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 "../XGL/xgl.h"
28 #include "../Time/fg_time.h"
29 #include "../Main/views.h"
35 static struct CelestialCoord sunPos;
37 float xSun, ySun, zSun;
39 struct SunPos fgCalcSunPos(struct OrbElements params)
47 /* calculate the eccentric anomaly */
48 EccAnom = fgCalcEccAnom(params.M, params.e);
50 /* calculate the Suns distance (r) and its true anomaly (v) */
51 xv = cos(EccAnom) - params.e;
52 yv = sqrt(1.0 - params.e*params.e) * sin(EccAnom);
54 r = sqrt(xv*xv + yv*yv);
56 /* calculate the the Sun's true longitude (lonsun) */
57 lonSun = v + params.w;
59 /* convert true longitude and distance to ecliptic rectangular geocentric
60 coordinates (xs, ys) */
61 solarPosition.xs = r * cos(lonSun);
62 solarPosition.ys = r * sin(lonSun);
67 struct CelestialCoord fgCalculateSun(struct OrbElements params, struct fgTIME t)
74 xe, ye, ze, ecl, actTime;
76 /* calculate the angle between ecliptic and equatorial coordinate system */
77 actTime = fgCalcActTime(t);
78 ecl = fgDegToRad(23.4393 - 3.563E-7 * actTime); // Angle now in Rads
80 /* calculate the sun's ecliptic position */
81 SolarPosition = fgCalcSunPos(params);
83 /* convert ecliptic coordinates to equatorial rectangular geocentric coordinates */
84 xe = SolarPosition.xs;
85 ye = SolarPosition.ys * cos(ecl);
86 ze = SolarPosition.ys * sin(ecl);
88 /* and finally... Calulate Right Ascention and Declination */
89 result.RightAscension = atan2( ye, xe);
90 result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
95 /* Initialize the Sun */
100 sun_obj = xglGenLists(1);
101 xglNewList(sun_obj, GL_COMPILE );
103 // xglBegin( GL_POINTS );
105 fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
106 sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
108 printf("Sun found at %f (ra), %f (dec)\n", sunPos.RightAscension,
112 /* give the moon a temporary color, for testing purposes */
113 // xglColor3f( 0.0, 1.0, 0.0);
114 // xglVertex3f( 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination),
115 // 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination),
116 // 190000.0 * sin(moonPos.Declination) );
117 //xglVertex3f(0.0, 0.0, 0.0);
119 // xglColor3f(1.0, 1.0, 1.0);
120 //xMoon = 190000.0 * cos(moonPos.RightAscension) * cos(moonPos.Declination);
121 //yMoon = 190000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination);
122 //zMoon = 190000.0 * sin(moonPos.Declination);
124 xSun = 60000.0 * cos(sunPos.RightAscension) * cos(sunPos.Declination);
125 ySun = 60000.0 * sin(sunPos.RightAscension) * cos(sunPos.Declination);
126 zSun = 60000.0 * sin(sunPos.Declination);
129 // xglTranslatef(x, y, z);
130 // xglScalef(16622.8, 16622.8, 16622.8);
131 // xglBegin(GL_TRIANGLES);
132 // for (i = 0; i < 20; i++)
133 // subdivide(&vdata[tindices[i][0]][0],
134 // &vdata[tindices[i][1]][0],
135 // &vdata[tindices[i][2]][0], 3);
136 // glutSolidSphere(1.0, 25, 25);
141 glutSolidSphere(1.0, 10, 10);
151 GLfloat color[4] = { 0.85, 0.65, 0.05, 1.0 };
152 /* double x_2, x_4, x_8, x_10; */
153 /* GLfloat ambient; */
154 /* GLfloat amb[3], diff[3]; */
157 t = &cur_time_params;
160 /* x_2 = t->sun_angle * t->sun_angle;
165 /* ambient = (0.4 * pow(1.1, -x_10 / 30.0));
166 if ( ambient < 0.3 ) ambient = 0.3;
167 if ( ambient > 1.0 ) ambient = 1.0;
168 amb[0] = 0.50 + ((ambient * 6.66) - 1.6);
169 amb[1] = 0.00 + ((ambient * 6.66) - 1.6);
170 amb[2] = 0.00 + ((ambient * 6.66) - 1.6);
173 printf("Color of the sun: %f, %f, %f\n"
174 "Ambient value : %f\n"
175 "Sun Angle : %f\n" , amb[0], amb[1], amb[2], ambient, t->sun_angle);
182 /* set lighting parameters */
183 /* xglLightfv(GL_LIGHT0, GL_AMBIENT, color );
184 xglLightfv(GL_LIGHT0, GL_DIFFUSE, color );
185 xglMaterialfv(GL_FRONT, GL_AMBIENT, amb);
186 xglMaterialfv(GL_FRONT, GL_DIFFUSE, diff); */
188 xglDisable( GL_LIGHTING );
191 xglTranslatef(xSun, ySun, zSun);
192 xglScalef(1400, 1400, 1400);
194 xglColor3f(0.85, 0.65, 0.05);
196 /* xglColor3fv( color ); */
197 /* xglutSolidSphere(1.0, 25, 25); */
198 xglCallList(sun_obj);
202 xglEnable( GL_LIGHTING );
207 /* Revision 1.6 1997/12/15 23:55:04 curt
208 /* Add xgl wrappers for debugging.
209 /* Generate terrain normals on the fly.
211 * Revision 1.5 1997/12/12 21:41:31 curt
212 * More light/material property tweaking ... still a ways off.
214 * Revision 1.4 1997/12/10 22:37:53 curt
215 * Prepended "fg" on the name of all global structures that didn't have it yet.
216 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
218 * Revision 1.3 1997/12/09 05:11:56 curt
219 * Working on tweaking lighting.
221 * Revision 1.2 1997/11/25 19:25:39 curt
222 * Changes to integrate Durk's moon/sun code updates + clean up.
224 * Revision 1.1 1997/10/25 03:16:11 curt
225 * Initial revision of code contributed by Durk Talsma.