se_mesh_import.cpp

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# ifdef WIN32
# include <sr_tree.h>
# include <se_mesh_import.h>
# else
# include <SR/sr_tree.h>
# include <SE/se_mesh_import.h>
# endif


//# define SR_USE_TRACE1 // basic messages
//# define SR_USE_TRACE2 // more messages
//# define SR_USE_TRACE4 // active contour
//# define SR_USE_TRACE5 // tree
# ifdef WIN32
# include <sr_trace.h>
# else
# include <SR/sr_trace.h>
# endif


//======================= static data =============================================

// Question: Could I substitute EdgeTree by an EdgeHashTable ...?

class Edge : public SrTreeNode
 { public :
   int a, b;      // Edge vertices, not oriented
   int v;         // The other vertex of the adjacent face
   int f;         // The index of the edge's face
   Edge *sym;     // The other edge, belonging to the other face sharing this edge
   Edge *e2, *e3; // The other two edges of this face
 public :
   Edge ( int i1=0, int i2=0, int i3=0 ) : f(0), sym(0), e2(0), e3(0) { a=i1; b=i2; v=i3; }
   void set_fac_elems ( Edge *b, Edge *c, int fac ) { e2=b; e3=c; f=fac; }
   void swap() { int tmp=a; a=b; b=tmp; }

   friend SrOutput& operator<< ( SrOutput& o, const Edge& e )
   { return o<<'['<<e.a<<' '<<e.b<<' '<<e.v<<"]"; }

   friend SrInput& operator>> ( SrInput& i, Edge& /*e*/ ) { return i; }

   friend int sr_compare ( const Edge* e1, const Edge* e2 );
};

int sr_compare ( const Edge *e1, const Edge *e2 )
 {
   if ( e1->a<e2->a ) return -1;
   if ( e1->a>e2->a ) return  1;
   if ( e1->b<e2->b ) return -1;
   if ( e1->b>e2->b ) return  1;
   return 0;
 }

/*
# ifdef SE_USR_TRACE4
struct PFace { SeBase *e; SeMeshBase *m; } PFaceInst;
FgOutput &operator << ( FgOutput &o, PFace &f )
 {
   o << '[';
   SeBase *e=f.e;
   while ( true )
    { o<<(int)f.m->index(e->vtx());
      e = e->nxt();
      if ( e!=f.e ) o<<' '; else break;
    }
   return o<<']';
 }
# define SR_TRACE_CONTOUR(x,s) { PFaceInst.e=x; PFaceInst.m=s; SR_TRACE4 ( "Active Contour = "<< PFaceInst ); }
# else
# define SR_TRACE_CONTOUR(x,s)
# endif
*/

# define SR_TRACE_CONTOUR(x,s)

//=========================== EdgeTree ========================================

class EdgeTree : public SrTree<Edge>
 { public :
//    EdgeTree()  {}
   public :
    Edge *insert_edge ( int a, int b, int v );
    bool  insert_face ( int a, int b, int c, int f );
    Edge* search_edge ( int a, int b );
    void  remove_face ( Edge *e );
 };

Edge *EdgeTree::insert_edge ( int a, int b, int v )
 {
   Edge *e = new Edge ( a, b, v );
   if ( !insert(e) )
    { Edge *x = cur();
      e->swap();
      if ( !insert(e) ) 
       { SR_TRACE2 ( "Could not insert edge ("<<a<<','<<b<<")!!" );
         delete e; 
         return 0; 
       }
      x->sym = e;
      e->sym = x;
    }
   else // search if the sym edge is there and set sym pointers
    {   // (to try: sort (a,b) to avoid checking if the sym exists...)
      Edge eba ( b, a, v );
      Edge *esym = search ( &eba );
      if ( esym )
       { esym->sym = e;
         e->sym = esym;
       }
    }
   return e;
 }

bool EdgeTree::insert_face ( int a, int b, int c, int f )
 {
   Edge *e1 = insert_edge ( a, b, c );
   Edge *e2 = insert_edge ( b, c, a );
   Edge *e3 = insert_edge ( c, a, b );
   
   if (e1) e1->set_fac_elems ( e2, e3, f );
   if (e2) e2->set_fac_elems ( e1, e3, f );
   if (e3) e3->set_fac_elems ( e1, e2, f );
 
   return e1&&e2&&e3? true:false;
 }

Edge* EdgeTree::search_edge ( int a, int b )
 {
   Edge key(a,b,0);

