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 **************************************************************************/
33 #include <Time/fg_time.h>
34 #include <Astro/orbits.h>
35 #include <Astro/planets.h>
36 #include <Astro/sun.h>
37 #include <Include/fg_constants.h>
38 #include <Main/fg_debug.h>
42 struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
43 struct OrbElements theSun,
44 struct fgTIME t, int idx)
53 eccAnom, r, v, ecl, actTime, R, s, ir, Nr, B, FV, ring_magn,
54 xv, yv, xh, yh, zh, xg, yg, zg, xe, ye, ze;
56 actTime = fgCalcActTime(t);
57 /* calculate the angle between ecliptic and equatorial coordinate system */
58 /* ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); */
59 ecl = 0.409093 - 6.2186E-9 * actTime;
61 /* calculate the eccentric anomaly */
62 eccAnom = fgCalcEccAnom(planet.M, planet.e);
64 /* calculate the planets distance (r) and true anomaly (v) */
65 xv = planet.a * (cos(eccAnom) - planet.e);
66 yv = planet.a * (sqrt(1.0 - planet.e*planet.e) * sin(eccAnom));
68 r = sqrt ( xv*xv + yv*yv);
70 /* calculate the planets position in 3-dimensional space */
71 xh = r * ( cos(planet.N) * cos(v+planet.w) - sin(planet.N) * sin(v+planet.w) * cos(planet.i));
72 yh = r * ( sin(planet.N) * cos(v+planet.w) + cos(planet.N) * sin(v+planet.w) * cos(planet.i));
73 zh = r * ( sin(v+planet.w) * sin(planet.i));
75 /* calculate the ecliptic longitude and latitude */
78 lonecl = atan2(yh, xh);
79 latecl = atan2(zh, sqrt ( xh*xh + yh*yh));
81 /* calculate the solar position */
83 SolarPosition = fgCalcSunPos(theSun);
84 xg = xh + SolarPosition.xs;
85 yg = yh + SolarPosition.ys;
89 ye = yg * cos(ecl) - zg * sin(ecl);
90 ze = yg * sin(ecl) + zg * cos(ecl);
92 result.RightAscension = atan2(ye,xe);
93 result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
96 /* Let's calculate the brightness of the planet */
97 R = sqrt ( xg*xg + yg*yg + zg*zg);
98 s = SolarPosition.dist;
99 FV = acos( (r*r + R*R - s*s) / (2*r*R));
100 FV *= 57.29578; /* convert radians to degrees */
103 case 2: /* mercury */
104 result.magnitude = -0.36 + 5*log10( r*R ) + 0.027 * FV + 2.2E-13 * pow(FV, 6);
107 result.magnitude = -4.34 + 5*log10( r*R ) + 0.013 * FV + 4.2E-07 * pow(FV,3);
110 result.magnitude = -1.51 + 5*log10( r*R ) + 0.016 * FV;
112 case 5: /* Jupiter */
113 result.magnitude = -9.25 + 5*log10( r*R ) + 0.014 * FV;
118 Nr = 2.9585076 + 6.6672E-7*actTime;
120 B = asin ( sin (result.Declination) * cos(ir) - cos(result.Declination) * sin (ir) * sin (result.RightAscension - Nr));
121 ring_magn = -2.6 * sin (fabs(B)) + 1.2 * pow(sin(B),2);
122 result.magnitude = -9.0 + 5*log10( r*R ) + 0.044 * FV + ring_magn;
125 result.magnitude = -7.15 + 5*log10( r*R) + 0.001 * FV;
127 case 8: /* Neptune */
128 result.magnitude = -6.90 + 5*log10 (r*R) + 0.001 *FV;
131 fgPrintf( FG_ASTRO, FG_ALERT, "index %d out of range !!!!\n", idx);
133 fgPrintf( FG_ASTRO, FG_DEBUG,
134 " Planet found at %f (ra), %f (dec)\n",
135 result.RightAscension, result.Declination);
136 fgPrintf( FG_ASTRO, FG_DEBUG,
137 " Geocentric dist %f\n"
138 " Heliocentric dist %f\n"
139 " Distance to the sun %f\n"
141 " Brightness %f\n", R, r, s, FV, result.magnitude);
146 void fgPlanetsInit( void )
149 struct CelestialCoord pltPos;
152 /* if the display list was already built during a previous init,
156 xglDeleteLists(planets, 1);
158 planets = xglGenLists(1);
159 xglNewList( planets, GL_COMPILE );
160 xglBegin( GL_POINTS );
163 /* Add the planets to all four display lists */
164 for ( i = 2; i < 9; i++ ) {
165 fgSolarSystemUpdate(&(pltOrbElements[i]), cur_time_params);
166 pltPos = fgCalculatePlanet(pltOrbElements[i],
167 pltOrbElements[0], cur_time_params, i);
169 /* give the planets a temporary color, for testing purposes */
170 /* xglColor3f( 1.0, 0.0, 0.0); */
171 /* scale magnitudes to (0.0 - 1.0) */
173 magnitude = (0.0 - pltPos.magnitude) / 5.0 + 1.0;
175 /* scale magnitudes again so they look ok */
177 magnitude * 0.7 + (((FG_STAR_LEVELS - 1) - i) * 0.1); */
179 /* the following statement could be made a little more sopisticated
180 for the moment: Stick to this one */
181 magnitude = magnitude * 0.7 + (3 * 0.1);
182 if ( magnitude > 1.0 ) { magnitude = 1.0; }
183 if ( magnitude < 0.0 ) { magnitude = 0.0; }
186 xglColor3f(magnitude, magnitude, magnitude);
187 /* xglColor3f(1.0, 1.0,1.0); */
189 xglVertex3f( 50000.0 * cos(pltPos.RightAscension) *
190 cos(pltPos.Declination),
191 50000.0 * sin(pltPos.RightAscension) *
192 cos(pltPos.Declination),
193 50000.0 * sin(pltPos.Declination) );
201 void fgPlanetsRender( void ) {
202 xglCallList(planets);
207 /* Revision 1.6 1998/02/12 21:59:36 curt
208 /* Incorporated code changes contributed by Charlie Hotchkiss
209 /* <chotchkiss@namg.us.anritsu.com>
211 * Revision 1.5 1998/02/03 23:20:12 curt
212 * Lots of little tweaks to fix various consistency problems discovered by
213 * Solaris' CC. Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
214 * passed arguments along to the real printf(). Also incorporated HUD changes
215 * by Michele America.
217 * Revision 1.4 1998/02/02 20:53:23 curt
220 * Revision 1.3 1998/01/27 00:47:47 curt
221 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
222 * system and commandline/config file processing code.
224 * Revision 1.2 1998/01/19 19:26:59 curt
225 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
226 * This should simplify things tremendously.
228 * Revision 1.1 1998/01/07 03:16:18 curt
229 * Moved from .../Src/Scenery/ to .../Src/Astro/
231 * Revision 1.4 1997/12/30 20:47:52 curt
232 * Integrated new event manager with subsystem initializations.
234 * Revision 1.3 1997/12/30 16:36:52 curt
235 * Merged in Durk's changes ...
237 * Revision 1.2 1997/12/12 21:41:29 curt
238 * More light/material property tweaking ... still a ways off.
240 * Revision 1.1 1997/10/25 03:16:10 curt
241 * Initial revision of code contributed by Durk Talsma.