geo/tcElevationData.cpp

   1 /***************************************************************************
   2  *   This file is part of Tecorrec.                                        *
   3  *   Copyright 2008 James Hogan <james@albanarts.com>                      *
   4  *                                                                         *
   5  *   Tecorrec is free software: you can redistribute it and/or modify      *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation, either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   Tecorrec is distributed in the hope that it will be useful,           *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with Tecorrec.  If not, write to the Free Software Foundation,  *
  17  *   Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.   *
  18  ***************************************************************************/
  19
  20 /**
  21  * @file tcElevationData.cpp
  22  * @brief Terrain elevation data.
  23  */
  24
  25 #include "tcElevationData.h"
  26 #include "tcSrtmData.h"
  27 #include <glVector.h>
  28
  29 #include <GL/gl.h>
  30
  31 #include <cmath>
  32
  33 /*
  34  * Constructors + destructor
  35  */
  36
  37 /// Initialise from SRTM data.
  38 tcElevationData::tcElevationData(tcSrtmData* srtm)
  39 : tcGeoData(tcGeoData::ElevationData)
  40 , m_srtm(srtm)
  41 {
  42 }
  43
  44 /// Destructor.
  45 tcElevationData::~tcElevationData()
  46 {
  47 }
  48
  49 /*
  50  * Rendering
  51  */
  52
  53 void tcElevationData::renderSchematic(double meanRadius, tcObserver* const observer)
  54 {
  55   tcGeoData::renderSchematic(meanRadius, observer);
  56
  57   const int iskip = 2;
  58   const int jskip = 2;
  59   for (int i = 0; i < m_srtm->lines()-1; i += iskip)
  60   {
  61     glBegin(GL_TRIANGLE_STRIP);
  62     {
  63       for (int j = 0; j < m_srtm->length(); j += jskip)
  64       {
  65         for (int k = 0; k <= iskip; k += iskip)
  66         {
  67           uint32_t alt = m_srtm->pixelAltitude(i+k,j);
  68           if (alt == 32768)
  69           {
  70             alt = 0;
  71             glColor4f(0.0f, 0.0f, 0.0f, 0.0f);
  72           }
  73           else
  74           {
  75             glColor4f(1.0f, 1.0f-(float)alt/3278.0f, 0.0f, 1.0f);
  76           }
  77           tcGeo coord = m_srtm->pixelCoordinate(i+k,j);
  78           GLvec3d dir = coord;
  79           double rad = meanRadius + alt;
  80           glVertex3(dir * rad);
  81         }
  82       }
  83     }
  84     glEnd();
  85   }
  86 }