<?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>geometryengine.cpp Example File | Qt OpenGL</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="qtopengl-index.html">Qt OpenGL</a></td><td ><a href="qtopengl-cube-example.html">Cube OpenGL ES 2.0 example</a></td><td >geometryengine.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtopengl-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">geometryengine.cpp Example File</h1> <span class="subtitle">cube/geometryengine.cpp</span> <!-- $$$cube/geometryengine.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 QtCore module 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 "geometryengine.h"</span> <span class="preprocessor">#include <QVector2D></span> <span class="preprocessor">#include <QVector3D></span> <span class="keyword">struct</span> VertexData { QVector3D position; QVector2D texCoord; }; GeometryEngine<span class="operator">::</span>GeometryEngine() : indexBuf(<span class="type"><a href="../qtgui/qopenglbuffer.html">QOpenGLBuffer</a></span><span class="operator">::</span>IndexBuffer) { initializeOpenGLFunctions(); <span class="comment">// Generate 2 VBOs</span> arrayBuf<span class="operator">.</span>create(); indexBuf<span class="operator">.</span>create(); <span class="comment">// Initializes cube geometry and transfers it to VBOs</span> initCubeGeometry(); } GeometryEngine<span class="operator">::</span><span class="operator">~</span>GeometryEngine() { arrayBuf<span class="operator">.</span>destroy(); indexBuf<span class="operator">.</span>destroy(); } <span class="type">void</span> GeometryEngine<span class="operator">::</span>initCubeGeometry() { <span class="comment">// For cube we would need only 8 vertices but we have to</span> <span class="comment">// duplicate vertex for each face because texture coordinate</span> <span class="comment">// is different.</span> VertexData vertices<span class="operator">[</span><span class="operator">]</span> <span class="operator">=</span> { <span class="comment">// Vertex data for face 0</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.0f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v0</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v1</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.0f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v2</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v3</span> <span class="comment">// Vertex data for face 1</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D( <span class="number">0.0f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v4</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v5</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)}<span class="operator">,</span> <span class="comment">// v6</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">1.0f</span>)}<span class="operator">,</span> <span class="comment">// v7</span> <span class="comment">// Vertex data for face 2</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v8</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">1.0f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v9</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">1.0f</span>)}<span class="operator">,</span> <span class="comment">// v10</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)}<span class="operator">,</span> <span class="comment">// v11</span> <span class="comment">// Vertex data for face 3</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v12</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">1.0f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v13</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v14</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">1.0f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v15</span> <span class="comment">// Vertex data for face 4</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v16</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.0f</span>)}<span class="operator">,</span> <span class="comment">// v17</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v18</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v19</span> <span class="comment">// Vertex data for face 5</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v20</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">0.5f</span>)}<span class="operator">,</span> <span class="comment">// v21</span> {QVector3D(<span class="operator">-</span><span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.33f</span><span class="operator">,</span> <span class="number">1.0f</span>)}<span class="operator">,</span> <span class="comment">// v22</span> {QVector3D( <span class="number">1.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1.0f</span>)<span class="operator">,</span> QVector2D(<span class="number">0.66f</span><span class="operator">,</span> <span class="number">1.0f</span>)} <span class="comment">// v23</span> }; <span class="comment">// Indices for drawing cube faces using triangle strips.</span> <span class="comment">// Triangle strips can be connected by duplicating indices</span> <span class="comment">// between the strips. If connecting strips have opposite</span> <span class="comment">// vertex order then last index of the first strip and first</span> <span class="comment">// index of the second strip needs to be duplicated. If</span> <span class="comment">// connecting strips have same vertex order then only last</span> <span class="comment">// index of the first strip needs to be duplicated.