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 **************************************************************************/
28 #include <simgear/debug/logstream.hxx>
29 #include <simgear/misc/fgpath.hxx>
31 #include <Main/options.hxx>
32 #include <Objects/texload.h>
35 # define exception c_exception
39 #include <FDM/flight.hxx>
44 /*************************************************************************
45 * Moon::Moon(FGTime *t)
46 * Public constructor for class Moon. Initializes the orbital elements and
47 * sets up the moon texture.
48 * Argument: The current time.
49 * the hard coded orbital elements for Moon are passed to
50 * CelestialBody::CelestialBody();
51 ************************************************************************/
52 Moon::Moon(FGTime *t) :
53 CelestialBody(125.1228, -0.0529538083,
55 318.0634, 0.1643573223,
58 115.3654, 13.0649929509, t)
63 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
65 xglGenTextures(1, &moon_texid);
66 xglBindTexture(GL_TEXTURE_2D, moon_texid);
67 #elif GL_EXT_texture_object
68 xglGenTexturesEXT(1, &moon_texid);
69 xglBindTextureEXT(GL_TEXTURE_2D, moon_texid);
74 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
75 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
76 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
78 // load in the texture data
79 FGPath tpath( current_options.get_fg_root() );
80 tpath.append( "Textures" );
81 tpath.append( "moon.rgb" );
83 if ( (moon_texbuf = read_rgb_texture(tpath.c_str(), &width, &height))
87 FGPath fg_tpath = tpath;
88 fg_tpath.append( ".gz" );
89 if ( (moon_texbuf = read_rgb_texture(fg_tpath.c_str(), &width, &height))
92 FG_LOG( FG_GENERAL, FG_ALERT,
93 "Error in loading moon texture " << tpath.str() );
98 glTexImage2D( GL_TEXTURE_2D,
103 GL_RGB, GL_UNSIGNED_BYTE,
106 // setup the halo texture
107 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
108 #ifdef GL_VERSION_1_1
109 xglGenTextures(1, &moon_halotexid);
110 xglBindTexture(GL_TEXTURE_2D, moon_halotexid);
111 #elif GL_EXT_texture_object
112 xglGenTexturesEXT(1, &moon_halotexid);
113 xglBindTextureEXT(GL_TEXTURE_2D, moon_halotexid);
118 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
119 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
120 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
122 glTexImage2D( GL_TEXTURE_2D,
127 GL_RGBA, GL_UNSIGNED_BYTE,
129 moonObject = gluNewQuadric();
134 CelestialBody(125.1228, -0.0529538083,
136 318.0634, 0.1643573223,
139 115.3654, 13.0649929509)
147 // delete moon_texbuf;
148 // delete moon_halotexbuf;
153 static int texWidth = 256; /* 64x64 is plenty */
163 texSize = texWidth*texWidth;
165 moon_halotexbuf = new GLubyte[texSize*4];
166 if (!moon_halotexbuf)
171 radius = (double)(texWidth / 2);
173 for (i=0; i < texWidth; i++) {
174 for (j=0; j < texWidth; j++) {
181 x = fabs((double)(i - (texWidth / 2)));
182 y = fabs((double)(j - (texWidth / 2)));
184 d = sqrt((x * x) + (y * y));
186 double t = 1.0 - (d / radius); // t is 1.0 at center, 0.0 at edge */
187 // inverse square looks nice
188 *(p+3) = (int)((double) 0x20 * (t*t));
195 //gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
197 // GL_UNSIGNED_BYTE, textureBuf);
203 /*****************************************************************************
204 * void Moon::updatePosition(FGTime *t, Star *ourSun)
205 * this member function calculates the actual topocentric position (i.e.)
