//  SMESH SMESH : implementaion of SMESH idl descriptions
//
//  Copyright (C) 2003  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
//  CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS 
// 
//  This library is free software; you can redistribute it and/or 
//  modify it under the terms of the GNU Lesser General Public 
//  License as published by the Free Software Foundation; either 
//  version 2.1 of the License. 
// 
//  This library is distributed in the hope that it will be useful, 
//  but WITHOUT ANY WARRANTY; without even the implied warranty of 
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
//  Lesser General Public License for more details. 
// 
//  You should have received a copy of the GNU Lesser General Public 
//  License along with this library; if not, write to the Free Software 
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA 
// 
//  See http://www.opencascade.org/SALOME/ or email : webmaster.salome@opencascade.org 
//
//
//
//  File   : SMESH_Hexa_3D.cxx
//  Author : Paul RASCLE, EDF
//  Module : SMESH
//  $Header$

using namespace std;
using namespace std;
#include "SMESH_Hexa_3D.hxx"
#include "SMESH_Quadrangle_2D.hxx"
#include "SMESH_Gen.hxx"
#include "SMESH_Mesh.hxx"

#include "SMDS_MeshElement.hxx"
#include "SMDS_MeshNode.hxx"
#include "SMDS_FacePosition.hxx"

#include <TopExp.hxx>
#include <TopTools_IndexedDataMapOfShapeListOfShape.hxx>
#include <TopTools_ListOfShape.hxx>
#include <TopTools_ListIteratorOfListOfShape.hxx>
#include <TColStd_ListIteratorOfListOfInteger.hxx>

#include <BRep_Tool.hxx>
#include <Geom_Surface.hxx>
#include <Geom_Curve.hxx>
#include <Geom2d_Curve.hxx>
#include <Handle_Geom2d_Curve.hxx>
#include <Handle_Geom_Curve.hxx>

#include "utilities.h"


//=============================================================================
/*!
 *  
 */
//=============================================================================

SMESH_Hexa_3D::SMESH_Hexa_3D(int hypId, int studyId,
			     SMESH_Gen* gen)
  : SMESH_3D_Algo(hypId, studyId, gen)
{
  MESSAGE("SMESH_Hexa_3D::SMESH_Hexa_3D");
  _name = "Hexa_3D";
//   _shapeType = TopAbs_SOLID;
  _shapeType = (1 << TopAbs_SHELL) | (1 << TopAbs_SOLID);// 1 bit /shape type
//   MESSAGE("_shapeType octal " << oct << _shapeType);
  for (int i=0; i<6; i++) _quads[i] = 0;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

SMESH_Hexa_3D::~SMESH_Hexa_3D()
{
  MESSAGE("SMESH_Hexa_3D::~SMESH_Hexa_3D");
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

bool SMESH_Hexa_3D::CheckHypothesis(SMESH_Mesh& aMesh,
				    const TopoDS_Shape& aShape)
{
  MESSAGE("SMESH_Hexa_3D::CheckHypothesis");

  bool isOk = true;

  // nothing to check

  return isOk;
}

//=============================================================================
/*!
 * Hexahedron mesh on hexaedron like form
 * -0.  - shape and face mesh verification
 * -1.  - identify faces and vertices of the "cube"
 * -2.  - Algorithm from:
 * "Application de l'interpolation transfinie à la création de maillages
 *  C0 ou G1 continus sur des triangles, quadrangles, tetraedres, pentaedres
 *  et hexaedres déformés."
 * Alain PERONNET - 8 janvier 1999
 */
//=============================================================================

bool SMESH_Hexa_3D::Compute(SMESH_Mesh& aMesh,
			    const TopoDS_Shape& aShape)
  throw (SALOME_Exception)
{
  MESSAGE("SMESH_Hexa_3D::Compute");

  bool isOk = false;
  const Handle(SMESHDS_Mesh)& meshDS = aMesh.GetMeshDS();
  SMESH_subMesh* theSubMesh = aMesh.GetSubMesh(aShape);
  //const Handle(SMESHDS_SubMesh)& subMeshDS = theSubMesh->GetSubMeshDS();

