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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "trackball.h"
#include "scene.h"
#include <cmath>
//============================================================================//
// TrackBall //
//============================================================================//
TrackBall::TrackBall(TrackMode mode)
: m_angularVelocity(0)
, m_paused(false)
, m_pressed(false)
, m_mode(mode)
{
m_axis = QVector3D(0, 1, 0);
m_rotation = QQuaternion();
m_lastTime = QTime::currentTime();
}
TrackBall::TrackBall(float angularVelocity, const QVector3D& axis, TrackMode mode)
: m_axis(axis)
, m_angularVelocity(angularVelocity)
, m_paused(false)
, m_pressed(false)
, m_mode(mode)
{
m_rotation = QQuaternion();
m_lastTime = QTime::currentTime();
}
void TrackBall::push(const QPointF& p, const QQuaternion &)
{
m_rotation = rotation();
m_pressed = true;
m_lastTime = QTime::currentTime();
m_lastPos = p;
m_angularVelocity = 0.0f;
}
void TrackBall::move(const QPointF& p, const QQuaternion &transformation)
{
if (!m_pressed)
return;
QTime currentTime = QTime::currentTime();
int msecs = m_lastTime.msecsTo(currentTime);
if (msecs <= 20)
return;
switch (m_mode) {
case Plane:
{
QLineF delta(m_lastPos, p);
m_angularVelocity = 180*delta.length() / (PI*msecs);
m_axis = QVector3D(-delta.dy(), delta.dx(), 0.0f).normalized();
m_axis = transformation.rotatedVector(m_axis);
m_rotation = QQuaternion::fromAxisAndAngle(m_axis, 180 / PI * delta.length()) * m_rotation;
}
break;
case Sphere:
{
QVector3D lastPos3D = QVector3D(m_lastPos.x(), m_lastPos.y(), 0.0f);
float sqrZ = 1 - QVector3D::dotProduct(lastPos3D, lastPos3D);
if (sqrZ > 0)
lastPos3D.setZ(std::sqrt(sqrZ));
else
lastPos3D.normalize();
QVector3D currentPos3D = QVector3D(p.x(), p.y(), 0.0f);
sqrZ = 1 - QVector3D::dotProduct(currentPos3D, currentPos3D);
if (sqrZ > 0)
currentPos3D.setZ(std::sqrt(sqrZ));
else
currentPos3D.normalize();
m_axis = QVector3D::crossProduct(lastPos3D, currentPos3D);
float angle = 180 / PI * std::asin(std::sqrt(QVector3D::dotProduct(m_axis, m_axis)));
m_angularVelocity = angle / msecs;
m_axis.normalize();
m_axis = transformation.rotatedVector(m_axis);
m_rotation = QQuaternion::fromAxisAndAngle(m_axis, angle) * m_rotation;
}
break;
}
m_lastPos = p;
m_lastTime = currentTime;
}
void TrackBall::release(const QPointF& p, const QQuaternion &transformation)
{
// Calling move() caused the rotation to stop if the framerate was too low.
move(p, transformation);
m_pressed = false;
}
void TrackBall::start()
{
m_lastTime = QTime::currentTime();
m_paused = false;
}
void TrackBall::stop()
{
m_rotation = rotation();
m_paused = true;
}
QQuaternion TrackBall::rotation() const
{
if (m_paused || m_pressed)
return m_rotation;
QTime currentTime = QTime::currentTime();
float angle = m_angularVelocity * m_lastTime.msecsTo(currentTime);
return QQuaternion::fromAxisAndAngle(m_axis, angle) * m_rotation;
}
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