Function angle

src/Attributes/VoxelDihedralAngleAttribute.cpp:13–16

namespace VoxelDihedralAngleAttributeHelper {
    Float angle(const Eigen::Ref<Vector3F>& n1,
            const Eigen::Ref<Vector3F>& n2) {
        return atan2(n1.cross(n2).norm(), n1.dot(n2));
    }

    Vector3F compute_normal(
            const Vector3F& v1,