+inline float length_squared(const glm::vec3 &v) noexcept {
+ return dot(v, v);
+}
+
+inline float distance_squared(const glm::vec3 &a, const glm::vec3 &b) noexcept {
+ return length_squared(a - b);
+}
+
+
+template <class T>
+inline bool iszero(const T &v) noexcept {
+ return length_squared(v) < std::numeric_limits<typename T::value_type>::epsilon();
+}
+
+