1 files changed, 44 insertions, 0 deletions
diff --git a/src/include/glm/gtx/vector_angle.inl b/src/include/glm/gtx/vector_angle.inl
new file mode 100644
index 0000000..b12f386
--- /dev/null
+++ b/src/include/glm/gtx/vector_angle.inl
@@ -0,0 +1,44 @@
+/// @ref gtx_vector_angle
+
+namespace glm
+{
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType angle
+	(
+		genType const& x,
+		genType const& y
+	)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'angle' only accept floating-point inputs");
+		return acos(clamp(dot(x, y), genType(-1), genType(1)));
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T angle(vec<L, T, Q> const& x, vec<L, T, Q> const& y)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'angle' only accept floating-point inputs");
+		return acos(clamp(dot(x, y), T(-1), T(1)));
+	}
+
+	//! \todo epsilon is hard coded to 0.01
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T orientedAngle(vec<2, T, Q> const& x, vec<2, T, Q> const& y)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'orientedAngle' only accept floating-point inputs");
+		T const Angle(acos(clamp(dot(x, y), T(-1), T(1))));
+
+		if(all(epsilonEqual(y, glm::rotate(x, Angle), T(0.0001))))
+			return Angle;
+		else
+			return -Angle;
+	}
+
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T orientedAngle(vec<3, T, Q> const& x, vec<3, T, Q> const& y, vec<3, T, Q> const& ref)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'orientedAngle' only accept floating-point inputs");
+
+		T const Angle(acos(clamp(dot(x, y), T(-1), T(1))));
+		return mix(Angle, -Angle, dot(ref, cross(x, y)) < T(0));
+	}
+}//namespace glm