</span> GLushort indices<span class="operator">[</span><span class="operator">]</span> <span class="operator">=</span> { <span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="comment">// Face 0 - triangle strip ( v0, v1, v2, v3)</span> <span class="number">4</span><span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">6</span><span class="operator">,</span> <span class="number">7</span><span class="operator">,</span> <span class="number">7</span><span class="operator">,</span> <span class="comment">// Face 1 - triangle strip ( v4, v5, v6, v7)</span> <span class="number">8</span><span class="operator">,</span> <span class="number">8</span><span class="operator">,</span> <span class="number">9</span><span class="operator">,</span> <span class="number">10</span><span class="operator">,</span> <span class="number">11</span><span class="operator">,</span> <span class="number">11</span><span class="operator">,</span> <span class="comment">// Face 2 - triangle strip ( v8, v9, v10, v11)</span> <span class="number">12</span><span class="operator">,</span> <span class="number">12</span><span class="operator">,</span> <span class="number">13</span><span class="operator">,</span> <span class="number">14</span><span class="operator">,</span> <span class="number">15</span><span class="operator">,</span> <span class="number">15</span><span class="operator">,</span> <span class="comment">// Face 3 - triangle strip (v12, v13, v14, v15)</span> <span class="number">16</span><span class="operator">,</span> <span class="number">16</span><span class="operator">,</span> <span class="number">17</span><span class="operator">,</span> <span class="number">18</span><span class="operator">,</span> <span class="number">19</span><span class="operator">,</span> <span class="number">19</span><span class="operator">,</span> <span class="comment">// Face 4 - triangle strip (v16, v17, v18, v19)</span> <span class="number">20</span><span class="operator">,</span> <span class="number">20</span><span class="operator">,</span> <span class="number">21</span><span class="operator">,</span> <span class="number">22</span><span class="operator">,</span> <span class="number">23</span> <span class="comment">// Face 5 - triangle strip (v20, v21, v22, v23)</span> }; <span class="comment">// Transfer vertex data to VBO 0</span> arrayBuf<span class="operator">.</span>bind(); arrayBuf<span class="operator">.</span>allocate(vertices<span class="operator">,</span> <span class="number">24</span> <span class="operator">*</span> <span class="keyword">sizeof</span>(VertexData)); <span class="comment">// Transfer index data to VBO 1</span> indexBuf<span class="operator">.</span>bind(); indexBuf<span class="operator">.</span>allocate(indices<span class="operator">,</span> <span class="number">34</span> <span class="operator">*</span> <span class="keyword">sizeof</span>(GLushort)); } <span class="type">void</span> GeometryEngine<span class="operator">::</span>drawCubeGeometry(<span class="type"><a href="../qtgui/qopenglshaderprogram.html">QOpenGLShaderProgram</a></span> <span class="operator">*</span>program) { <span class="comment">// Tell OpenGL which VBOs to use</span> arrayBuf<span class="operator">.</span>bind(); indexBuf<span class="operator">.</span>bind(); <span class="comment">// Offset for position</span> quintptr offset <span class="operator">=</span> <span class="number">0</span>; <span class="comment">// Tell OpenGL programmable pipeline how to locate vertex position data</span> <span class="type">int</span> vertexLocation <span class="operator">=</span> program<span class="operator">-</span><span class="operator">></span>attributeLocation(<span class="string">"a_position"</span>); program<span class="operator">-</span><span class="operator">></span>enableAttributeArray(vertexLocation); program<span class="operator">-</span><span class="operator">></span>setAttributeBuffer(vertexLocation<span class="operator">,</span> GL_FLOAT<span class="operator">,</span> offset<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="keyword">sizeof</span>(VertexData)); <span class="comment">// Offset for texture coordinate</span> offset <span class="operator">+</span><span class="operator">=</span> <span class="keyword">sizeof</span>(QVector3D); <span class="comment">// Tell OpenGL programmable pipeline how to locate vertex texture coordinate data</span> <span class="type">int</span> texcoordLocation <span class="operator">=</span> program<span class="operator">-</span><span class="operator">></span>attributeLocation(<span class="string">"a_texcoord"</span>); program<span class="operator">-</span><span class="operator">></span>enableAttributeArray(texcoordLocation); program<span class="operator">-</span><span class="operator">></span>setAttributeBuffer(texcoordLocation<span class="operator">,</span> GL_FLOAT<span class="operator">,</span> offset<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="keyword">sizeof</span>(VertexData)); <span class="comment">// Draw cube geometry using indices from VBO 1</span> glDrawElements(GL_TRIANGLE_STRIP<span class="operator">,</span> <span class="number">34</span><span class="operator">,</span> GL_UNSIGNED_SHORT<span class="operator">,</span> <span class="number">0</span>); } </pre> </div> <!-- @@@cube/geometryengine.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>