diff options
author | Konstantin Ritt <ritt.ks@gmail.com> | 2015-02-09 17:50:25 +0400 |
---|---|---|
committer | Konstantin Ritt <ritt.ks@gmail.com> | 2015-02-14 05:45:00 +0000 |
commit | 5d784deb71edd1e6584cd2f118d27dd3be2da5e6 (patch) | |
tree | 6152eae42ac7299652fae4475e7d5bc0f5725c94 /src/gui/math3d | |
parent | 255ecba26909408d57c0d58ca211f810c66ce126 (diff) |
[QQuaternion] Introduce toAxisAndAngle()
This operation is the exact opposite to QQuaternion::fromAxisAndAngle()
(so that it is a way to extract the axis and angle values suitable
to create the same quaternion via QQuaternion::fromAxisAndAngle()).
Change-Id: I41fda58f5fb2b867cccd6b2faf58ab671fa070da
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
Diffstat (limited to 'src/gui/math3d')
-rw-r--r-- | src/gui/math3d/qquaternion.cpp | 50 | ||||
-rw-r--r-- | src/gui/math3d/qquaternion.h | 9 |
2 files changed, 59 insertions, 0 deletions
diff --git a/src/gui/math3d/qquaternion.cpp b/src/gui/math3d/qquaternion.cpp index 8e59e8a2f1..9c8fa3310d 100644 --- a/src/gui/math3d/qquaternion.cpp +++ b/src/gui/math3d/qquaternion.cpp @@ -363,8 +363,21 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const #ifndef QT_NO_VECTOR3D /*! + \fn void QQuaternion::toAxisAndAngle(QVector3D *axis, float *angle) const + \since 5.5 + \overload + + Extracts a 3D axis \a axis and a rotating angle \a angle (in degrees) + that corresponds to this quaternion. + + \sa fromAxisAndAngle() +*/ + +/*! Creates a normalized quaternion that corresponds to rotating through \a angle degrees about the specified 3D \a axis. + + \sa toAxisAndAngle() */ QQuaternion QQuaternion::fromAxisAndAngle(const QVector3D& axis, float angle) { @@ -382,8 +395,45 @@ QQuaternion QQuaternion::fromAxisAndAngle(const QVector3D& axis, float angle) #endif /*! + \since 5.5 + + Extracts a 3D axis (\a x, \a y, \a z) and a rotating angle \a angle (in degrees) + that corresponds to this quaternion. + + \sa fromAxisAndAngle() +*/ +void QQuaternion::toAxisAndAngle(float *x, float *y, float *z, float *angle) const +{ + Q_ASSERT(x && y && z && angle); + + // The quaternion representing the rotation is + // q = cos(A/2)+sin(A/2)*(x*i+y*j+z*k) + + float length = xp * xp + yp * yp + zp * zp; + if (!qFuzzyIsNull(length)) { + *x = xp; + *y = yp; + *z = zp; + if (!qFuzzyIsNull(length - 1.0f)) { + length = sqrtf(length); + *x /= length; + *y /= length; + *z /= length; + } + *angle = 2.0f * acosf(wp); + } else { + // angle is 0 (mod 2*pi), so any axis will fit + *x = *y = *z = *angle = 0.0f; + } + + *angle = qRadiansToDegrees(*angle); +} + +/*! Creates a normalized quaternion that corresponds to rotating through \a angle degrees about the 3D axis (\a x, \a y, \a z). + + \sa toAxisAndAngle() */ QQuaternion QQuaternion::fromAxisAndAngle (float x, float y, float z, float angle) diff --git a/src/gui/math3d/qquaternion.h b/src/gui/math3d/qquaternion.h index d4ad3df597..eb835ef806 100644 --- a/src/gui/math3d/qquaternion.h +++ b/src/gui/math3d/qquaternion.h @@ -115,8 +115,10 @@ public: operator QVariant() const; #ifndef QT_NO_VECTOR3D + inline void toAxisAndAngle(QVector3D *axis, float *angle) const; static QQuaternion fromAxisAndAngle(const QVector3D& axis, float angle); #endif + void toAxisAndAngle(float *x, float *y, float *z, float *angle) const; static QQuaternion fromAxisAndAngle (float x, float y, float z, float angle); @@ -299,6 +301,13 @@ inline QVector3D QQuaternion::vector() const return QVector3D(xp, yp, zp); } +inline void QQuaternion::toAxisAndAngle(QVector3D *axis, float *angle) const +{ + float aX, aY, aZ; + toAxisAndAngle(&aX, &aY, &aZ, angle); + *axis = QVector3D(aX, aY, aZ); +} + #endif inline void QQuaternion::setVector(float aX, float aY, float aZ) |