Add operator[] to QVectorND classes

Change-Id: Ia786d4fab64da974bb60f24c05325925d42a1e70
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/gui/math3d/qvector2d.cpp

@@ -160,6 +160,25 @@ QVector2D::QVector2D(const QVector4D& vector)
     \sa y(), setX()
 */
 
+/*! \fn float &QVector2D::operator[](int i)
+    \since 5.2
+
+    Returns the component of the vector at index position \a i
+    as a modifiable reference.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 2).
+*/
+
+/*! \fn float QVector2D::operator[](int i) const
+    \since 5.2
+
+    Returns the component of the vector at index position \a i.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 2).
+*/
+
 /*!
     Returns the length of the vector from the origin.
 

src/gui/math3d/qvector2d.h

@@ -76,6 +76,9 @@ public:
     void setX(float x);
     void setY(float y);
 
+    float &operator[](int i);
+    float operator[](int i) const;
+
     float length() const;
     float lengthSquared() const;
 
@@ -145,6 +148,18 @@ inline float QVector2D::y() const { return yp; }
 inline void QVector2D::setX(float aX) { xp = aX; }
 inline void QVector2D::setY(float aY) { yp = aY; }
 
+inline float &QVector2D::operator[](int i)
+{
+    Q_ASSERT(uint(i) < 2u);
+    return *(&xp + i);
+}
+
+inline float QVector2D::operator[](int i) const
+{
+    Q_ASSERT(uint(i) < 2u);
+    return *(&xp + i);
+}
+
 inline QVector2D &QVector2D::operator+=(const QVector2D &vector)
 {
     xp += vector.xp;

src/gui/math3d/qvector3d.cpp

@@ -196,6 +196,25 @@ QVector3D::QVector3D(const QVector4D& vector)
     \sa z(), setX(), setY()
 */
 
+/*! \fn float &QVector3D::operator[](int i)
+    \since 5.2
+
+    Returns the component of the vector at index position \a i
+    as a modifiable reference.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 3).
+*/
+
+/*! \fn float QVector3D::operator[](int i) const
+    \since 5.2
+
+    Returns the component of the vector at index position \a i.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 3).
+*/
+
 /*!
     Returns the normalized unit vector form of this vector.
 

src/gui/math3d/qvector3d.h

@@ -79,6 +79,9 @@ public:
     void setY(float y);
     void setZ(float z);
 
+    float &operator[](int i);
+    float operator[](int i) const;
+
     float length() const;
     float lengthSquared() const;
 
@@ -160,6 +163,18 @@ inline void QVector3D::setX(float aX) { xp = aX; }
 inline void QVector3D::setY(float aY) { yp = aY; }
 inline void QVector3D::setZ(float aZ) { zp = aZ; }
 
+inline float &QVector3D::operator[](int i)
+{
+    Q_ASSERT(uint(i) < 3u);
+    return *(&xp + i);
+}
+
+inline float QVector3D::operator[](int i) const
+{
+    Q_ASSERT(uint(i) < 3u);
+    return *(&xp + i);
+}
+
 inline QVector3D &QVector3D::operator+=(const QVector3D &vector)
 {
     xp += vector.xp;

src/gui/math3d/qvector4d.cpp

@@ -225,6 +225,25 @@ QVector4D::QVector4D(const QVector3D& vector, float wpos)
     \sa w(), setX(), setY(), setZ()
 */
 
+/*! \fn float &QVector4D::operator[](int i)
+    \since 5.2
+
+    Returns the component of the vector at index position \a i
+    as a modifiable reference.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 4).
+*/
+
+/*! \fn float QVector4D::operator[](int i) const
+    \since 5.2
+
+    Returns the component of the vector at index position \a i.
+
+    \a i must be a valid index position in the vector (i.e., 0 <= \a i
+    < 4).
+*/
+
 /*!
     Returns the length of the vector from the origin.
 

src/gui/math3d/qvector4d.h

@@ -82,6 +82,9 @@ public:
     void setZ(float z);
     void setW(float w);
 
+    float &operator[](int i);
+    float operator[](int i) const;
+
     float length() const;
     float lengthSquared() const;
 
@@ -158,6 +161,18 @@ inline void QVector4D::setY(float aY) { yp = aY; }
 inline void QVector4D::setZ(float aZ) { zp = aZ; }
 inline void QVector4D::setW(float aW) { wp = aW; }
 
+inline float &QVector4D::operator[](int i)
+{
+    Q_ASSERT(uint(i) < 4u);
+    return *(&xp + i);
+}
+
+inline float QVector4D::operator[](int i) const
+{
+    Q_ASSERT(uint(i) < 4u);
+    return *(&xp + i);
+}
+
 inline QVector4D &QVector4D::operator+=(const QVector4D &vector)
 {
     xp += vector.xp;

tests/auto/gui/math3d/qvectornd/tst_qvectornd.cpp

@@ -57,6 +57,10 @@ private slots:
     void create3();
     void create4();
 
+    void modify2();
+    void modify3();
+    void modify4();
+
     void length2_data();
     void length2();
     void length3_data();
@@ -570,6 +574,82 @@ void tst_QVectorND::create4()
     QVERIFY(v14.isNull());
 }
 
+// Test modifying vectors in various ways
+void tst_QVectorND::modify2()
+{
+    const float e = 2.7182818f;
+    const float pi = 3.14159f;
+    const QVector2D p(e, pi);
+
+    QVector2D p1;
+    p1.setX(e);
+    p1.setY(pi);
+    QVERIFY(qFuzzyCompare(p, p1));
+
+    QVector2D p2;
+    p2[0] = e;
+    p2[1] = pi;
+    QVERIFY(qFuzzyCompare(p, p2));
+
+    QVector2D p3;
+    for (int i = 0; i < 2; ++i)
+        p3[i] = p[i];
+    QVERIFY(qFuzzyCompare(p, p3));
+}
+
+void tst_QVectorND::modify3()
+{
+    const float one = 1.0f;
+    const float e = 2.7182818f;
+    const float pi = 3.14159f;
+    const QVector3D p(one, e, pi);
+
+    QVector3D p1;
+    p1.setX(one);
+    p1.setY(e);
+    p1.setZ(pi);
+    QVERIFY(qFuzzyCompare(p, p1));
+
+    QVector3D p2;
+    p2[0] = one;
+    p2[1] = e;
+    p2[2] = pi;
+    QVERIFY(qFuzzyCompare(p, p2));
+
+    QVector3D p3;
+    for (int i = 0; i < 3; ++i)
+        p3[i] = p[i];
+    QVERIFY(qFuzzyCompare(p, p3));
+}
+
+void tst_QVectorND::modify4()
+{
+    const float one = 1.0f;
+    const float e = 2.7182818f;
+    const float pi = 3.14159f;
+    const float big = 1.0e6f;
+    const QVector4D p(one, e, pi, big);
+
+    QVector4D p1;
+    p1.setX(one);
+    p1.setY(e);
+    p1.setZ(pi);
+    p1.setW(big);
+    QVERIFY(qFuzzyCompare(p, p1));
+
+    QVector4D p2;
+    p2[0] = one;
+    p2[1] = e;
+    p2[2] = pi;
+    p2[3] = big;
+    QVERIFY(qFuzzyCompare(p, p2));
+
+    QVector4D p3;
+    for (int i = 0; i < 4; ++i)
+        p3[i] = p[i];
+    QVERIFY(qFuzzyCompare(p, p3));
+}
+
 // Test vector length computation for 2D vectors.
 void tst_QVectorND::length2_data()
 {