1 files changed, 57 insertions, 0 deletions
diff --git a/include/gal/opengl/glm/gtx/vector_angle.inl b/include/gal/opengl/glm/gtx/vector_angle.inl
new file mode 100644
index 0000000..ad221b1
--- /dev/null
+++ b/include/gal/opengl/glm/gtx/vector_angle.inl
@@ -0,0 +1,57 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// OpenGL Mathematics Copyright (c) 2005 - 2013 G-Truc Creation (www.g-truc.net)
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Created : 2005-12-30
+// Updated : 2008-09-29
+// Licence : This source is under MIT License
+// File    : glm/gtx/vector_angle.inl
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+namespace glm
+{
+	template <typename genType> 
+	GLM_FUNC_QUALIFIER typename genType::value_type angle
+	(
+		genType const & x, 
+		genType const & y
+	)
+	{
+		return degrees(acos(dot(x, y)));
+	}
+
+	//! \todo epsilon is hard coded to 0.01
+	template <typename valType> 
+	GLM_FUNC_QUALIFIER valType orientedAngle
+	(
+		detail::tvec2<valType> const & x, 
+		detail::tvec2<valType> const & y
+	)
+	{
+#ifdef GLM_FORCE_RADIANS
+		valType const Angle(acos(dot(x, y)));
+#else
+		valType const Angle(glm::degrees(acos(dot(x, y))));
+#endif
+		detail::tvec2<valType> const TransformedVector(glm::rotate(x, Angle));
+		if(all(epsilonEqual(y, TransformedVector, valType(0.01))))
+			return Angle;
+		else
+			return -Angle;
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER valType orientedAngle
+	(
+		detail::tvec3<valType> const & x,
+		detail::tvec3<valType> const & y,
+		detail::tvec3<valType> const & ref
+	)
+	{
+		valType const Angle(glm::degrees(glm::acos(glm::dot(x, y))));
+
+		if(glm::dot(ref, glm::cross(x, y)) < valType(0))
+			return -Angle;
+		else
+			return Angle;
+	}
+}//namespace glm