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flightgear/Simulator/Astro/moon.cxx
Tim Moore 66a0be21da Merge FG_Simulator as subdirectory
2009-09-14 13:38:55 +02:00

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/**************************************************************************
* moon.cxx
* Written by Durk Talsma. Originally started October 1997, for distribution
* with the FlightGear project. Version 2 was written in August and
* September 1998. This code is based upon algorithms and data kindly
* provided by Mr. Paul Schlyter. (pausch@saaf.se).
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
* (Log is kept at end of this file)
**************************************************************************/
#include <FDM/flight.hxx>
#include <string.h>
#include "moon.hxx"
#include <Debug/logstream.hxx>
#include <Objects/texload.h>
#ifdef __BORLANDC__
# define exception c_exception
#endif
#include <math.h>
/*************************************************************************
* Moon::Moon(fgTIME *t)
* Public constructor for class Moon. Initializes the orbital elements and
* sets up the moon texture.
* Argument: The current time.
* the hard coded orbital elements for Moon are passed to
* CelestialBody::CelestialBody();
************************************************************************/
Moon::Moon(fgTIME *t) :
CelestialBody(125.1228, -0.0529538083,
5.1454, 0.00000,
318.0634, 0.1643573223,
60.266600, 0.000000,
0.054900, 0.000000,
115.3654, 13.0649929509, t)
{
string tpath, fg_tpath;
int width, height;
FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
#ifdef GL_VERSION_1_1
xglGenTextures(1, &moon_texid);
xglBindTexture(GL_TEXTURE_2D, moon_texid);
#elif GL_EXT_texture_object
xglGenTexturesEXT(1, &moon_texid);
xglBindTextureEXT(GL_TEXTURE_2D, moon_texid);
#else
# error port me
#endif
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// load in the texture data
tpath = current_options.get_fg_root() + "/Textures/" + "moon.rgb";
if ( (moon_texbuf = read_rgb_texture(tpath.c_str(), &width, &height))
== NULL )
{
// Try compressed
fg_tpath = tpath + ".gz";
if ( (moon_texbuf = read_rgb_texture(fg_tpath.c_str(), &width, &height))
== NULL )
{
FG_LOG( FG_GENERAL, FG_ALERT,
"Error in loading moon texture " << tpath );
exit(-1);
}
}
glTexImage2D( GL_TEXTURE_2D,
0,
GL_RGB,
256, 256,
0,
GL_RGB, GL_UNSIGNED_BYTE,
moon_texbuf);
// setup the halo texture
FG_LOG( FG_GENERAL, FG_INFO, "Initializing Moon Texture");
#ifdef GL_VERSION_1_1
xglGenTextures(1, &moon_halotexid);
xglBindTexture(GL_TEXTURE_2D, moon_halotexid);
#elif GL_EXT_texture_object
xglGenTexturesEXT(1, &moon_halotexid);
xglBindTextureEXT(GL_TEXTURE_2D, moon_halotexid);
#else
# error port me
#endif
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
setHalo();
glTexImage2D( GL_TEXTURE_2D,
0,
GL_RGBA,
256, 256,
0,
GL_RGBA, GL_UNSIGNED_BYTE,
moon_halotexbuf);
moonObject = gluNewQuadric();
}
Moon::~Moon()
{
//delete moonObject;
delete moon_texbuf;
delete moon_halotexbuf;
}
static int texWidth = 256; /* 64x64 is plenty */
void Moon::setHalo()
{
int texSize;
//void *textureBuf;
GLubyte *p;
int i,j;
double radius;
texSize = texWidth*texWidth;
moon_halotexbuf = new GLubyte[texSize*4];
if (!moon_halotexbuf)
return; // Ugly!