  // 0.  - shape and face mesh verification
  // 0.1 - shape must be a solid (or a shell) with 6 faces
  MESSAGE("---");

  vector<SMESH_subMesh*> meshFaces;
  for (TopExp_Explorer exp(aShape,TopAbs_FACE);exp.More();exp.Next())
    {
      SMESH_subMesh* aSubMesh = aMesh.GetSubMeshContaining(exp.Current());
      ASSERT (aSubMesh);
      meshFaces.push_back(aSubMesh);
    }
  if (meshFaces.size() != 6)
    {
      SCRUTE(meshFaces.size());
      ASSERT(0);
      return false;
    }

  // 0.2 - is each face meshed with Quadrangle_2D? (so, with a wire of 4 edges)
  MESSAGE("---");

  for (int i=0; i<6; i++)
    {
      TopoDS_Shape aShape = meshFaces[i]->GetSubShape();
      SMESH_Algo* algo = _gen->GetAlgo(aMesh, aShape);
      string algoName = algo->GetName();
      if (algoName != "Quadrangle_2D")
	{
	  // *** delete _quads
	  SCRUTE(algoName);
	  ASSERT(0);
	  return false;
	}
      SMESH_Quadrangle_2D* quadAlgo =dynamic_cast<SMESH_Quadrangle_2D*> (algo);
      ASSERT(quadAlgo);
      try
	{
	  _quads[i] = quadAlgo->CheckAnd2Dcompute(aMesh, aShape);
	  // *** to delete after usage
	}
      catch (SALOME_Exception& S_ex)
	{
	  // *** delete _quads
	  // *** throw exception
	  ASSERT(0);
	}
    }

  // 1.  - identify faces and vertices of the "cube"
  // 1.1 - ancestor maps vertex->edges in the cube
  MESSAGE("---");

  TopTools_IndexedDataMapOfShapeListOfShape MS;
  TopExp::MapShapesAndAncestors(aShape, TopAbs_VERTEX, TopAbs_EDGE, MS);

  // 1.2 - first face is choosen as face Y=0 of the unit cube
  MESSAGE("---");

  const TopoDS_Shape& aFace = meshFaces[0]->GetSubShape();
  const TopoDS_Face& F = TopoDS::Face(aFace);

  // 1.3 - identify the 4 vertices of the face Y=0: V000, V100, V101, V001
  MESSAGE("---");

  int i = 0;
  TopoDS_Edge E = _quads[0]->edge[i]; //edge will be Y=0,Z=0 on unit cube
  double f,l;
  Handle(Geom2d_Curve) C2d = BRep_Tool::CurveOnSurface(E,F,f,l);
  TopoDS_Vertex VFirst, VLast;
  TopExp::Vertices(E, VFirst, VLast); // corresponds to f and l
  bool isForward = (((l-f)*(_quads[0]->last[i] - _quads[0]->first[i])) > 0);

  if (isForward)
    {
      _cube.V000 = VFirst; // will be (0,0,0) on the unit cube
      _cube.V100 = VLast;  // will be (1,0,0) on the unit cube
    }
  else
    {
      _cube.V000 = VLast;
      _cube.V100 = VFirst;
    }
  
  i = 1;
  E = _quads[0]->edge[i];
  C2d = BRep_Tool::CurveOnSurface(E,F,f,l);
  TopExp::Vertices(E, VFirst, VLast);
  isForward = (((l-f)*(_quads[0]->last[i] - _quads[0]->first[i])) > 0);
  if (isForward) _cube.V101 = VLast;  // will be (1,0,1) on the unit cube
  else _cube.V101 = VFirst;

  i = 2;
  E = _quads[0]->edge[i];
  C2d = BRep_Tool::CurveOnSurface(E,F,f,l);
  TopExp::Vertices(E, VFirst, VLast);
  isForward = (((l-f)*(_quads[0]->last[i] - _quads[0]->first[i])) > 0);
  if (isForward) _cube.V001 = VLast;  // will be (0,0,1) on the unit cube
  else _cube.V001 = VFirst;

  // 1.4 - find edge X=0, Z=0 (ancestor of V000 not in face Y=0)
  //     - find edge X=1, Z=0 (ancestor of V100 not in face Y=0)
  //     - find edge X=1, Z=1 (ancestor of V101 not in face Y=0) 
  //     - find edge X=0, Z=1 (ancestor of V001 not in face Y=0)
  MESSAGE("---");

