Now collapse methods (diagonal, counter-diag, and edge) return bool success and take optional parameter of type Pos (around which to rotate to find all affected quads). Also added an iterator that goes around Pos that returns quads (only once per quad).

vcg/complex/trimesh/bitquad_support.h

@@ -84,6 +84,7 @@ typedef typename MeshType::FaceType* FaceTypeP;
 typedef typename MeshType::VertexType VertexType;
 typedef typename MeshType::FaceIterator FaceIterator;
 typedef typename MeshType::VertexIterator VertexIterator;
+typedef typename face::Pos<FaceType> Pos;
 
 static void MarkFaceF(FaceType *f){
   f->V(0)->SetS();
@@ -553,11 +554,17 @@ static bool CollapseEdgeDirect(FaceType &f, int w0, MeshType& m){
   return true;
 }
 
-static bool CollapseEdge(FaceType &f, int w0, MeshType& m){
+// collapses an edge. Optional output pos can be iterated around to find affected faces
+static bool CollapseEdge(FaceType &f, int w0, MeshType& m, Pos *affected =NULL){
   FaceTypeP f0 = &f;
-  
   assert(!f0->IsF(w0)); // don't use this method to collapse diag.
 
+  if (affected) {
+    int w1 = 3-w0-FauxIndex(f0); // the edge whihc is not the collapsed one nor the faux
+    affected->F() = f0->FFp(w1);
+    affected->E() = f0->FFi(w1);
+  }
+  
   FaceTypeP f1 = f0->FFp(w0); 
   int w1 = f0->FFi(w0); 
   
@@ -581,13 +588,15 @@ static bool CollapseEdge(FaceType &f, int w0, MeshType& m){
    if k == 0.5, new vertex in the middle, etc
 */
 
-static void CollapseCounterDiag(FaceType &f, ScalarType interpol, MeshType& m){
+static bool CollapseCounterDiag(FaceType &f, ScalarType interpol, MeshType& m, Pos* affected=NULL){
   //CoordType p;
   //int fauxa = FauxIndex(&f);
   //p = f.V(fauxa)->P()*(1-k) + f.V( (fauxa+1)%3 )->P()*(k);
   
+  if (!CheckFlipDiag(f)) return false;
+
   FlipDiag(f);
-  CollapseDiag(f,interpol,m);
+  return CollapseDiag(f,interpol,m,affected);
 }
 
 /*
@@ -604,11 +613,49 @@ static void CollapseCounterDiag(FaceType &f, ScalarType k, MeshType& m){
 //  CollapseDiag(f,p,m);
 //}
 
+// rotates around vertex
+class Iterator{
+private:
+  Pos start, cur;
+  bool over;
+public:
+  Iterator(Pos& pos){
+    start = cur = Pos(pos.F(), pos.E());
+    over = false;
+  }
+  bool End() const {
+    return over;
+  }
+  void operator ++ () {
+    if (cur.F()->IsF(cur.E())) {
+      // jump over faux diag
+      int i = cur.F()->FFi( cur.E() ); 
+      cur.F() = cur.F()->FFp( cur.E() );
+      cur.E() = (i+2)%3;
+    }
+    // jump over real edge
+    FaceType *f =cur.F()->FFp( cur.E() );
+    if (f==cur.F()) over=true; // border found
+    cur.E() = (cur.F()->FFi( cur.E() ) +2 )%3; 
+    cur.F() = f;
 
-static void CollapseDiag(FaceType &f, ScalarType interpol, MeshType& m){
+    if (cur.F()==start.F()) over=true;
+
+  }
+  Pos GetPos(){
+    return cur;
+  }  
+};
+
+static bool CollapseDiag(FaceType &f, ScalarType interpol, MeshType& m, Pos* affected =NULL){
     
   FaceType* fa = &f;
   int fauxa = FauxIndex(fa);
+  if (affected) {
+    int w1 = 2-fauxa; // any edge but not the faux
+    affected->F() = fa->FFp(w1);
+    affected->E() = fa->FFi(w1);
+  }
   FaceType* fb = fa->FFp(fauxa);
   assert (fb!=fa);
   int fauxb = FauxIndex(fb);
@@ -655,6 +702,7 @@ static void CollapseDiag(FaceType &f, ScalarType interpol, MeshType& m){
   SetValency(vb, GetValency(vb)+GetValency(va)-2);
   if (DELETE_VERTICES) Allocator<MeshType>::DeleteVertex(m,*vb);
   
+  return true;
 }      
 
 
@@ -741,7 +789,7 @@ static void UpdateValencyInQuality(MeshType& m){
 }
 
 static bool HasConsistentValencyFlag(MeshType &m) {
-  UpdateValencyInFlags(m);
+  //UpdateValencyInFlags(m);
   UpdateValencyInQuality(m);
   for (VertexIterator vi = m.vert.begin();  vi!=m.vert.end(); vi++) if (!vi->IsD()) {
     if (GetValency(&*vi)!=vi->Q()) return false;