Function for getting first two components of a vector.

src/Math/Test/Vector3Test.cpp

@@ -28,6 +28,7 @@ using namespace Corrade::Utility;
 namespace Magnum { namespace Math { namespace Test {
 
 typedef Math::Vector3<float> Vector3;
+typedef Math::Vector2<float> Vector2;
 
 void Vector3Test::construct() {
     QVERIFY((Vector3(1, 2, 3) == Vector<3, float>(1.0f, 2.0f, 3.0f)));
@@ -47,6 +48,10 @@ void Vector3Test::axis() {
     QVERIFY(Vector3::zAxis(7.0f) == Vector3(0.0f, 0.0f, 7.0f));
 }
 
+void Vector3Test::twoComponent() {
+    QVERIFY(Vector3(1.0f, 2.0f, 3.0f).xy() == Vector2(1.0f, 2.0f));
+}
+
 void Vector3Test::debug() {
     ostringstream o;
     Debug(&o) << Vector3(0.5f, 15.0f, 1.0f);

src/Math/Test/Vector3Test.h

@@ -26,6 +26,7 @@ class Vector3Test: public QObject {
         void construct();
         void cross();
         void axis();
+        void twoComponent();
 
         void debug();
 };

src/Math/Test/Vector4Test.cpp

@@ -29,6 +29,7 @@ namespace Magnum { namespace Math { namespace Test {
 
 typedef Math::Vector4<float> Vector4;
 typedef Math::Vector3<float> Vector3;
+typedef Math::Vector2<float> Vector2;
 
 void Vector4Test::construct() {
     QVERIFY(Vector4() == Vector4(0.0f, 0.0f, 0.0f, 1.0f));
@@ -40,6 +41,10 @@ void Vector4Test::threeComponent() {
     QVERIFY(Vector4(1.0f, 2.0f, 3.0f, 4.0f).xyz() == Vector3(1.0f, 2.0f, 3.0f));
 }
 
+void Vector4Test::twoComponent() {
+    QVERIFY(Vector4(1.0f, 2.0f, 3.0f, 4.0f).xy() == Vector2(1.0f, 2.0f));
+}
+
 void Vector4Test::debug() {
     ostringstream o;
     Debug(&o) << Vector4(0.5f, 15.0f, 1.0f, 1.0f);

src/Math/Test/Vector4Test.h

@@ -25,6 +25,7 @@ class Vector4Test: public QObject {
     private slots:
         void construct();
         void threeComponent();
+        void twoComponent();
 
         void debug();
 };

src/Math/Vector3.h

@@ -19,7 +19,7 @@
  * @brief Class Magnum::Math::Vector3
  */
 
-#include "Vector.h"
+#include "Vector2.h"
 
 namespace Magnum { namespace Math {
 
@@ -78,6 +78,12 @@ template<class T> class Vector3: public Vector<3, T> {
         inline void setY(T value) { (*this)[1] = value; }   /**< @brief Set Y component */
         inline void setZ(T value) { (*this)[2] = value; }   /**< @brief Set Z component */
 
+        /**
+         * @brief XY part of the vector
+         * @return First two components of the vector
+         */
+        inline constexpr Vector2<T> xy() const { return Vector2<T>::from(Vector<3, T>::data()); }
+
         inline constexpr T r() const { return x(); }        /**< @brief R component */
         inline constexpr T g() const { return x(); }        /**< @brief G component */
         inline constexpr T b() const { return z(); }        /**< @brief B component */

src/Math/Vector4.h

@@ -71,6 +71,12 @@ template<class T> class Vector4: public Vector<4, T> {
          */
         inline constexpr Vector3<T> xyz() const { return Vector3<T>::from(Vector<4, T>::data()); }
 
+        /**
+         * @brief XY part of the vector
+         * @return First two components of the vector
+         */
+        inline constexpr Vector2<T> xy() const { return Vector2<T>::from(Vector<4, T>::data()); }
+
         inline constexpr T r() const { return x(); }    /**< @brief R component */
         inline constexpr T g() const { return y(); }    /**< @brief G component */
         inline constexpr T b() const { return z(); }    /**< @brief B component */