topographicseries.cpp Example File

texturesurface/topographicseries.cpp
 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Data Visualization module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:GPL$
 ** 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.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3 or (at your option) any later version
 ** approved by the KDE Free Qt Foundation. The licenses are as published by
 ** the Free Software Foundation and appearing in the file LICENSE.GPL3
 ** included in the packaging of this file. Please review the following
 ** information to ensure the GNU General Public License requirements will
 ** be met: https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "topographicseries.h"

 using namespace QtDataVisualization;

 // Value used to encode height data as RGB value on PNG file
 const float packingFactor = 11983.0f;

 TopographicSeries::TopographicSeries()
 {
     setDrawMode(QSurface3DSeries::DrawSurface);
     setFlatShadingEnabled(true);
     setBaseColor(Qt::white);
 }

 TopographicSeries::~TopographicSeries()
 {
 }

 void TopographicSeries::setTopographyFile(const QString file, float width, float height)
 {
     QImage heightMapImage(file);
     uchar *bits = heightMapImage.bits();
     int imageHeight = heightMapImage.height();
     int imageWidth = heightMapImage.width();
     int widthBits = imageWidth * 4;
     float stepX = width / float(imageWidth);
     float stepZ = height / float(imageHeight);

     QSurfaceDataArray *dataArray = new QSurfaceDataArray;
     dataArray->reserve(imageHeight);
     for (int i = 0; i < imageHeight; i++) {
         int p = i * widthBits;
         float z = height - float(i) * stepZ;
         QSurfaceDataRow *newRow = new QSurfaceDataRow(imageWidth);
         for (int j = 0; j < imageWidth; j++) {
             uchar aa = bits[p + 0];
             uchar rr = bits[p + 1];
             uchar gg = bits[p + 2];
             uint color = uint((gg << 16) + (rr << 8) + aa);
             float y = float(color) / packingFactor;
             (*newRow)[j].setPosition(QVector3D(float(j) * stepX, y, z));
             p = p + 4;
         }
         *dataArray << newRow;
     }

     dataProxy()->resetArray(dataArray);

     m_sampleCountX = float(imageWidth);
     m_sampleCountZ = float(imageHeight);
 }