   Edge *e = search(&key);
   if ( !e )
    { key.swap();
      e=search(&key);
    }

   return e;
 }

void EdgeTree::remove_face ( Edge *e )
 {
   if (!e) return;

   // e2 and/or e3 can be null in case non-manifold edges were found during the
   // construction of the edge tree with start()
   Edge *e2 = e->e2;
   Edge *e3 = e->e3;

   extract ( e );
   if ( e->sym  ) e->sym->sym=0;

   if (e2) 
    { if ( e2->sym ) e2->sym->sym=0;
      remove ( e2 );
    }

   if (e3)
    { if ( e3->sym ) e3->sym->sym=0;
      remove ( e3 );
    }
 } 

//======================= internal data ==================================

static SeBase* init ( SeMeshImport *self, SeMeshBase* m, int a, int b )
 {
   SeBase *s = m->init ();
   m->index(s->vtx(),(semeshindex)b);
   m->index(s->nxt()->vtx(),(semeshindex)a);
   self->attach_vtx_info ( s->vtx(), b );        
   self->attach_vtx_info ( s->nxt()->vtx(), a );
   self->attach_edg_info ( s->edg(), b, a );
   return s;
 }

static SeBase* mev ( SeMeshImport *self, SeMeshBase* m, SeBase* s, int ev, int v )
 {
   s = m->mev ( s );
   self->attach_edg_info ( s->edg(), ev, v );
   self->attach_vtx_info ( s->vtx(), v );
   m->index ( s->vtx(), (semeshindex)v );
   return s;
 }

static SeBase* mef ( SeMeshImport *self, SeMeshBase* m, SeBase* s1, SeBase* s2, int a, int b, int f )
 {
   s2 = m->mef ( s1, s2 );
   self->attach_edg_info ( s2->edg(), a, b );
   self->attach_fac_info ( s2->fac(), f );
   return s2;
 }

class SeMeshImport::Data
 { public :
    SeMeshImport *self;
    EdgeTree tree;
    SrArray<SeBase*> active_contours;    // stack of contours
    SrArray<SeBase*> contours_to_solve;  // keep contours that will result in genus or holes
    SrArray<SeBase*> vtxsymedges;        // keep pointer for vertices already inserted
   public :
    Data ( SeMeshImport *x );
    SeMeshBase *init_shell ();
    int start ( const int *triangles, int numtris, int numvtx );
    void solve_lasting_contours ( SeMeshBase *m );
    void glue_face_on_one_edge ( SeMeshBase *m, SeBase *&s, Edge *e );
    void glue_face_on_two_edges ( SeMeshBase *m, SeBase *&s, Edge *e );
    void glue_face_on_three_edges ( SeMeshBase *m, SeBase *s, Edge *e );
 };

SeMeshImport::Data::Data ( SeMeshImport *x ) 
 {
   vtxsymedges.size(0);
   vtxsymedges.capacity(256);
   active_contours.size(0);
   active_contours.capacity(32);
   self = x;
 }

SeMeshBase *SeMeshImport::Data::init_shell ()
 {  
   SR_TRACE1 ( "Getting new shell..." );
   SeMeshBase *m = self->get_new_shell ();
   if ( !m ) return 0;

   SR_TRACE1 ( "Getting seed face from the root of the tree..." );

   Edge *e = tree.root();
   int a=e->a; int b=e->b; int c=e->v; // the order of the vertices is random
   int f=e->f;
   tree.remove_face ( e );
   delete e;

