Flattening generates mesh with indices = 0 about boundary-first-flattening HOT 6 CLOSED

#include <Bff.h>
#include <MeshIO.h>
#include <iostream>

int main(int argc, char** argv) {

	std::ifstream ifs("./test_mesh.obj");
	std::stringstream ss_content;
	std::string content;
	std::istringstream iss_content;

	if(ifs) {
		std::cout << "Reading file!" << std::endl;
		ss_content << ifs.rdbuf();
		content = ss_content.str();
		iss_content = std::istringstream(content);
	}

	ifs.close();

	Mesh test_mesh;

	if(!MeshIO::read(iss_content,test_mesh))
		std::cout << "Reading problems!" << std::endl;

	test_mesh.write("./output_test_mesh.obj", false, false);


	return 0;

}

v 0.707107 -0.707107 0
v 0.707107 0.707107 0
v -0.707107 0.707107 0
v -0.707107 -0.707107 0
vt 1 2e-08
vt -1e-08 1
vt 1e-08 -1
vt -1e-08 1
vt -1 -2e-08
vt 1e-08 -1
f 1/3 2/1 3/2
f 1/6 3/4 4/5

#include <Bff.h>
#include <MeshIO.h>
#include <iostream>

int main(int argc, char** argv) {

	Mesh test_mesh;

	if(!test_mesh.read("./test_mesh.obj"))
		std::cout << "Reading problems!" << std::endl;

	BFF flattening_module(test_mesh);

	EigenDenseMatrix boundaryData(flattening_module.data->bN);

	std::cout << "flattening mesh" << std::endl;

	flattening_module.flatten(boundaryData,true);

	std::cout << "mesh flattened, now storing into a file" << std::endl;

	test_mesh.write("./output_test_mesh.obj",false,true);


	return 0;

}

v 0.707107 -0.707107 0
v 0.707107 0.707107 0
v -0.707107 0.707107 0
v -0.707107 -0.707107 0
vt 0.853553 0.853553
vt 0.146447 0.853553
vt 0.853553 0.146447
vt 0.146447 0.853553
vt 0.146447 0.146447
vt 0.853553 0.146447
f 1/3 2/1 3/2
f 1/6 3/4 4/5