  TopoDS_Edge E_0Y0 = EdgeNotInFace(aMesh, aShape, F, _cube.V000, MS);
  ASSERT(! E_0Y0.IsNull());

  TopoDS_Edge E_1Y0 = EdgeNotInFace(aMesh, aShape, F, _cube.V100, MS);
  ASSERT(! E_1Y0.IsNull());
  
  TopoDS_Edge E_1Y1 = EdgeNotInFace(aMesh, aShape, F, _cube.V101, MS);
  ASSERT(! E_1Y1.IsNull());

  TopoDS_Edge E_0Y1 = EdgeNotInFace(aMesh, aShape, F, _cube.V001, MS);
  ASSERT(! E_0Y1.IsNull());
  
  // 1.5 - identify the 4 vertices in face Y=1: V010, V110, V111, V011
  MESSAGE("---");

  TopExp::Vertices(E_0Y0, VFirst, VLast);
  if (VFirst.IsSame(_cube.V000)) _cube.V010 = VLast;
  else _cube.V010 = VFirst;

  TopExp::Vertices(E_1Y0, VFirst, VLast);
  if (VFirst.IsSame(_cube.V100)) _cube.V110 = VLast;
  else _cube.V110 = VFirst;

  TopExp::Vertices(E_1Y1, VFirst, VLast);
  if (VFirst.IsSame(_cube.V101)) _cube.V111 = VLast;
  else _cube.V111 = VFirst;

  TopExp::Vertices(E_0Y1, VFirst, VLast);
  if (VFirst.IsSame(_cube.V001)) _cube.V011 = VLast;
  else _cube.V011 = VFirst;

  // 1.6 - find remaining faces given 4 vertices
  MESSAGE("---");

  _indY0 = 0;
  _cube.quad_Y0 = _quads[_indY0];

  _indY1 = GetFaceIndex(aMesh, aShape, meshFaces,
			_cube.V010,_cube.V011,_cube.V110,_cube.V111);
  _cube.quad_Y1 = _quads[_indY1];

  _indZ0 = GetFaceIndex(aMesh, aShape, meshFaces,
			_cube.V000,_cube.V010,_cube.V100,_cube.V110);
  _cube.quad_Z0 = _quads[_indZ0];

  _indZ1 = GetFaceIndex(aMesh, aShape, meshFaces,
		  _cube.V001,_cube.V011,_cube.V101,_cube.V111);
  _cube.quad_Z1 = _quads[_indZ1];

  _indX0 = GetFaceIndex(aMesh, aShape, meshFaces,
			_cube.V000,_cube.V001,_cube.V010,_cube.V011);
  _cube.quad_X0 = _quads[_indX0];

  _indX1 = GetFaceIndex(aMesh, aShape, meshFaces,
			_cube.V100,_cube.V101,_cube.V110,_cube.V111);
  _cube.quad_X1 = _quads[_indX1];

  MESSAGE("---");

  // 1.7 - get convertion coefs from face 2D normalized to 3D normalized

  Conv2DStruct cx0; // for face X=0
  Conv2DStruct cx1; // for face X=1
  Conv2DStruct cy0;
  Conv2DStruct cy1;
  Conv2DStruct cz0;
  Conv2DStruct cz1;

  GetConv2DCoefs(*_cube.quad_X0, meshFaces[_indX0]->GetSubShape(),
		 _cube.V000,_cube.V010,_cube.V011,_cube.V001,
		 cx0);
  GetConv2DCoefs(*_cube.quad_X1, meshFaces[_indX1]->GetSubShape(),
		 _cube.V100,_cube.V110,_cube.V111,_cube.V101,
		 cx1);
  GetConv2DCoefs(*_cube.quad_Y0, meshFaces[_indY0]->GetSubShape(),
		 _cube.V000,_cube.V100,_cube.V101,_cube.V001,
		 cy0);
  GetConv2DCoefs(*_cube.quad_Y1, meshFaces[_indY1]->GetSubShape(),
		 _cube.V010,_cube.V110,_cube.V111,_cube.V011,
		 cy1);
  GetConv2DCoefs(*_cube.quad_Z0, meshFaces[_indZ0]->GetSubShape(),
		 _cube.V000,_cube.V100,_cube.V110,_cube.V010,
		 cz0);
  GetConv2DCoefs(*_cube.quad_Z1, meshFaces[_indZ1]->GetSubShape(),
		 _cube.V001,_cube.V101,_cube.V111,_cube.V011,
		 cz1);

