Added relaxOnlyConstrainedFlag to the voronoi processing relax procedure that allow to relax only the vertexes that are constrainted (onto their domain) ignoring all the other samples (except the fixed one). It allows to get more even distributions on the constrains.

vcg/complex/algorithms/voronoi_processing.h

@@ -57,6 +57,7 @@ struct VoronoiProcessingParameter
     triangulateRegion=false;
     unbiasedSeedFlag = true;
     geodesicRelaxFlag = true;
+    relaxOnlyConstrainedFlag=false;
     refinementRatio = 5.0f;
   }
   int colorStrategy;
@@ -72,6 +73,8 @@ struct VoronoiProcessingParameter
                                 /// domains, for example moving only along some linear features
                                 /// like border of creases.
 
+  bool relaxOnlyConstrainedFlag;
+
   bool preserveFixedSeed;       /// If true the 'fixed' seeds are not moved during relaxation.
                                 /// \see FixVertexVector function to see how to fix a set of seeds.
 
@@ -1176,7 +1179,9 @@ static void FixVertexVector(MeshType &m, std::vector<VertexType *> &vertToFixVec
 }
 
 /// \brief Perform a Lloyd relaxation cycle over a mesh
-///
+///  It uses two conventions:
+///  1) a few vertexes can remain fixed, you have to set a per vertex bool attribute named 'fixed'
+///  2)
 ///
 
 static int VoronoiRelaxing(MeshType &m, std::vector<VertexType *> &seedVec,
@@ -1188,6 +1193,14 @@ static int VoronoiRelaxing(MeshType &m, std::vector<VertexType *> &seedVec,
   tri::RequireCompactness(m);
   for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
     assert(vi->VFp() && "Require mesh without unreferenced vertexes\n");
+  std::vector<VertexType *> selectedVec;
+  if(vpp.relaxOnlyConstrainedFlag)
+  {
+    for(size_t i=0;i<seedVec.size();++i)
+      if(seedVec[i]->IsS())
+        selectedVec.push_back(seedVec[i]);
+    std::swap(seedVec,selectedVec);
+  }
 
   tri::UpdateFlags<MeshType>::FaceBorderFromVF(m);
   tri::UpdateFlags<MeshType>::VertexBorderFromFace(m);
@@ -1246,6 +1259,18 @@ static int VoronoiRelaxing(MeshType &m, std::vector<VertexType *> &seedVec,
   if(iter==relaxIter)
     tri::Geodesic<MeshType>::Compute(m, seedVec, df,std::numeric_limits<ScalarType>::max(),0,&sources);
 
+  if(vpp.relaxOnlyConstrainedFlag)
+  {
+    std::swap(seedVec,selectedVec);
+    int i=0,j=0;
+    for(i=0,j=0;i<seedVec.size();++i){
+      if(seedVec[i]->IsS())
+      {
+        seedVec[i]=selectedVec[j];
+        ++j;
+      }
+    }
+  }
   return iter;
 }