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 **************************************************************************/
35 #include <Debug/fg_debug.h>
36 #include <Include/fg_constants.h>
37 #include <Main/views.hxx>
38 #include <Time/fg_time.h>
39 #include <Time/sunpos.hxx>
47 static struct CelestialCoord sunPos;
49 fgSUNPOS solarPosition;
51 void fgCalcSunPos(struct OrbElements params)
53 double EccAnom, xv, yv, v, r;
55 /* calculate the eccentric anomaly */
56 EccAnom = fgCalcEccAnom(params.M, params.e);
58 /* calculate the Suns distance (r) and its true anomaly (v) */
59 xv = cos(EccAnom) - params.e;
60 yv = sqrt(1.0 - params.e*params.e) * sin(EccAnom);
62 r = sqrt(xv*xv + yv*yv);
64 /* calculate the the Sun's true longitude (lonsun) */
65 solarPosition.lonSun = v + params.w;
67 /* convert true longitude and distance to ecliptic rectangular
68 geocentric coordinates (xs, ys) */
69 solarPosition.xs = r * cos (solarPosition.lonSun);
70 solarPosition.ys = r * sin (solarPosition.lonSun);
71 solarPosition.dist = r;
72 /* return solarPosition; */
76 struct CelestialCoord fgCalculateSun (struct OrbElements params,
79 struct CelestialCoord result;
80 double xe, ye, ze, ecl, actTime;
82 /* calculate the angle between ecliptic and equatorial coordinate
84 actTime = fgCalcActTime (t);
85 ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); // Angle now in Rads
87 /* calculate the sun's ecliptic position */
88 fgCalcSunPos (params);
90 /* convert ecliptic coordinates to equatorial rectangular
91 * geocentric coordinates */
92 xe = solarPosition.xs;
93 ye = solarPosition.ys * cos (ecl);
94 ze = solarPosition.ys * sin (ecl);
96 /* and finally... Calulate Right Ascention and Declination */
97 result.RightAscension = atan2 (ye, xe);
98 result.Declination = atan2 (ze, sqrt (xe * xe + ye * ye));
103 /* Initialize the Sun */
104 void fgSunInit( void ) {
108 float xSun, ySun, zSun;
110 /* GLfloat color[4] = { 1.00, 1.00, 1.00, 1.00 }; */
111 double x_2, x_4, x_8, x_10;
115 l = &cur_light_params;
116 t = &cur_time_params;
119 fgPrintf( FG_ASTRO, FG_INFO, " Initializing the Sun\n");
121 // Calculate basic sun position
122 fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
123 sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
125 // Calculate additional sun position parameters based on the above
126 // position that are needed by other parts of FG
129 fgPrintf( FG_ASTRO, FG_INFO,
130 "Sun found at %f (ra), %f (dec)\n",
131 sunPos.RightAscension, sunPos.Declination);
133 xSun = 60000.0 * cos(sunPos.RightAscension) * cos(sunPos.Declination);
134 ySun = 60000.0 * sin(sunPos.RightAscension) * cos(sunPos.Declination);
135 zSun = 60000.0 * sin(sunPos.Declination);
139 xglDeleteLists(sun_obj, 1);
142 /* printf("First time through, creating sun display list\n"); */
144 sun_obj = xglGenLists(1);
145 xglNewList(sun_obj, GL_COMPILE );
148 t = &cur_time_params;
150 l = &cur_light_params;
152 x_2 = l->sun_angle * l->sun_angle;
157 ambient = (0.4 * pow(1.1, -x_10 / 30.0));
158 if ( ambient < 0.3 ) ambient = 0.3;
159 if ( ambient > 1.0 ) ambient = 1.0;
161 amb[0] = 0.00 + ((ambient * 6.0) - 1.0); /* minimum val = 0.8 */
162 amb[1] = 0.00 + ((ambient * 11.0) - 3.0); /* minimum val = 0.3 */
163 amb[2] = 0.00 + ((ambient * 12.0) - 3.6); /* minimum val = 0.0 */
166 if (amb[0] > 1.0) amb[0] = 1.0;
167 if (amb[1] > 1.0) amb[1] = 1.0;
168 if (amb[2] > 1.0) amb[2] = 1.0;
170 fgPrintf( FG_ASTRO, FG_DEBUG,
171 "Color of the sun: %f, %f, %f\n"
172 "Ambient value : %f\n"
174 amb[0], amb[1], amb[2], ambient, l->sun_angle);
177 xglTranslatef(xSun, ySun, zSun);
178 xglScalef(1400, 1400, 1400);
179 xglColor3f(amb[0], amb[1], amb[2]);
180 glutSolidSphere(1.0, 10, 10);
187 void fgSunRender( void ) {
188 xglCallList(sun_obj);
193 /* Revision 1.1 1998/04/22 13:21:36 curt
194 /* C++ - ifing the code a bit.
