STLExplorer.H

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#ifdef CH_LANG_CC
/*
 *      _______              __
 *     / ___/ /  ___  __ _  / /  ___
 *    / /__/ _ \/ _ \/  V \/ _ \/ _ \
 *    \___/_//_/\___/_/_/_/_.__/\___/
 *    Please refer to Copyright.txt, in Chombo's root directory.
 */
#endif

#ifndef _STLEXPLORER_H_
#define _STLEXPLORER_H_

#include "ProblemDomain.H"
#include "RealVect.H"
#include "IntVect.H"
#include "Box.H"
#include "MayDay.H"
#include "RefCountedPtr.H"

#include "STLMesh.H"
#include "STLBox.H"
#include "CellEdge.H"

#include "KDTree.H"

#include "NamespaceHeader.H"

/*
 * Class to explore an STL mesh
 * has member functions that
 * 1) build a K-D tree of the vertices
 * 2) search for nearest triangles given
 *  a) a point (return 1 triangle)
 *  b) a cell/volume (return all triangles with some part inside the volume)
 * 3) find intersection of a triangle with a single edge
 * 4) find intersection(s) of the whole mesh and an edge
 */

class STLExplorer
{
public:

  /// Constructor - just need a mesh
  STLExplorer(RefCountedPtr<STLMesh> a_stlmesh);

  /*
  /// Copy constructor
  STLExplorer(const STLExplorer& a_inputExplorer);
  */

  /// Destructor
  ~STLExplorer();

  /// builds cellToTriangles - connectivity between box and stlmesh
  void Explore(RefCountedPtr<STLBox> a_sb);

  void Explore(const Box&           a_region,
               const ProblemDomain& a_domain,
               const RealVect&      a_origin,
               const RealVect&      a_dx);


  /// return the point of intersection between a cellEdge and the mesh
  /// and whether the two nodes are inside or outside
  /// a_intersectPt is bogus if both nodes are inside or both outside
  void GetCellEdgeIntersection(const CellEdge& a_celledge,
                               RealVect&       a_intersectPt,
                               bool&           a_isNode0Inside,
                               bool&           a_isNode1Inside);

  /// return whether or not a point is inside or outside the domain
  void GetPointInOut(const IntVect&  a_point,
                     bool&           a_inout);

  // get methods for temporary variables
  void GetVertMap(Vector<IntVect>** a_vertmap);
  void GetTriMap(Vector<Vector<IntVect> >** a_trimap);
  void GetSTLBox(RefCountedPtr<STLBox>& a_sb);

protected:

  // actual data (shared)
  RefCountedPtr<STLMesh> m_msh;   // pointer to mesh
  RefCountedPtr<STLBox>  m_sb;    // pointer to mesh<->box data
  KDTree*                m_ptree; // pointer to the KDTree of nodes

  bool m_freestlbox; // true if STLExplorer should free the stlbox when destroyed
  bool m_printdebug; // if true, will print (lots of) debug info

  // (temporary data holder) vertex index -> cell (cell that a vertex is in)
  // only used in FindCellsOnEdges (to fill in cells between vertices of mesh)
  // NOTE: this structure may contain IntVects that are invalid (outside of m_box)
  Vector<IntVect> m_vertmap;

  // (temporary data holder) triangle index -> cell (Vector of cells in a given triangle)
  // only used in FindCellsInTriangles (to fill in intervening cells within triangles)
  // NOTE: this structure may contain IntVects that are invalid (outside of m_box)
  Vector<Vector<IntVect> > m_trimap;

  // overall function to explore a box
  void DoExplore();

  // sets map<IntVect,TriInCell> cellmap (adds on cells as we find them)
  // and  Vector<Intvect> vertmap
  void FindCellsOnVertices();

  // goes along triangle edges and finds cells (sets left & right triangles)
  // sets cellmap (inserts cells) and trimap
  void FindCellsOnEdges();

  // fills in any cells completely contained by the triangle
  // sets cellmap (inserts cells) and trimap
  void FindCellsInTriangles();

  // removes all cells that lie outside of the Box from consideration
  // modifies cellmap, trimap, vertmap (call before setting edgemap and nodemap)
  void RemoveCellsOutsideDomain();

  // stores the set of cell edges on the boundary
  // builds edgemap and nodemap
  void FindCellEdgesOnBondary();

  // builds a KDTree of the nodes that we know are inside/outside
  void BuildKDTree();

  // returns whether node0 or node1 of the cell edge is inside the domain
  bool WhichNodeIsInside(const CellEdge& celledge,
                         const int&      triangle);

  // returns whether node0 and node1 
  void FindEdgeInOut(const CellEdge& celledge,
                     bool&           isNode0Inside,
                     bool&           isNode1Inside);

  // same as above, but uses a KDTree instead of exhaustive search
  void FindEdgeInOutWithKDTree(const CellEdge& celledge,
                               bool&           isNode0Inside,
                               bool&           isNode1Inside);

  // given a triangle and an edge, find the intersection
  RealVect FindPlaneLineIntersection(const CellEdge& celledge,
                                     const int&      triangle);

  // return true if point lies within the triangle (up to the tolerance mesh.tol??)
  bool IsPointInTriangle(const RealVect& point,
                         const int&      triangle);

  // return true if the point lies on the edge (up to the tolerance mesh.tol)
  bool IsPointOnCellEdge(const RealVect& point,
                         const CellEdge& celledge);

  // note, i is an input and is incremented in FillInCellLine
  void FillInCellLine(vector<IntVect>& cells,
                      int&             i,
                      const int&       itri,
                      const int&       idir0,
                      const int&       idir1);

protected:
  void RecursiveKDTreeInsert(vector<pair<RealVect,pair<IntVect,bool>*> > &allNodes,
                             const int                                   &nstart,
                             const int                                   &nend,
                             const int                                   &depth);

private:
  STLExplorer()
  {
    MayDay::Abort("STLExplorer uses strong construction");
  }

  void operator=(const STLExplorer& a_inputReader)
  {
    MayDay::Abort("STLExplorer doesn't allow assignment");
  }
};

#include "NamespaceFooter.H"
#endif