273 lines
8.4 KiB
C++
273 lines
8.4 KiB
C++
/**************************************************************************
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* planets.c
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*
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* Written 1997 by Durk Talsma, started October, 1997. For the flight gear
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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* (Log is kept at end of this file)
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**************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#ifdef HAVE_WINDOWS_H
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# include <windows.h>
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#endif
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#include <GL/glut.h>
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#include <XGL/xgl.h>
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#include <Debug/fg_debug.h>
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#include <Include/fg_constants.h>
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#include <Time/fg_time.hxx>
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#include <Time/light.hxx>
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#include "orbits.hxx"
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#include "planets.hxx"
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#include "sun.hxx"
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GLint planets = 0;
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struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
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struct OrbElements theSun,
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struct fgTIME t, int idx)
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{
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struct CelestialCoord result;
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fgSUNPOS SolarPosition;
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double eccAnom, r, v, ecl, actTime, R, s, ir, Nr, B, FV, ring_magn,
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xv, yv, xh, yh, zh, xg, yg, zg, xe, ye, ze;
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actTime = fgCalcActTime(t);
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/*calculate the angle between ecliptic and equatorial coordinate system */
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ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime);
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/* calculate the eccentric anomaly */
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eccAnom = fgCalcEccAnom(planet.M, planet.e);
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/* calculate the planets distance (r) and true anomaly (v) */
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xv = planet.a * (cos(eccAnom) - planet.e);
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yv = planet.a * (sqrt(1.0 - planet.e*planet.e) * sin(eccAnom));
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v = atan2(yv, xv);
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r = sqrt ( xv*xv + yv*yv);
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/* calculate the planets position in 3-dimensional space */
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xh = r * (cos (planet.N) * cos (v + planet.w) -
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sin (planet.N) * sin (v + planet.w) * cos (planet.i));
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yh = r * (sin (planet.N) * cos (v + planet.w) +
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cos (planet.N) * sin (v + planet.w) * cos (planet.i));
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zh = r * ( sin(v+planet.w) * sin(planet.i));
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/* calculate the ecliptic longitude and latitude */
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xg = xh + solarPosition.xs;
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yg = yh + solarPosition.ys;
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zg = zh;
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xe = xg;
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ye = yg * cos(ecl) - zg * sin(ecl);
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ze = yg * sin(ecl) + zg * cos(ecl);
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result.RightAscension = atan2(ye,xe);
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result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
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/* Let's calculate the brightness of the planet */
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R = sqrt ( xg*xg + yg*yg + zg*zg);
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s = SolarPosition.dist;
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FV = acos( (r*r + R*R - s*s) / (2*r*R));
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FV *= 57.29578; /* convert radians to degrees */
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switch(idx)
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{
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case 2: /* mercury */
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result.magnitude = -0.36 + 5*log10( r*R ) + 0.027 * FV + 2.2E-13 * pow(FV, 6);
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break;
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case 3: /*venus */
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result.magnitude = -4.34 + 5*log10( r*R ) + 0.013 * FV + 4.2E-07 * pow(FV,3);
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break;
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case 4: /* mars */
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result.magnitude = -1.51 + 5*log10( r*R ) + 0.016 * FV;
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break;
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case 5: /* Jupiter */
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result.magnitude = -9.25 + 5*log10( r*R ) + 0.014 * FV;
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break;
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case 6: /* Saturn */
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ir = 0.4897394;
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Nr = 2.9585076 + 6.6672E-7*actTime;
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B = asin (sin (result.Declination) * cos (ir) -
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cos (result.Declination) * sin (ir) *
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sin (result.RightAscension - Nr));
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ring_magn = -2.6 * sin (fabs(B)) + 1.2 * pow(sin(B),2);
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result.magnitude = -9.0 + 5*log10( r*R ) + 0.044 * FV + ring_magn;
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break;
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case 7: /* Uranus */
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result.magnitude = -7.15 + 5*log10( r*R) + 0.001 * FV;
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break;
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case 8: /* Neptune */
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result.magnitude = -6.90 + 5*log10 (r*R) + 0.001 *FV;
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break;
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default:
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fgPrintf( FG_ASTRO, FG_ALERT, "index %d out of range !!!!\n", idx);
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}
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fgPrintf( FG_ASTRO, FG_DEBUG,
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" Planet found at %f (ra), %f (dec)\n",
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result.RightAscension, result.Declination);
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fgPrintf( FG_ASTRO, FG_DEBUG,
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" Geocentric dist %f\n"
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" Heliocentric dist %f\n"
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" Distance to the sun %f\n"
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" Phase angle %f\n"
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" Brightness %f\n", R, r, s, FV, result.magnitude);
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return result;
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}
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void fgPlanetsInit( void )
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{
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struct fgLIGHT *l;
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int i;
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struct CelestialCoord pltPos;
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double magnitude;
