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 **************************************************************************/
26 # define exception c_exception
30 #include <simgear/debug/logstream.hxx>
32 #include <Time/sunpos.hxx>
33 #include <Time/light.hxx>
34 #include <Main/options.hxx>
38 /*************************************************************************
39 * Star::Star(FGTime *t)
40 * Public constructor for class Star
41 * Argument: The current time.
42 * the hard coded orbital elements our sun are passed to
43 * CelestialBody::CelestialBody();
44 * note that the word sun is avoided, in order to prevent some compilation
45 * problems on sun systems
46 ************************************************************************/
47 Star::Star(FGTime *t) :
48 CelestialBody (0.000000, 0.0000000000,
50 282.9404, 4.7093500E-5,
53 356.0470, 0.98560025850, t)
56 FG_LOG( FG_GENERAL, FG_INFO, "Initializing Sun Texture");
58 xglGenTextures(1, &sun_texid);
59 xglBindTexture(GL_TEXTURE_2D, sun_texid);
60 #elif GL_EXT_texture_object
61 xglGenTexturesEXT(1, &sun_texid);
62 xglBindTextureEXT(GL_TEXTURE_2D, sun_texid);
67 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
68 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
69 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
71 glTexImage2D( GL_TEXTURE_2D,
76 GL_RGBA, GL_UNSIGNED_BYTE,
79 SunObject = gluNewQuadric();
82 printf("gluNewQuadric(SunObject) failed !\n");
98 static int texWidth = 256; /* 64x64 is plenty */
100 void Star::setTexture()
108 texSize = texWidth*texWidth;
110 sun_texbuf = new GLubyte[texSize*4];
116 radius = (double)(texWidth / 2);
118 for (i=0; i < texWidth; i++) {
119 for (j=0; j < texWidth; j++) {
126 x = fabs((double)(i - (texWidth / 2)));
127 y = fabs((double)(j - (texWidth / 2)));
129 d = sqrt((x * x) + (y * y));
131 double t = 1.0 - (d / radius); // t is 1.0 at center, 0.0 at edge */
132 // inverse square looks nice
133 *(p+3) = (int)((double) 0xff * (t*t));
140 //gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
142 // GL_UNSIGNED_BYTE, textureBuf);
145 /*************************************************************************
146 * void Jupiter::updatePosition(FGTime *t, Star *ourSun)
148 * calculates the current position of our sun.
149 *************************************************************************/
150 void Star::updatePosition(FGTime *t)
157 updateOrbElements(t);
159 actTime = fgCalcActTime(t);
160 ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); // Angle in Radians
161 eccAnom = fgCalcEccAnom(M, e); // Calculate the eccentric Anomaly (also known as solving Kepler's equation)
163 xv = cos(eccAnom) - e;
164 yv = sqrt (1.0 - e*e) * sin(eccAnom);
165 v = atan2 (yv, xv); // the sun's true anomaly
166 distance = r = sqrt (xv*xv + yv*yv); // and its distance
168 lonEcl = v + w; // the sun's true longitude
171 // convert the sun's true longitude to ecliptic rectangular
172 // geocentric coordinates (xs, ys)
173 xs = r * cos (lonEcl);
174 ys = r * sin (lonEcl);
176 // convert ecliptic coordinates to equatorial rectangular
177 // geocentric coordinates
183 // And finally, calculate right ascension and declination
184 rightAscension = atan2 (ye, xe);
185 declination = atan2 (ze, sqrt (xe*xe + ye*ye));
188 void Star::newImage(void)
190 /*static float stars[3];
195 fgLIGHT *l = &cur_light_params;
196 float sun_angle = l->sun_angle;
198 if( sun_angle*RAD_TO_DEG < 100 ) { // else no need to draw sun
201 double x_2, x_4, x_8, x_10;
206 // daily variation sun gets larger near horizon
207 /*if(sun_angle*RAD_TO_DEG > 84.0 && sun_angle*RAD_TO_DEG < 95)
209 double sun_grow = 9*fabs(94-sun_angle*RAD_TO_DEG);
210 sun_size = (int)(sun_size + sun_size * cos(sun_grow*DEG_TO_RAD));
212 x_2 = sun_angle * sun_angle;
216 ambient = (float)(0.4 * pow (1.1, - x_10 / 30.0));
217 if (ambient < 0.3) ambient = 0.3;
218 if (ambient > 1.0) ambient = 1.0;
220 amb[0] = ((ambient * 6.0) - 1.0); // minimum value = 0.8
221 amb[1] = ((ambient * 11.0) - 3.0); // minimum value = 0.3
222 amb[2] = ((ambient * 12.0) - 3.6); // minimum value = 0.0
225 if (amb[0] > 1.0) amb[0] = 1.0;
226 if (amb[1] > 1.0) amb[1] = 1.0;
227 if (amb[2] > 1.0) amb[2] = 1.0;
231 xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
232 xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
233 xglTranslatef(0,60000,0);
234 if (current_options.get_textures())
236 glEnable(GL_TEXTURE_2D); // TEXTURE ENABLED
237 glEnable(GL_BLEND); // BLEND ENABLED
239 // glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
240 glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
241 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
242 glBindTexture(GL_TEXTURE_2D, sun_texid);
245 glTexCoord2f(0.0f, 0.0f); glVertex3f(-5000, 0.0, -5000);
246 glTexCoord2f(1.0f, 0.0f); glVertex3f( 5000, 0.0, -5000);
247 glTexCoord2f(1.0f, 1.0f); glVertex3f( 5000, 0.0, 5000);
248 glTexCoord2f(0.0f, 1.0f); glVertex3f(-5000, 0.0, 5000);
251 xglDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
252 xglDisable(GL_BLEND); // BLEND DISABLED
256 glDisable(GL_LIGHTING); // LIGHTING DISABLED
257 glDisable(GL_BLEND); // BLEND DISABLED
260 xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
261 xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
263 xglTranslatef(0,60000,0);
264 gluSphere( SunObject, sun_size, 10, 10 );
267 glDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
268 glDisable(GL_BLEND); // BLEND DISABLED