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#include "turning_number.h"
#include "PI.h"
template <typename DerivedV>
IGL_INLINE typename DerivedV::Scalar igl::turning_number(
const Eigen::MatrixBase<DerivedV> & V)
{
typedef typename DerivedV::Scalar Scalar;
constexpr Scalar TWO_PI = 2.0 * igl::PI;
const int n = V.rows();
Scalar total_angle = 0.0;
for (int i = 0; i < n; i++)
{
Eigen::Matrix<Scalar, 1, 2> current = V.row(i).head(2);
Eigen::Matrix<Scalar, 1, 2> next = V.row((i + 1) % n).head(2);
Eigen::Matrix<Scalar, 1, 2> d1 = next - current;
Eigen::Matrix<Scalar, 1, 2> d2 = V.row((i + 2) % n).head(2) - next;
const Scalar angle = atan2(
d1(0)*d2(1) - d1(1)*d2(0),
d1(0)*d2(0) + d1(1)*d2(1));
total_angle += angle;
}
return total_angle / TWO_PI;
}
#ifdef IGL_STATIC_LIBRARY
// Explicit template specialization
template double igl::turning_number<Eigen::Matrix<double, -1, 2, 0, -1, 2> >(Eigen::MatrixBase<Eigen::Matrix<double, -1, 2, 0, -1, 2> > const&);
template double igl::turning_number<Eigen::Matrix<double, -1, -1, 0, -1, -1> >(Eigen::MatrixBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&);
#endif