source: trunk/src/gui/math3d/qvector4d.cpp@ 605

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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.

    \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*=()
*/

/*!