad *Quad;
  vtkDoubleArray *Scalars;

private:
  vtkQuadraticLinearQuad (const vtkQuadraticLinearQuad &);  // Not implemented.
  void operator = (const vtkQuadraticLinearQuad &);  // Not implemented.
};
//----------------------------------------------------------------------------
inline int vtkQuadraticLinearQuad::GetParametricCenter(double pcoords[3])
{
  pcoords[0] = pcoords[1] = 0.5;
  pcoords[2] = 0.;
  return 0;
}

#endif
