# QVector4D Class

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

Header: | #include <QVector4D> |

CMake: | find_package(Qt6 REQUIRED COMPONENTS Gui) target_link_libraries(mytarget PRIVATE Qt6::Gui) |

qmake: | QT += gui |

## Public Functions

QVector4D(QVector3D vector, float wpos) | |

QVector4D(QVector3D vector) | |

QVector4D(QVector2D vector, float zpos, float wpos) | |

QVector4D(QVector2D vector) | |

QVector4D(QPointF point) | |

QVector4D(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*=(QVector4D vector) |

QVector4D & | operator+=(QVector4D vector) |

QVector4D & | operator-=(QVector4D vector) |

QVector4D & | operator/=(float divisor) |

QVector4D & | operator/=(QVector4D vector) |

float & | operator[](int i) |

float | operator[](int i) const |

## Static Public Members

float | dotProduct(QVector4D v1, QVector4D v2) |

## Related Non-Members

bool | qFuzzyCompare(QVector4D v1, QVector4D v2) |

bool | operator!=(QVector4D v1, QVector4D v2) |

QVector4D | operator*(float factor, QVector4D vector) |

QVector4D | operator*(QVector4D vector, float factor) |

QVector4D | operator*(QVector4D v1, QVector4D v2) |

QVector4D | operator+(QVector4D v1, QVector4D v2) |

QVector4D | operator-(QVector4D v1, QVector4D v2) |

QVector4D | operator-(QVector4D vector) |

QVector4D | operator/(QVector4D vector, float divisor) |

QVector4D | operator/(QVector4D vector, QVector4D divisor) |

QDataStream & | operator<<(QDataStream &stream, QVector4D vector) |

bool | operator==(QVector4D v1, QVector4D v2) |

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

## Detailed Description

Vectors are one of the main building blocks of 4D affine representations of 3D space. They consist of four finite floating-point coordinates, traditionally called x, y, z and w.

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(QVector3D *vector*, float *wpos*)

Constructs a 4D vector from the specified 3D *vector*. The w coordinate is set to *wpos*, which must be finite.

**See also **toVector3D().

### QVector4D::QVector4D(QVector3D *vector*)

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

**See also **toVector3D().

### QVector4D::QVector4D(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, each of which must be finite.

**See also **toVector2D().

### QVector4D::QVector4D(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(QPointF *point*)

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

### QVector4D::QVector4D(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*). All parameters must be finite.

### QVector4D::QVector4D()

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

`[static] `

float QVector4D::dotProduct(QVector4D *v1*, 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 current 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 finite *w* coordinate.

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

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

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

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

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

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

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

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

Sets the z coordinate of this point to the given finite *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. The x and y coordinates are rounded to nearest integers.

**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 finite *factor*, and returns a reference to this vector.

**See also **operator/=() and operator*().

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

Multiplies each component of this vector by the corresponding component of *vector* and returns a reference to this vector.

**See also **operator/=() and operator*().

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

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

**See also **operator-=().

### QVector4D &QVector4D::operator-=(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. The *divisor* must not be either zero or NaN.

**See also **operator*=().

`[since 5.5] `

QVector4D &QVector4D::operator/=(QVector4D *vector*)

Divides each component of this vector by the corresponding component of *vector* and returns a reference to this vector.

The *vector* must have no component that is either zero or NaN.

This function was introduced in Qt 5.5.

**See also **operator*=() and operator/().

`[since 5.2] `

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.

`[since 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(QVector4D *v1*, QVector4D *v2*)

Returns `true`

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

### bool operator!=(QVector4D *v1*, QVector4D *v2*)

Returns `true`

if *v1* is not equal to *v2*; otherwise returns `false`

. This operator uses an exact floating-point comparison.

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

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

**See also **QVector4D::operator*=().

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

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

**See also **QVector4D::operator*=().

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

Returns the QVector4D object formed by multiplying each component of *v1* by the corresponding component of *v2*.

**Note: **This is not a cross product of *v1* and *v2* in any sense. (Its components add up to the dot product of *v1* and *v2*.)

**See also **QVector4D::operator*=().

### QVector4D operator+(QVector4D *v1*, 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+=().

### QVector4D operator-(QVector4D *v1*, QVector4D *v2*)

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

**See also **QVector4D::operator-=().

### QVector4D operator-(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`

.

### QVector4D operator/(QVector4D *vector*, float *divisor*)

Returns the QVector4D object formed by dividing each component of the given *vector* by the given *divisor*.

The *divisor* must not be either zero or NaN.

**See also **QVector4D::operator/=().

`[since 5.5] `

QVector4D operator/(QVector4D *vector*, QVector4D *divisor*)

Returns the QVector4D object formed by dividing each component of the given *vector* by the corresponding component of the given *divisor*.

The *divisor* must have no component that is either zero or NaN.

This function was introduced in Qt 5.5.

**See also **QVector4D::operator/=().

### QDataStream &operator<<(QDataStream &*stream*, 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==(QVector4D *v1*, 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.

© 2023 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.