C++ function for finding mesh (.obj file) silhouettes (a list of boundary meshes)

I have a program that is able to read a .obj file, which is basically a 3D mesh file, and render the mesh. All mesh operations are contained in a [login to view URL] file. I need a C++ function to output a list of silhouette points (boundary vertices) of the mesh object. I've attached my code here. Please read the [login to view URL], in which i've explained the code a bit the operation entrance is the autorig() method. budget is $30-$60