Fixed quat slerp using mix function when cosTheta close to 1

glm/gtc/quaternion.inl

@@ -451,20 +451,20 @@ namespace detail
 		T const & a
 	)
 	{
-        T cosTheta = dot(x, y);
-        if(cosTheta <= epsilon<T>())
-        {
-            return detail::tquat<T>(
-                mix(x.x, y.x, a),
-                mix(x.y, y.y, a),
-                mix(x.z, y.z, a),
-                mix(x.w, y.w, a));
-        }
-        else
-        {
-            T angle = acos(cosTheta);
-            return (glm::sin((T(1) - a) * angle) * x + glm::sin(a * angle) * y) / glm::sin(angle);
-        }
+		T cosTheta = dot(x, y);
+		if(glm::abs(cosTheta - T(1)) <= epsilon<T>())
+		{
+			return detail::tquat<T>(
+				mix(x.x, y.x, a),
+				mix(x.y, y.y, a),
+				mix(x.z, y.z, a),
+				mix(x.w, y.w, a));
+		}
+		else
+		{
+			T angle = acos(cosTheta);
+			return (glm::sin((T(1) - a) * angle) * x + glm::sin(a * angle) * y) / glm::sin(angle);
+		}
 	}
 
 	template <typename T> 

readme.txt

@@ -44,6 +44,7 @@ GLM 0.9.4.1: 2012-12-17
 - Fixed interaction between quaternion and euler angles.
 - Fixed GTC_constants build
 - Fixed GTX_multiple
+- Fixed quat slerp using mix function when cosTheta close to 1
 
 ================================================================================
 GLM 0.9.4.0: 2012-11-18