simgear/ephemeris/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 <simgear/compiler.h>
  34
  35 #ifdef FG_HAVE_STD_INCLUDES
  36 #  include <cmath>
  37 #  include <cstdio>
  38 #  include <cstring>
  39 #  include <ctime>
  40 #else
  41 #  include <math.h>
  42 #  include <stdio.h>
  43 #  include <string.h>
  44 #  include <time.h>
  45 #endif
  46
  47 #include <string>
  48
  49 #include <GL/glut.h>
  50 #include <simgear/xgl/xgl.h>
  51
  52 #include <simgear/constants.h>
  53 #include <simgear/debug/logstream.hxx>
  54 #include <simgear/misc/fgpath.hxx>
  55 #include <simgear/misc/fgstream.hxx>
  56 #include <simgear/misc/stopwatch.hxx>
  57
  58 #include <Aircraft/aircraft.hxx>
  59 #include <Main/options.hxx>
  60 #include <Main/views.hxx>
  61 #include <Time/fg_time.hxx>
  62
  63 #include "stars.hxx"
  64
  65 // FG_USING_STD(getline);
  66
  67 #define EpochStart           (631065600)
  68 #define DaysSinceEpoch(secs) (((secs)-EpochStart)*(1.0/(24*3600)))
  69 #define FG_MAX_STARS 3500
  70
  71 // Define four structures, each with varying amounts of stars
  72 static GLint stars[FG_STAR_LEVELS];
  73
  74
  75 // Initialize the Star Management Subsystem
  76 int fgStarsInit( void ) {
  77     // -dw- avoid local data > 32k error by dynamic allocation of the
  78     // array, problem for some compilers
  79     Point3D *starlist = new Point3D[FG_MAX_STARS];
  80     // struct CelestialCoord pltPos;
  81     double right_ascension, declination, magnitude;
  82     double min_magnitude[FG_STAR_LEVELS];
  83     // double ra_save, decl_save;
  84     // double ra_save1, decl_save1;
  85     int i, j, starcount, count;
  86
  87     FG_LOG( FG_ASTRO, FG_INFO, "Initializing stars" );
  88
  89     if ( FG_STAR_LEVELS < 4 ) {
  90         FG_LOG( FG_ASTRO, FG_ALERT, "Big whups in stars.cxx" );
  91         exit(-1);
  92     }
  93
  94     // build the full path name to the stars data base file
  95     FGPath path ( current_options.get_fg_root() );
  96     path.append( "Astro/stars" );
  97     FG_LOG( FG_ASTRO, FG_INFO, "  Loading stars from " << path.str() );
  98
  99     fg_gzifstream in( path.str() );
 100     if ( ! in ) {
 101         FG_LOG( FG_ASTRO, FG_ALERT, "Cannot open star file: " << path.str() );
 102         exit(-1);
 103     }
 104
 105     starcount = 0;
 106
 107     StopWatch timer;
 108     timer.start();
 109
 110     // read in each line of the file
 111     while ( ! in.eof() && starcount < FG_MAX_STARS )
 112     {
 113         in >> skipcomment;
 114         string name;
 115         getline( in, name, ',' );
 116         in >> starlist[starcount];
 117         ++starcount;
 118     }
 119
 120     timer.stop();
 121     FG_LOG( FG_ASTRO, FG_INFO,
 122             "Loaded " << starcount << " stars in "
 123             << timer.elapsedSeconds() << " seconds" );
 124
 125     min_magnitude[0] = 4.2;
 126     min_magnitude[1] = 3.6;
 127     min_magnitude[2] = 3.0;
 128     min_magnitude[3] = 2.4;
 129     min_magnitude[4] = 1.8;
 130     min_magnitude[5] = 1.2;
 131     min_magnitude[6] = 0.6;
 132     min_magnitude[7] = 0.0;
 133
 134     // build the various star display lists
 135     for ( i = 0; i < FG_STAR_LEVELS; i++ ) {
 136
 137         stars[i] = xglGenLists(1);
 138         xglNewList( stars[i], GL_COMPILE );
 139         xglBegin( GL_POINTS );
 140
 141         count = 0;
 142
 143         for ( j = 0; j < starcount; j++ ) {
 144             magnitude = starlist[j].z();
 145             // printf("magnitude = %.2f\n", magnitude);
 146
 147             if ( magnitude < min_magnitude[i] ) {
 148                 right_ascension = starlist[j].x();
 149                 declination = starlist[j].y();
 150
 151                 count++;
 152
 153                 // scale magnitudes to (0.0 - 1.0)
 154                 magnitude = (0.0 - magnitude) / 5.0 + 1.0;
 155
 156                 // scale magnitudes again so they look ok
 157                 if ( magnitude > 1.0 ) { magnitude = 1.0; }
 158                 if ( magnitude < 0.0 ) { magnitude = 0.0; }
 159                 // magnitude =
 160                 //     magnitude * 0.7 + (((FG_STAR_LEVELS - 1) - i) * 0.042);
 161
 162                 magnitude = magnitude * 0.9 +
 163                     (((FG_STAR_LEVELS - 1) - i) * 0.014);
