gui/math3d/qvector4d.cpp

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#include "qvector4d.h"
#include "qvector3d.h"
#include "qvector2d.h"
#include <QtCore/qdebug.h>
#include <QtCore/qvariant.h>
#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

#ifndef QT_NO_VECTOR4D

/*!
    \class QVector4D
    \brief The QVector4D class represents a vector or vertex in 4D space.
    \since 4.6
    \ingroup painting-3D

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

    \bold{Note:} By design values in the QVector4D instance are stored as \c float.
    This means that on platforms where the \c qreal arguments to QVector4D
    functions are represented by \c double values, it is possible to
    lose precision.

    \sa QQuaternion, QVector2D, QVector3D
*/

/*!
    \fn QVector4D::QVector4D()

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

/*!
    \fn QVector4D::QVector4D(qreal xpos, qreal ypos, qreal zpos, qreal wpos)

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

/*!
    \fn QVector4D::QVector4D(const QPoint& point)

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

/*!
    \fn QVector4D::QVector4D(const QPointF& point)

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

#ifndef QT_NO_VECTOR2D

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

    \sa toVector2D()
*/
QVector4D::QVector4D(const QVector2D& vector)
{
    xp = vector.xp;
    yp = vector.yp;
    zp = 0.0f;
    wp = 0.0f;
}

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

    \sa toVector2D()
*/
QVector4D::QVector4D(const QVector2D& vector, qreal zpos, qreal wpos)
{
    xp = vector.xp;
    yp = vector.yp;
    zp = zpos;
    wp = wpos;
}

#endif

#ifndef QT_NO_VECTOR3D

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

    \sa toVector3D()
*/
QVector4D::QVector4D(const QVector3D& vector)
{
    xp = vector.xp;
    yp = vector.yp;
    zp = vector.zp;
    wp = 0.0f;
}

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

    \sa toVector3D()
*/
QVector4D::QVector4D(const QVector3D& vector, qreal wpos)
{
    xp = vector.xp;
    yp = vector.yp;
    zp = vector.zp;
    wp = wpos;
}

#endif

/*!
    \fn bool QVector4D::isNull() const

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

/*!
    \fn qreal QVector4D::x() const

    Returns the x coordinate of this point.

    \sa setX(), y(), z(), w()
*/

/*!
    \fn qreal QVector4D::y() const

    Returns the y coordinate of this point.

    \sa setY(), x(), z(), w()
*/

/*!
    \fn qreal QVector4D::z() const

    Returns the z coordinate of this point.

    \sa setZ(), x(), y(), w()
*/

/*!
    \fn qreal QVector4D::w() const

    Returns the w coordinate of this point.

    \sa setW(), x(), y(), z()
*/

/*!
    \fn void QVector4D::setX(qreal x)

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

    \sa x(), setY(), setZ(), setW()
*/

/*!
    \fn void QVector4D::setY(qreal y)

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

    \sa y(), setX(), setZ(), setW()
*/

/*!
    \fn void QVector4D::setZ(qreal z)

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

    \sa z(), setX(), setY(), setW()
*/

/*!
    \fn void QVector4D::setW(qreal w)

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

    \sa w(), setX(), setY(), setZ()
*/

/*!
    Returns the length of the vector from the origin.

    \sa lengthSquared(), normalized()
*/
qreal QVector4D::length() const
{
    return qSqrt(xp * xp + yp * yp + zp * zp + wp * wp);
}

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

    \sa length(), dotProduct()
*/
qreal QVector4D::lengthSquared() const
{
    return xp * xp + yp * yp + zp * zp + wp * wp;
}

/*!
    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.

    \sa length(), normalize()
*/
QVector4D QVector4D::normalized() const
{
    // Need some extra precision if the length is very small.
    double len = double(xp) * double(xp) +
                 double(yp) * double(yp) +
                 double(zp) * double(zp) +
                 double(wp) * double(wp);
    if (qFuzzyIsNull(len - 1.0f))
        return *this;
    else if (!qFuzzyIsNull(len))
        return *this / qSqrt(len);
    else
        return QVector4D();
}

/*!
    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.

    \sa length(), normalized()
*/
void QVector4D::normalize()
{
    // Need some extra precision if the length is very small.
    double len = double(xp) * double(xp) +
                 double(yp) * double(yp) +
                 double(zp) * double(zp) +
                 double(wp) * double(wp);
    if (qFuzzyIsNull(len - 1.0f) || qFuzzyIsNull(len))
        return;

    len = qSqrt(len);

    xp /= len;
    yp /= len;
    zp /= len;
    wp /= len;
}

/*!
    \fn QVector4D &QVector4D::operator+=(const QVector4D &vector)

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

    \sa operator-=()
*/

/*!
    \fn QVector4D &QVector4D::operator-=(const QVector4D &vector)

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

    \sa operator+=()
*/

/*!
    \fn QVector4D &QVector4D::operator*=(qreal factor)

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

    \sa operator/=()
*/

/*!
    \fn QVector4D &QVector4D::operator*=(const QVector4D &vector)

