1 /**************************************************************************
3 * Written by Durk Talsma. Originally started October 1997, for distribution
4 * with the FlightGear project. Version 2 was written in August and
5 * September 1998. This code is based upon algorithms and data kindly
6 * provided by Mr. Paul Schlyter. (pausch@saaf.se).
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 **************************************************************************/
25 #include <FDM/flight.hxx>
30 #include <Debug/logstream.hxx>
31 #include <Main/options.hxx>
32 #include <Misc/fgpath.hxx>
33 #include <Objects/texload.h>
36 # define exception c_exception
41 /*************************************************************************
42 * Moon::Moon(FGTime *t)
43 * Public constructor for class Moon. Initializes the orbital elements and
44 * sets up the moon texture.
45 * Argument: The current time.
46 * the hard coded orbital elements for Moon are passed to
47 * CelestialBody::CelestialBody();
48 ************************************************************************/
49 Moon::Moon(FGTime *t) :
50 CelestialBody(125.1228, -0.0529538083,
52 318.0634, 0.1643573223,
55 115.3654, 13.0649929509, t)
59 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
61 xglGenTextures(1, &moon_texid);
62 xglBindTexture(GL_TEXTURE_2D, moon_texid);
63 #elif GL_EXT_texture_object
64 xglGenTexturesEXT(1, &moon_texid);
65 xglBindTextureEXT(GL_TEXTURE_2D, moon_texid);
70 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
71 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
72 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
74 // load in the texture data
75 FGPath tpath( current_options.get_fg_root() );
76 tpath.append( "Textures" );
77 tpath.append( "moon.rgb" );
79 if ( (moon_texbuf = read_rgb_texture(tpath.c_str(), &width, &height))
83 FGPath fg_tpath = tpath;
84 fg_tpath.append( ".gz" );
85 if ( (moon_texbuf = read_rgb_texture(fg_tpath.c_str(), &width, &height))
88 FG_LOG( FG_GENERAL, FG_ALERT,
89 "Error in loading moon texture " << tpath.str() );
94 glTexImage2D( GL_TEXTURE_2D,
99 GL_RGB, GL_UNSIGNED_BYTE,
102 // setup the halo texture
103 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
104 #ifdef GL_VERSION_1_1
105 xglGenTextures(1, &moon_halotexid);
106 xglBindTexture(GL_TEXTURE_2D, moon_halotexid);
107 #elif GL_EXT_texture_object
108 xglGenTexturesEXT(1, &moon_halotexid);
109 xglBindTextureEXT(GL_TEXTURE_2D, moon_halotexid);
114 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
115 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
116 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
118 glTexImage2D( GL_TEXTURE_2D,
123 GL_RGBA, GL_UNSIGNED_BYTE,
125 moonObject = gluNewQuadric();
132 delete moon_halotexbuf;
136 static int texWidth = 256; /* 64x64 is plenty */
146 texSize = texWidth*texWidth;
148 moon_halotexbuf = new GLubyte[texSize*4];
149 if (!moon_halotexbuf)
154 radius = (double)(texWidth / 2);
156 for (i=0; i < texWidth; i++) {
157 for (j=0; j < texWidth; j++) {
160 x = fabs((double)(i - (texWidth / 2)));
161 y = fabs((double)(j - (texWidth / 2)));
163 d = sqrt((x * x) + (y * y));
166 double t = 1.0 - (d / radius); // t is 1.0 at center, 0.0 at edge */
167 // inverse square looks nice
168 *p = (int)((double)0xff * (t * t));
169 *(p+1) = (int)((double) 0xff * (t*t));
170 *(p+2) = (int)((double) 0xff * (t*t));
183 //gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
185 // GL_UNSIGNED_BYTE, textureBuf);
190 /*****************************************************************************
191 * void Moon::updatePosition(FGTime *t, Star *ourSun)
192 * this member function calculates the actual topocentric position (i.e.)
