Math: ability to normalize DualQuaternion.

Also hope that this is proper implementation.

src/Math/DualQuaternion.h

@@ -208,6 +208,11 @@ template<class T> class DualQuaternion: public Dual<Quaternion<T>> {
             return Math::sqrt(lengthSquared());
         }
 
+        /** @brief Normalized quaternion (of length 1) */
+        inline DualQuaternion<T> normalized() const {
+            return (*this)/length();
+        }
+
         /**
          * @brief Inverted dual quaternion
          *

src/Math/Test/DualQuaternionTest.cpp

@@ -31,6 +31,7 @@ class DualQuaternionTest: public Corrade::TestSuite::Tester {
 
         void lengthSquared();
         void length();
+        void normalized();
 
         void quaternionConjugated();
         void dualConjugated();
@@ -60,6 +61,7 @@ DualQuaternionTest::DualQuaternionTest() {
 
              &DualQuaternionTest::lengthSquared,
              &DualQuaternionTest::length,
+             &DualQuaternionTest::normalized,
 
              &DualQuaternionTest::quaternionConjugated,
              &DualQuaternionTest::dualConjugated,
@@ -103,6 +105,13 @@ void DualQuaternionTest::length() {
     CORRADE_COMPARE(a.length(), Dual(5.477226f, -0.821584f));
 }
 
+void DualQuaternionTest::normalized() {
+    DualQuaternion a({{1.0f, 2.0f, 3.0f}, -4.0f}, {{0.5f, -3.0f, 3.0f}, 2.0f});
+    DualQuaternion b({{0.182574f, 0.365148f, 0.547723f}, -0.730297f}, {{0.118673f, -0.49295f, 0.629881f}, 0.255604f});
+    CORRADE_COMPARE(a.normalized().length(), 1.0f);
+    CORRADE_COMPARE(a.normalized(), b);
+}
+
 void DualQuaternionTest::quaternionConjugated() {
     DualQuaternion a({{ 1.0f,  2.0f,  3.0f}, -4.0f}, {{ 0.5f, -3.1f,  3.3f}, 2.0f});
     DualQuaternion b({{-1.0f, -2.0f, -3.0f}, -4.0f}, {{-0.5f,  3.1f, -3.3f}, 2.0f});