206 * the position of the moon as seen from the current position on the surface
208 ****************************************************************************/
209 void Moon::updatePosition(FGTime *t, double lat, Star *ourSun)
212 eccAnom, ecl, actTime,
213 xv, yv, v, r, xh, yh, zh, xg, yg, zg, xe, ye, ze,
214 Ls, Lm, D, F, mpar, gclat, rho, HA, g,
220 air = ¤t_aircraft;
223 updateOrbElements(t);
224 actTime = fgCalcActTime(t);
226 // calculate the angle between ecliptic and equatorial coordinate system
228 ecl = ((DEG_TO_RAD * 23.4393) - (DEG_TO_RAD * 3.563E-7) * actTime);
229 eccAnom = fgCalcEccAnom(M, e); // Calculate the eccentric anomaly
230 xv = a * (cos(eccAnom) - e);
231 yv = a * (sqrt(1.0 - e*e) * sin(eccAnom));
232 v = atan2(yv, xv); // the moon's true anomaly
233 r = sqrt (xv*xv + yv*yv); // and its distance
235 // estimate the geocentric rectangular coordinates here
236 xh = r * (cos(N) * cos (v+w) - sin (N) * sin(v+w) * cos(i));
237 yh = r * (sin(N) * cos (v+w) + cos (N) * sin(v+w) * cos(i));
238 zh = r * (sin(v+w) * sin(i));
240 // calculate the ecliptic latitude and longitude here
241 lonEcl = atan2 (yh, xh);
242 latEcl = atan2(zh, sqrt(xh*xh + yh*yh));
244 /* Calculate a number of perturbatioin, i.e. disturbances caused by the
245 * gravitational infuence of the sun and the other major planets.
246 * The largest of these even have a name */
247 Ls = ourSun->getM() + ourSun->getw();
252 lonEcl += DEG_TO_RAD * (-1.274 * sin (M - 2*D)
254 -0.186 * sin(ourSun->getM())
255 -0.059 * sin(2*M - 2*D)
256 -0.057 * sin(M - 2*D + ourSun->getM())
257 +0.053 * sin(M + 2*D)
258 +0.046 * sin(2*D - ourSun->getM())
259 +0.041 * sin(M - ourSun->getM())
261 -0.031 * sin(M + ourSun->getM())
262 -0.015 * sin(2*F - 2*D)
263 +0.011 * sin(M - 4*D)
265 latEcl += DEG_TO_RAD * (-0.173 * sin(F-2*D)
266 -0.055 * sin(M - F - 2*D)
267 -0.046 * sin(M + F - 2*D)
268 +0.033 * sin(F + 2*D)
269 +0.017 * sin(2*M + F)
271 r += (-0.58 * cos(M - 2*D)
274 // FG_LOG(FG_GENERAL, FG_INFO, "Running moon update");
275 xg = r * cos(lonEcl) * cos(latEcl);
276 yg = r * sin(lonEcl) * cos(latEcl);
277 zg = r * sin(latEcl);
280 ye = yg * cos(ecl) -zg * sin(ecl);
281 ze = yg * sin(ecl) +zg * cos(ecl);
283 geoRa = atan2(ye, xe);
284 geoDec = atan2(ze, sqrt(xe*xe + ye*ye));
286 /* FG_LOG( FG_GENERAL, FG_INFO,
287 "(geocentric) geoRa = (" << (RAD_TO_DEG * geoRa)
288 << "), geoDec= (" << (RAD_TO_DEG * geoDec) << ")" ); */
291 // Given the moon's geocentric ra and dec, calculate its
292 // topocentric ra and dec. i.e. the position as seen from the
293 // surface of the earth, instead of the center of the earth
295 // First calculate the moon's parrallax, that is, the apparent size of the
296 // (equatorial) radius of the earth, as seen from the moon
297 mpar = asin ( 1 / r);
298 // FG_LOG( FG_GENERAL, FG_INFO, "r = " << r << " mpar = " << mpar );
299 // FG_LOG( FG_GENERAL, FG_INFO, "lat = " << f->get_Latitude() );
301 gclat = lat - 0.003358 *
302 sin (2 * DEG_TO_RAD * lat );
303 // FG_LOG( FG_GENERAL, FG_INFO, "gclat = " << gclat );
305 rho = 0.99883 + 0.00167 * cos(2 * DEG_TO_RAD * lat);
306 // FG_LOG( FG_GENERAL, FG_INFO, "rho = " << rho );
311 HA = t->getLst() - (3.8197186 * geoRa);
312 /* FG_LOG( FG_GENERAL, FG_INFO, "t->getLst() = " << t->getLst()
313 << " HA = " << HA ); */
315 g = atan (tan(gclat) / cos ((HA / 3.8197186)));
316 // FG_LOG( FG_GENERAL, FG_INFO, "g = " << g );
318 rightAscension = geoRa - mpar * rho * cos(gclat) * sin(HA) / cos (geoDec);
319 declination = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
321 /* FG_LOG( FG_GENERAL, FG_INFO,
322 "Ra = (" << (RAD_TO_DEG *rightAscension)
323 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" ); */
328 /************************************************************************
329 * void Moon::newImage()
331 * This function regenerates a new visual image of the moon, which is added to
332 * solarSystem display list.
