From: Jiri Vlasak <hubacji1@fel.cvut.cz>
Date: Sun, 19 Mar 2023 21:27:22 +0000 (+0100)
Subject: Add arc len computation method to point
X-Git-Url: https://rtime.felk.cvut.cz/gitweb/hubacji1/iamcar2.git/commitdiff_plain/2921634dd3f757e8f6389b7890995d1839c3491e

Add arc len computation method to point
---

diff --git a/bcar/incl/bcar.hh b/bcar/incl/bcar.hh
index 3afde08..ebe6557 100644
--- a/bcar/incl/bcar.hh
+++ b/bcar/incl/bcar.hh
@@ -92,6 +92,12 @@ public:
 	/*! Return Euclidean distance to `p`. */
 	double edist(Point const& p) const;
 
+	/*! Return length of arc between two points when radius is kwown.
+	 *
+	 * \see https://math.stackexchange.com/questions/1595872/arclength-between-two-points-on-a-circle-not-knowing-theta
+	 */
+	double arc_len(Point const& p, double r);
+
 	/*! Generate output for plotting with gnuplot. */
 	void gen_gnuplot_to(std::ostream& out);
 
diff --git a/bcar/src/bcar.cc b/bcar/src/bcar.cc
index 44763d7..01f479c 100644
--- a/bcar/src/bcar.cc
+++ b/bcar/src/bcar.cc
@@ -145,6 +145,12 @@ Point::edist(Point const& p) const
 	return sqrt(pow(p.x() - this->_x, 2.0) + pow(p.y() - this->_y, 2.0));
 }
 
+double
+Point::arc_len(Point const& p, double r)
+{
+	return 2 * r * asin(this->edist(p) / 2 / r);
+}
+
 void
 Point::gen_gnuplot_to(std::ostream& out)
 {