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
36 float xSun, ySun, zSun;
38 struct SunPos fgCalcSunPos(struct OrbElements params)
46 /* calculate the eccentric anomaly */
47 EccAnom = fgCalcEccAnom(params.M, params.e);
49 /* calculate the Suns distance (r) and its true anomaly (v) */
50 xv = cos(EccAnom) - params.e;
51 yv = sqrt(1.0 - params.e*params.e) * sin(EccAnom);
53 r = sqrt(xv*xv + yv*yv);
55 /* calculate the the Sun's true longitude (lonsun) */
56 lonSun = v + params.w;
58 /* convert true longitude and distance to ecliptic rectangular geocentric
59 coordinates (xs, ys) */
60 solarPosition.xs = r * cos(lonSun);
61 solarPosition.ys = r * sin(lonSun);
66 struct CelestialCoord fgCalculateSun(struct OrbElements params, struct fgTIME t)
73 xe, ye, ze, ecl, actTime;
75 /* calculate the angle between ecliptic and equatorial coordinate system */
76 actTime = fgCalcActTime(t);
77 ecl = fgDegToRad(23.4393 - 3.563E-7 * actTime); // Angle now in Rads
79 /* calculate the sun's ecliptic position */
80 SolarPosition = fgCalcSunPos(params);
82 /* convert ecliptic coordinates to equatorial rectangular geocentric coordinates */
83 xe = SolarPosition.xs;
84 ye = SolarPosition.ys * cos(ecl);
85 ze = SolarPosition.ys * sin(ecl);
87 /* and finally... Calulate Right Ascention and Declination */
88 result.RightAscension = atan2( ye, xe);
89 result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
94 /* Initialize the Sun */
98 // sun = glGenLists(1);
99 // glNewList(sun, GL_COMPILE );
100 // glBegin( GL_POINTS );
101 fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
102 sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
104 printf("Sun found at %f (ra), %f (dec)\n", sunPos.RightAscension, sunPos.Declination);
106 /* give the moon a temporary color, for testing purposes */
107 // glColor3f( 0.0, 1.0, 0.0);
108 // glVertex3f( 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination),
109 // 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination),
110 // 190000.0 * sin(moonPos.Declination) );
111 //glVertex3f(0.0, 0.0, 0.0);
113 // glColor3f(1.0, 1.0, 1.0);
114 //xMoon = 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination);
115 //yMoon = 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination);
116 //zMoon = 190000.0 * sin(moonPos.Declination);
117 xSun = 60000.0 * cos(sunPos.RightAscension) * cos(sunPos.Declination);
118 ySun = 60000.0 * sin(sunPos.RightAscension) * cos(sunPos.Declination);
119 zSun = 60000.0 * sin(sunPos.Declination);
122 // glTranslatef(x, y, z);
123 // glScalef(16622.8, 16622.8, 16622.8);
124 // glBegin(GL_TRIANGLES);
125 // for (i = 0; i < 20; i++)
126 // subdivide(&vdata[tindices[i][0]][0],
127 // &vdata[tindices[i][1]][0],
128 // &vdata[tindices[i][2]][0], 3);
129 // glutSolidSphere(1.0, 25, 25);
141 GLfloat color[4] = { 0.85, 0.65, 0.05, 1.0 };
142 /* double x_2, x_4, x_8, x_10; */
143 /* GLfloat ambient; */
144 /* GLfloat amb[3], diff[3]; */
147 t = &cur_time_params;
150 /* x_2 = t->sun_angle * t->sun_angle;
155 /* ambient = (0.4 * pow(1.1, -x_10 / 30.0));
156 if ( ambient < 0.3 ) ambient = 0.3;
157 if ( ambient > 1.0 ) ambient = 1.0;
158 amb[0] = 0.50 + ((ambient * 6.66) - 1.6);
159 amb[1] = 0.00 + ((ambient * 6.66) - 1.6);
160 amb[2] = 0.00 + ((ambient * 6.66) - 1.6);
163 printf("Color of the sun: %f, %f, %f\n"
164 "Ambient value : %f\n"
165 "Sun Angle : %f\n" , amb[0], amb[1], amb[2], ambient, t->sun_angle);
172 /* set lighting parameters */
173 /* glLightfv(GL_LIGHT0, GL_AMBIENT, color );
174 glLightfv(GL_LIGHT0, GL_DIFFUSE, color );
175 glMaterialfv(GL_FRONT, GL_AMBIENT, amb);
176 glMaterialfv(GL_FRONT, GL_DIFFUSE, diff); */
178 glDisable( GL_LIGHTING );
180 glTranslatef(xSun, ySun, zSun);
181 glScalef(1400, 1400, 1400);
183 /* glutSolidSphere(1.0, 25, 25); */
184 glutSolidSphere(1.0, 10, 10);
187 glEnable( GL_LIGHTING );
192 /* Revision 1.2 1997/11/25 19:25:39 curt
193 /* Changes to integrate Durk's moon/sun code updates + clean up.
195 * Revision 1.1 1997/10/25 03:16:11 curt
196 * Initial revision of code contributed by Durk Talsma.