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>
43 /*************************************************************************
44 * Moon::Moon(FGTime *t)
45 * Public constructor for class Moon. Initializes the orbital elements and
46 * sets up the moon texture.
47 * Argument: The current time.
48 * the hard coded orbital elements for Moon are passed to
49 * CelestialBody::CelestialBody();
50 ************************************************************************/
51 Moon::Moon(FGTime *t) :
52 CelestialBody(125.1228, -0.0529538083,
54 318.0634, 0.1643573223,
57 115.3654, 13.0649929509, t)
61 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
63 xglGenTextures(1, &moon_texid);
64 xglBindTexture(GL_TEXTURE_2D, moon_texid);
65 #elif GL_EXT_texture_object
66 xglGenTexturesEXT(1, &moon_texid);
67 xglBindTextureEXT(GL_TEXTURE_2D, moon_texid);
72 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
73 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
74 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
76 // load in the texture data
77 FGPath tpath( current_options.get_fg_root() );
78 tpath.append( "Textures" );
79 tpath.append( "moon.rgb" );
81 if ( (moon_texbuf = read_rgb_texture(tpath.c_str(), &width, &height))
85 FGPath fg_tpath = tpath;
86 fg_tpath.append( ".gz" );
87 if ( (moon_texbuf = read_rgb_texture(fg_tpath.c_str(), &width, &height))
90 FG_LOG( FG_GENERAL, FG_ALERT,
91 "Error in loading moon texture " << tpath.str() );
96 glTexImage2D( GL_TEXTURE_2D,
101 GL_RGB, GL_UNSIGNED_BYTE,
104 // setup the halo texture
105 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
106 #ifdef GL_VERSION_1_1
107 xglGenTextures(1, &moon_halotexid);
108 xglBindTexture(GL_TEXTURE_2D, moon_halotexid);
109 #elif GL_EXT_texture_object
110 xglGenTexturesEXT(1, &moon_halotexid);
111 xglBindTextureEXT(GL_TEXTURE_2D, moon_halotexid);
116 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
117 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
118 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
120 glTexImage2D( GL_TEXTURE_2D,
125 GL_RGBA, GL_UNSIGNED_BYTE,
127 moonObject = gluNewQuadric();
134 delete moon_halotexbuf;
138 static int texWidth = 256; /* 64x64 is plenty */
148 texSize = texWidth*texWidth;
150 moon_halotexbuf = new GLubyte[texSize*4];
151 if (!moon_halotexbuf)
156 radius = (double)(texWidth / 2);
158 for (i=0; i < texWidth; i++) {
159 for (j=0; j < texWidth; j++) {
166 x = fabs((double)(i - (texWidth / 2)));
167 y = fabs((double)(j - (texWidth / 2)));
169 d = sqrt((x * x) + (y * y));
171 double t = 1.0 - (d / radius); // t is 1.0 at center, 0.0 at edge */
172 // inverse square looks nice
173 *(p+3) = (int)((double) 0x20 * (t*t));
180 //gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
182 // GL_UNSIGNED_BYTE, textureBuf);
187 /*****************************************************************************
188 * void Moon::updatePosition(FGTime *t, Star *ourSun)
189 * this member function calculates the actual topocentric position (i.e.)
190 * the position of the moon as seen from the current position on the surface
192 ****************************************************************************/
193 void Moon::updatePosition(FGTime *t, Star *ourSun)
196 eccAnom, ecl, actTime,
197 xv, yv, v, r, xh, yh, zh, xg, yg, zg, xe, ye, ze,
198 Ls, Lm, D, F, mpar, gclat, rho, HA, g,
204 air = ¤t_aircraft;
207 updateOrbElements(t);
208 actTime = fgCalcActTime(t);
210 // calculate the angle between ecliptic and equatorial coordinate system
212 ecl = ((DEG_TO_RAD * 23.4393) - (DEG_TO_RAD * 3.563E-7) * actTime);
213 eccAnom = fgCalcEccAnom(M, e); // Calculate the eccentric anomaly
214 xv = a * (cos(eccAnom) - e);
215 yv = a * (sqrt(1.0 - e*e) * sin(eccAnom));
216 v = atan2(yv, xv); // the moon's true anomaly
217 r = sqrt (xv*xv + yv*yv); // and its distance
219 // estimate the geocentric rectangular coordinates here
220 xh = r * (cos(N) * cos (v+w) - sin (N) * sin(v+w) * cos(i));
221 yh = r * (sin(N) * cos (v+w) + cos (N) * sin(v+w) * cos(i));
222 zh = r * (sin(v+w) * sin(i));
224 // calculate the ecliptic latitude and longitude here
225 lonEcl = atan2 (yh, xh);
226 latEcl = atan2(zh, sqrt(xh*xh + yh*yh));
228 /* Calculate a number of perturbatioin, i.e. disturbances caused by the
229 * gravitational infuence of the sun and the other major planets.