   SR_TRACE1 ( "Creating seed face = ["<<a<<" "<<b<<" "<<c<<"]" );

   m->begin_indexing ();

   SeBase *s;

   s = init ( self, m, a, b );
   s = mev ( self, m, s, b, c );
   mef ( self, m, s, s->nxt()->nxt(), a, c, f );

   vtxsymedges[c] = s;
   vtxsymedges[b] = s->nxt();
   vtxsymedges[a] = s->nxt()->nxt();

   active_contours.push() = s;

   SR_TRACE2 ("seed face info: "<<(int)s->sym()->fac()<<", active face info: "<<(int)s->fac() );

   return m;
 }

int SeMeshImport::Data::start ( const int *triangles, int numtris, int numvtx )
 {  
   int i;

   active_contours.size(0);

   SR_TRACE1 ( "Initializing vertices table with size "<<numvtx<<"..." );
   vtxsymedges.size(numvtx);
   for ( i=0; i<vtxsymedges.size(); i++ )  vtxsymedges[i]=0;

   SR_TRACE1 ( "Creating edge tree..." );

   const int *tri=triangles;
   int faces_with_edges_not_inserted=0;
   for ( i=0; i<numtris; i++ ) 
    { if ( !tree.insert_face(tri[0],tri[1],tri[2],i) ) 
        faces_with_edges_not_inserted++;
      tri += 3;
    }

   return faces_with_edges_not_inserted;
 }

static SeBase* coincident_contour ( SeBase *s1, SeBase *s2 )
 {
   SeBase *x = s2;
   while ( s1->vtx() != x->nxt()->vtx() )
    { x = x->nxt();
      if ( x==s2 ) return 0; // not coincident 
    }

   // a common starting vertex was found, so that the contours will be coincident
   // or we'll have non-manifold vertices. Let's verify :
   s2 = x;
   do { if ( s1->vtx() != s2->nxt()->vtx() )
         { printf("Non-manifold vertex detected!\n"); return 0; }
        s1 = s1->nxt();
        s2 = s2->pri();
      } while ( s2!=x );

   return x;
 }

// should finished the contours by detecting loops to join or holes info to attach
void SeMeshImport::Data::solve_lasting_contours ( SeMeshBase *m )
 {
   int i;
   bool genus_increased;
   SeBase *s, *c;

   while ( !contours_to_solve.empty() )
    { genus_increased = false;
      s = contours_to_solve.pop();
      SR_TRACE_CONTOUR(s,m);
      for ( i=0; i<contours_to_solve.size(); i++ )
       { c = coincident_contour(s,contours_to_solve[i]);
         if ( c )
          { SR_TRACE1 ( "Making one genus..." );
            SR_TRACE_CONTOUR(c,m);
            contours_to_solve.remove(i);//[i]=contours_to_solve.pop();
            genus_increased = true;
            m->mg ( s, c );
            break;
          }
       }
      if ( !genus_increased )
       { SR_TRACE1 ( "Closing last contour as a hole..." );
         self->attach_hole_info ( s->fac() );
       }
    }
 }

void SeMeshImport::Data::glue_face_on_one_edge ( SeMeshBase *m, SeBase *&s, Edge *e )
 {
   tree.remove_face ( e );

   SeBase *snxt = s->nxt();

   s = mev ( self, m, s, e->a, e->v );
   s = mef ( self, m, snxt, s, e->b, e->v, e->f );

   vtxsymedges[e->a] = s->nxt()->sym();
   vtxsymedges[e->b] = snxt;
   vtxsymedges[e->v] = snxt->pri();
   s = snxt;

   delete e;
 }

void SeMeshImport::Data::glue_face_on_two_edges ( SeMeshBase* m, SeBase*& s, Edge* e )
 {
   tree.remove_face ( e );
   SeElement *ve  = vtxsymedges[e->v]->vtx();
   SeBase *s1, *s2;

