1 /**************************************************************************
4 * Written 1997 by Durk Talsma, started October, 1997. For the flight gear
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.
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.
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.
22 * (Log is kept at end of this file)
23 **************************************************************************/
37 #include <Debug/fg_debug.h>
38 #include <Include/fg_constants.h>
39 #include <Main/views.hxx>
40 #include <Time/fg_time.hxx>
41 #include <Time/sunpos.hxx>
49 static struct CelestialCoord sunPos;
51 fgSUNPOS solarPosition;
53 void fgCalcSunPos(struct OrbElements params)
55 double EccAnom, xv, yv, v, r;
57 /* calculate the eccentric anomaly */
58 EccAnom = fgCalcEccAnom(params.M, params.e);
60 /* calculate the Suns distance (r) and its true anomaly (v) */
61 xv = cos(EccAnom) - params.e;
62 yv = sqrt(1.0 - params.e*params.e) * sin(EccAnom);
64 r = sqrt(xv*xv + yv*yv);
66 /* calculate the the Sun's true longitude (lonsun) */
67 solarPosition.lonSun = v + params.w;
69 /* convert true longitude and distance to ecliptic rectangular
70 geocentric coordinates (xs, ys) */
71 solarPosition.xs = r * cos (solarPosition.lonSun);
72 solarPosition.ys = r * sin (solarPosition.lonSun);
73 solarPosition.dist = r;
74 /* return solarPosition; */
78 struct CelestialCoord fgCalculateSun (struct OrbElements params,
81 struct CelestialCoord result;
82 double xe, ye, ze, ecl, actTime;
84 /* calculate the angle between ecliptic and equatorial coordinate
86 actTime = fgCalcActTime (t);
87 ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); // Angle now in Rads
89 /* calculate the sun's ecliptic position */
90 fgCalcSunPos (params);
92 /* convert ecliptic coordinates to equatorial rectangular
93 * geocentric coordinates */
94 xe = solarPosition.xs;
95 ye = solarPosition.ys * cos (ecl);
96 ze = solarPosition.ys * sin (ecl);
98 /* and finally... Calulate Right Ascention and Declination */
99 result.RightAscension = atan2 (ye, xe);
100 result.Declination = atan2 (ze, sqrt (xe * xe + ye * ye));
105 /* Initialize the Sun */
106 void fgSunInit( void ) {
110 float xSun, ySun, zSun;
112 /* GLfloat color[4] = { 1.00, 1.00, 1.00, 1.00 }; */
113 double x_2, x_4, x_8, x_10;
117 l = &cur_light_params;
118 t = &cur_time_params;
121 fgPrintf( FG_ASTRO, FG_INFO, " Initializing the Sun\n");
123 // Calculate basic sun position
124 fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
125 sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
127 // Calculate additional sun position parameters based on the above
128 // position that are needed by other parts of FG
131 fgPrintf( FG_ASTRO, FG_INFO,
132 "Sun found at %f (ra), %f (dec)\n",
133 sunPos.RightAscension, sunPos.Declination);
135 xSun = 60000.0 * cos(sunPos.RightAscension) * cos(sunPos.Declination);
136 ySun = 60000.0 * sin(sunPos.RightAscension) * cos(sunPos.Declination);
137 zSun = 60000.0 * sin(sunPos.Declination);
141 xglDeleteLists(sun_obj, 1);
144 /* printf("First time through, creating sun display list\n"); */
146 sun_obj = xglGenLists(1);
147 xglNewList(sun_obj, GL_COMPILE );
150 t = &cur_time_params;
152 l = &cur_light_params;
154 x_2 = l->sun_angle * l->sun_angle;
159 ambient = (0.4 * pow(1.1, -x_10 / 30.0));
160 if ( ambient < 0.3 ) ambient = 0.3;
161 if ( ambient > 1.0 ) ambient = 1.0;
163 amb[0] = 0.00 + ((ambient * 6.0) - 1.0); /* minimum val = 0.8 */
164 amb[1] = 0.00 + ((ambient * 11.0) - 3.0); /* minimum val = 0.3 */
165 amb[2] = 0.00 + ((ambient * 12.0) - 3.6); /* minimum val = 0.0 */
168 if (amb[0] > 1.0) amb[0] = 1.0;
169 if (amb[1] > 1.0) amb[1] = 1.0;
170 if (amb[2] > 1.0) amb[2] = 1.0;
172 fgPrintf( FG_ASTRO, FG_DEBUG,
173 "Color of the sun: %f, %f, %f\n"
174 "Ambient value : %f\n"
176 amb[0], amb[1], amb[2], ambient, l->sun_angle);
179 xglTranslatef(xSun, ySun, zSun);
180 xglScalef(1400, 1400, 1400);
181 xglColor3f(amb[0], amb[1], amb[2]);
182 glutSolidSphere(1.0, 10, 10);
189 void fgSunRender( void ) {
190 xglCallList(sun_obj);
195 /* Revision 1.4 1998/04/26 05:10:02 curt
196 /* "struct fgLIGHT" -> "fgLIGHT" because fgLIGHT is typedef'd.
