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flightgear/Scenery/stars.c
curt ad22cbffca Working on getting stars right.
1997-09-05 01:35:53 +00:00

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6.4 KiB
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/**************************************************************************
* stars.c -- data structures and routines for managing and rendering stars.
*
* Written by Curtis Olson, started August 1997.
*
* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
* (Log is kept at end of this file)
**************************************************************************/
#ifdef WIN32
# include <windows.h>
#endif
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <GL/glut.h>
#include "stars.h"
#include "../constants.h"
#include "../general.h"
#include "../GLUT/views.h"
#include "../Aircraft/aircraft.h"
#define EpochStart (631065600)
#define DaysSinceEpoch(secs) (((secs)-EpochStart)*(1.0/(24*3600)))
static GLint stars;
/* Initialize the Star Management Subsystem */
void fgStarsInit() {
FILE *fd;
struct GENERAL *g;
char path[1024];
char line[256], name[256];
char *front, *end;
double right_ascension, declination, magnitude;
double ra_save, decl_save;
double ra_save1, decl_save1;
double ra_save2, decl_save2;
GLfloat mag[4] = {0.0, 0.0, 0.0, 1.0};
int count;
g = &general;
/* build the full path name to the stars data base file */
path[0] = '\0';
strcat(path, g->root_dir);
strcat(path, "/Scenery/");
strcat(path, "Stars.dat");
printf("Loading Stars: %s\n", path);
if ( (fd = fopen(path, "r")) == NULL ) {
printf("Cannot open star file: '%s'\n", path);
return;
}
stars = glGenLists(1);
glNewList( stars, GL_COMPILE );
glBegin( GL_POINTS );
/* read in each line of the file */
count = 0;
while ( (fgets(line, 256, fd) != NULL) && (count < FG_MAX_STARS) ) {
front = line;
/* printf("Read line = %s", front); */
/* advance to first non-whitespace character */
while ( (front[0] == ' ') || (front[0] == '\t') ) {
front++;
}
/* printf("Line length (after trimming) = %d\n", strlen(front)); */
if ( front[0] == '#' ) {
/* comment */
} else if ( strlen(front) <= 1 ) {
/* blank line */
} else {
/* star data line */
/* get name */
end = front;
while ( end[0] != ',' ) {
end++;
}
end[0] = '\0';
strcpy(name, front);
front = end;
front++;
sscanf(front, "%lf,%lf,%lf\n",
&right_ascension, &declination, &magnitude);
if ( strcmp(name, "Deneb") == 0 ) {
printf("\n*** Marking %s\n\n", name);
ra_save = right_ascension;
decl_save = declination;
}
if ( strcmp(name, "Alderamin") == 0 ) {
printf("\n*** Marking %s\n\n", name);
ra_save1 = right_ascension;
decl_save1 = declination;
}
/* scale magnitudes to (0.0 - 1.0) */
magnitude = (-1.46 - magnitude) / 10.0 + 1.0;
/* scale magnitudes again so they look ok */
magnitude = magnitude * 0.8 + 0.2;
mag[0] = mag[1] = mag[2] = magnitude;
printf("Found star: %d %s, %.3f %.3f %.3f\n", count,
name, right_ascension, declination, magnitude);
glColor3f( mag[0], mag[1], mag[2] );
glVertex3f( 190000.0 * sin(right_ascension) * cos(declination),
190000.0 * cos(right_ascension) * cos(declination),
190000.0 * sin(declination) );
count++;
} /* if valid line */
} /* while */
fclose(fd);
glEnd();
glBegin(GL_LINE_LOOP);
glColor3f(1.0, 0.0, 0.0);
glVertex3f( 190000.0 * sin(ra_save-0.2) * cos(decl_save-0.2),
190000.0 * cos(ra_save-0.2) * cos(decl_save-0.2),
190000.0 * sin(decl_save-0.2) );
glVertex3f( 190000.0 * sin(ra_save+0.2) * cos(decl_save-0.2),
190000.0 * cos(ra_save+0.2) * cos(decl_save-0.2),
190000.0 * sin(decl_save-0.2) );
glVertex3f( 190000.0 * sin(ra_save+0.2) * cos(decl_save+0.2),
190000.0 * cos(ra_save+0.2) * cos(decl_save+0.2),
190000.0 * sin(decl_save+0.2) );
glVertex3f( 190000.0 * sin(ra_save-0.2) * cos(decl_save+0.2),
190000.0 * cos(ra_save-0.2) * cos(decl_save+0.2),
190000.0 * sin(decl_save+0.2) );
glEnd();
glBegin(GL_LINE_LOOP);
glColor3f(0.0, 1.0, 0.0);
glVertex3f( 190000.0 * sin(ra_save1-0.2) * cos(decl_save1-0.2),
190000.0 * cos(ra_save1-0.2) * cos(decl_save1-0.2),
190000.0 * sin(decl_save1-0.2) );
glVertex3f( 190000.0 * sin(ra_save1+0.2) * cos(decl_save1-0.2),
190000.0 * cos(ra_save1+0.2) * cos(decl_save1-0.2),
190000.0 * sin(decl_save1-0.2) );
glVertex3f( 190000.0 * sin(ra_save1+0.2) * cos(decl_save1+0.2),
190000.0 * cos(ra_save1+0.2) * cos(decl_save1+0.2),
190000.0 * sin(decl_save1+0.2) );
glVertex3f( 190000.0 * sin(ra_save1-0.2) * cos(decl_save1+0.2),
190000.0 * cos(ra_save1-0.2) * cos(decl_save1+0.2),
190000.0 * sin(decl_save1+0.2) );
glEnd();
glEndList();
}
/* Draw the Stars */
void fgStarsRender() {
struct FLIGHT *f;
struct VIEW *v;
double angle;
f = &current_aircraft.flight;
v = &current_view;
printf("RENDERING STARS\n");
glDisable( GL_FOG );
glDisable( GL_LIGHTING );
glPushMatrix();
glTranslatef( v->view_pos.x, v->view_pos.y, v->view_pos.z );
angle = FG_2PI * fmod(DaysSinceEpoch(time(NULL)), 1.0);
glRotatef( -angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
printf("Rotating stars by %.2f\n", -angle * RAD_TO_DEG);
glCallList(stars);
glPopMatrix();
glEnable( GL_LIGHTING );
glEnable( GL_FOG );
}
/* $Log$
/* Revision 1.5 1997/09/05 01:35:59 curt
/* Working on getting stars right.
/*
* Revision 1.4 1997/09/04 02:17:38 curt
* Shufflin' stuff.
*
* Revision 1.3 1997/08/29 17:55:28 curt
* Worked on properly aligning the stars.
*
* Revision 1.2 1997/08/27 21:32:30 curt
* Restructured view calculation code. Added stars.
*
* Revision 1.1 1997/08/27 03:34:48 curt
* Initial revision.
*
*/
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