<?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>main.cpp Example File | Qt Widgets 5.12.2</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 >main.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.2 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">main.cpp Example File</h1> <span class="subtitle">graphicsview/boxes/main.cpp</span> <!-- $$$graphicsview/boxes/main.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="comment">//#include <GL/glew.h></span> <span class="preprocessor">#include "glextensions.h"</span> <span class="preprocessor">#include "scene.h"</span> <span class="preprocessor">#include <QtWidgets></span> <span class="preprocessor">#include <QGLWidget></span> <span class="keyword">class</span> GraphicsView : <span class="keyword">public</span> <span class="type"><a href="qgraphicsview.html">QGraphicsView</a></span> { <span class="keyword">public</span>: GraphicsView() { setWindowTitle(tr(<span class="string">"Boxes"</span>)); setRenderHints(<span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span><span class="operator">::</span>Antialiasing <span class="operator">|</span> <span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span><span class="operator">::</span>SmoothPixmapTransform); <span class="comment">//setRenderHints(QPainter::SmoothPixmapTransform);</span> } <span class="keyword">protected</span>: <span class="type">void</span> resizeEvent(<span class="type"><a href="../qtgui/qresizeevent.html">QResizeEvent</a></span> <span class="operator">*</span>event) override { <span class="keyword">if</span> (scene()) scene()<span class="operator">-</span><span class="operator">></span>setSceneRect(<span class="type"><a href="../qtcore/qrect.html">QRect</a></span>(<span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)<span class="operator">,</span> event<span class="operator">-</span><span class="operator">></span>size())); <span class="type"><a href="qgraphicsview.html">QGraphicsView</a></span><span class="operator">::</span>resizeEvent(event); } }; <span class="keyword">inline</span> bool matchString(<span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>extensionString<span class="operator">,</span> <span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>subString) { <span class="type">int</span> subStringLength <span class="operator">=</span> strlen(subString); <span class="keyword">return</span> (strncmp(extensionString<span class="operator">,</span> subString<span class="operator">,</span> subStringLength) <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>) <span class="operator">&</span><span class="operator">&</span> ((extensionString<span class="operator">[</span>subStringLength<span class="operator">]</span> <span class="operator">=</span><span class="operator">=</span> <span class="char">' '</span>) <span class="operator">|</span><span class="operator">|</span> (extensionString<span class="operator">[</span>subStringLength<span class="operator">]</span> <span class="operator">=</span><span class="operator">=</span> <span class="char">'\0'</span>)); } bool necessaryExtensionsSupported() { <span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>extensionString <span class="operator">=</span> <span class="keyword">reinterpret_cast</span><span class="operator"><</span><span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span><span class="operator">></span>(glGetString(GL_EXTENSIONS)); <span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>p <span class="operator">=</span> extensionString; <span class="keyword">const</span> <span class="type">int</span> GL_EXT_FBO <span class="operator">=</span> <span class="number">1</span>; <span class="keyword">const</span> <span class="type">int</span> GL_ARB_VS <span class="operator">=</span> <span class="number">2</span>; <span class="keyword">const</span> <span class="type">int</span> GL_ARB_FS <span class="operator">=</span> <span class="number">4</span>; <span class="keyword">const</span> <span class="type">int</span> GL_ARB_SO <span class="operator">=</span> <span class="number">8</span>; <span class="type">int</span> extensions <span class="operator">=</span> <span class="number">0</span>; <span class="keyword">while</span> (<span class="operator">*</span>p) { <span class="keyword">if</span> (matchString(p<span class="operator">,</span> <span class="string">"GL_EXT_framebuffer_object"</span>)) extensions <span class="operator">|</span><span class="operator">=</span> GL_EXT_FBO; <span class="keyword">else</span> <span class="keyword">if</span> (matchString(p<span class="operator">,</span> <span class="string">"GL_ARB_vertex_shader"</span>)) extensions <span class="operator">|</span><span class="operator">=</span> GL_ARB_VS; <span class="keyword">else</span> <span class="keyword">if</span> (matchString(p<span class="operator">,</span> <span class="string">"GL_ARB_fragment_shader"</span>)) extensions <span class="operator">|</span><span class="operator">=</span> GL_ARB_FS; <span class="keyword">else</span> <span class="keyword">if</span> (matchString(p<span class="operator">,</span> <span class="string">"GL_ARB_shader_objects"</span>)) extensions <span class="operator">|</span><span class="operator">=</span> GL_ARB_SO; <span class="keyword">while</span> ((<span class="operator">*</span>p <span class="operator">!