193 * the position of the moon as seen from the current position on the surface
195 ****************************************************************************/
196 void Moon::updatePosition(FGTime *t, Star *ourSun)
199 eccAnom, ecl, actTime,
200 xv, yv, v, r, xh, yh, zh, xg, yg, zg, xe, ye, ze,
201 Ls, Lm, D, F, mpar, gclat, rho, HA, g,
207 air = ¤t_aircraft;
210 updateOrbElements(t);
211 actTime = fgCalcActTime(t);
213 // calculate the angle between ecliptic and equatorial coordinate system
215 ecl = ((DEG_TO_RAD * 23.4393) - (DEG_TO_RAD * 3.563E-7) * actTime);
216 eccAnom = fgCalcEccAnom(M, e); // Calculate the eccentric anomaly
217 xv = a * (cos(eccAnom) - e);
218 yv = a * (sqrt(1.0 - e*e) * sin(eccAnom));
219 v = atan2(yv, xv); // the moon's true anomaly
220 r = sqrt (xv*xv + yv*yv); // and its distance
222 // estimate the geocentric rectangular coordinates here
223 xh = r * (cos(N) * cos (v+w) - sin (N) * sin(v+w) * cos(i));
224 yh = r * (sin(N) * cos (v+w) + cos (N) * sin(v+w) * cos(i));
225 zh = r * (sin(v+w) * sin(i));
227 // calculate the ecliptic latitude and longitude here
228 lonEcl = atan2 (yh, xh);
229 latEcl = atan2(zh, sqrt(xh*xh + yh*yh));
231 /* Calculate a number of perturbatioin, i.e. disturbances caused by the
232 * gravitational infuence of the sun and the other major planets.
233 * The largest of these even have a name */
234 Ls = ourSun->getM() + ourSun->getw();
239 lonEcl += DEG_TO_RAD * (-1.274 * sin (M - 2*D)
241 -0.186 * sin(ourSun->getM())
242 -0.059 * sin(2*M - 2*D)
243 -0.057 * sin(M - 2*D + ourSun->getM())
244 +0.053 * sin(M + 2*D)
245 +0.046 * sin(2*D - ourSun->getM())
246 +0.041 * sin(M - ourSun->getM())
248 -0.031 * sin(M + ourSun->getM())
249 -0.015 * sin(2*F - 2*D)
250 +0.011 * sin(M - 4*D)
252 latEcl += DEG_TO_RAD * (-0.173 * sin(F-2*D)
253 -0.055 * sin(M - F - 2*D)
254 -0.046 * sin(M + F - 2*D)
255 +0.033 * sin(F + 2*D)
256 +0.017 * sin(2*M + F)
258 r += (-0.58 * cos(M - 2*D)
261 FG_LOG(FG_GENERAL, FG_INFO, "Running moon update");
262 xg = r * cos(lonEcl) * cos(latEcl);
263 yg = r * sin(lonEcl) * cos(latEcl);
264 zg = r * sin(latEcl);
267 ye = yg * cos(ecl) -zg * sin(ecl);
268 ze = yg * sin(ecl) +zg * cos(ecl);
270 geoRa = atan2(ye, xe);
271 geoDec = atan2(ze, sqrt(xe*xe + ye*ye));
273 /* FG_LOG( FG_GENERAL, FG_INFO,
274 "(geocentric) geoRa = (" << (RAD_TO_DEG * geoRa)
275 << "), geoDec= (" << (RAD_TO_DEG * geoDec) << ")" ); */
278 // Given the moon's geocentric ra and dec, calculate its
279 // topocentric ra and dec. i.e. the position as seen from the
280 // surface of the earth, instead of the center of the earth
282 // First calculate the moon's parrallax, that is, the apparent size of the
283 // (equatorial) radius of the earth, as seen from the moon
284 mpar = asin ( 1 / r);
285 // FG_LOG( FG_GENERAL, FG_INFO, "r = " << r << " mpar = " << mpar );
286 // FG_LOG( FG_GENERAL, FG_INFO, "lat = " << f->get_Latitude() );
288 gclat = f->get_Latitude() - 0.003358 *
289 sin (2 * DEG_TO_RAD * f->get_Latitude() );
290 // FG_LOG( FG_GENERAL, FG_INFO, "gclat = " << gclat );
292 rho = 0.99883 + 0.00167 * cos(2 * DEG_TO_RAD * f->get_Latitude());
293 // FG_LOG( FG_GENERAL, FG_INFO, "rho = " << rho );
298 HA = t->getLst() - (3.8197186 * geoRa);
299 /* FG_LOG( FG_GENERAL, FG_INFO, "t->getLst() = " << t->getLst()
300 << " HA = " << HA ); */
302 g = atan (tan(gclat) / cos ((HA / 3.8197186)));
303 // FG_LOG( FG_GENERAL, FG_INFO, "g = " << g );
305 rightAscension = geoRa - mpar * rho * cos(gclat) * sin(HA) / cos (geoDec);
306 declination = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
308 /* FG_LOG( FG_GENERAL, FG_INFO,
309 "Ra = (" << (RAD_TO_DEG *rightAscension)
310 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" ); */
314 /************************************************************************
315 * void Moon::newImage()
317 * This function regenerates a new visual image of the moon, which is added to
318 * solarSystem display list.