  // 1.8 - create a 3D structure for normalized values

  MESSAGE("---");
  int nbx = _cube.quad_Y0->nbPts[0];
  int nby = _cube.quad_Y0->nbPts[1];
  int nbz;
  if (cx0.a1 != 0) nbz = _cube.quad_X0->nbPts[1];
  else  nbz = _cube.quad_X0->nbPts[0];
  //SCRUTE(nbx);
  //SCRUTE(nby);
  //SCRUTE(nbz);
  int nbxyz= nbx*nby*nbz;
  Point3DStruct* np = new Point3DStruct[nbxyz];

  // 1.9 - store node indexes of faces

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indX0]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_X0;
    int i=0; // j = x/face , k = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int j = cx0.ia*i1 + cx0.ib*j1 + cx0.ic; // j = x/face
	  int k = cx0.ja*i1 + cx0.jb*j1 + cx0.jc; // k = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indX1]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_X1;
    int i=nbx-1; // j = x/face , k = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int j = cx1.ia*i1 + cx1.ib*j1 + cx1.ic; // j = x/face
	  int k = cx1.ja*i1 + cx1.jb*j1 + cx1.jc; // k = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indY0]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_Y0;
    int j=0; // i = x/face , k = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int i = cy0.ia*i1 + cy0.ib*j1 + cy0.ic; // i = x/face
	  int k = cy0.ja*i1 + cy0.jb*j1 + cy0.jc; // k = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indY1]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_Y1;
    int j=nby-1; // i = x/face , k = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int i = cy1.ia*i1 + cy1.ib*j1 + cy1.ic; // i = x/face
	  int k = cy1.ja*i1 + cy1.jb*j1 + cy1.jc; // k = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indZ0]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_Z0;
    int k=0; // i = x/face , j = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int i = cz0.ia*i1 + cz0.ib*j1 + cz0.ic; // i = x/face
	  int j = cz0.ja*i1 + cz0.jb*j1 + cz0.jc; // j = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  {
    const TopoDS_Face& F = TopoDS::Face(meshFaces[_indZ1]->GetSubShape());
    const TColStd_ListOfInteger& indElt
      = aMesh.GetSubMesh(F)->GetSubMeshDS()->GetIDNodes();
    TColStd_ListIteratorOfListOfInteger itf(indElt);

    faceQuadStruct* quad = _cube.quad_Z1;
    int k=nbz-1; // i = x/face , j = y/face
    int nbdown = quad->nbPts[0];
    int nbright = quad->nbPts[1];

    for (; itf.More(); itf.Next())
      {
	int nodeId = itf.Value();
	Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
	Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
	Handle (SMDS_FacePosition) fpos
	  = Handle (SMDS_FacePosition)::DownCast(node->GetPosition());
	double ri = fpos->GetUParameter();
	double rj = fpos->GetVParameter();
	int i1 = int(ri);
	int j1 = int(rj);
	int ij1 = j1*nbdown +i1;
	quad->uv_grid[ij1].nodeId = nodeId;
      }

    for (int i1=0; i1<nbdown; i1++)
      for (int j1=0; j1<nbright; j1++)
	{
	  int ij1 = j1*nbdown +i1;
	  int i = cz1.ia*i1 + cz1.ib*j1 + cz1.ic; // i = x/face
	  int j = cz1.ja*i1 + cz1.jb*j1 + cz1.jc; // j = y/face
	  int ijk = k*nbx*nby + j*nbx + i;
	  //MESSAGE(" "<<ij1<<" "<<i<<" "<<j<<" "<<ijk);
	  np[ijk].nodeId = quad->uv_grid[ij1].nodeId;
	  //SCRUTE(np[ijk].nodeId);
	}
  }