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l = &cur_light_params;
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/* if the display list was already built during a previous init,
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then recycle it */
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if (planets) {
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xglDeleteLists(planets, 1);
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}
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planets = xglGenLists(1);
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xglNewList( planets, GL_COMPILE );
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xglBegin( GL_POINTS );
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/* Add the planets to all four display lists */
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for ( i = 2; i < 9; i++ ) {
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fgSolarSystemUpdate(&(pltOrbElements[i]), cur_time_params);
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pltPos = fgCalculatePlanet(pltOrbElements[i],
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pltOrbElements[0], cur_time_params, i);
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magnitude = (0.0 - pltPos.magnitude) / 5.0 + 1.0;
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/* scale magnitudes again so they look ok */
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/* magnitude =
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magnitude * 0.7 + (((FG_STAR_LEVELS - 1) - i) * 0.1); */
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/* the following statement could be made a little more sopisticated
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for the moment: Stick to this one */
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magnitude = magnitude * 0.7 + (3 * 0.1);
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if ( magnitude > 1.0 ) { magnitude = 1.0; }
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if ( magnitude < 0.0 ) { magnitude = 0.0; }
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/* Add planets to the display list, based on sun_angle and current
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magnitude It's pretty experimental... */
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if ((double) (l->sun_angle - FG_PI_2) >
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((magnitude - 1.0) * -20 * DEG_TO_RAD))
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{
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xglColor3f (magnitude, magnitude, magnitude);
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printf ("Sun Angle to Horizon (in Rads) = %f\n",
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(double) (l->sun_angle - FG_PI_2));
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printf ("Transformed Magnitude is :%f %f\n",
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magnitude, (magnitude - 1.0) * -20 * DEG_TO_RAD);
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xglVertex3f (50000.0 * cos (pltPos.RightAscension) *
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cos (pltPos.Declination),
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50000.0 * sin (pltPos.RightAscension) *
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cos (pltPos.Declination),
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50000.0 * sin (pltPos.Declination));
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}
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}
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xglEnd();
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xglEndList();
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}
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void fgPlanetsRender( void ) {
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xglCallList(planets);
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}
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/* $Log$
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/* Revision 1.3 1998/04/25 22:06:25 curt
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/* Edited cvs log messages in source files ... bad bad bad!
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/*
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* Revision 1.2 1998/04/24 00:45:02 curt
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* Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
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* Fixed a bug when generating sky colors.
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*
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* Revision 1.1 1998/04/22 13:21:31 curt
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* C++ - ifing the code a bit.
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*
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* Revision 1.9 1998/04/18 04:13:57 curt
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* Moved fg_debug.c to it's own library.
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*
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* Revision 1.8 1998/04/03 21:52:50 curt
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* Converting to Gnu autoconf system.
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*
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* Revision 1.7 1998/02/23 19:07:55 curt
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* Incorporated Durk's Astro/ tweaks. Includes unifying the sun position
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* calculation code between sun display, and other FG sections that use this
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* for things like lighting.
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*
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* Revision 1.6 1998/02/12 21:59:36 curt
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* Incorporated code changes contributed by Charlie Hotchkiss
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* <chotchkiss@namg.us.anritsu.com>
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*
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* Revision 1.5 1998/02/03 23:20:12 curt
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* Lots of little tweaks to fix various consistency problems discovered by
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* Solaris' CC. Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
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* passed arguments along to the real printf(). Also incorporated HUD changes
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* by Michele America.
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*
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* Revision 1.4 1998/02/02 20:53:23 curt
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* To version 0.29
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*
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* Revision 1.3 1998/01/27 00:47:47 curt
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* Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
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* system and commandline/config file processing code.
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*
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* Revision 1.2 1998/01/19 19:26:59 curt
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* Merged in make system changes from Bob Kuehne <rpk@sgi.com>
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* This should simplify things tremendously.
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*
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* Revision 1.1 1998/01/07 03:16:18 curt
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* Moved from .../Src/Scenery/ to .../Src/Astro/
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*
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* Revision 1.4 1997/12/30 20:47:52 curt
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* Integrated new event manager with subsystem initializations.
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*
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* Revision 1.3 1997/12/30 16:36:52 curt
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* Merged in Durk's changes ...
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*
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* Revision 1.2 1997/12/12 21:41:29 curt
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* More light/material property tweaking ... still a ways off.
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*
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* Revision 1.1 1997/10/25 03:16:10 curt
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* Initial revision of code contributed by Durk Talsma.
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*
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*/
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