geo/tcObserver.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 tcObserver.cpp
  22  * @brief Viewing information for an observer.
  23  */
  24
  25 #include "tcObserver.h"
  26 #include <glMatrix.h>
  27
  28 #include <GL/gl.h>
  29
  30 #include <cmath>
  31
  32 /*
  33  * Constructors + destructor
  34  */
  35
  36 /// Primary constructor.
  37 tcObserver::tcObserver()
  38 : m_focus(0.0, 0.0)
  39 , m_focusAltitude(1000e3)
  40 , m_view(0, M_PI/2)
  41 , m_range(100e3)
  42 {
  43 }
  44
  45 /// Destructor.
  46 tcObserver::~tcObserver()
  47 {
  48 }
  49
  50 /*
  51  * Main interface
  52  */
  53
  54 /// Set up the OpenGL projection matrix for this observer.
  55 void tcObserver::setupProjection(double aspect) const
  56 {
  57   glMatrixMode(GL_PROJECTION);
  58   glLoadIdentity();
  59   #define SIZE 5.0
  60   #define NEAR_DISTANCE 10.0
  61   glFrustum(-SIZE*aspect, SIZE*aspect, -SIZE, SIZE, NEAR_DISTANCE, 20000e3);
  62   glMatrixMode(GL_MODELVIEW);
  63 }
  64
  65 void drawAxes(float size)
  66 {
  67   glPushMatrix();
  68   glScalef(size, size, size);
  69   glBegin(GL_LINES);
  70   {
  71     glColor3f(1.0f, 1.0f, 1.0f);
  72     glVertex3f(0.0f, 0.0f, 0.0f);
  73     glColor3f(0.0f, 1.0f, 1.0f);
  74     glVertex3f(1.0f, 0.0f, 0.0f);
  75
  76     glColor3f(1.0f, 1.0f, 1.0f);
  77     glVertex3f(0.0f, 0.0f, 0.0f);
  78     glColor3f(1.0f, 0.0f, 1.0f);
  79     glVertex3f(0.0f, 1.0f, 0.0f);
  80
  81     glColor3f(1.0f, 1.0f, 1.0f);
  82     glVertex3f(0.0f, 0.0f, 0.0f);
  83     glColor3f(1.0f, 1.0f, 0.0f);
  84     glVertex3f(0.0f, 0.0f, 1.0f);
  85   }
  86   glEnd();
  87
  88   glPointSize(5);
  89   glEnable(GL_POINT_SMOOTH);
  90   glBegin(GL_POINTS);
  91   {
  92     glColor3f(1.0f, 1.0f, 1.0f);
  93     glVertex3f(0.0f, 0.0f, 0.0f);
  94
  95     glColor3f(0.0f, 1.0f, 1.0f);
  96     glVertex3f(1.0f, 0.0f, 0.0f);
  97
  98     glColor3f(1.0f, 0.0f, 1.0f);
  99     glVertex3f(0.0f, 1.0f, 0.0f);
 100
 101     glColor3f(1.0f, 1.0f, 0.0f);
 102     glVertex3f(0.0f, 0.0f, 1.0f);
 103   }
 104   glEnd();
 105   glPointSize(1);
 106   glPopMatrix();
 107 }
 108
 109 /// Set up the OpenGL modelview matrix for this observer.
 110 void tcObserver::setupModelView() const
 111 {
 112   glLoadIdentity();
 113
 114   // Translate to focus
 115   glTranslatef(0.0f, 0.0f, -m_range);
 116
 117   //drawAxes(50e3f);
 118
 119   // Rotate to surface space
 120   glMultMatrix(m_view);
 121
 122   //drawAxes(50e3f);
 123
 124   // Translate to origin
 125   glTranslatef(0.0f, 0.0f, -m_focusAltitude);
 126
 127   // Rotate to model space
 128   glMultMatrix(m_focus);
 129
 130   //drawAxes(1000e3f);
 131 }
 132
 133 /*
 134  * Mutators
 135  */
 136
 137 /// Adjust the focus directly.
 138 void tcObserver::setFocus(const tcGeo& focus, double altitude)
 139 {
 140   m_focus = focus;
 141   m_focusAltitude = altitude;
 142 }
 143
 144 /// Adjust the focus altitude.
 145 void tcObserver::setFocusAltitude(double altitude)
 146 {
 147   m_focusAltitude = altitude;
 148 }
 149
 150 /// Make a local transformation of the focus.
 151 void tcObserver::moveFocusRelative(double dx, double dy)
 152 {
 153   dx *= 2.0 * m_range / m_focusAltitude;
 154   dy *= 2.0 * m_range / m_focusAltitude;
 155   m_focus.setLat(m_focus.lat() - sin(m_view.azim()) * dx
 156                                + cos(m_view.azim()) * dy);
 157   m_focus.setLon(m_focus.lon() - cos(m_view.azim()) * dx
 158                                - sin(m_view.azim()) * dy);
 159 }
 160
 161 /// Adjust the range exponentially.
 162 void tcObserver::adjustRange(double x)
 163 {
 164   m_range *= exp(x);
 165 }
 166
 167 /// Adjust the azimuth in radians.
 168 void tcObserver::adjustAzimuth(double daz)
 169 {
 170   m_view.setAzim(m_view.azim() + daz);
 171 }
 172
 173 /// Adjust the elevation in radians.
 174 void tcObserver::adjustElevation(double del)
 175 {
 176   m_view.setElev(m_view.elev() + del);
 177 }
 178
 179 /*
 180  * Accessors
 181  */
 182
 183 /// Get the current focus position.
 184 tcGeo tcObserver::focus() const
 185 {
 186   return m_focus;
 187 }
 188
 189 /// Get the current range from the focus.
 190 double tcObserver::range() const
 191 {
 192   return m_range;
 193 }
 194
 195 /// Get the position of the actual observer.
 196 maths::Vector<3,double> tcObserver::position() const
 197 {
 198   // transform m_view*m_range+(0,0,m_focusAltitude) into object space
 199   maths::Vector<3,double> focusOrientedObs = m_view;
 200   focusOrientedObs *= m_range;
 201   focusOrientedObs[2] += m_focusAltitude;
 202   return focusOrientedObs * m_focus.operator maths::Matrix<3,double>();
 203 }
 204
 205 /// Get a ray into the scene from a point on the screen.
 206 maths::Vector<3,double> tcObserver::ray(const maths::Vector<2,double>& pos, double aspect)
 207 {
 208   // Vector to near plane
 209   maths::Vector<3,double> toNear(SIZE*aspect*(-1.0 + 2.0*pos[0]),
 210                                  SIZE*(-1.0 + 2.0*pos[1]),
 211                                  -NEAR_DISTANCE);
 212   // Normalize
 213   toNear.normalize();
 214   // Rotate into modelview
 215   return (toNear * m_view.operator maths::Matrix<3,double>()) * m_focus.operator maths::Matrix<3,double>();
 216 }