320 * Arguments: Right Ascension and declination
323 **************************************************************************/
324 void Moon::newImage()
326 fgLIGHT *l = &cur_light_params;
327 float moon_angle = l->moon_angle;
329 /*double x_2, x_4, x_8, x_10;
334 GLfloat moonColor[4] = {0.85, 0.75, 0.35, 1.0};
335 GLfloat black[4] = {0.0, 0.0, 0.0, 1.0};
336 GLfloat white[4] = {1.0, 1.0, 1.0, 0.0};
338 if( moon_angle*RAD_TO_DEG < 100 )
340 FG_LOG( FG_ASTRO, FG_INFO, "Generating Moon Image" );
344 xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
345 xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
347 FG_LOG( FG_GENERAL, FG_INFO,
348 "Ra = (" << (RAD_TO_DEG *rightAscension)
349 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" );
350 xglTranslatef(0.0, 60000.0, 0.0);
351 glEnable(GL_BLEND); // BLEND ENABLED
354 if (current_options.get_textures())
356 glBlendFunc(GL_SRC_ALPHA, GL_ONE);
357 glEnable(GL_TEXTURE_2D); // TEXTURE ENABLED
358 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
359 glBindTexture(GL_TEXTURE_2D, moon_halotexid);
362 glTexCoord2f(0.0f, 0.0f); glVertex3f(-5000, 0.0, -5000);
363 glTexCoord2f(1.0f, 0.0f); glVertex3f( 5000, 0.0, -5000);
364 glTexCoord2f(1.0f, 1.0f); glVertex3f( 5000, 0.0, 5000);
365 glTexCoord2f(0.0f, 1.0f); glVertex3f(-5000, 0.0, 5000);
369 xglEnable(GL_LIGHTING); // LIGHTING ENABLED
370 xglEnable( GL_LIGHT0 );
371 // set lighting parameters
372 xglLightfv(GL_LIGHT0, GL_AMBIENT, white );
373 xglLightfv(GL_LIGHT0, GL_DIFFUSE, white );
374 // xglEnable( GL_CULL_FACE );
375 xglMaterialfv(GL_FRONT, GL_AMBIENT, black);
376 xglMaterialfv(GL_FRONT, GL_DIFFUSE, moonColor);
378 //glEnable(GL_TEXTURE_2D);
380 glBlendFunc(GL_ONE, GL_ONE);
382 //glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
383 // Draw the moon-proper
385 if (current_options.get_textures())
387 glBindTexture(GL_TEXTURE_2D, moon_texid);
388 gluQuadricTexture(moonObject, GL_TRUE );
390 gluSphere(moonObject, moonSize, 12, 12 );
391 glDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
392 glDisable(GL_BLEND); // BLEND DISABLED
395 glDisable(GL_LIGHTING); // Lighting Disabled.