230 * The largest of these even have a name */
231 Ls = ourSun->getM() + ourSun->getw();
236 lonEcl += DEG_TO_RAD * (-1.274 * sin (M - 2*D)
238 -0.186 * sin(ourSun->getM())
239 -0.059 * sin(2*M - 2*D)
240 -0.057 * sin(M - 2*D + ourSun->getM())
241 +0.053 * sin(M + 2*D)
242 +0.046 * sin(2*D - ourSun->getM())
243 +0.041 * sin(M - ourSun->getM())
245 -0.031 * sin(M + ourSun->getM())
246 -0.015 * sin(2*F - 2*D)
247 +0.011 * sin(M - 4*D)
249 latEcl += DEG_TO_RAD * (-0.173 * sin(F-2*D)
250 -0.055 * sin(M - F - 2*D)
251 -0.046 * sin(M + F - 2*D)
252 +0.033 * sin(F + 2*D)
253 +0.017 * sin(2*M + F)
255 r += (-0.58 * cos(M - 2*D)
258 FG_LOG(FG_GENERAL, FG_INFO, "Running moon update");
259 xg = r * cos(lonEcl) * cos(latEcl);
260 yg = r * sin(lonEcl) * cos(latEcl);
261 zg = r * sin(latEcl);
264 ye = yg * cos(ecl) -zg * sin(ecl);
265 ze = yg * sin(ecl) +zg * cos(ecl);
267 geoRa = atan2(ye, xe);
268 geoDec = atan2(ze, sqrt(xe*xe + ye*ye));
270 /* FG_LOG( FG_GENERAL, FG_INFO,
271 "(geocentric) geoRa = (" << (RAD_TO_DEG * geoRa)
272 << "), geoDec= (" << (RAD_TO_DEG * geoDec) << ")" ); */
275 // Given the moon's geocentric ra and dec, calculate its
276 // topocentric ra and dec. i.e. the position as seen from the
277 // surface of the earth, instead of the center of the earth
279 // First calculate the moon's parrallax, that is, the apparent size of the
280 // (equatorial) radius of the earth, as seen from the moon
281 mpar = asin ( 1 / r);
282 // FG_LOG( FG_GENERAL, FG_INFO, "r = " << r << " mpar = " << mpar );
283 // FG_LOG( FG_GENERAL, FG_INFO, "lat = " << f->get_Latitude() );
285 gclat = f->get_Latitude() - 0.003358 *
286 sin (2 * DEG_TO_RAD * f->get_Latitude() );
287 // FG_LOG( FG_GENERAL, FG_INFO, "gclat = " << gclat );
289 rho = 0.99883 + 0.00167 * cos(2 * DEG_TO_RAD * f->get_Latitude());
290 // FG_LOG( FG_GENERAL, FG_INFO, "rho = " << rho );
295 HA = t->getLst() - (3.8197186 * geoRa);
296 /* FG_LOG( FG_GENERAL, FG_INFO, "t->getLst() = " << t->getLst()
297 << " HA = " << HA ); */
299 g = atan (tan(gclat) / cos ((HA / 3.8197186)));
300 // FG_LOG( FG_GENERAL, FG_INFO, "g = " << g );
302 rightAscension = geoRa - mpar * rho * cos(gclat) * sin(HA) / cos (geoDec);
303 declination = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
305 /* FG_LOG( FG_GENERAL, FG_INFO,
306 "Ra = (" << (RAD_TO_DEG *rightAscension)
307 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" ); */
311 /************************************************************************
312 * void Moon::newImage()
314 * This function regenerates a new visual image of the moon, which is added to
315 * solarSystem display list.
317 * Arguments: Right Ascension and declination
320 **************************************************************************/
321 void Moon::newImage()
323 fgLIGHT *l = &cur_light_params;
324 float moon_angle = l->moon_angle;
326 /*double x_2, x_4, x_8, x_10;
331 GLfloat moonColor[4] = {0.85, 0.75, 0.35, 1.0};
332 GLfloat black[4] = {0.0, 0.0, 0.0, 1.0};
333 GLfloat white[4] = {1.0, 1.0, 1.0, 0.0};
335 if( moon_angle*RAD_TO_DEG < 100 )
337 FG_LOG( FG_ASTRO, FG_INFO, "Generating Moon Image" );
341 xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
342 xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
344 FG_LOG( FG_GENERAL, FG_INFO,
345 "Ra = (" << (RAD_TO_DEG *rightAscension)
346 << "), Dec= (" << (RAD_TO_DEG *declination) << ")" );
347 xglTranslatef(0.0, 60000.0, 0.0);
348 glEnable(GL_BLEND); // BLEND ENABLED
351 if (current_options.get_textures())
353 // glBlendFunc(GL_SRC_ALPHA, GL_ONE);
354 glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
355 glEnable(GL_TEXTURE_2D); // TEXTURE ENABLED
356 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
357 glBindTexture(GL_TEXTURE_2D, moon_halotexid);
360 glTexCoord2f(0.0f, 0.0f); glVertex3f(-5000, 0.0, -5000);
361 glTexCoord2f(1.0f, 0.0f); glVertex3f( 5000, 0.0, -5000);
362 glTexCoord2f(1.0f, 1.0f); glVertex3f( 5000, 0.0, 5000);
363 glTexCoord2f(0.0f, 1.0f); glVertex3f(-5000, 0.0, 5000);
367 xglEnable(GL_LIGHTING); // LIGHTING ENABLED
368 xglEnable( GL_LIGHT0 );
369 // set lighting parameters
370 xglLightfv(GL_LIGHT0, GL_AMBIENT, white );
371 xglLightfv(GL_LIGHT0, GL_DIFFUSE, white );
372 // Enable( GL_CULL_FACE );
373 xglMaterialfv(GL_FRONT, GL_AMBIENT, black);
374 xglMaterialfv(GL_FRONT, GL_DIFFUSE, moonColor);
375 //glEnable(GL_TEXTURE_2D);
377 glBlendFunc(GL_ONE, GL_ONE);
379 //glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
380 // Draw the moon-proper
382 if (current_options.get_textures())
384 glBindTexture(GL_TEXTURE_2D, moon_texid);
385 gluQuadricTexture(moonObject, GL_TRUE );
387 gluSphere(moonObject, moonSize, 12, 12 );
388 glDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
389 glDisable(GL_BLEND); // BLEND DISABLED
392 glDisable(GL_LIGHTING); // Lighting Disabled.