- Qt 5.15
- Qt GUI
- C++ Classes
- QVector4D
- Qt 5.15.18 Reference Documentation

# QVector4D Class

The QVector4D class represents a vector or vertex in 4D space. More...

Header: | #include <QVector4D>
qmake: | QT += gui
Since: | Qt 4.6

This class was introduced in Qt 4.6.

- List of all members, including inherited members

## Public Functions

| QVector4D(const QVector3D &vector, float wpos)
| QVector4D(const QVector3D &vector)
| QVector4D(const QVector2D &vector, float zpos, float wpos)
| QVector4D(const QVector2D &vector)
| QVector4D(const QPointF &point)
| QVector4D(const QPoint &point)
| QVector4D(float xpos, float ypos, float zpos, float wpos)
| QVector4D()
bool | isNull() const
float | length() const
float | lengthSquared() const
void | normalize()
QVector4D | normalized() const
void | setW(float w)
void | setX(float x)
void | setY(float y)
void | setZ(float z)
QPoint | toPoint() const
QPointF | toPointF() const
QVector2D | toVector2D() const
QVector2D | toVector2DAffine() const
QVector3D | toVector3D() const
QVector3D | toVector3DAffine() const
float | w() const
float | x() const
float | y() const
float | z() const
QVariant | operator QVariant() const
QVector4D & | operator*=(float factor)
QVector4D & | operator*=(const QVector4D &vector)
QVector4D & | operator+=(const QVector4D &vector)
QVector4D & | operator-=(const QVector4D &vector)
QVector4D & | operator/=(float divisor)
QVector4D & | operator/=(const QVector4D &vector)
float & | operator[](int i)
float | operator[](int i) const

## Static Public Members

float | dotProduct(const QVector4D &v1, const QVector4D &v2)

## Related Non-Members

bool | qFuzzyCompare(const QVector4D &v1, const QVector4D &v2)
bool | operator!=(const QVector4D &v1, const QVector4D &v2)
const QVector4D | operator*(float factor, const QVector4D &vector)
const QVector4D | operator*(const QVector4D &vector, float factor)
const QVector4D | operator*(const QVector4D &v1, const QVector4D &v2)
const QVector4D | operator+(const QVector4D &v1, const QVector4D &v2)
const QVector4D | operator-(const QVector4D &v1, const QVector4D &v2)
const QVector4D | operator-(const QVector4D &vector)
const QVector4D | operator/(const QVector4D &vector, float divisor)
const QVector4D | operator/(const QVector4D &vector, const QVector4D &divisor)
QDataStream & | operator<<(QDataStream &stream, const QVector4D &vector)
bool | operator==(const QVector4D &v1, const QVector4D &v2)
QDataStream & | operator>>(QDataStream &stream, QVector4D &vector)

## Detailed Description

The QVector4D class can also be used to represent vertices in 4D space. We therefore do not need to provide a separate vertex class.

See also QQuaternion, QVector2D, and QVector3D.

## Member Function Documentation

### QVector4D::QVector4D(const QVector3D &vector, float wpos)

Constructs a 4D vector from the specified 3D vector. The w coordinate is set to wpos.

See also toVector3D().

### QVector4D::QVector4D(const QVector3D &vector)

Constructs a 4D vector from the specified 3D vector. The w coordinate is set to zero.

See also toVector3D().

### QVector4D::QVector4D(const QVector2D &vector, float zpos, float wpos)

Constructs a 4D vector from the specified 2D vector. The z and w coordinates are set to zpos and wpos respectively.

See also toVector2D().

### QVector4D::QVector4D(const QVector2D &vector)

Constructs a 4D vector from the specified 2D vector. The z and w coordinates are set to zero.

See also toVector2D().

### QVector4D::QVector4D(const QPointF &point)

Constructs a vector with x and y coordinates from a 2D point, and z and w coordinates of 0.

### QVector4D::QVector4D(const QPoint &point)

Constructs a vector with x and y coordinates from a 2D point, and z and w coordinates of 0.

### QVector4D::QVector4D(float xpos, float ypos, float zpos, float wpos)

Constructs a vector with coordinates (xpos, ypos, zpos, wpos).

### QVector4D::QVector4D()

Constructs a null vector, i.e. with coordinates (0, 0, 0, 0).

### `[static]` float QVector4D::dotProduct(const QVector4D &v1, const QVector4D &v2)

Returns the dot product of v1 and v2.

### bool QVector4D::isNull() const

Returns `true` if the x, y, z, and w coordinates are set to 0.0, otherwise returns `false`.

### float QVector4D::length() const

Returns the length of the vector from the origin.

See also lengthSquared() and normalized().

### float QVector4D::lengthSquared() const

Returns the squared length of the vector from the origin. This is equivalent to the dot product of the vector with itself.

See also length() and dotProduct().

### void QVector4D::normalize()

Normalizes the currect vector in place. Nothing happens if this vector is a null vector or the length of the vector is very close to 1.

See also length() and normalized().

### QVector4D QVector4D::normalized() const

Returns the normalized unit vector form of this vector.

If this vector is null, then a null vector is returned. If the length of the vector is very close to 1, then the vector will be returned as-is. Otherwise the normalized form of the vector of length 1 will be returned.

See also length() and normalize().

### void QVector4D::setW(float w)

Sets the w coordinate of this point to the given w coordinate.

See also w(), setX(), setY(), and setZ().

### void QVector4D::setX(float x)

Sets the x coordinate of this point to the given x coordinate.

See also x(), setY(), setZ(), and setW().

### void QVector4D::setY(float y)

Sets the y coordinate of this point to the given y coordinate.

See also y(), setX(), setZ(), and setW().

