From 95d034a14f78aaefd6990de180f715c8b4d510b1 Mon Sep 17 00:00:00 2001 From: Konstantin Ritt Date: Thu, 26 Feb 2015 18:04:43 +0400 Subject: Introduce QQuaternion::fromDirection() ...which constructs a quaternion using specified forward and upward directions, so that the resulting Z axis "faces" a given forward direction. Change-Id: Ib77b8ab5c359a4880b0d946face87026acdc6f0b Reviewed-by: Paul Lemire Reviewed-by: Michael Krasnyk Reviewed-by: Lars Knoll --- src/gui/math3d/qquaternion.cpp | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'src/gui/math3d/qquaternion.cpp') diff --git a/src/gui/math3d/qquaternion.cpp b/src/gui/math3d/qquaternion.cpp index 6914a0b45e..4b35ee4e79 100644 --- a/src/gui/math3d/qquaternion.cpp +++ b/src/gui/math3d/qquaternion.cpp @@ -717,11 +717,41 @@ QQuaternion QQuaternion::fromAxes(const QVector3D &xAxis, const QVector3D &yAxis return QQuaternion::fromRotationMatrix(rot3x3); } +/*! + \since 5.5 + + Constructs the quaternion using specified forward direction \a direction + and upward direction \a up. + If the upward direction was not specified or the forward and upward + vectors are collinear, a new orthonormal upward direction will be generated. + + \sa fromAxes(), rotationTo() +*/ +QQuaternion QQuaternion::fromDirection(const QVector3D &direction, const QVector3D &up) +{ + if (qFuzzyIsNull(direction.x()) && qFuzzyIsNull(direction.y()) && qFuzzyIsNull(direction.z())) + return QQuaternion(); + + const QVector3D zAxis(direction.normalized()); + QVector3D xAxis(QVector3D::crossProduct(up, zAxis)); + if (qFuzzyIsNull(xAxis.lengthSquared())) { + // collinear or invalid up vector; derive shortest arc to new direction + return QQuaternion::rotationTo(QVector3D(0.0f, 0.0f, 1.0f), zAxis); + } + + xAxis.normalize(); + const QVector3D yAxis(QVector3D::crossProduct(zAxis, xAxis)); + + return QQuaternion::fromAxes(xAxis, yAxis, zAxis); +} + /*! \since 5.5 Returns the shortest arc quaternion to rotate from the direction described by the vector \a from to the direction described by the vector \a to. + + \sa fromDirection() */ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to) { -- cgit v1.2.3