  // 2.0 - for each node of the cube:
  //       - get the 8 points 3D = 8 vertices of the cube
  //       - get the 12 points 3D on the 12 edges of the cube
  //       - get the 6 points 3D on the 6 faces with their ID
  //       - compute the point 3D
  //       - store the point 3D in SMESHDS, store its ID in 3D structure

  TopoDS_Shell aShell;
  TopExp_Explorer exp(aShape,TopAbs_SHELL);
  if (exp.More())
    {
      aShell = TopoDS::Shell(exp.Current());
    }
  else
    {
      MESSAGE("no shell...");
      ASSERT(0);
    }

  MESSAGE("---");
  Pt3 p000, p001, p010, p011, p100, p101, p110, p111;
  Pt3 px00, px01, px10, px11;
  Pt3 p0y0, p0y1, p1y0, p1y1;
  Pt3 p00z, p01z, p10z, p11z;
  Pt3 pxy0, pxy1, px0z, px1z, p0yz, p1yz;

  GetPoint(p000,     0,     0,     0, nbx, nby, nbz, np, meshDS);
  GetPoint(p001,     0,     0, nbz-1, nbx, nby, nbz, np, meshDS);
  GetPoint(p010,     0, nby-1,     0, nbx, nby, nbz, np, meshDS);
  GetPoint(p011,     0, nby-1, nbz-1, nbx, nby, nbz, np, meshDS);
  GetPoint(p100, nbx-1,     0,     0, nbx, nby, nbz, np, meshDS);
  GetPoint(p101, nbx-1,     0, nbz-1, nbx, nby, nbz, np, meshDS);
  GetPoint(p110, nbx-1, nby-1,     0, nbx, nby, nbz, np, meshDS);
  GetPoint(p111, nbx-1, nby-1, nbz-1, nbx, nby, nbz, np, meshDS);

  for (int i=1; i<nbx-1; i++)
    {
      for (int j=1; j<nby-1; j++)
	{
	  for (int k=1; k<nbz-1; k++)
	    {
	      // *** seulement maillage regulier
	      // 12 points on edges
	      GetPoint(px00,     i,     0,     0, nbx, nby, nbz, np, meshDS);
	      GetPoint(px01,     i,     0, nbz-1, nbx, nby, nbz, np, meshDS);
	      GetPoint(px10,     i, nby-1,     0, nbx, nby, nbz, np, meshDS);
	      GetPoint(px11,     i, nby-1, nbz-1, nbx, nby, nbz, np, meshDS);

	      GetPoint(p0y0,     0,     j,     0, nbx, nby, nbz, np, meshDS);
	      GetPoint(p0y1,     0,     j, nbz-1, nbx, nby, nbz, np, meshDS);
	      GetPoint(p1y0, nbx-1,     j,     0, nbx, nby, nbz, np, meshDS);
	      GetPoint(p1y1, nbx-1,     j, nbz-1, nbx, nby, nbz, np, meshDS);

	      GetPoint(p00z,     0,     0,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(p01z,     0, nby-1,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(p10z, nbx-1,     0,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(p11z, nbx-1, nby-1,     k, nbx, nby, nbz, np, meshDS);

	      // 12 points on faces
	      GetPoint(pxy0,     i,     j,     0, nbx, nby, nbz, np, meshDS);
	      GetPoint(pxy1,     i,     j, nbz-1, nbx, nby, nbz, np, meshDS);
	      GetPoint(px0z,     i,     0,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(px1z,     i, nby-1,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(p0yz,     0,     j,     k, nbx, nby, nbz, np, meshDS);
	      GetPoint(p1yz, nbx-1,     j,     k, nbx, nby, nbz, np, meshDS);

	      int ijk = k*nbx*nby + j*nbx + i;
	      double x = double(i)/double(nbx-1); // *** seulement
	      double y = double(j)/double(nby-1); // *** maillage
	      double z = double(k)/double(nbz-1); // *** regulier