p = moon_halotexbuf;
radius = (double)(texWidth / 2);
for (i=0; i < texWidth; i++) {
for (j=0; j < texWidth; j++) {
double x, y, d;
x = fabs((double)(i - (texWidth / 2)));
y = fabs((double)(j - (texWidth / 2)));
d = sqrt((x * x) + (y * y));
if (d < radius)
{
double t = 1.0 - (d / radius); // t is 1.0 at center, 0.0 at edge */
// inverse square looks nice
*p = (int)((double)0xff * (t * t));
*(p+1) = (int)((double) 0xff * (t*t));
*(p+2) = (int)((double) 0xff * (t*t));
*(p+3) = 0x11;
}
else
{
*p = 0x00;
*(p+1) = 0x00;
*(p+2) = 0x00;
*(p+3) = 0x11;
}
p += 4;
}
}
//gluBuild2DMipmaps(GL_TEXTURE_2D, 1, texWidth, texWidth,
// GL_LUMINANCE,
// GL_UNSIGNED_BYTE, textureBuf);
//free(textureBuf);
}
/*****************************************************************************
* void Moon::updatePosition(fgTIME *t, Star *ourSun)
* this member function calculates the actual topocentric position (i.e.)
* the position of the moon as seen from the current position on the surface
* of the moon.
****************************************************************************/
void Moon::updatePosition(fgTIME *t, Star *ourSun)
{
double
eccAnom, ecl, actTime,
xv, yv, v, r, xh, yh, zh, xg, yg, zg, xe, ye, ze,
Ls, Lm, D, F, mpar, gclat, rho, HA, g,
geoRa, geoDec;
fgAIRCRAFT *air;
FGInterface *f;
air = &current_aircraft;
f = air->fdm_state;
updateOrbElements(t);
actTime = fgCalcActTime(t);
// calculate the angle between ecliptic and equatorial coordinate system
// in Radians
ecl = ((DEG_TO_RAD * 23.4393) - (DEG_TO_RAD * 3.563E-7) * actTime);
eccAnom = fgCalcEccAnom(M, e); // Calculate the eccentric anomaly
xv = a * (cos(eccAnom) - e);
yv = a * (sqrt(1.0 - e*e) * sin(eccAnom));
v = atan2(yv, xv); // the moon's true anomaly
r = sqrt (xv*xv + yv*yv); // and its distance
// estimate the geocentric rectangular coordinates here
xh = r * (cos(N) * cos (v+w) - sin (N) * sin(v+w) * cos(i));
yh = r * (sin(N) * cos (v+w) + cos (N) * sin(v+w) * cos(i));
zh = r * (sin(v+w) * sin(i));
// calculate the ecliptic latitude and longitude here
lonEcl = atan2 (yh, xh);
latEcl = atan2(zh, sqrt(xh*xh + yh*yh));
/* Calculate a number of perturbatioin, i.e. disturbances caused by the
* gravitational infuence of the sun and the other major planets.
* The largest of these even have a name */
Ls = ourSun->getM() + ourSun->getw();
Lm = M + w + N;
D = Lm - Ls;
F = Lm - N;
lonEcl += DEG_TO_RAD * (-1.274 * sin (M - 2*D)
+0.658 * sin (2*D)
-0.186 * sin(ourSun->getM())
-0.059 * sin(2*M - 2*D)
-0.057 * sin(M - 2*D + ourSun->getM())
+0.053 * sin(M + 2*D)
+0.046 * sin(2*D - ourSun->getM())
+0.041 * sin(M - ourSun->getM())
-0.035 * sin(D)
-0.031 * sin(M + ourSun->getM())
-0.015 * sin(2*F - 2*D)
+0.011 * sin(M - 4*D)
);
latEcl += DEG_TO_RAD * (-0.173 * sin(F-2*D)
-0.055 * sin(M - F - 2*D)
-0.046 * sin(M + F - 2*D)
+0.033 * sin(F + 2*D)
+0.017 * sin(2*M + F)
);
r += (-0.58 * cos(M - 2*D)
-0.46 * cos(2*D)
);
FG_LOG(FG_GENERAL, FG_INFO, "Running moon update");
xg = r * cos(lonEcl) * cos(latEcl);
yg = r * sin(lonEcl) * cos(latEcl);
zg = r * sin(latEcl);
xe = xg;
ye = yg * cos(ecl) -zg * sin(ecl);
ze = yg * sin(ecl) +zg * cos(ecl);
geoRa = atan2(ye, xe);
geoDec = atan2(ze, sqrt(xe*xe + ye*ye));
// Given the moon's geocentric ra and dec, calculate its
// topocentric ra and dec. i.e. the position as seen from the
// surface of the earth, instead of the center of the earth
// First calculate the moon's parrallax, that is, the apparent size of the
// (equatorial) radius of the earth, as seen from the moon
mpar = asin ( 1 / r);
gclat = f->get_Latitude() - 0.003358 *
sin (2 * DEG_TO_RAD * f->get_Latitude() );
rho = 0.99883 + 0.00167 * cos(2 * DEG_TO_RAD * f->get_Latitude());
if (geoRa < 0)
geoRa += (2*FG_PI);
HA = t->lst - (3.8197186 * geoRa);
g = atan (tan(gclat) / cos ((HA / 3.8197186)));
rightAscension = geoRa - mpar * rho * cos(gclat) * sin(HA) / cos (geoDec);
declination = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
}
/************************************************************************
* void Moon::newImage()
*
* This function regenerates a new visual image of the moon, which is added to
* solarSystem display list.
