Math: added sign() function.

src/Math/Functions.h

@@ -161,6 +161,28 @@ template<std::size_t size, class T> Vector<size, T> max(const Vector<size, T>& a
 }
 #endif
 
+/**
+@brief Sign
+
+Returns `1.0` if @f$ x > 0 @f$, `0.0` if @f$ @p x = 0 @f$ and `-1.0` if
+@f$ x < 0 @f$.
+*/
+#ifdef DOXYGEN_GENERATING_OUTPUT
+template<class T> inline T sign(const T scalar);
+#else
+template<class T> inline typename std::enable_if<std::is_arithmetic<T>::value, T>::type sign(const T& scalar) {
+    if(scalar > T(0)) return T(1);
+    if(scalar < T(0)) return T(-1);
+    return T(0);
+}
+template<std::size_t size, class T> Vector<size, T> sign(const Vector<size, T>& a) {
+    Vector<size, T> out;
+    for(std::size_t i = 0; i != size; ++i)
+        out[i] = sign(a[i]);
+    return out;
+}
+#endif
+
 /** @brief Absolute value */
 #ifdef DOXYGEN_GENERATING_OUTPUT
 template<class T> inline T abs(const T& a);

src/Math/Test/FunctionsTest.cpp

@@ -35,6 +35,7 @@ class FunctionsTest: public Corrade::TestSuite::Tester {
 
         void min();
         void max();
+        void sign();
         void abs();
         void sqrt();
         void clamp();
@@ -66,6 +67,7 @@ typedef Math::Vector3<Int> Vector3i;
 FunctionsTest::FunctionsTest() {
     addTests({&FunctionsTest::min,
               &FunctionsTest::max,
+              &FunctionsTest::sign,
               &FunctionsTest::abs,
               &FunctionsTest::sqrt,
               &FunctionsTest::clamp,
@@ -96,6 +98,13 @@ void FunctionsTest::max() {
     CORRADE_COMPARE(Math::max(Vector3i(5, -3, 2), Vector3i(9, -5, 18)), Vector3i(9, -3, 18));
 }
 
+void FunctionsTest::sign() {
+    CORRADE_COMPARE(Math::sign(3516), 1);
+    CORRADE_COMPARE(Math::sign(0.0f), 0.0f);
+    CORRADE_COMPARE(Math::sign(-3.7), -1.0);
+    CORRADE_COMPARE(Math::sign(Vector3i(0, -3, 2)), Vector3i(0, -1, 1));
+}
+
 void FunctionsTest::abs() {
     CORRADE_COMPARE(Math::abs(-5), 5);
     CORRADE_COMPARE(Math::abs(5), 5);