    Multiplies the components of this vector by the corresponding
    components in \a vector.
*/

/*!
    \fn QVector4D &QVector4D::operator/=(qreal divisor)

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

    \sa operator*=()
*/

/*!
    Returns the dot product of \a v1 and \a v2.
*/
qreal QVector4D::dotProduct(const QVector4D& v1, const QVector4D& v2)
{
    return v1.xp * v2.xp + v1.yp * v2.yp + v1.zp * v2.zp + v1.wp * v2.wp;
}

/*!
    \fn bool operator==(const QVector4D &v1, const QVector4D &v2)
    \relates QVector4D

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

/*!
    \fn bool operator!=(const QVector4D &v1, const QVector4D &v2)
    \relates QVector4D

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

/*!
    \fn const QVector4D operator+(const QVector4D &v1, const QVector4D &v2)
    \relates QVector4D

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

    \sa QVector4D::operator+=()
*/

/*!
    \fn const QVector4D operator-(const QVector4D &v1, const QVector4D &v2)
    \relates QVector4D

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

    \sa QVector4D::operator-=()
*/

/*!
    \fn const QVector4D operator*(qreal factor, const QVector4D &vector)
    \relates QVector4D

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

    \sa QVector4D::operator*=()
*/

/*!
    \fn const QVector4D operator*(const QVector4D &vector, qreal factor)
    \relates QVector4D

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

    \sa QVector4D::operator*=()
*/

/*!
    \fn const QVector4D operator*(const QVector4D &v1, const QVector4D& v2)
    \relates QVector4D

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

    \sa QVector4D::operator*=()
*/

/*!
    \fn const QVector4D operator-(const QVector4D &vector)
    \relates QVector4D
    \overload

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

    Equivalent to \c {QVector4D(0,0,0,0) - vector}.
*/

/*!
    \fn const QVector4D operator/(const QVector4D &vector, qreal divisor)
    \relates QVector4D

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

    \sa QVector4D::operator/=()
*/

/*!
    \fn bool qFuzzyCompare(const QVector4D& v1, const QVector4D& v2)
    \relates QVector4D

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

#ifndef QT_NO_VECTOR2D

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

    \sa toVector2DAffine(), toVector3D(), toPoint()
*/
QVector2D QVector4D::toVector2D() const
{
    return QVector2D(xp, yp, 1);
}

/*!
    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.

    \sa toVector2D(), toVector3DAffine(), toPoint()
*/
QVector2D QVector4D::toVector2DAffine() const
{
    if (qIsNull(wp))
        return QVector2D();
    return QVector2D(xp / wp, yp / wp, 1);
}

#endif

#ifndef QT_NO_VECTOR3D

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

    \sa toVector3DAffine(), toVector2D(), toPoint()
*/
QVector3D QVector4D::toVector3D() const
{
    return QVector3D(xp, yp, zp, 1);
}

/*!
    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.

    \sa toVector3D(), toVector2DAffine(), toPoint()
*/
QVector3D QVector4D::toVector3DAffine() const
{
    if (qIsNull(wp))
        return QVector3D();
    return QVector3D(xp / wp, yp / wp, zp / wp, 1);
}

#endif

/*!
    \fn QPoint QVector4D::toPoint() const

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

    \sa toPointF(), toVector2D()
*/

/*!
    \fn QPointF QVector4D::toPointF() const

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

    \sa toPoint(), toVector2D()
*/

/*!
    Returns the 4D vector as a QVariant.
*/
QVector4D::operator QVariant() const
{
    return QVariant(QVariant::Vector4D, this);
}

#ifndef QT_NO_DEBUG_STREAM

QDebug operator<<(QDebug dbg, const QVector4D &vector)
{
    dbg.nospace() << "QVector4D("
        << vector.x() << ", " << vector.y() << ", "
        << vector.z() << ", " << vector.w() << ')';
    return dbg.space();
}

#endif

#ifndef QT_NO_DATASTREAM

/*!
    \fn QDataStream &operator<<(QDataStream &stream, const QVector4D &vector)
    \relates QVector4D

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

    \sa {Serializing Qt Data Types}
*/

QDataStream &operator<<(QDataStream &stream, const QVector4D &vector)
{
    stream << double(vector.x()) << double(vector.y())
           << double(vector.z()) << double(vector.w());
    return stream;
}

/*!
    \fn QDataStream &operator>>(QDataStream &stream, QVector4D &vector)
    \relates QVector4D

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

    \sa {Serializing Qt Data Types}
*/

QDataStream &operator>>(QDataStream &stream, QVector4D &vector)
{
    double x, y, z, w;
    stream >> x;
    stream >> y;
    stream >> z;
    stream >> w;
    vector.setX(qreal(x));
    vector.setY(qreal(y));
    vector.setZ(qreal(z));
    vector.setW(qreal(w));
    return stream;
}

#endif // QT_NO_DATASTREAM

#endif // QT_NO_VECTOR4D

QT_END_NAMESPACE