Sophie: qt4-doc-4:4.6.3-0.2mdv2010.2 i586

qt4-doc-4.6.3-0.2mdv2010.2.i586.rpm

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <title>Qt 4.6: trackball.cpp Example File (demos/boxes/trackball.cpp)</title>
  <link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://qt.nokia.com/"><img src="images/qt-logo.png" align="left" border="0" /></a></td>
<td width="1">&nbsp;&nbsp;</td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a>&nbsp;&middot; <a href="classes.html"><font color="#004faf">All&nbsp;Classes</font></a>&nbsp;&middot; <a href="functions.html"><font color="#004faf">All&nbsp;Functions</font></a>&nbsp;&middot; <a href="overviews.html"><font color="#004faf">Overviews</font></a></td></tr></table><h1 class="title">trackball.cpp Example File<br /><span class="small-subtitle">demos/boxes/trackball.cpp</span>
</h1>
<pre><span class="comment"> /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial Usage
 ** Licensees holding valid Qt Commercial licenses may use this file in
 ** accordance with the Qt Commercial License Agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and Nokia.
 **
 ** 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 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU Lesser General Public License version 2.1 requirements
 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** In addition, as a special exception, Nokia gives you certain additional
 ** rights.  These rights are described in the Nokia Qt LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3.0 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU General Public License version 3.0 requirements will be
 ** met: http://www.gnu.org/copyleft/gpl.html.
 **
 ** If you have questions regarding the use of this file, please contact
 ** Nokia at qt-info@nokia.com.
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/</span>

 #include &quot;trackball.h&quot;
 #include &quot;scene.h&quot;

<span class="comment"> //============================================================================//</span>
<span class="comment"> //                                  TrackBall                                 //</span>
<span class="comment"> //============================================================================//</span>

 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&amp; 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&amp; p, const QQuaternion &amp;)
 {
     m_rotation = rotation();
     m_pressed = true;
     m_lastTime = QTime::currentTime();
     m_lastPos = p;
     m_angularVelocity = 0.0f;
 }

 void TrackBall::move(const QPointF&amp; p, const QQuaternion &amp;transformation)
 {
     if (!m_pressed)
         return;

     QTime currentTime = QTime::currentTime();
     int msecs = m_lastTime.msecsTo(currentTime);
     if (msecs &lt;= 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 &gt; 0)
                 lastPos3D.setZ(sqrt(sqrZ));
             else
                 lastPos3D.normalize();

             QVector3D currentPos3D = QVector3D(p.x(), p.y(), 0.0f);
             sqrZ = 1 - QVector3D::dotProduct(currentPos3D, currentPos3D);
             if (sqrZ &gt; 0)
                 currentPos3D.setZ(sqrt(sqrZ));
             else
                 currentPos3D.normalize();

             m_axis = QVector3D::crossProduct(lastPos3D, currentPos3D);
             float angle = 180 / PI * asin(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&amp; p, const QQuaternion &amp;transformation)
 {
     <span class="comment">// Calling move() caused the rotation to stop if the framerate was too low.</span>
     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;
 }</pre>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="40%" align="left">Copyright &copy; 2010 Nokia Corporation and/or its subsidiary(-ies)</td>
<td width="20%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="40%" align="right"><div align="right">Qt 4.6.3</div></td>
</tr></table></div></address></body>
</html>