198 * Revision 1.3 1998/04/25 22:06:26 curt
199 * Edited cvs log messages in source files ... bad bad bad!
201 * Revision 1.2 1998/04/24 00:45:04 curt
202 * Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
203 * Fixed a bug when generating sky colors.
205 * Revision 1.1 1998/04/22 13:21:36 curt
206 * C++ - ifing the code a bit.
208 * Revision 1.10 1998/04/18 04:13:58 curt
209 * Moved fg_debug.c to it's own library.
211 * Revision 1.9 1998/04/03 21:52:51 curt
212 * Converting to Gnu autoconf system.
214 * Revision 1.8 1998/03/09 22:47:25 curt
215 * Incorporated Durk's updates.
217 * Revision 1.7 1998/02/23 19:07:56 curt
218 * Incorporated Durk's Astro/ tweaks. Includes unifying the sun position
219 * calculation code between sun display, and other FG sections that use this
220 * for things like lighting.
222 * Revision 1.6 1998/02/12 21:59:39 curt
223 * Incorporated code changes contributed by Charlie Hotchkiss
224 * <chotchkiss@namg.us.anritsu.com>
226 * Revision 1.5 1998/02/02 20:53:24 curt
229 * Revision 1.4 1998/01/27 00:47:50 curt
230 * Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
231 * system and commandline/config file processing code.
233 * Revision 1.3 1998/01/19 19:27:00 curt
234 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
235 * This should simplify things tremendously.
237 * Revision 1.2 1998/01/19 18:40:18 curt
238 * Tons of little changes to clean up the code and to remove fatal errors
239 * when building with the c++ compiler.
241 * Revision 1.1 1998/01/07 03:16:20 curt
242 * Moved from .../Src/Scenery/ to .../Src/Astro/
244 * Revision 1.12 1998/01/05 18:44:36 curt
245 * Add an option to advance/decrease time from keyboard.
247 * Revision 1.11 1997/12/30 23:09:40 curt
248 * Worked on winding problem without luck, so back to calling glFrontFace()
249 * 3 times for each scenery area.
251 * Revision 1.10 1997/12/30 20:47:54 curt
252 * Integrated new event manager with subsystem initializations.
254 * Revision 1.9 1997/12/30 16:36:54 curt
255 * Merged in Durk's changes ...
257 * Revision 1.8 1997/12/19 23:35:00 curt
258 * Lot's of tweaking with sky rendering and lighting.
260 * Revision 1.7 1997/12/17 23:12:16 curt
261 * Fixed so moon and sun display lists aren't recreate periodically.
263 * Revision 1.6 1997/12/15 23:55:04 curt
264 * Add xgl wrappers for debugging.
265 * Generate terrain normals on the fly.
267 * Revision 1.5 1997/12/12 21:41:31 curt
268 * More light/material property tweaking ... still a ways off.
270 * Revision 1.4 1997/12/10 22:37:53 curt
271 * Prepended "fg" on the name of all global structures that didn't have it yet.
272 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
274 * Revision 1.3 1997/12/09 05:11:56 curt
275 * Working on tweaking lighting.
277 * Revision 1.2 1997/11/25 19:25:39 curt
278 * Changes to integrate Durk's moon/sun code updates + clean up.
280 * Revision 1.1 1997/10/25 03:16:11 curt
281 * Initial revision of code contributed by Durk Talsma.