Math: use Rad for Vector::angle().

src/Math/Test/VectorTest.cpp

@@ -63,6 +63,7 @@ class VectorTest: public Corrade::TestSuite::Tester {
         void configuration();
 };
 
+typedef Math::Rad<float> Rad;
 typedef Vector<3, float> Vector3;
 typedef Vector<4, float> Vector4;
 typedef Vector<4, std::int32_t> Vector4i;
@@ -305,17 +306,18 @@ void VectorTest::projectedOntoNormalized() {
 void VectorTest::angle() {
     std::ostringstream o;
     Error::setOutput(&o);
-    CORRADE_COMPARE(Vector3::angle(Vector3(2.0f, 3.0f, 4.0f).normalized(), {1.0f, -2.0f, 3.0f}),
-                    std::numeric_limits<Vector3::Type>::quiet_NaN());
+    auto angle = Vector3::angle(Vector3(2.0f, 3.0f, 4.0f).normalized(), {1.0f, -2.0f, 3.0f});
+    CORRADE_VERIFY(angle != angle);
     CORRADE_COMPARE(o.str(), "Math::Vector::angle(): vectors must be normalized\n");
 
     o.str("");
-    CORRADE_COMPARE(Vector3::angle({2.0f, 3.0f, 4.0f}, Vector3(1.0f, -2.0f, 3.0f).normalized()),
-                    std::numeric_limits<Vector3::Type>::quiet_NaN());
+    angle = Vector3::angle({2.0f, 3.0f, 4.0f}, Vector3(1.0f, -2.0f, 3.0f).normalized());
+    CORRADE_VERIFY(angle != angle);
     CORRADE_COMPARE(o.str(), "Math::Vector::angle(): vectors must be normalized\n");
 
-    CORRADE_COMPARE(Vector3::angle(Vector3(2.0f, 3.0f, 4.0f).normalized(), Vector3(1.0f, -2.0f, 3.0f).normalized()),
-                    rad(1.162514f));
+    CORRADE_COMPARE(Vector3::angle(Vector3(2.0f,  3.0f, 4.0f).normalized(),
+                                   Vector3(1.0f, -2.0f, 3.0f).normalized()),
+                    Rad(1.162514f));
 }
 
 void VectorTest::debug() {

src/Math/Vector.h

@@ -25,6 +25,7 @@
 #include <Utility/Debug.h>
 #include <Utility/ConfigurationValue.h>
 
+#include "Math/Angle.h"
 #include "Math/BoolVector.h"
 #include "Math/MathTypeTraits.h"
 
@@ -78,16 +79,16 @@ template<std::size_t size, class T> class Vector {
         }
 
         /**
-         * @brief Angle between normalized vectors (in radians)
+         * @brief Angle between normalized vectors
          *
          * Expects that both vectors are normalized. @f[
          *      \theta = acos \left( \frac{\boldsymbol a \cdot \boldsymbol b}{|\boldsymbol a| \cdot |\boldsymbol b|} \right) = acos (\boldsymbol a \cdot \boldsymbol b)
          * @f]
          */
-        inline static T angle(const Vector<size, T>& normalizedA, const Vector<size, T>& normalizedB) {
+        inline static Rad<T> angle(const Vector<size, T>& normalizedA, const Vector<size, T>& normalizedB) {
             CORRADE_ASSERT(MathTypeTraits<T>::equals(normalizedA.dot(), T(1)) && MathTypeTraits<T>::equals(normalizedB.dot(), T(1)),
-                           "Math::Vector::angle(): vectors must be normalized", std::numeric_limits<T>::quiet_NaN());
-            return std::acos(dot(normalizedA, normalizedB));
+                           "Math::Vector::angle(): vectors must be normalized", Rad<T>(std::numeric_limits<T>::quiet_NaN()));
+            return Rad<T>(std::acos(dot(normalizedA, normalizedB)));
         }
 
         /**