### void QVector4D::setZ(float z)

Sets the z coordinate of this point to the given z coordinate.

See also z(), setX(), setY(), and setW().

### QPoint QVector4D::toPoint() const

Returns the QPoint form of this 4D vector. The z and w coordinates are dropped.

See also toPointF() and toVector2D().

### QPointF QVector4D::toPointF() const

Returns the QPointF form of this 4D vector. The z and w coordinates are dropped.

See also toPoint() and toVector2D().

### QVector2D QVector4D::toVector2D() const

Returns the 2D vector form of this 4D vector, dropping the z and w coordinates.

See also toVector2DAffine(), toVector3D(), and toPoint().

### QVector2D QVector4D::toVector2DAffine() const

Returns the 2D vector form of this 4D vector, dividing the x and y coordinates by the w coordinate and dropping the z coordinate. Returns a null vector if w is zero.

See also toVector2D(), toVector3DAffine(), and toPoint().

### QVector3D QVector4D::toVector3D() const

Returns the 3D vector form of this 4D vector, dropping the w coordinate.

See also toVector3DAffine(), toVector2D(), and toPoint().

### QVector3D QVector4D::toVector3DAffine() const

Returns the 3D vector form of this 4D vector, dividing the x, y, and z coordinates by the w coordinate. Returns a null vector if w is zero.

See also toVector3D(), toVector2DAffine(), and toPoint().

### float QVector4D::w() const

Returns the w coordinate of this point.

See also setW(), x(), y(), and z().

### float QVector4D::x() const

Returns the x coordinate of this point.

See also setX(), y(), z(), and w().

### float QVector4D::y() const

Returns the y coordinate of this point.

See also setY(), x(), z(), and w().

### float QVector4D::z() const

Returns the z coordinate of this point.

See also setZ(), x(), y(), and w().

### QVariant QVector4D::operator QVariant() const

Returns the 4D vector as a QVariant.

### QVector4D &QVector4D::operator*=(float factor)

Multiplies this vector's coordinates by the given factor, and returns a reference to this vector.

See also operator/=().

### QVector4D &QVector4D::operator*=(const QVector4D &vector)

Multiplies the components of this vector by the corresponding components in vector.

### QVector4D &QVector4D::operator+=(const QVector4D &vector)

Adds the given vector to this vector and returns a reference to this vector.

See also operator-=().

### QVector4D &QVector4D::operator-=(const QVector4D &vector)

Subtracts the given vector from this vector and returns a reference to this vector.

See also operator+=().

### QVector4D &QVector4D::operator/=(float divisor)

Divides this vector's coordinates by the given divisor, and returns a reference to this vector.

See also operator*=().

### QVector4D &QVector4D::operator/=(const QVector4D &vector)

Divides the components of this vector by the corresponding components in vector.

This function was introduced in Qt 5.5.

See also operator*=().

### float &QVector4D::operator[](int i)

Returns the component of the vector at index position i as a modifiable reference.

i must be a valid index position in the vector (i.e., 0 <= i < 4).

This function was introduced in Qt 5.2.

### float QVector4D::operator[](int i) const

Returns the component of the vector at index position i.

i must be a valid index position in the vector (i.e., 0 <= i < 4).

This function was introduced in Qt 5.2.

## Related Non-Members

### bool qFuzzyCompare(const QVector4D &v1, const QVector4D &v2)

Returns `true` if v1 and v2 are equal, allowing for a small fuzziness factor for floating-point comparisons; false otherwise.

### bool operator!=(const QVector4D &v1, const QVector4D &v2)

Returns `true` if v1 is not equal to v2; otherwise returns `false`. This operator uses an exact floating-point comparison.

### const QVector4D operator*(float factor, const QVector4D &vector)

Returns a copy of the given vector, multiplied by the given factor.

See also QVector4D::operator*=().

### const QVector4D operator*(const QVector4D &vector, float factor)

Returns a copy of the given vector, multiplied by the given factor.

See also QVector4D::operator*=().

### const QVector4D operator*(const QVector4D &v1, const QVector4D &v2)

Returns the vector consisting of the multiplication of the components from v1 and v2.

See also QVector4D::operator*=().

### const QVector4D operator+(const QVector4D &v1, const QVector4D &v2)

Returns a QVector4D object that is the sum of the given vectors, v1 and v2; each component is added separately.

See also QVector4D::operator+=().

### const QVector4D operator-(const QVector4D &v1, const QVector4D &v2)

Returns a QVector4D object that is formed by subtracting v2 from v1; each component is subtracted separately.

See also QVector4D::operator-=().

### const QVector4D operator-(const QVector4D &vector)

This is an overloaded function.

Returns a QVector4D object that is formed by changing the sign of all three components of the given vector.

Equivalent to `QVector4D(0,0,0,0) - vector`.

### const QVector4D operator/(const QVector4D &vector, float divisor)

Returns the QVector4D object formed by dividing all four components of the given vector by the given divisor.

See also QVector4D::operator/=().

### const QVector4D operator/(const QVector4D &vector, const QVector4D &divisor)

Returns the QVector4D object formed by dividing components of the given vector by a respective components of the given divisor.

This function was introduced in Qt 5.5.

See also QVector4D::operator/=().

### QDataStream &operator<<(QDataStream &stream, const QVector4D &vector)

Writes the given vector to the given stream and returns a reference to the stream.

See also Serializing Qt Data Types.

### bool operator==(const QVector4D &v1, const QVector4D &v2)

Returns `true` if v1 is equal to v2; otherwise returns `false`. This operator uses an exact floating-point comparison.

### QDataStream &operator>>(QDataStream &stream, QVector4D &vector)

Reads a 4D vector from the given stream into the given vector and returns a reference to the stream.

See also Serializing Qt Data Types.