问使用#CGAL实现二维网格的三角形角度

EN

// faces_iterator iterates through the triangles of l_cdt CDT triangulation

CGAL::Point_2<K> vertex1 = l_cdt.triangle(faces_iterator)[0];
CGAL::Point_2<K> vertex2 = l_cdt.triangle(faces_iterator)[1];
CGAL::Point_2<K> vertex3 = l_cdt.triangle(faces_iterator)[2];

double a = CGAL::sqrt((vertex2.x() - vertex3.x()) * (vertex2.x() - vertex3.x()) + (vertex2.y() - vertex3.y()) * (vertex2.y() - vertex3.y()));
double b = CGAL::sqrt((vertex1.x() - vertex3.x()) * (vertex1.x() - vertex3.x()) + (vertex1.y() - vertex3.y()) * (vertex1.y() - vertex3.y()));
double c = CGAL::sqrt((vertex2.x() - vertex1.x()) * (vertex2.x() - vertex1.x()) + (vertex2.y() - vertex1.y()) * (vertex2.y() - vertex1.y()));

// constants::PI is just π, for conversion to degrees instead of radians 
double angle1 = ((std::acos((b*b + c*c - a*a) / (2*b*c))) * 180) / constants::PI;
double angle2 = ((std::acos((a*a + c*c - b*b) / (2*a*c))) * 180) / constants::PI;
double angle3 = ((std::acos((a*a + b*b - c*c) / (2*b*a))) * 180) / constants::PI;