	      Pt3 X;
	      for (int i=0; i<3; i++)
		{
		  X[i] =
		     (1-x)*p0yz[i] + x*p1yz[i]
		    +(1-y)*px0z[i] + y*px1z[i]
		    +(1-z)*pxy0[i] + z*pxy1[i]
		    -(1-x)*((1-y)*p00z[i] + y*p01z[i])
		    -   x *((1-y)*p10z[i] + y*p11z[i])
		    -(1-y)*((1-z)*px00[i] + z*px01[i])
		    -   y *((1-z)*px10[i] + z*px11[i])
		    -(1-z)*((1-x)*p0y0[i] + x*p1y0[i])
		    -   z *((1-x)*p0y1[i] + x*p1y1[i])
		    +(1-x)*( (1-y)*((1-z)*p000[i] + z*p001[i])
			    +   y *((1-z)*p010[i] + z*p011[i]))
		    +   x *( (1-y)*((1-z)*p100[i] + z*p101[i])
			    +   y *((1-z)*p110[i] + z*p111[i]));
		}


	      int myNodeId = meshDS->AddNode(X[0],X[1],X[2]);
 	      //MESSAGE("point "<<myNodeId<<" "<<X[0]<<" "<<X[1]<<" "<<X[2]);
	      np[ijk].nodeId = myNodeId;
	      Handle (SMDS_MeshElement) elt = meshDS->FindNode(myNodeId);
	      Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);

	      //meshDS->SetNodeInVolume(node, TopoDS::Solid(aShape));
	      meshDS->SetNodeInVolume(node, aShell);
	    }
	}
    }

  //2.1 - for each node of the cube (less 3 *1 Faces):
  //      - store hexahedron in SMESHDS

  for (int i=0; i<nbx-1; i++)
    for (int j=0; j<nby-1; j++)
      for (int k=0; k<nbz-1; k++)
	{
	  int n1 =    k *nbx*nby +    j *nbx + i;
	  int n2 =    k *nbx*nby +    j *nbx + i+1;
	  int n3 =    k *nbx*nby + (j+1)*nbx + i+1;
	  int n4 =    k *nbx*nby + (j+1)*nbx + i;
	  int n5 = (k+1)*nbx*nby +    j *nbx + i;
	  int n6 = (k+1)*nbx*nby +    j *nbx + i+1;
	  int n7 = (k+1)*nbx*nby + (j+1)*nbx + i+1;
	  int n8 = (k+1)*nbx*nby + (j+1)*nbx + i;

// 	  MESSAGE(" "<<n1<<" "<<n2<<" "<<n3<<" "<<n4<<" "<<n5<<" "<<n6<<" "<<n7<<" "<<n8);
 	  //MESSAGE(" "<<np[n1].nodeId<<" "<<np[n2].nodeId<<" "<<np[n3].nodeId<<" "<<np[n4].nodeId<<" "<<np[n5].nodeId<<" "<<np[n6].nodeId<<" "<<np[n7].nodeId<<" "<<np[n8].nodeId);

	  int hexa = meshDS->AddVolume(np[n1].nodeId,
				       np[n2].nodeId,
				       np[n3].nodeId,
				       np[n4].nodeId,
				       np[n5].nodeId,
				       np[n6].nodeId,
				       np[n7].nodeId,
				       np[n8].nodeId);
	  Handle (SMDS_MeshElement) elt = meshDS->FindElement(hexa);
	  meshDS->SetMeshElementOnShape(elt, aShell);

	  // *** 5 tetrahedres ... verifier orientations,
	  //     mettre en coherence &vec quadrangles-> triangles
	  //     choisir afficher 1 parmi edges, face et volumes
// 	  int tetra1 = meshDS->AddVolume(np[n1].nodeId,
// 					 np[n2].nodeId,
// 					 np[n4].nodeId,
// 					 np[n5].nodeId);
// 	  int tetra2 = meshDS->AddVolume(np[n2].nodeId,
// 					 np[n3].nodeId,
// 					 np[n4].nodeId,
// 					 np[n7].nodeId);
// 	  int tetra3 = meshDS->AddVolume(np[n5].nodeId,
// 					 np[n6].nodeId,
// 					 np[n7].nodeId,
// 					 np[n2].nodeId);
// 	  int tetra4 = meshDS->AddVolume(np[n5].nodeId,
// 					 np[n7].nodeId,
// 					 np[n8].nodeId,
// 					 np[n4].nodeId);
// 	  int tetra5 = meshDS->AddVolume(np[n5].nodeId,
// 					 np[n7].nodeId,
// 					 np[n2].nodeId,
// 					 np[n4].nodeId);

