src/Astro/stars.cxx

   1 // stars.cxx -- data structures and routines for managing and rendering stars.
   2 //
   3 // Written by Curtis Olson, started August 1997.
   4 //
   5 // Copyright (C) 1997  Curtis L. Olson  - curt@me.umn.edu
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 //
  21 // $Id$
  22 //*************************************************************************/
  23
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include <config.h>
  27 #endif
  28
  29 #ifdef HAVE_WINDOWS_H
  30 #  include <windows.h>
  31 #endif
  32
  33 #include "Include/compiler.h"
  34 #ifdef FG_HAVE_STD_INCLUDES
  35 #  include <cmath>
  36 #  include <cstdio>
  37 #  include <cstring>
  38 #  include <ctime>
  39 #else
  40 #  include <math.h>
  41 #  include <stdio.h>
  42 #  include <string.h>
  43 #  include <time.h>
  44 #endif
  45
  46 #include <string>
  47
  48 #include <GL/glut.h>
  49 #include <XGL/xgl.h>
  50
  51 #include <Aircraft/aircraft.hxx>
  52 #include <Debug/logstream.hxx>
  53 #include <Include/fg_constants.h>
  54 #include <Misc/fgpath.hxx>
  55 #include <Misc/fgstream.hxx>
  56 #include <Misc/stopwatch.hxx>
  57 #include <Main/options.hxx>
  58 #include <Main/views.hxx>
  59 #include <Time/fg_time.hxx>
  60 #include "Misc/stopwatch.hxx"
  61
  62 #include "stars.hxx"
  63
  64 FG_USING_STD(getline);
  65
  66 #define EpochStart           (631065600)
  67 #define DaysSinceEpoch(secs) (((secs)-EpochStart)*(1.0/(24*3600)))
  68 #define FG_MAX_STARS 3500
  69
  70 // Define four structures, each with varying amounts of stars
  71 static GLint stars[FG_STAR_LEVELS];
  72
  73
  74 // Initialize the Star Management Subsystem
  75 int fgStarsInit( void ) {
  76     // -dw- avoid local data > 32k error by dynamic allocation of the
  77     // array, problem for some compilers
  78     Point3D *starlist = new Point3D[FG_MAX_STARS];
  79     // struct CelestialCoord pltPos;
  80     double right_ascension, declination, magnitude;
  81     double min_magnitude[FG_STAR_LEVELS];
  82     // double ra_save, decl_save;
  83     // double ra_save1, decl_save1;
  84     int i, j, starcount, count;
  85
  86     FG_LOG( FG_ASTRO, FG_INFO, "Initializing stars" );
  87
  88     if ( FG_STAR_LEVELS < 4 ) {
  89         FG_LOG( FG_ASTRO, FG_ALERT, "Big whups in stars.cxx" );
  90         exit(-1);
  91     }
  92
  93     // build the full path name to the stars data base file
  94     FGPath path ( current_options.get_fg_root() );
  95     path.append( "Astro/stars" );
  96     FG_LOG( FG_ASTRO, FG_INFO, "  Loading stars from " << path.str() );
  97
  98     fg_gzifstream in( path.str() );
  99     if ( ! in ) {
 100         FG_LOG( FG_ASTRO, FG_ALERT, "Cannot open star file: " << path.str() );
 101         exit(-1);
 102     }
 103
 104     starcount = 0;
 105
 106     StopWatch timer;
 107     timer.start();
 108
 109     // read in each line of the file
 110     while ( ! in.eof() && starcount < FG_MAX_STARS )
 111     {
 112         in >> skipcomment;
 113         string name;
 114         getline( in, name, ',' );
 115         in >> starlist[starcount];
 116         ++starcount;
 117     }
 118
 119     timer.stop();
 120     FG_LOG( FG_ASTRO, FG_INFO,
 121             "Loaded " << starcount << " stars in "
 122             << timer.elapsedSeconds() << " seconds" );
 123
 124     min_magnitude[0] = 4.2;
 125     min_magnitude[1] = 3.6;
 126     min_magnitude[2] = 3.0;
 127     min_magnitude[3] = 2.4;
 128     min_magnitude[4] = 1.8;
 129     min_magnitude[5] = 1.2;
 130     min_magnitude[6] = 0.6;
 131     min_magnitude[7] = 0.0;
 132
 133     // build the various star display lists
 134     for ( i = 0; i < FG_STAR_LEVELS; i++ ) {
 135
 136         stars[i] = xglGenLists(1);
 137         xglNewList( stars[i], GL_COMPILE );
 138         xglBegin( GL_POINTS );
 139
 140         count = 0;
 141
 142         for ( j = 0; j < starcount; j++ ) {
 143             magnitude = starlist[j].z();
 144             // printf("magnitude = %.2f\n", magnitude);
 145
 146             if ( magnitude < min_magnitude[i] ) {
 147                 right_ascension = starlist[j].x();
 148                 declination = starlist[j].y();
 149
 150                 count++;
 151
 152                 // scale magnitudes to (0.0 - 1.0)
 153                 magnitude = (0.0 - magnitude) / 5.0 + 1.0;
 154
 155                 // scale magnitudes again so they look ok
 156                 if ( magnitude > 1.0 ) { magnitude = 1.0; }
 157                 if ( magnitude < 0.0 ) { magnitude = 0.0; }
