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     GLfloat mag[4] = {0.0, 0.0, 0.0, 1.0};
  66     int count;
  67
  68     g = &general;
  69
  70     /* build the full path name to the stars data base file */
  71     path[0] = '\0';
  72     strcat(path, g->root_dir);
  73     strcat(path, "/Scenery/");
  74     strcat(path, "Stars.dat");
  75
  76     printf("Loading Stars: %s\n", path);
  77
  78     if ( (fd = fopen(path, "r")) == NULL ) {
  79         printf("Cannot open star file: '%s'\n", path);
  80         return;
  81     }
  82
  83     stars = glGenLists(1);
  84     glNewList( stars, GL_COMPILE );
  85     glBegin( GL_POINTS );
  86
  87     /* read in each line of the file */
  88     count = 0;
  89     while ( (fgets(line, 256, fd) != NULL) && (count < FG_MAX_STARS) ) {
  90         front = line;
  91
  92         /* printf("Read line = %s", front); */
  93
  94         /* advance to first non-whitespace character */
  95         while ( (front[0] == ' ') || (front[0] == '\t') ) {
  96             front++;
  97         }
  98
  99         /* printf("Line length (after trimming) = %d\n", strlen(front)); */
 100
 101         if ( front[0] == '#' ) {
 102             /* comment */
 103         } else if ( strlen(front) <= 1 ) {
 104             /* blank line */
 105         } else {
 106             /* star data line */
 107
 108             /* get name */
 109             end = front;
 110             while ( end[0] != ',' ) {
 111                 end++;
 112             }
 113             end[0] = '\0';
 114             strcpy(name, front);
 115             front = end;
 116             front++;
 117
 118             sscanf(front, "%lf,%lf,%lf\n",
 119                    &right_ascension, &declination, &magnitude);
 120
 121             if ( strcmp(name, "Deneb") == 0 ) {
 122                 printf("\n*** Marking %s\n\n", name);
 123                 ra_save = right_ascension;
 124                 decl_save = declination;
 125             }
 126
 127             if ( strcmp(name, "Alderamin") == 0 ) {
 128                 printf("\n*** Marking %s\n\n", name);
 129                 ra_save1 = right_ascension;
 130                 decl_save1 = declination;
 131             }
 132
 133             /* scale magnitudes to (0.0 - 1.0) */
 134             magnitude = (-1.46 - magnitude) / 10.0 + 1.0;
 135
 136             /* scale magnitudes again so they look ok */
 137             magnitude = magnitude * 0.8 + 0.2;
 138             mag[0] = mag[1] = mag[2] = magnitude;
 139
 140             printf("Found star: %d %s, %.3f %.3f %.3f\n", count,
 141                name, right_ascension, declination, magnitude);
 142
 143             glColor3f( mag[0], mag[1], mag[2] );
 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
 199     f = &current_aircraft.flight;
 200     v = &current_view;
 201
 202     printf("RENDERING STARS\n");
 203
 204     glDisable( GL_FOG );
 205     glDisable( GL_LIGHTING );
 206     glPushMatrix();
 207
 208     glTranslatef( v->view_pos.x, v->view_pos.y, v->view_pos.z );
 209
 210     angle = FG_2PI * fmod(DaysSinceEpoch(time(NULL)), 1.0);
 211     glRotatef( -angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
 212     printf("Rotating stars by %.2f\n", -angle * RAD_TO_DEG);
 213
 214     glCallList(stars);
 215
 216     glPopMatrix();
 217     glEnable( GL_LIGHTING );
 218     glEnable( GL_FOG );
 219 }
 220
 221
 222 /* $Log$
 223 /* Revision 1.5  1997/09/05 01:35:59  curt
 224 /* Working on getting stars right.
 225 /*
 226  * Revision 1.4  1997/09/04 02:17:38  curt
 227  * Shufflin' stuff.
 228  *
 229  * Revision 1.3  1997/08/29 17:55:28  curt
 230  * Worked on properly aligning the stars.
 231  *
 232  * Revision 1.2  1997/08/27 21:32:30  curt
 233  * Restructured view calculation code.  Added stars.
 234  *
 235  * Revision 1.1  1997/08/27 03:34:48  curt
 236  * Initial revision.
 237  *
 238  */