   if ( s->pri()->vtx()==ve ) 
    { s1=s->nxt(); s2=s->pri(); }
   else
    { s1=s->nxt()->nxt(); s2=s; }

   mef ( self, m, s1, s2, m->index(s1->vtx()), m->index(s2->vtx()), e->f );
   s = s1->pri();

   vtxsymedges[(int)m->index(s->vtx())] = s;
   vtxsymedges[(int)m->index(s1->vtx())] = s1;
   delete e;
 }

void SeMeshImport::Data::glue_face_on_three_edges ( SeMeshBase* /*m*/, SeBase* s, Edge* e )
 {
   tree.remove_face ( e );
   self->attach_fac_info ( s->fac(), e->f );   
   delete e;
 }

//======================== SeMeshImport ========================================

SeMeshImport::SeMeshImport ()
 {
   _data = new Data ( this );
 }

SeMeshImport::~SeMeshImport () 
 {
   for ( int i=0; i<shells.size(); i++ ) delete shells[i];
   delete _data;
 }

void SeMeshImport::compress_buffers ()
 {
   shells.compress();
   _data->vtxsymedges.capacity(0);
   _data->active_contours.capacity(0);
 }

SeMeshImport::Msg SeMeshImport::start (  const int *triangles, int numtris, int numvtxs )
 {  
   SR_TRACE1 ( "Start :" );

   int not_inserted = _data->start ( triangles, numtris, numvtxs );

   shells.size(0);
   SeMeshBase *m = _data->init_shell (); // will push something in active_contours
   if ( !m ) return MsgNullShell;
   shells.push()=m;

   SR_TRACE_CONTOUR(_data->active_contours.top(),m);
   SR_TRACE4 ( "Face info of active contour = " << (int)(_data->active_contours.top()->fac()) );
   SR_TRACE5 ( "Tree = "<<_data->tree );
   SR_TRACE1 ( "Start finished !" );
   SR_TRACE1 ( "Faces Lost: "<<not_inserted );

   return not_inserted>0? MsgNonManifoldFacesLost : MsgOk;
 }

static SeBase* in_same_face ( SeBase *e, SeElement *v )
 {
   SeBase *x = e;
   do { if ( x->vtx()==v ) return x;
        x = x->nxt();
      } while ( x!=e );
   return 0;
 }

SeMeshImport::Msg SeMeshImport::next_step ()
 {
   int a, b;
   Edge *e;
   SeBase *ini, *s, *sv;

   int edges_found = 0;

   SR_TRACE2 ( " " );
   SR_TRACE2 ( "Next step :" );

   EdgeTree &tree = _data->tree;
   SrArray<SeBase*> &active_contours = _data->active_contours;
   SrArray<SeBase*> &contours_to_solve = _data->contours_to_solve;
   SrArray<SeBase*> &vtxsymedges = _data->vtxsymedges;

   SR_TRACE2 ( "Active contours : "<<active_contours.size() );

   if ( tree.empty() )
    { SR_TRACE1 ( "Empty tree: no more faces to glue." );
      if ( !active_contours.empty() ) 
       { while ( !active_contours.empty() ) contours_to_solve.push()=active_contours.pop();
         SR_TRACE1 ( "Solving "<<contours_to_solve.size()<<" open contour(s)..." );
         _data->solve_lasting_contours ( shells.top() );
       }
      for ( int i=0; i<shells.size(); i++ ) shells[i]->end_indexing();
      SR_TRACE1 ( "Finished : "<<shells.size()<<" shell(s), last shell V-E+F="<<shells.top()->euler() );
      return MsgFinished;
    }
   else if ( active_contours.empty() ) 
    { SR_TRACE1 ( "Starting new shell "<<shells.size()<<"... " );
      shells.push() = _data->init_shell();
      return MsgOk; // return now to cope with degenerated data (a shell with a single triangle).
    }

