Vector2: Add function to rotate a 2D vector

src/lib/matrix/matrix/Vector2.hpp

@@ -71,6 +71,31 @@ public:
 		return (*this).cross(b);
 	}
 
+	/**
+	 * @brief rotate vector
+	 *
+	 * @param[in] angle [rad] The angle around the positive out of plane axis.
+	 */
+	void rotate(const Type angle)
+	{
+		Vector2 &v(*this);
+		Type sin_angle = sin(angle);
+		Type cos_angle = cos(angle);
+		v = Vector2(
+			    cos_angle * v(0) - sin_angle * v(1),
+			    sin_angle * v(0) + cos_angle * v(1)
+		    );
+	}
+
+	/**
+	 * @brief Transform vector to new coordinate system
+	 *
+	 * @param[in] angle [rad] The rotation of new coordinate system around the positive out of plane axis.
+	 */
+	void transform(const Type angle)
+	{
+		this->rotate(-angle);
+	}
 };
 
 

src/lib/matrix/test/MatrixVector2Test.cpp

@@ -64,4 +64,20 @@ TEST(MatrixVector2Test, Vector2)
 	Vector2f h(g);
 	EXPECT_FLOAT_EQ(h(0), 1.23f);
 	EXPECT_FLOAT_EQ(h(1), 423.4f);
+
+	// rotate 2D vector
+	Vector2f i(1.0f, 0.0f);
+	i.rotate(M_PI_PRECISE / 4.f);
+	EXPECT_FLOAT_EQ(i(0), i(1));
+	i.rotate(M_PI_PRECISE / 4.f);
+	EXPECT_FLOAT_EQ(i(0), 0.f);
+	EXPECT_FLOAT_EQ(i(1), 1.f);
+
+	// transform vector
+	Vector2f j(1.0f, 0.0f);
+	j.transform(-M_PI_PRECISE / 4.f);
+	EXPECT_FLOAT_EQ(j(0), j(1));
+	j.transform(-M_PI_PRECISE / 4.f);
+	EXPECT_FLOAT_EQ(j(0), 0.f);
+	EXPECT_FLOAT_EQ(j(1), 1.f);
 }