mesh.cpp Example File

hellovulkancubes/mesh.cpp
 /****************************************************************************
 **
 ** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples 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."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "mesh.h"
 #include <QtConcurrentRun>
 #include <QFile>

 void Mesh::load(const QString &fn)
 {
     reset();
     m_maybeRunning = true;
     m_future = QtConcurrent::run([fn]() {
         MeshData md;
         QFile f(fn);
         if (!f.open(QIODevice::ReadOnly)) {
             qWarning("Failed to open %s", qPrintable(fn));
             return md;
         }
         QByteArray buf = f.readAll();
         const char *p = buf.constData();
         quint32 format;
         memcpy(&format, p, 4);
         if (format != 1) {
             qWarning("Invalid format in %s", qPrintable(fn));
             return md;
         }
         int ofs = 4;
         memcpy(&md.vertexCount, p + ofs, 4);
         ofs += 4;
         memcpy(md.aabb, p + ofs, 6 * 4);
         ofs += 6 * 4;
         const int byteCount = md.vertexCount * 8 * 4;
         md.geom.resize(byteCount);
         memcpy(md.geom.data(), p + ofs, byteCount);
         return md;
     });
 }

 MeshData *Mesh::data()
 {
     if (m_maybeRunning && !m_data.isValid())
         m_data = m_future.result();

     return &m_data;
 }

 void Mesh::reset()
 {
     *data() = MeshData();
     m_maybeRunning = false;
 }