Math: converting Vector2 to Complex and back.

src/Math/Complex.h

@@ -24,6 +24,7 @@
 #include <Utility/Debug.h>
 
 #include "Math/Matrix.h"
+#include "Math/Vector2.h"
 
 namespace Magnum { namespace Math {
 
@@ -94,6 +95,16 @@ template<class T> class Complex {
          */
         inline constexpr /*implicit*/ Complex(T real, T imaginary = T(0)): _real(real), _imaginary(imaginary) {}
 
+        /**
+         * @brief Construct complex number from vector
+         *
+         * To be used in transformations later. @f[
+         *      c = v_x + iv_y
+         * @f]
+         * @see operator Vector2(), transformVector(), transformVectorNormalized()
+         */
+        inline constexpr explicit Complex(const Vector2<T>& vector): _real(vector.x()), _imaginary(vector.y()) {}
+
         /** @brief Equality comparison */
         inline bool operator==(const Complex<T>& other) const {
             return MathTypeTraits<T>::equals(_real, other._real) &&
@@ -111,6 +122,17 @@ template<class T> class Complex {
         /** @brief Imaginary part */
         inline constexpr T imaginary() const { return _imaginary; }
 
+        /**
+         * @brief Convert complex number to vector
+         *
+         * @f[
+         *      \boldsymbol v = \begin{pmatrix} a \\ b \end{pmatrix}
+         * @f]
+         */
+        inline constexpr explicit operator Vector2<T>() const {
+            return {_real, _imaginary};
+        }
+
         /**
          * @brief Rotation angle of complex number
          *

src/Math/Test/ComplexTest.cpp

@@ -27,6 +27,7 @@ class ComplexTest: public Corrade::TestSuite::Tester {
 
         void construct();
         void constructDefault();
+        void constructFromVector();
         void compare();
 
         void constExpressions();
@@ -55,6 +56,7 @@ class ComplexTest: public Corrade::TestSuite::Tester {
 ComplexTest::ComplexTest() {
     addTests(&ComplexTest::construct,
              &ComplexTest::constructDefault,
+             &ComplexTest::constructFromVector,
              &ComplexTest::compare,
 
              &ComplexTest::constExpressions,
@@ -100,6 +102,14 @@ void ComplexTest::constructDefault() {
     CORRADE_COMPARE(Complex().length(), 1.0f);
 }
 
+void ComplexTest::constructFromVector() {
+    Vector2 vec(1.5f, -3.0f);
+
+    Complex a(vec);
+    CORRADE_COMPARE(a, Complex(1.5f, -3.0f));
+    CORRADE_COMPARE(Vector2(a), vec);
+}
+
 void ComplexTest::compare() {
     CORRADE_VERIFY(Complex(3.7f, -1.0f+MathTypeTraits<float>::epsilon()/2) == Complex(3.7f, -1.0f));
     CORRADE_VERIFY(Complex(3.7f, -1.0f+MathTypeTraits<float>::epsilon()*2) != Complex(3.7f, -1.0f));