i am trying to code a function in C++ that gives me the connected components of a triangular mesh.
I have a custom class that modelize a 3D triangular mesh.
My goal is to obtain a std::vector<Mesh2d> with contain a connected component of my mesh in each component.
class Mesh2d{
std::vector<R3>* node_ptr;
std::vector<Elt2d> elt;
public:
Mesh2d(){};
Mesh2d(std::vector<R3>& node){}
void Load(const string& filename){}
void PushBack(const Elt2d& e){}
std::vector<Elt2d>::iterator begin(){}
std::vector<Elt2d>::iterator end(){}
std::vector<int> Num(const int& j) const {}
void Plot(string filename) const {}
const Elt2d& operator[](const int& j) const {}
std::vector<Elt2d> const GetElt() const {}
void GetBoundary(Mesh& mesh){}
friend std::vector<Elt2d> adj(Elt2d e, Mesh2d mesh){}
friend int find_index(Elt2d e,Mesh2d mesh){}
friend void DFS(int j , std::vector<bool> visited, Mesh2d boundary, std::vector<Mesh2d> ConnectedComponents, int n){
visited[j] = true;
std::cout<<"visited = " << visited << std::endl;
ConnectedComponents[n].PushBack(boundary[j]);
Elt2d e = boundary[j];
std::vector<Elt2d> neighbor = adj(e,boundary);
for(int i = 0; i<neighbor.size(); ++i){
// std::cout<<"i = " << i << std::endl;
int p = find_index(neighbor[i], boundary);
if(visited[p] == false){
DFS(p, visited, boundary, ConnectedComponents, n);
}
}
}
std::vector<Mesh2d> Boundary(Mesh mesh){
Mesh2d boundary;
boundary.GetBoundary(mesh);
std::vector<Mesh2d> ConnectedComponents;
std::vector<bool> visited(boundary.NbElt(),false);
std::vector<bool> True(boundary.NbElt(),true);
int k = 0;
for(int j = 0; j<boundary.NbElt(); ++j){
ConnectedComponents.resize(k+1);
std::cout<<"j =" << j << std::endl;
Elt2d e = boundary[j];
if(visited[j]==false){
DFS(j, visited, boundary, ConnectedComponents,k);
ConnectedComponents[k].PushBack(boundary[j]);
std::cout<< "NbCC = " << ConnectedComponents.size() << std::endl;
}
++k;
std::cout<<"k = " << k << std::endl;
}
return ConnectedComponents;
}
};
Where R3 and Elt2d are custom class representing 3D vectors and triangle.
My problem is with the two function DFS and Boundary, i'm using a depth-first search algorithm to explore my mesh (with the triangle as nodes). But i am getting a strange bug where my vector visited changes some of its value to false. If I print my visited vector for a small mesh i get this :
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 1 1 1 1 1 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 0 1 1 1 1 0 1
visited = 1 1 1 1 1 0 1 1 1 1 0 1
visited = 1 1 1 1 1 1 1 1 1 1 0 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 1 0 1 1 1 1 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 1 1 1 1 1 0 1
visited = 1 1 1 1 1 1 1 1 1 1 0 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 1 1 1 1 1 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 0 1 1 1 1 1 1
visited = 1 1 1 1 1 0 1 1 1 1 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 1 1 1 1 1 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 0 0 1 1 1 0 1 1
visited = 1 1 1 1 1 0 1 1 1 0 1 1
visited = 1 1 1 1 1 1 1 1 1 0 1 1
visited = 1 1 1 1 1 1 1 1 1 1 1 1
visited = 1 1 1 1 1 0 1 1 1 1 1 1
I have absolutely no clue why it's happening.
Please keep in mind that I am a beginner with C++ and some part (or a lot) of my code can look silly.
Any help would be greatly appreciated