 164                 // printf("  Found star: %d %s, %.3f %.3f %.3f\n", count,
 165                 //        name, right_ascension, declination, magnitude);
 166
 167                 xglColor3f( magnitude, magnitude, magnitude );
 168                 //xglColor3f(0,0,0);*/
 169                 xglVertex3f( 50000.0*cos(right_ascension)*cos(declination),
 170                              50000.0*sin(right_ascension)*cos(declination),
 171                              50000.0*sin(declination) );
 172             }
 173         } // while
 174
 175         xglEnd();
 176
 177         /*
 178         xglBegin(GL_LINE_LOOP);
 179         xglColor3f(1.0, 0.0, 0.0);
 180         xglVertex3f( 50000.0 * cos(ra_save-0.2) * cos(decl_save-0.2),
 181                     50000.0 * sin(ra_save-0.2) * cos(decl_save-0.2),
 182                     50000.0 * sin(decl_save-0.2) );
 183         xglVertex3f( 50000.0 * cos(ra_save+0.2) * cos(decl_save-0.2),
 184                     50000.0 * sin(ra_save+0.2) * cos(decl_save-0.2),
 185                     50000.0 * sin(decl_save-0.2) );
 186         xglVertex3f( 50000.0 * cos(ra_save+0.2) * cos(decl_save+0.2),
 187                     50000.0 * sin(ra_save+0.2) * cos(decl_save+0.2),
 188                     50000.0 * sin(decl_save+0.2) );
 189         xglVertex3f( 50000.0 * cos(ra_save-0.2) * cos(decl_save+0.2),
 190                     50000.0 * sin(ra_save-0.2) * cos(decl_save+0.2),
 191                     50000.0 * sin(decl_save+0.2) );
 192         xglEnd();
 193         */
 194
 195         /*
 196         xglBegin(GL_LINE_LOOP);
 197         xglColor3f(0.0, 1.0, 0.0);
 198         xglVertex3f( 50000.0 * cos(ra_save1-0.2) * cos(decl_save1-0.2),
 199                     50000.0 * sin(ra_save1-0.2) * cos(decl_save1-0.2),
 200                     50000.0 * sin(decl_save1-0.2) );
 201         xglVertex3f( 50000.0 * cos(ra_save1+0.2) * cos(decl_save1-0.2),
 202                     50000.0 * sin(ra_save1+0.2) * cos(decl_save1-0.2),
 203                     50000.0 * sin(decl_save1-0.2) );
 204         xglVertex3f( 50000.0 * cos(ra_save1+0.2) * cos(decl_save1+0.2),
 205                     50000.0 * sin(ra_save1+0.2) * cos(decl_save1+0.2),
 206                     50000.0 * sin(decl_save1+0.2) );
 207         xglVertex3f( 50000.0 * cos(ra_save1-0.2) * cos(decl_save1+0.2),
 208                     50000.0 * sin(ra_save1-0.2) * cos(decl_save1+0.2),
 209                     50000.0 * sin(decl_save1+0.2) );
 210         xglEnd();
 211         */
 212
 213         xglEndList();
 214
 215         FG_LOG( FG_ASTRO, FG_INFO,
 216                 "  Loading " << count << " stars brighter than "
 217                 << min_magnitude[i] );
 218     }
 219
 220     return 1;  // OK, we got here because initialization worked.
 221 }
 222
 223
 224 // Draw the Stars
 225 void fgStarsRender( void ) {
 226     FGInterface *f;
 227     fgLIGHT *l;
 228     FGTime *t;
 229     int i;
 230
 231     f = current_aircraft.fdm_state;
 232     l = &cur_light_params;
 233     t = FGTime::cur_time_params;
 234
 235     // FG_PI_2 + 0.1 is about 6 degrees after sundown and before sunrise
 236
 237     // t->sun_angle = 3.0; // to force stars to be drawn (for testing)
 238
 239     // render the stars
 240     if ( l->sun_angle > (FG_PI_2 + 5 * DEG_TO_RAD ) ) {
 241         // determine which star structure to draw
 242         if ( l->sun_angle > (FG_PI_2 + 10.0 * DEG_TO_RAD ) ) {
 243             i = 0;
 244         } else if ( l->sun_angle > (FG_PI_2 + 8.8 * DEG_TO_RAD ) ) {
 245             i = 1;
 246         } else if ( l->sun_angle > (FG_PI_2 + 7.5 * DEG_TO_RAD ) ) {
 247             i = 2;
 248         } else if ( l->sun_angle > (FG_PI_2 + 7.0 * DEG_TO_RAD ) ) {
 249             i = 3;
 250         } else if ( l->sun_angle > (FG_PI_2 + 6.5 * DEG_TO_RAD ) ) {
 251             i = 4;
 252         } else if ( l->sun_angle > (FG_PI_2 + 6.0 * DEG_TO_RAD ) ) {
 253             i = 5;
 254         } else if ( l->sun_angle > (FG_PI_2 + 5.5 * DEG_TO_RAD ) ) {
 255             i = 6;
 256         } else {
 257             i = 7;
 258         }
 259
 260         // printf("RENDERING STARS = %d (night)\n", i);
 261
 262         xglCallList(stars[i]);
 263     } else {
 264         // printf("not RENDERING STARS (day)\n");
 265     }
 266 }
 267
 268