	}
  
  return true;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

void SMESH_Hexa_3D::GetPoint(Pt3 p,
			     int i, int j, int k,
			     int nbx, int nby, int nbz,
			     Point3DStruct *np,
			     const Handle(SMESHDS_Mesh)& meshDS)
{
  int ijk = k*nbx*nby + j*nbx + i;
  int nodeId = np[ijk].nodeId;
  Handle (SMDS_MeshElement) elt = meshDS->FindNode(nodeId);
  Handle (SMDS_MeshNode) node = meshDS->GetNode(1, elt);
  p[0] = node->X();
  p[1] = node->Y();
  p[2] = node->Z();
  //MESSAGE(" "<<i<<" "<<j<<" "<<k<<" "<<p[0]<<" "<<p[1]<<" "<<p[2]);
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

int SMESH_Hexa_3D::GetFaceIndex(SMESH_Mesh& aMesh,
				const TopoDS_Shape& aShape,
				const vector<SMESH_subMesh*>& meshFaces,
				const TopoDS_Vertex& V0,
				const TopoDS_Vertex& V1,
				const TopoDS_Vertex& V2,
				const TopoDS_Vertex& V3)
{
  MESSAGE("SMESH_Hexa_3D::GetFaceIndex");
  int faceIndex = -1;
  for (int i=1; i<6; i++)
    {
      const TopoDS_Shape& aFace = meshFaces[i]->GetSubShape();
      //const TopoDS_Face& F = TopoDS::Face(aFace);
      TopTools_IndexedMapOfShape M;
      TopExp::MapShapes(aFace, TopAbs_VERTEX, M);
      bool verticesInShape = false;
      if (M.Contains(V0))
	if (M.Contains(V1))
	  if (M.Contains(V2))
	    if (M.Contains(V3)) verticesInShape = true;
      if (verticesInShape)
	{
	  faceIndex = i;
	  break;
	}
    }
  ASSERT(faceIndex>0);
  SCRUTE(faceIndex);
  return faceIndex;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

TopoDS_Edge
SMESH_Hexa_3D::EdgeNotInFace(SMESH_Mesh& aMesh,
			     const TopoDS_Shape& aShape,
			     const TopoDS_Face& aFace,
			     const TopoDS_Vertex& aVertex,
			     const TopTools_IndexedDataMapOfShapeListOfShape& MS)
{
  MESSAGE("SMESH_Hexa_3D::EdgeNotInFace");
  TopTools_IndexedDataMapOfShapeListOfShape MF;
  TopExp::MapShapesAndAncestors(aFace, TopAbs_VERTEX, TopAbs_EDGE, MF);
  const TopTools_ListOfShape& ancestorsInSolid = MS.FindFromKey(aVertex);
  const TopTools_ListOfShape& ancestorsInFace  = MF.FindFromKey(aVertex);
  SCRUTE(ancestorsInSolid.Extent());
  SCRUTE(ancestorsInFace.Extent());
  ASSERT(ancestorsInSolid.Extent() == 6); // 6 (edges doublees)
  ASSERT(ancestorsInFace.Extent() == 2);
  
  TopoDS_Edge E;
  E.Nullify();    
  TopTools_ListIteratorOfListOfShape its(ancestorsInSolid);
  for ( ; its.More();its.Next())
  {
    TopoDS_Shape ancestor = its.Value();
    TopTools_ListIteratorOfListOfShape itf(ancestorsInFace);
    bool isInFace = false;
    for ( ; itf.More();itf.Next())
      {
	TopoDS_Shape ancestorInFace = itf.Value();
	if (ancestorInFace.IsSame(ancestor))
	  {
	    isInFace = true;
	    break;
	  }
      }
    if (! isInFace)
      {
	E = TopoDS::Edge(ancestor);
	break;
      }
  }
  return E;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

