From 8780a2d7e50b4fb4eddf8f76639378a7eb9d4568 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sun, 25 Apr 2021 14:39:25 +0300
Subject: [PATCH] Add angle(vector,vector)

---
 libs/geom/include/psemek/geom/vector.hpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libs/geom/include/psemek/geom/vector.hpp b/libs/geom/include/psemek/geom/vector.hpp
index ce12dac5..aaf0b282 100644
--- a/libs/geom/include/psemek/geom/vector.hpp
+++ b/libs/geom/include/psemek/geom/vector.hpp
@@ -314,6 +314,12 @@ namespace psemek::geom
 		return std::atan2(v[1], v[0]);
 	}
 
+	template <typename T, std::size_t N>
+	T angle(vector<T, N> const & v0, vector<T, N> const & v1)
+	{
+		return std::acos(std::max(T{-1}, std::min(T{1}, dot(v0, v1))));
+	}
+
 	template <typename T, std::size_t N>
 	vector<T, N> pointwise_mult(vector<T, N> const & v0, vector<T, N> const & v1)
 	{