<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>trackball.cpp Example File | Qt Widgets 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-graphicsview-boxes-example.html">Boxes</a></td><td >trackball.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">trackball.cpp Example File</h1> <span class="subtitle">graphicsview/boxes/trackball.cpp</span> <!-- $$$graphicsview/boxes/trackball.cpp-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the demonstration applications of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** 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 https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "trackball.h"</span> <span class="preprocessor">#include "scene.h"</span> <span class="preprocessor">#include <qmath.h></span> <span class="preprocessor">#include <cmath></span> <span class="comment">//============================================================================//</span> <span class="comment">// TrackBall //</span> <span class="comment">//============================================================================//</span> TrackBall<span class="operator">::</span>TrackBall(TrackMode mode) : m_angularVelocity(<span class="number">0</span>) <span class="operator">,</span> m_paused(<span class="keyword">false</span>) <span class="operator">,</span> m_pressed(<span class="keyword">false</span>) <span class="operator">,</span> m_mode(mode) { m_axis <span class="operator">=</span> QVector3D(<span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">0</span>); m_rotation <span class="operator">=</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span>(); m_lastTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); } TrackBall<span class="operator">::</span>TrackBall(<span class="type">float</span> angularVelocity<span class="operator">,</span> <span class="keyword">const</span> QVector3D<span class="operator">&</span> axis<span class="operator">,</span> TrackMode mode) : m_axis(axis) <span class="operator">,</span> m_angularVelocity(angularVelocity) <span class="operator">,</span> m_paused(<span class="keyword">false</span>) <span class="operator">,</span> m_pressed(<span class="keyword">false</span>) <span class="operator">,</span> m_mode(mode) { m_rotation <span class="operator">=</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span>(); m_lastTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); } <span class="type">void</span> TrackBall<span class="operator">::</span>push(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span><span class="operator">&</span> p<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span> <span class="operator">&</span>) { m_rotation <span class="operator">=</span> rotation(); m_pressed <span class="operator">=</span> <span class="keyword">true</span>; m_lastTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); m_lastPos <span class="operator">=</span> p; m_angularVelocity <span class="operator">=</span> <span class="number">0.0f</span>; } <span class="type">void</span> TrackBall<span class="operator">::</span>move(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span><span class="operator">&</span> p<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span> <span class="operator">&</span>transformation) { <span class="keyword">if</span> (<span class="operator">!</span>m_pressed) <span class="keyword">return</span>; <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> currentTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); <span class="type">int</span> msecs <span class="operator">=</span> m_lastTime<span class="operator">.</span>msecsTo(currentTime); <span class="keyword">if</span> (msecs <span class="operator"><</span><span class="operator">=</span> <span class="number">20</span>) <span class="keyword">return</span>; <span class="keyword">switch</span> (m_mode) { <span class="keyword">case</span> Plane: { <span class="type"><a href="../qtcore/qlinef.html">QLineF</a></span> delta(m_lastPos<span class="operator">,</span> p); <span class="keyword">const</span> <span class="type">float</span> angleDelta <span class="operator">=</span> <a href="../qtcore/qtmath.html#qRadiansToDegrees-1">qRadiansToDegrees</a>(<span class="type">float</span>(delta<span class="operator">.</span>length())); m_angularVelocity <span class="operator">=</span> angleDelta <span class="operator">/</span> msecs; m_axis <span class="operator">=</span> QVector3D(<span class="operator">-</span>delta<span class="operator">.</span>dy()<span class="operator">,</span> delta<span class="operator">.</span>dx()<span class="operator">,</span> <span class="number">0.0f</span>)<span class="operator">.</span>normalized(); m_axis <span class="operator">=</span> transformation<span class="operator">.