 158                 // magnitude =
 159                 //     magnitude * 0.7 + (((FG_STAR_LEVELS - 1) - i) * 0.042);
 160
 161                 magnitude = magnitude * 0.9 +
 162                     (((FG_STAR_LEVELS - 1) - i) * 0.014);
 163                 // printf("  Found star: %d %s, %.3f %.3f %.3f\n", count,
 164                 //        name, right_ascension, declination, magnitude);
 165
 166                 xglColor3f( magnitude, magnitude, magnitude );
 167                 //xglColor3f(0,0,0);*/
 168                 xglVertex3f( 50000.0*cos(right_ascension)*cos(declination),
 169                              50000.0*sin(right_ascension)*cos(declination),
 170                              50000.0*sin(declination) );
 171             }
 172         } // while
 173
 174         xglEnd();
 175
 176         /*
 177         xglBegin(GL_LINE_LOOP);
 178         xglColor3f(1.0, 0.0, 0.0);
 179         xglVertex3f( 50000.0 * cos(ra_save-0.2) * cos(decl_save-0.2),
 180                     50000.0 * sin(ra_save-0.2) * cos(decl_save-0.2),
 181                     50000.0 * sin(decl_save-0.2) );
 182         xglVertex3f( 50000.0 * cos(ra_save+0.2) * cos(decl_save-0.2),
 183                     50000.0 * sin(ra_save+0.2) * cos(decl_save-0.2),
 184                     50000.0 * sin(decl_save-0.2) );
 185         xglVertex3f( 50000.0 * cos(ra_save+0.2) * cos(decl_save+0.2),
 186                     50000.0 * sin(ra_save+0.2) * cos(decl_save+0.2),
 187                     50000.0 * sin(decl_save+0.2) );
 188         xglVertex3f( 50000.0 * cos(ra_save-0.2) * cos(decl_save+0.2),
 189                     50000.0 * sin(ra_save-0.2) * cos(decl_save+0.2),
 190                     50000.0 * sin(decl_save+0.2) );
 191         xglEnd();
 192         */
 193
 194         /*
 195         xglBegin(GL_LINE_LOOP);
 196         xglColor3f(0.0, 1.0, 0.0);
 197         xglVertex3f( 50000.0 * cos(ra_save1-0.2) * cos(decl_save1-0.2),
 198                     50000.0 * sin(ra_save1-0.2) * cos(decl_save1-0.2),
 199                     50000.0 * sin(decl_save1-0.2) );
 200         xglVertex3f( 50000.0 * cos(ra_save1+0.2) * cos(decl_save1-0.2),
 201                     50000.0 * sin(ra_save1+0.2) * cos(decl_save1-0.2),
 202                     50000.0 * sin(decl_save1-0.2) );
 203         xglVertex3f( 50000.0 * cos(ra_save1+0.2) * cos(decl_save1+0.2),
 204                     50000.0 * sin(ra_save1+0.2) * cos(decl_save1+0.2),
 205                     50000.0 * sin(decl_save1+0.2) );
 206         xglVertex3f( 50000.0 * cos(ra_save1-0.2) * cos(decl_save1+0.2),
 207                     50000.0 * sin(ra_save1-0.2) * cos(decl_save1+0.2),
 208                     50000.0 * sin(decl_save1+0.2) );
 209         xglEnd();
 210         */
 211
 212         xglEndList();
 213
 214         FG_LOG( FG_ASTRO, FG_INFO,
 215                 "  Loading " << count << " stars brighter than "
 216                 << min_magnitude[i] );
 217     }
 218
 219     return 1;  // OK, we got here because initialization worked.
 220 }
 221
 222
 223 // Draw the Stars
 224 void fgStarsRender( void ) {
 225     FGInterface *f;
 226     fgLIGHT *l;
 227     FGTime *t;
 228     int i;
 229
 230     f = current_aircraft.fdm_state;
 231     l = &cur_light_params;
 232     t = FGTime::cur_time_params;
 233
 234     // FG_PI_2 + 0.1 is about 6 degrees after sundown and before sunrise
 235
 236     // t->sun_angle = 3.0; // to force stars to be drawn (for testing)
 237
 238     // render the stars
 239     if ( l->sun_angle > (FG_PI_2 + 5 * DEG_TO_RAD ) ) {
 240         // determine which star structure to draw
 241         if ( l->sun_angle > (FG_PI_2 + 10.0 * DEG_TO_RAD ) ) {
 242             i = 0;
 243         } else if ( l->sun_angle > (FG_PI_2 + 8.8 * DEG_TO_RAD ) ) {
 244             i = 1;
 245         } else if ( l->sun_angle > (FG_PI_2 + 7.5 * DEG_TO_RAD ) ) {
 246             i = 2;
 247         } else if ( l->sun_angle > (FG_PI_2 + 7.0 * DEG_TO_RAD ) ) {
 248             i = 3;
 249         } else if ( l->sun_angle > (FG_PI_2 + 6.5 * DEG_TO_RAD ) ) {
 250             i = 4;
 251         } else if ( l->sun_angle > (FG_PI_2 + 6.0 * DEG_TO_RAD ) ) {
 252             i = 5;
 253         } else if ( l->sun_angle > (FG_PI_2 + 5.5 * DEG_TO_RAD ) ) {
 254             i = 6;
 255         } else {
 256             i = 7;
 257         }
 258
 259         // printf("RENDERING STARS = %d (night)\n", i);
 260
 261         xglCallList(stars[i]);
 262     } else {
 263         // printf("not RENDERING STARS (day)\n");
 264     }
 265 }
 266
 267