*
* Arguments: Right Ascension and declination
*
* return value: none
**************************************************************************/
void Moon::newImage()
{
fgLIGHT *l = &cur_light_params;
float moon_angle = l->moon_angle;
/*double x_2, x_4, x_8, x_10;
GLfloat ambient;
GLfloat amb[4];*/
int moonSize = 750;
GLfloat moonColor[4] = {0.85, 0.75, 0.35, 1.0};
GLfloat black[4] = {0.0, 0.0,0.0,1.0};
GLfloat white[4] = {1.0, 1.0,1.0,1.0};
if( moon_angle*RAD_TO_DEG < 100 )
{
/*
x_2 = moon_angle * moon_angle;
x_4 = x_2 * x_2;
x_8 = x_4 * x_4;
x_10 = x_8 * x_2;
ambient = (float)(0.4 * pow (1.1, - x_10 / 30.0));
if (ambient < 0.3) ambient = 0.3;
if (ambient > 1.0) ambient = 1.0;
amb[0] = ((ambient * 6.0) - 1.0); // minimum value = 0.8
amb[1] = ((ambient * 11.0) - 3.0); // minimum value = 0.3
amb[2] = ((ambient * 12.0) - 3.6); // minimum value = 0.0
amb[3] = 1.00;
if (amb[0] > 1.0) amb[0] = 1.0;
if (amb[1] > 1.0) amb[1] = 1.0;
if (amb[2] > 1.0) amb[2] = 1.0;
xglColor3fv(amb);
xglColor3f(1.0, 1.0, 1.0); */
xglPushMatrix();
{
//xglRotatef(-90, 0.0, 0.0, 1.0);
xglRotatef(((RAD_TO_DEG * rightAscension)- 90.0), 0.0, 0.0, 1.0);
xglRotatef((RAD_TO_DEG * declination), 1.0, 0.0, 0.0);
FG_LOG( FG_GENERAL, FG_INFO,
"Ra = (" << (RAD_TO_DEG *rightAscension)
<< "), Dec= (" << (RAD_TO_DEG *declination) << ")" );
xglTranslatef(0.0, 58600.0, 0.0);
glEnable(GL_TEXTURE_2D); // TEXTURE ENABLED
glEnable(GL_BLEND); // BLEND ENABLED
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D, moon_halotexid);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-5000, 0.0, -5000);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 5000, 0.0, -5000);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 5000, 0.0, 5000);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-5000, 0.0, 5000);
glEnd();
xglEnable(GL_LIGHTING); // LIGHTING ENABLED
xglEnable( GL_LIGHT0 );
// set lighting parameters
xglLightfv(GL_LIGHT0, GL_AMBIENT, white );
xglLightfv(GL_LIGHT0, GL_DIFFUSE, white );
xglEnable( GL_CULL_FACE );
xglMaterialfv(GL_FRONT, GL_AMBIENT, black);
xglMaterialfv(GL_FRONT, GL_DIFFUSE, moonColor);
//glEnable(GL_TEXTURE_2D);
glBlendFunc(GL_ONE, GL_ONE);
//glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D, moon_texid);
//glDisable(GL_LIGHTING); // LIGHTING DISABLED
gluQuadricTexture(moonObject, GL_TRUE );
gluSphere(moonObject, moonSize, 12, 12 );
glDisable(GL_TEXTURE_2D); // TEXTURE DISABLED
glDisable(GL_BLEND); // BLEND DISABLED
}
xglPopMatrix();
glDisable(GL_LIGHTING); // LIGHTING DISABLED
}
else
{
}
}
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