Scenery/stars.c

   1 /**************************************************************************
   2  * stars.c -- data structures and routines for managing and rendering stars.
   3  *
   4  * Written by Curtis Olson, started August 1997.
   5  *
   6  * Copyright (C) 1997  Curtis L. Olson  - curt@infoplane.com
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  * $Id$
  23  * (Log is kept at end of this file)
  24  **************************************************************************/
  25
  26
  27 #ifdef WIN32
  28 #  include <windows.h>
  29 #endif
  30
  31 #include <math.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <time.h>
  35
  36 #include <GL/glut.h>
  37
  38 #include "stars.h"
  39
  40 #include "../constants.h"
  41 #include "../general.h"
  42
  43 #include "../GLUT/views.h"
  44 #include "../Aircraft/aircraft.h"
  45
  46
  47 #define EpochStart           (631065600)
  48 #define DaysSinceEpoch(secs) (((secs)-EpochStart)*(1.0/(24*3600)))
  49
  50
  51 static GLint stars;
  52
  53
  54 /* Initialize the Star Management Subsystem */
  55 void fgStarsInit() {
  56     FILE *fd;
  57     struct GENERAL *g;
  58     char path[1024];
  59     char line[256], name[256];
  60     char *front, *end;
  61     double right_ascension, declination, magnitude;
  62     double ra_save, decl_save;
  63     double ra_save1, decl_save1;
  64     double ra_save2, decl_save2;
  65     int count;
  66
  67     g = &general;
  68
  69     /* build the full path name to the stars data base file */
  70     path[0] = '\0';
  71     strcat(path, g->root_dir);
  72     strcat(path, "/Scenery/");
  73     strcat(path, "Stars.dat");
  74
  75     printf("Loading Stars: %s\n", path);
  76
  77     if ( (fd = fopen(path, "r")) == NULL ) {
  78         printf("Cannot open star file: '%s'\n", path);
  79         return;
  80     }
  81
  82     stars = glGenLists(1);
  83     glNewList( stars, GL_COMPILE );
  84     glBegin( GL_POINTS );
  85
  86     /* read in each line of the file */
  87     count = 0;
  88     while ( (fgets(line, 256, fd) != NULL) && (count < FG_MAX_STARS) ) {
  89         front = line;
  90
  91         /* printf("Read line = %s", front); */
  92
  93         /* advance to first non-whitespace character */
  94         while ( (front[0] == ' ') || (front[0] == '\t') ) {
  95             front++;
  96         }
  97
  98         /* printf("Line length (after trimming) = %d\n", strlen(front)); */
  99
 100         if ( front[0] == '#' ) {
 101             /* comment */
 102         } else if ( strlen(front) <= 1 ) {
 103             /* blank line */
 104         } else {
 105             /* star data line */
 106
 107             /* get name */
 108             end = front;
 109             while ( end[0] != ',' ) {
 110                 end++;
 111             }
 112             end[0] = '\0';
 113             strcpy(name, front);
 114             front = end;
 115             front++;
 116
 117             sscanf(front, "%lf,%lf,%lf\n",
 118                    &right_ascension, &declination, &magnitude);
 119
 120             if ( strcmp(name, "Merak") == 0 ) {
 121                 printf("\n*** Marking %s\n\n", name);
 122                 ra_save = right_ascension;
 123                 decl_save = declination;
 124             }
 125
 126             if ( strcmp(name, "Rastaban") == 0 ) {
 127                 printf("\n*** Marking %s\n\n", name);
 128                 ra_save1 = right_ascension;
 129                 decl_save1 = declination;
 130             }
 131
 132             /* scale magnitudes to (0.0 - 1.0) */
 133             magnitude = (0.0 - magnitude) / 5.0 + 1.0;
 134
 135             /* scale magnitudes again so they look ok */
 136             if ( magnitude > 1.0 ) { magnitude = 1.0; }
 137             if ( magnitude < 0.0 ) { magnitude = 0.0; }
 138             magnitude = magnitude * 0.8 + 0.2;
 139
