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 **************************************************************************/
26 #include "../Time/fg_time.h"
27 #include "../Main/views.h"
33 static struct CelestialCoord sunPos;
35 float xSun, ySun, zSun;
37 struct SunPos fgCalcSunPos(struct OrbElements params)
45 /* calculate the eccentric anomaly */
46 EccAnom = fgCalcEccAnom(params.M, params.e);
48 /* calculate the Suns distance (r) and its true anomaly (v) */
49 xv = cos(EccAnom) - params.e;
50 yv = sqrt(1.0 - params.e*params.e) * sin(EccAnom);
52 r = sqrt(xv*xv + yv*yv);
54 /* calculate the the Sun's true longitude (lonsun) */
55 lonSun = v + params.w;
57 /* convert true longitude and distance to ecliptic rectangular geocentric
58 coordinates (xs, ys) */
59 solarPosition.xs = r * cos(lonSun);
60 solarPosition.ys = r * sin(lonSun);
65 struct CelestialCoord fgCalculateSun(struct OrbElements params, struct fgTIME t)
72 xe, ye, ze, ecl, actTime;
74 /* calculate the angle between ecliptic and equatorial coordinate system */
75 actTime = fgCalcActTime(t);
76 ecl = fgDegToRad(23.4393 - 3.563E-7 * actTime); // Angle now in Rads
78 /* calculate the sun's ecliptic position */
79 SolarPosition = fgCalcSunPos(params);
81 /* convert ecliptic coordinates to equatorial rectangular geocentric coordinates */
82 xe = SolarPosition.xs;
83 ye = SolarPosition.ys * cos(ecl);
84 ze = SolarPosition.ys * sin(ecl);
86 /* and finally... Calulate Right Ascention and Declination */
87 result.RightAscension = atan2( ye, xe);
88 result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
93 /* Initialize the Sun */
99 glNewList(sun, GL_COMPILE );
101 // glBegin( GL_POINTS );
103 fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
104 sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
106 printf("Sun found at %f (ra), %f (dec)\n", sunPos.RightAscension,
110 /* give the moon a temporary color, for testing purposes */
111 // glColor3f( 0.0, 1.0, 0.0);
112 // glVertex3f( 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination),
113 // 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination),
114 // 190000.0 * sin(moonPos.Declination) );
115 //glVertex3f(0.0, 0.0, 0.0);
117 // glColor3f(1.0, 1.0, 1.0);
118 //xMoon = 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination);
119 //yMoon = 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination);
120 //zMoon = 190000.0 * sin(moonPos.Declination);
122 xSun = 60000.0 * cos(sunPos.RightAscension) * cos(sunPos.Declination);
123 ySun = 60000.0 * sin(sunPos.RightAscension) * cos(sunPos.Declination);
124 zSun = 60000.0 * sin(sunPos.Declination);
127 // glTranslatef(x, y, z);
128 // glScalef(16622.8, 16622.8, 16622.8);
129 // glBegin(GL_TRIANGLES);
130 // for (i = 0; i < 20; i++)
131 // subdivide(&vdata[tindices[i][0]][0],
132 // &vdata[tindices[i][1]][0],
133 // &vdata[tindices[i][2]][0], 3);
134 // glutSolidSphere(1.0, 25, 25);
139 glColor3f(0.85, 0.65, 0.05);
140 glutSolidSphere(1.0, 10, 10);
150 GLfloat color[4] = { 0.85, 0.65, 0.05, 1.0 };
151 /* double x_2, x_4, x_8, x_10; */
152 /* GLfloat ambient; */
153 /* GLfloat amb[3], diff[3]; */
156 t = &cur_time_params;
159 /* x_2 = t->sun_angle * t->sun_angle;
164 /* ambient = (0.4 * pow(1.1, -x_10 / 30.0));
165 if ( ambient < 0.3 ) ambient = 0.3;
166 if ( ambient > 1.0 ) ambient = 1.0;
167 amb[0] = 0.50 + ((ambient * 6.66) - 1.6);
168 amb[1] = 0.00 + ((ambient * 6.66) - 1.6);
169 amb[2] = 0.00 + ((ambient * 6.66) - 1.6);
172 printf("Color of the sun: %f, %f, %f\n"
173 "Ambient value : %f\n"
174 "Sun Angle : %f\n" , amb[0], amb[1], amb[2], ambient, t->sun_angle);
181 /* set lighting parameters */
182 /* glLightfv(GL_LIGHT0, GL_AMBIENT, color );
183 glLightfv(GL_LIGHT0, GL_DIFFUSE, color );
184 glMaterialfv(GL_FRONT, GL_AMBIENT, amb);
185 glMaterialfv(GL_FRONT, GL_DIFFUSE, diff); */
187 glDisable( GL_LIGHTING );
190 glTranslatef(xSun, ySun, zSun);
191 glScalef(1400, 1400, 1400);
193 /* glColor3fv( color ); */
194 /* glutSolidSphere(1.0, 25, 25); */
199 glEnable( GL_LIGHTING );
204 /* Revision 1.4 1997/12/10 22:37:53 curt
205 /* Prepended "fg" on the name of all global structures that didn't have it yet.
206 /* i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
208 * Revision 1.3 1997/12/09 05:11:56 curt
209 * Working on tweaking lighting.
211 * Revision 1.2 1997/11/25 19:25:39 curt
212 * Changes to integrate Durk's moon/sun code updates + clean up.
214 * Revision 1.1 1997/10/25 03:16:11 curt
215 * Initial revision of code contributed by Durk Talsma.