334 * Arguments: Right Ascension and declination
337 **************************************************************************/
338 void Moon::newImage()
340 fgLIGHT *l = &cur_light_params;
341 float moon_angle = l->moon_angle;
343 /*double x_2, x_4, x_8, x_10;
348 GLfloat moonColor[4] = {0.85, 0.75, 0.35, 1.0};
349 GLfloat black[4] = {0.0, 0.0, 0.0, 1.0};
350 GLfloat white[4] = {1.0, 1.0, 1.0, 0.0};
352 if( moon_angle*RAD_TO_DEG < 100 )
354 FG_LOG( FG_ASTRO, FG_INFO, "Generating Moon Image" );
358 xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
359 xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
361 FG_LOG( FG_GENERAL, FG_INFO,
362 "Ra = (" << (RAD_TO_DEG *rightAscension)
363 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" );
364 xglTranslatef(0.0, 60000.0, 0.0);
365 glEnable(GL_BLEND); // BLEND ENABLED
368 if (current_options.get_textures())
370 // glBlendFunc(GL_SRC_ALPHA, GL_ONE);
371 glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
372 glEnable(GL_TEXTURE_2D); // TEXTURE ENABLED
373 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
374 glBindTexture(GL_TEXTURE_2D, moon_halotexid);
377 glTexCoord2f(0.0f, 0.0f); glVertex3f(-5000, 0.0, -5000);
378 glTexCoord2f(1.0f, 0.0f); glVertex3f( 5000, 0.0, -5000);
379 glTexCoord2f(1.0f, 1.0f); glVertex3f( 5000, 0.0, 5000);
380 glTexCoord2f(0.0f, 1.0f); glVertex3f(-5000, 0.0, 5000);
384 xglEnable(GL_LIGHTING); // LIGHTING ENABLED
385 xglEnable( GL_LIGHT0 );
386 // set lighting parameters
387 xglLightfv(GL_LIGHT0, GL_AMBIENT, white );
388 xglLightfv(GL_LIGHT0, GL_DIFFUSE, white );
389 // Enable( GL_CULL_FACE );
390 xglMaterialfv(GL_FRONT, GL_AMBIENT, black);
391 xglMaterialfv(GL_FRONT, GL_DIFFUSE, moonColor);
392 //glEnable(GL_TEXTURE_2D);
394 glBlendFunc(GL_ONE, GL_ONE);
396 //glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
397 // Draw the moon-proper
399 if (current_options.get_textures())
401 glBindTexture(GL_TEXTURE_2D, moon_texid);
402 gluQuadricTexture(moonObject, GL_TRUE );
404 gluSphere(moonObject, moonSize, 12, 12 );
405 glDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
406 glDisable(GL_BLEND); // BLEND DISABLED
409 glDisable(GL_LIGHTING); // Lighting Disabled.