 140             printf("Found star: %d %s, %.3f %.3f %.3f\n", count,
 141                name, right_ascension, declination, magnitude);
 142
 143             glColor3f( magnitude, magnitude, magnitude );
 144             glVertex3f( 190000.0 * sin(right_ascension) * cos(declination),
 145                         -190000.0 * cos(right_ascension) * cos(declination),
 146                         190000.0 * sin(declination) );
 147
 148             count++;
 149         } /* if valid line */
 150
 151     } /* while */
 152
 153     fclose(fd);
 154
 155     glEnd();
 156
 157     glBegin(GL_LINE_LOOP);
 158         glColor3f(1.0, 0.0, 0.0);
 159         glVertex3f( 190000.0 * sin(ra_save-0.2) * cos(decl_save-0.2),
 160                     -190000.0 * cos(ra_save-0.2) * cos(decl_save-0.2),
 161                     190000.0 * sin(decl_save-0.2) );
 162         glVertex3f( 190000.0 * sin(ra_save+0.2) * cos(decl_save-0.2),
 163                     -190000.0 * cos(ra_save+0.2) * cos(decl_save-0.2),
 164                     190000.0 * sin(decl_save-0.2) );
 165         glVertex3f( 190000.0 * sin(ra_save+0.2) * cos(decl_save+0.2),
 166                     -190000.0 * cos(ra_save+0.2) * cos(decl_save+0.2),
 167                     190000.0 * sin(decl_save+0.2) );
 168         glVertex3f( 190000.0 * sin(ra_save-0.2) * cos(decl_save+0.2),
 169                     -190000.0 * cos(ra_save-0.2) * cos(decl_save+0.2),
 170                     190000.0 * sin(decl_save+0.2) );
 171     glEnd();
 172
 173     glBegin(GL_LINE_LOOP);
 174         glColor3f(0.0, 1.0, 0.0);
 175         glVertex3f( 190000.0 * sin(ra_save1-0.2) * cos(decl_save1-0.2),
 176                     -190000.0 * cos(ra_save1-0.2) * cos(decl_save1-0.2),
 177                     190000.0 * sin(decl_save1-0.2) );
 178         glVertex3f( 190000.0 * sin(ra_save1+0.2) * cos(decl_save1-0.2),
 179                     -190000.0 * cos(ra_save1+0.2) * cos(decl_save1-0.2),
 180                     190000.0 * sin(decl_save1-0.2) );
 181         glVertex3f( 190000.0 * sin(ra_save1+0.2) * cos(decl_save1+0.2),
 182                     -190000.0 * cos(ra_save1+0.2) * cos(decl_save1+0.2),
 183                     190000.0 * sin(decl_save1+0.2) );
 184         glVertex3f( 190000.0 * sin(ra_save1-0.2) * cos(decl_save1+0.2),
 185                     -190000.0 * cos(ra_save1-0.2) * cos(decl_save1+0.2),
 186                     190000.0 * sin(decl_save1+0.2) );
 187     glEnd();
 188
 189     glEndList();
 190 }
 191
 192
 193 /* Draw the Stars */
 194 void fgStarsRender() {
 195     struct FLIGHT *f;
 196     struct VIEW *v;
 197     double angle;
 198     static double warp = 0;
 199
 200     f = &current_aircraft.flight;
 201     v = &current_view;
 202
 203     printf("RENDERING STARS\n");
 204
 205     glDisable( GL_FOG );
 206     glDisable( GL_LIGHTING );
 207     glPushMatrix();
 208
 209     glTranslatef( v->view_pos.x, v->view_pos.y, v->view_pos.z );
 210
 211     angle = FG_2PI * fmod(DaysSinceEpoch(time(NULL)), 1.0);
 212     warp += 0.5 * DEG_TO_RAD;
 213     warp = 240.0 * DEG_TO_RAD;
 214     glRotatef( -(angle+warp) * RAD_TO_DEG, 0.0, 0.0, 1.0 );
 215     printf("Rotating stars by %.2f + %.2f\n", -angle * RAD_TO_DEG,
 216         warp * RAD_TO_DEG);
 217
 218     glCallList(stars);
 219
 220     glPopMatrix();
 221     glEnable( GL_LIGHTING );
 222     glEnable( GL_FOG );
 223 }
 224
 225
 226 /* $Log$
 227 /* Revision 1.6  1997/09/05 14:17:31  curt
 228 /* More tweaking with stars.
 229 /*
 230  * Revision 1.5  1997/09/05 01:35:59  curt
 231  * Working on getting stars right.
 232  *
 233  * Revision 1.4  1997/09/04 02:17:38  curt
 234  * Shufflin' stuff.
 235  *
 236  * Revision 1.3  1997/08/29 17:55:28  curt
 237  * Worked on properly aligning the stars.
 238  *
 239  * Revision 1.2  1997/08/27 21:32:30  curt
 240  * Restructured view calculation code.  Added stars.
 241  *
 242  * Revision 1.1  1997/08/27 03:34:48  curt
 243  * Initial revision.
 244  *
 245  */