Math: function for projecting vector onto another.

src/Math/Test/VectorTest.cpp

@@ -38,6 +38,7 @@ VectorTest::VectorTest() {
              &VectorTest::dotSelf,
              &VectorTest::length,
              &VectorTest::normalized,
+             &VectorTest::projected,
              &VectorTest::sum,
              &VectorTest::product,
              &VectorTest::min,
@@ -93,6 +94,14 @@ void VectorTest::normalized() {
     CORRADE_COMPARE(Vector4(1.0f, 1.0f, 1.0f, 1.0f).normalized(), Vector4(0.5f, 0.5f, 0.5f, 0.5f));
 }
 
+void VectorTest::projected() {
+    Vector3 line(1.0f, -1.0f, 0.5f);
+    Vector3 projected = Vector3(1.0f, 2.0f, 3.0f).projected(line);
+
+    CORRADE_COMPARE(projected, Vector3(0.222222f, -0.222222f, 0.111111f));
+    CORRADE_COMPARE(projected.normalized(), line.normalized());
+}
+
 void VectorTest::sum() {
     CORRADE_COMPARE(Vector3(1.0f, 2.0f, 4.0f).sum(), 7.0f);
 }

src/Math/Test/VectorTest.h

@@ -30,6 +30,7 @@ class VectorTest: public Corrade::TestSuite::Tester {
         void dotSelf();
         void length();
         void normalized();
+        void projected();
         void sum();
         void product();
         void min();

src/Math/Vector.h

@@ -224,6 +224,15 @@ template<std::size_t size, class T> class Vector: public RectangularMatrix<1, si
             return *this/length();
         }
 
+        /**
+         * @brief Vector projected onto another
+         *
+         * Returns vector projected onto line defined by @p other.
+         */
+        inline Vector<size, T> projected(const Vector<size, T>& other) const {
+            return other*dot(*this, other)/other.dot();
+        }
+
         /** @brief Sum of values in the vector */
         T sum() const {
             T out(0);