#include <test_common.h>
#include <igl/doublearea.h>

class doublearea : public ::testing::TestWithParam<std::string> {};

TEST_P(doublearea, VF_vs_ABC )
{
  Eigen::MatrixXd V;
  Eigen::MatrixXi F;
  test_common::load_mesh(GetParam(), V, F);

  // Check that computing double area with (V,F) is the same as computing
  // double area with (V1,V2,V2)
  Eigen::VectorXd A1,A2;
  igl::doublearea(V,F,A1);
  Eigen::MatrixXd A(F.rows(),3);
  Eigen::MatrixXd B(F.rows(),3);
  Eigen::MatrixXd C(F.rows(),3);
  for(int f = 0;f<F.rows();f++)
  {
    A.row(f) = V.row(F(f,0));
    B.row(f) = V.row(F(f,1));
    C.row(f) = V.row(F(f,2));
  }
  igl::doublearea(A,B,C,A2);
  ASSERT_EQ(A1.size(),A2.size());
  for(int a = 0;a<A1.size();a++)
  {
    ASSERT_NEAR(A1(a),A2(a),1e-15);
  }
}

INSTANTIATE_TEST_CASE_P
(
 all_meshes,
 doublearea,
 ::testing::ValuesIn(test_common::all_meshes()),
 test_common::string_test_name
);