196 * Revision 1.10 1998/04/18 04:13:58 curt
197 * Moved fg_debug.c to it's own library.
199 * Revision 1.9 1998/04/03 21:52:51 curt
200 * Converting to Gnu autoconf system.
202 * Revision 1.8 1998/03/09 22:47:25 curt
203 * Incorporated Durk's updates.
205 * Revision 1.7 1998/02/23 19:07:56 curt
206 * Incorporated Durk's Astro/ tweaks. Includes unifying the sun position
207 * calculation code between sun display, and other FG sections that use this
208 * for things like lighting.
210 * Revision 1.6 1998/02/12 21:59:39 curt
211 * Incorporated code changes contributed by Charlie Hotchkiss
212 * <chotchkiss@namg.us.anritsu.com>
214 * Revision 1.5 1998/02/02 20:53:24 curt
217 * Revision 1.4 1998/01/27 00:47:50 curt
218 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
219 * system and commandline/config file processing code.
221 * Revision 1.3 1998/01/19 19:27:00 curt
222 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
223 * This should simplify things tremendously.
225 * Revision 1.2 1998/01/19 18:40:18 curt
226 * Tons of little changes to clean up the code and to remove fatal errors
227 * when building with the c++ compiler.
229 * Revision 1.1 1998/01/07 03:16:20 curt
230 * Moved from .../Src/Scenery/ to .../Src/Astro/
232 * Revision 1.12 1998/01/05 18:44:36 curt
233 * Add an option to advance/decrease time from keyboard.
235 * Revision 1.11 1997/12/30 23:09:40 curt
236 * Worked on winding problem without luck, so back to calling glFrontFace()
237 * 3 times for each scenery area.
239 * Revision 1.10 1997/12/30 20:47:54 curt
240 * Integrated new event manager with subsystem initializations.
242 * Revision 1.9 1997/12/30 16:36:54 curt
243 * Merged in Durk's changes ...
245 * Revision 1.8 1997/12/19 23:35:00 curt
246 * Lot's of tweaking with sky rendering and lighting.
248 * Revision 1.7 1997/12/17 23:12:16 curt
249 * Fixed so moon and sun display lists aren't recreate periodically.
251 * Revision 1.6 1997/12/15 23:55:04 curt
252 * Add xgl wrappers for debugging.
253 * Generate terrain normals on the fly.
255 * Revision 1.5 1997/12/12 21:41:31 curt
256 * More light/material property tweaking ... still a ways off.
258 * Revision 1.4 1997/12/10 22:37:53 curt
259 * Prepended "fg" on the name of all global structures that didn't have it yet.
260 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
262 * Revision 1.3 1997/12/09 05:11:56 curt
263 * Working on tweaking lighting.
265 * Revision 1.2 1997/11/25 19:25:39 curt
266 * Changes to integrate Durk's moon/sun code updates + clean up.
268 * Revision 1.1 1997/10/25 03:16:11 curt
269 * Initial revision of code contributed by Durk Talsma.