  void SMESH_Hexa_3D::GetConv2DCoefs(const faceQuadStruct& quad,
				     const TopoDS_Shape& aShape,
				     const TopoDS_Vertex& V0,
				     const TopoDS_Vertex& V1,
				     const TopoDS_Vertex& V2,
				     const TopoDS_Vertex& V3,
				     Conv2DStruct& conv)
{
  MESSAGE("SMESH_Hexa_3D::GetConv2DCoefs");
  const TopoDS_Face& F = TopoDS::Face(aShape);
  TopoDS_Edge E = quad.edge[0];
  double f,l;
  Handle(Geom2d_Curve) C2d = BRep_Tool::CurveOnSurface(E,F,f,l);
  TopoDS_Vertex VFirst, VLast;
  TopExp::Vertices(E, VFirst, VLast); // corresponds to f and l
  bool isForward = (((l-f)*(quad.last[0] - quad.first[0])) > 0);
  TopoDS_Vertex VA, VB;
  if (isForward)
    {
      VA = VFirst; VB = VLast;
    }
  else
    {
     VA = VLast; VB = VFirst;
    }
  int a1,b1,c1,a2,b2,c2;
  if (VA.IsSame(V0))
    if (VB.IsSame(V1))
      {
	a1= 1; b1= 0; c1= 0; // x
	a2= 0; b2= 1; c2= 0; // y
      }
    else
      {
	ASSERT(VB.IsSame(V3));
	a1= 0; b1= 1; c1= 0; // y
	a2= 1; b2= 0; c2= 0; // x
      }
  if (VA.IsSame(V1))
    if (VB.IsSame(V2))
      {
	a1= 0; b1=-1; c1= 1; // 1-y
	a2= 1; b2= 0; c2= 0; // x
      }
    else
      {
	ASSERT(VB.IsSame(V0));
	a1=-1; b1= 0; c1= 1; // 1-x
	a2= 0; b2= 1; c2= 0; // y
      }
  if (VA.IsSame(V2))
    if (VB.IsSame(V3))
      {
	a1=-1; b1= 0; c1= 1; // 1-x
	a2= 0; b2=-1; c2= 1; // 1-y
      }
    else
      {
	ASSERT(VB.IsSame(V1));
	a1= 0; b1=-1; c1= 1; // 1-y
	a2=-1; b2= 0; c2= 1; // 1-x
      }
  if (VA.IsSame(V3))
    if (VB.IsSame(V0))
      {
	a1= 0; b1= 1; c1= 0; // y
	a2=-1; b2= 0; c2= 1; // 1-x
      }
    else
      {
	ASSERT(VB.IsSame(V2));
	a1= 1; b1= 0; c1= 0;  // x
	a2= 0; b2=-1; c2= 1;  // 1-y
      }
  MESSAGE("X = "<<c1<<"+ "<<a1<<"*x + "<<b1<<"*y");
  MESSAGE("Y = "<<c2<<"+ "<<a2<<"*x + "<<b2<<"*y");
  conv.a1=a1; conv.b1=b1; conv.c1=c1;
  conv.a2=a2; conv.b2=b2; conv.c2=c2;

  int nbdown = quad.nbPts[0];
  int nbright = quad.nbPts[1];
  conv.ia = int(a1);
  conv.ib = int(b1);
  conv.ic = int(c1*a1*a1)*(nbdown-1) + int(c1*b1*b1)*(nbright-1);
  conv.ja = int(a2);
  conv.jb = int(b2);
  conv.jc = int(c2*a2*a2)*(nbdown-1) + int(c2*b2*b2)*(nbright-1);
  MESSAGE("I "<<conv.ia<<" "<<conv.ib<<" "<<conv.ic);
  MESSAGE("J "<<conv.ja<<" "<<conv.jb<<" "<<conv.jc);
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

ostream & SMESH_Hexa_3D::SaveTo(ostream & save)
{
  return save << this;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

istream & SMESH_Hexa_3D::LoadFrom(istream & load)
{
  return load >> (*this);
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

ostream & operator << (ostream & save, SMESH_Hexa_3D & hyp)
{
  return save;
}

//=============================================================================
/*!
 *  
 */
//=============================================================================

istream & operator >> (istream & load, SMESH_Hexa_3D & hyp)
{
  return load;
}