</span><span class="operator">=</span> <span class="char">' '</span>) <span class="operator">&</span><span class="operator">&</span> (<span class="operator">*</span>p <span class="operator">!</span><span class="operator">=</span> <span class="char">'\0'</span>)) <span class="operator">+</span><span class="operator">+</span>p; <span class="keyword">if</span> (<span class="operator">*</span>p <span class="operator">=</span><span class="operator">=</span> <span class="char">' '</span>) <span class="operator">+</span><span class="operator">+</span>p; } <span class="keyword">return</span> (extensions <span class="operator">=</span><span class="operator">=</span> <span class="number">15</span>); } <span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span><span class="operator">*</span>argv) { <span class="type"><a href="qapplication.html">QApplication</a></span> app(argc<span class="operator">,</span> argv); <span class="keyword">if</span> ((<span class="type">QGLFormat</span><span class="operator">::</span>openGLVersionFlags() <span class="operator">&</span> <span class="type">QGLFormat</span><span class="operator">::</span>OpenGL_Version_1_5) <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>) { <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>critical(<span class="number">0</span><span class="operator">,</span> <span class="string">"OpenGL features missing"</span><span class="operator">,</span> <span class="string">"OpenGL version 1.5 or higher is required to run this demo.\n"</span> <span class="string">"The program will now exit."</span>); <span class="keyword">return</span> <span class="operator">-</span><span class="number">1</span>; } <span class="type">int</span> maxTextureSize <span class="operator">=</span> <span class="number">1024</span>; <span class="type">QGLWidget</span> <span class="operator">*</span>widget <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QGLWidget</span>(<span class="type">QGLFormat</span>(QGL<span class="operator">::</span>SampleBuffers)); widget<span class="operator">-</span><span class="operator">></span>makeCurrent(); <span class="keyword">if</span> (<span class="operator">!</span>necessaryExtensionsSupported()) { <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>critical(<span class="number">0</span><span class="operator">,</span> <span class="string">"OpenGL features missing"</span><span class="operator">,</span> <span class="string">"The OpenGL extensions required to run this demo are missing.\n"</span> <span class="string">"The program will now exit."</span>); <span class="keyword">delete</span> widget; <span class="keyword">return</span> <span class="operator">-</span><span class="number">2</span>; } <span class="comment">// Check if all the necessary functions are resolved.</span> <span class="keyword">if</span> (<span class="operator">!</span>getGLExtensionFunctions()<span class="operator">.</span>resolve(widget<span class="operator">-</span><span class="operator">></span>context())) { <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>critical(<span class="number">0</span><span class="operator">,</span> <span class="string">"OpenGL features missing"</span><span class="operator">,</span> <span class="string">"Failed to resolve OpenGL functions required to run this demo.\n"</span> <span class="string">"The program will now exit."</span>); <span class="keyword">delete</span> widget; <span class="keyword">return</span> <span class="operator">-</span><span class="number">3</span>; } <span class="comment">// TODO: Make conditional for final release</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>information(<span class="number">0</span><span class="operator">,</span> <span class="string">"For your information"</span><span class="operator">,</span> <span class="string">"This demo can be GPU and CPU intensive and may\n"</span> <span class="string">"work poorly or not at all on your system."</span>); widget<span class="operator">-</span><span class="operator">></span>makeCurrent(); <span class="comment">// The current context must be set before calling Scene's constructor</span> Scene scene(<span class="number">1024</span><span class="operator">,</span> <span class="number">768</span><span class="operator">,</span> maxTextureSize); GraphicsView view; view<span class="operator">.</span>setViewport(widget); view<span class="operator">.</span>setViewportUpdateMode(<span class="type"><a href="qgraphicsview.html">QGraphicsView</a></span><span class="operator">::</span>FullViewportUpdate); view<span class="operator">.</span>setScene(<span class="operator">&</span>scene); view<span class="operator">.</span>show(); <span class="keyword">return</span> app<span class="operator">.</span>exec(); } </pre> </div> <!-- @@@graphicsview/boxes/main.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>