</span>rotatedVector(m_axis); m_rotation <span class="operator">=</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span><span class="operator">::</span>fromAxisAndAngle(m_axis<span class="operator">,</span> angleDelta) <span class="operator">*</span> m_rotation; } <span class="keyword">break</span>; <span class="keyword">case</span> Sphere: { QVector3D lastPos3D <span class="operator">=</span> QVector3D(m_lastPos<span class="operator">.</span>x()<span class="operator">,</span> m_lastPos<span class="operator">.</span>y()<span class="operator">,</span> <span class="number">0.0f</span>); <span class="type">float</span> sqrZ <span class="operator">=</span> <span class="number">1</span> <span class="operator">-</span> QVector3D<span class="operator">::</span>dotProduct(lastPos3D<span class="operator">,</span> lastPos3D); <span class="keyword">if</span> (sqrZ <span class="operator">></span> <span class="number">0</span>) lastPos3D<span class="operator">.</span>setZ(std<span class="operator">::</span>sqrt(sqrZ)); <span class="keyword">else</span> lastPos3D<span class="operator">.</span>normalize(); QVector3D currentPos3D <span class="operator">=</span> QVector3D(p<span class="operator">.</span>x()<span class="operator">,</span> p<span class="operator">.</span>y()<span class="operator">,</span> <span class="number">0.0f</span>); sqrZ <span class="operator">=</span> <span class="number">1</span> <span class="operator">-</span> QVector3D<span class="operator">::</span>dotProduct(currentPos3D<span class="operator">,</span> currentPos3D); <span class="keyword">if</span> (sqrZ <span class="operator">></span> <span class="number">0</span>) currentPos3D<span class="operator">.</span>setZ(std<span class="operator">::</span>sqrt(sqrZ)); <span class="keyword">else</span> currentPos3D<span class="operator">.</span>normalize(); m_axis <span class="operator">=</span> QVector3D<span class="operator">::</span>crossProduct(lastPos3D<span class="operator">,</span> currentPos3D); <span class="type">float</span> angle <span class="operator">=</span> <a href="../qtcore/qtmath.html#qRadiansToDegrees-1">qRadiansToDegrees</a>(std<span class="operator">::</span>asin(m_axis<span class="operator">.</span>length())); m_angularVelocity <span class="operator">=</span> angle <span class="operator">/</span> msecs; m_axis<span class="operator">.</span>normalize(); m_axis <span class="operator">=</span> transformation<span class="operator">.</span>rotatedVector(m_axis); m_rotation <span class="operator">=</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span><span class="operator">::</span>fromAxisAndAngle(m_axis<span class="operator">,</span> angle) <span class="operator">*</span> m_rotation; } <span class="keyword">break</span>; } m_lastPos <span class="operator">=</span> p; m_lastTime <span class="operator">=</span> currentTime; } <span class="type">void</span> TrackBall<span class="operator">::</span>release(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span><span class="operator">&</span> p<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span> <span class="operator">&</span>transformation) { <span class="comment">// Calling move() caused the rotation to stop if the framerate was too low.</span> move(p<span class="operator">,</span> transformation); m_pressed <span class="operator">=</span> <span class="keyword">false</span>; } <span class="type">void</span> TrackBall<span class="operator">::</span>start() { m_lastTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); m_paused <span class="operator">=</span> <span class="keyword">false</span>; } <span class="type">void</span> TrackBall<span class="operator">::</span>stop() { m_rotation <span class="operator">=</span> rotation(); m_paused <span class="operator">=</span> <span class="keyword">true</span>; } <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span> TrackBall<span class="operator">::</span>rotation() <span class="keyword">const</span> { <span class="keyword">if</span> (m_paused <span class="operator">|</span><span class="operator">|</span> m_pressed) <span class="keyword">return</span> m_rotation; <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> currentTime <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime(); <span class="type">float</span> angle <span class="operator">=</span> m_angularVelocity <span class="operator">*</span> m_lastTime<span class="operator">.</span>msecsTo(currentTime); <span class="keyword">return</span> <span class="type"><a href="../qtgui/qquaternion.html">QQuaternion</a></span><span class="operator">::</span>fromAxisAndAngle(m_axis<span class="operator">,</span> angle) <span class="operator">*</span> m_rotation; } </pre> </div> <!-- @@@graphicsview/boxes/trackball.cpp --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>