   s = ini = active_contours.top();

   while ( true )
    { 
      a = (int) shells.top()->index(s->vtx());
      b = (int) shells.top()->index(s->nxt()->vtx());
      SR_TRACE2 ( "Searching edge "<<a<<" "<<b<<"... " );
      e = tree.search_edge ( a, b ); // will search {a,b} or {b,a}

      if ( e )
       { edges_found++;

         sv = 0;
         if ( vtxsymedges[e->v] ) // the other vertex is already in the mesh
         sv = in_same_face ( s, vtxsymedges[e->v]->vtx() );

         if ( !vtxsymedges[e->v] || !sv ) // if the other vertex is free or is in another contour
          { SR_TRACE1 ( "Gluing face "<<a<<" "<<b<<" "<<e->v<<" on one edge... " );
            _data->glue_face_on_one_edge ( shells.top(), s, e );
            active_contours.top() = s;
            SR_TRACE_CONTOUR(s,shells.top());
            SR_TRACE5 ( "Tree = "<<tree );
            return MsgOk;
          }
         else if ( s->nxt()->nxt()->nxt()==s ) // trying to close the active contour that is a triangle
          { SR_TRACE1 ( "Gluing last face "<<a<<" "<<b<<" "<<e->v<<" of current active contour..." );
            _data->glue_face_on_three_edges ( shells.top(), s, e );
            active_contours.pop();
            SR_TRACE1 ( "Active contour popped... " );
            SR_TRACE5 ( "Tree = "<<tree );
            return MsgOk;
          }
         else if ( s->nxt()->nxt()->vtx()==vtxsymedges[e->v]->vtx() ||
                   s->pri()->vtx()==vtxsymedges[e->v]->vtx() )
          { SR_TRACE1 ( "Gluing face "<<a<<" "<<b<<" "<<e->v<<" on two edges... " );
            _data->glue_face_on_two_edges ( shells.top(), s, e );
            active_contours.top() = s;
            SR_TRACE_CONTOUR(s,shells.top());
            SR_TRACE5 ( "Tree = "<<tree );
            return MsgOk;
          }
         else if ( sv )
          { SR_TRACE1 ( "Connecting one edge, and pushing one active contour... " );
            shells.top()->mef ( s, sv );
            attach_edg_info ( s->edg(), shells.top()->index(s->vtx()), shells.top()->index(sv->vtx()) );
            active_contours.push()=sv;
            return MsgOk;
          }
         else
          { SR_TRACE1 ( "XXXXXXXXXXXXXXXXXX undef situation!! XXXXXXXXXXXXXXXXXXXXXXXXXXXX" );
            SR_TRACE_CONTOUR(active_contours.top(),shells.top());
            SR_TRACE1 ( "s = ["<<a<<","<<b<<"] v="<<e->v);
            SR_TRACE1 ( "s.fac="<<(int)s->fac()<<", vfac="<<(int)vtxsymedges[e->v]->fac() );
          }
        }
       else
        { // e not in the edge tree: input data is not fully connected!
        }

      s = s->nxt();
      if ( s==ini ) break;// already passed all edges of the active contour
    }

   // At this point we looked into all edges of the active_contour,
   // but no faces were glued and the tree is not empty.

   SR_TRACE1 ( "No more faces could be glued to the actual contour!" );
   contours_to_solve.push() = active_contours.pop();
   
   return MsgOk;
 }

//============================== virtuals ==================================

void SeMeshImport::attach_vtx_info ( SeVertex* /*v*/, int /*vi*/ )
 { 
 }

void SeMeshImport::attach_edg_info ( SeEdge* /*e*/, int /*a*/, int /*b*/ )
 { 
 }

void SeMeshImport::attach_fac_info ( SeFace* /*f*/, int /*fi*/ )
 {
 }

void SeMeshImport::attach_hole_info ( SeFace* /*f*/ )
 { 
 }

//============================== end of file ===============================