QQuaternion Class

Member Function Documentation

QQuaternion::QQuaternion()

Constructs an identity quaternion, i.e. with coordinates (1, 0, 0, 0).

QQuaternion::QQuaternion(qreal scalar, qreal xpos, qreal ypos, qreal zpos)

Constructs a quaternion with the vector (xpos, ypos, zpos) and scalar.

QQuaternion::QQuaternion(qreal scalar, const QVector3D & vector)

Constructs a quaternion vector from the specified vector and scalar.

See also vector() and scalar().

QQuaternion::QQuaternion(const QVector4D & vector)

Constructs a quaternion from the components of vector.

QQuaternion QQuaternion::conjugate() const

Returns the conjugate of this quaternion, which is (-x, -y, -z, scalar).

QQuaternion QQuaternion::fromAxisAndAngle(const QVector3D & axis, qreal angle) [static]

Creates a normalized quaternion that corresponds to rotating through angle degrees about the specified 3D axis.

QQuaternion QQuaternion::fromAxisAndAngle(qreal x, qreal y, qreal z, qreal angle) [static]

Creates a normalized quaternion that corresponds to rotating through angle degrees about the 3D axis (x, y, z).

bool QQuaternion::isIdentity() const

Returns true if the x, y, and z components of this quaternion are set to 0.0, and the scalar component is set to 1.0; otherwise returns false.

bool QQuaternion::isNull() const

Returns true if the x, y, z, and scalar components of this quaternion are set to 0.0; otherwise returns false.

qreal QQuaternion::length() const

Returns the length of the quaternion. This is also called the "norm".

See also lengthSquared() and normalized().

qreal QQuaternion::lengthSquared() const

Returns the squared length of the quaternion.

See also length().

QQuaternion QQuaternion::nlerp(const QQuaternion & q1, const QQuaternion & q2, qreal t) [static]

Interpolates along the shortest linear path between the rotational positions q1 and q2. The value t should be between 0 and 1, indicating the distance to travel between q1 and q2. The result will be normalized().

If t is less than or equal to 0, then q1 will be returned. If t is greater than or equal to 1, then q2 will be returned.

The nlerp() function is typically faster than slerp() and will give approximate results to spherical interpolation that are good enough for some applications.

See also slerp().

void QQuaternion::normalize()

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

See also length() and normalized().

QQuaternion QQuaternion::normalized() const

Returns the normalized unit form of this quaternion.

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

See also length() and normalize().

QVector3D QQuaternion::rotatedVector(const QVector3D & vector) const

Rotates vector with this quaternion to produce a new vector in 3D space. The following code:

 QVector3D result = q.rotatedVector(vector);

is equivalent to the following:

 QVector3D result = (q * QQuaternion(0, vector) * q.conjugate()).vector();

qreal QQuaternion::scalar() const

Returns the scalar component of this quaternion.

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

void QQuaternion::setScalar(qreal scalar)

Sets the scalar component of this quaternion to scalar.

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

void QQuaternion::setVector(const QVector3D & vector)

Sets the vector component of this quaternion to vector.

See also vector() and setScalar().

void QQuaternion::setVector(qreal x, qreal y, qreal z)

Sets the vector component of this quaternion to (x, y, z).

See also vector() and setScalar().

void QQuaternion::setX(qreal x)

Sets the x coordinate of this quaternion's vector to the given x coordinate.

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

void QQuaternion::setY(qreal y)

Sets the y coordinate of this quaternion's vector to the given y coordinate.

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

void QQuaternion::setZ(qreal z)

Sets the z coordinate of this quaternion's vector to the given z coordinate.

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

QQuaternion QQuaternion::slerp(const QQuaternion & q1, const QQuaternion & q2, qreal t) [static]

Interpolates along the shortest spherical path between the rotational positions q1 and q2. The value t should be between 0 and 1, indicating the spherical distance to travel between q1 and q2.

If t is less than or equal to 0, then q1 will be returned. If t is greater than or equal to 1, then q2 will be returned.

See also nlerp().

QVector4D QQuaternion::toVector4D() const

Returns this quaternion as a 4D vector.

QVector3D QQuaternion::vector() const

Returns the vector component of this quaternion.

See also setVector() and scalar().

qreal QQuaternion::x() const

Returns the x coordinate of this quaternion's vector.

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

qreal QQuaternion::y() const

Returns the y coordinate of this quaternion's vector.

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

qreal QQuaternion::z() const

Returns the z coordinate of this quaternion's vector.

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

QQuaternion::operator QVariant() const

Returns the quaternion as a QVariant.

QQuaternion & QQuaternion::operator*=(qreal factor)

Multiplies this quaternion's components by the given factor, and returns a reference to this quaternion.

See also operator/=().

QQuaternion & QQuaternion::operator*=(const QQuaternion & quaternion)

Multiplies this quaternion by quaternion and returns a reference to this quaternion.

QQuaternion & QQuaternion::operator+=(const QQuaternion & quaternion)

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

See also operator-=().

QQuaternion & QQuaternion::operator-=(const QQuaternion & quaternion)

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

See also operator+=().

QQuaternion & QQuaternion::operator/=(qreal divisor)

Divides this quaternion's components by the given divisor, and returns a reference to this quaternion.

See also operator*=().