From: curt <curt>
Date: Mon, 23 Feb 1998 19:07:49 +0000 (+0000)
Subject: Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=20cf326fec07113e0702a7367a162febf0fade88;p=simgear.git

Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
calculation code between sun display, and other FG sections that use this
for things like lighting.
---

diff --git a/Astro/moon.c b/Astro/moon.c
index 11c63667..3b18a488 100644
--- a/Astro/moon.c
+++ b/Astro/moon.c
@@ -38,7 +38,7 @@
 struct CelestialCoord moonPos;
 
 static float xMoon, yMoon, zMoon;
-static GLint moon;
+static GLint moon = 0;
 
 
 
@@ -67,8 +67,8 @@ struct CelestialCoord fgCalculateMoon(struct OrbElements params,
   /* calculate the angle between ecliptic and equatorial coordinate
    * system, in Radians */
   actTime = fgCalcActTime(t);
-  /* ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime);*/
-  ecl = 0.409093 - 6.2186E-9 * actTime;
+  ecl = ((DEG_TO_RAD * 23.4393) - (DEG_TO_RAD * 3.563E-7) * actTime);
+  /*ecl = 0.409093 - 6.2186E-9 * actTime; */
 							
   /* calculate the eccentric anomaly */
   eccAnom = fgCalcEccAnom(params.M, params.e);
@@ -80,8 +80,10 @@ struct CelestialCoord fgCalculateMoon(struct OrbElements params,
   r = sqrt(xv*xv + yv*yv);
   
   /* estimate the geocentric rectangular coordinates here */
-  xh = r * (cos(params.N) * cos(v + params.w) - sin(params.N) * sin(v + params.w) * cos(params.i));
-  yh = r * (sin(params.N) * cos(v + params.w) + cos(params.N) * sin(v + params.w) * cos(params.i));
+  xh = r * (cos (params.N) * cos (v + params.w) -
+	    sin (params.N) * sin (v + params.w) * cos (params.i));
+  yh = r * (sin (params.N) * cos (v + params.w) +
+	    cos (params.N) * sin (v + params.w) * cos (params.i));
   zh = r * (sin(v + params.w) * sin(params.i));
   
   /* calculate the ecliptic latitude and longitude here */
@@ -90,7 +92,7 @@ struct CelestialCoord fgCalculateMoon(struct OrbElements params,
 
   /* calculate a number of perturbations, i.e. disturbances caused by
    * the gravitational influence of the sun and the other mayor
-   * planets, the largest even have their own names */
+   * planets. The largest of these even have their own names */
   Ls = sunParams.M + sunParams.w;
   Lm =    params.M +    params.w + params.N;
   D = Lm - Ls;
@@ -155,24 +157,19 @@ struct CelestialCoord fgCalculateMoon(struct OrbElements params,
 
      
 
-  topocCoord.RightAscension = geocCoord.RightAscension - mpar * rho * cos(gclat) * sin(HA) / cos(geocCoord.Declination);
-  topocCoord.Declination = geocCoord.Declination - mpar * rho * sin(gclat) * sin(g - geocCoord.Declination) / sin(g);
+  topocCoord.RightAscension = geocCoord.RightAscension -
+      mpar * rho * cos (gclat) * sin (HA) / cos (geocCoord.Declination);
+  topocCoord.Declination = geocCoord.Declination -
+      mpar * rho * sin (gclat) * sin (g - geocCoord.Declination) / sin (g);
   return topocCoord;
 }
 
 
 void fgMoonInit( void ) {
-    /* struct fgLIGHT *l; */
-    static int dl_exists = 0;
-    /* GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 }; */
-    GLfloat moonColor[4] = {0.85, 0.65, 0.05, 1.0};
+    GLfloat moonColor[4] = {0.85, 0.75, 0.35, 1.0};
     GLfloat black[4] = { 0.0, 0.0, 0.0, 1.0 };
 
     fgPrintf( FG_ASTRO, FG_INFO, "Initializing the Moon\n");
-
-    /* l = &cur_light_params; */
-
-    /* position the moon */
     fgSolarSystemUpdate(&(pltOrbElements[1]), cur_time_params);
     moonPos = fgCalculateMoon(pltOrbElements[1], pltOrbElements[0], 
 			      cur_time_params);
@@ -184,52 +181,41 @@ void fgMoonInit( void ) {
     yMoon = 60000.0 * sin(moonPos.RightAscension) * cos(moonPos.Declination);
     zMoon = 60000.0 * sin(moonPos.Declination);
 
-    if ( !dl_exists ) {
-	dl_exists = 1;
-
-	/* printf("First time through, creating moon display list\n"); */
-
-	moon = xglGenLists(1);
-	xglNewList(moon, GL_COMPILE );
-
-	/* xglMaterialfv(GL_FRONT, GL_AMBIENT, l->scene_clear);
-	   xglMaterialfv(GL_FRONT, GL_DIFFUSE, moon_color); */
-	xglMaterialfv(GL_FRONT, GL_AMBIENT, black);
-	xglMaterialfv(GL_FRONT, GL_DIFFUSE, moonColor);
-
-	glutSolidSphere(1.0, 10, 10);
-
-	xglEndList();
+    if (moon) {
+ 	xglDeleteLists (moon, 1);
     }
+
+    moon = xglGenLists (1);
+    xglNewList (moon, GL_COMPILE);
+  
+    xglMaterialfv (GL_FRONT, GL_AMBIENT, black);
+    xglMaterialfv (GL_FRONT, GL_DIFFUSE, moonColor);
+    xglPushMatrix ();
+    xglTranslatef (xMoon, yMoon, zMoon);
+    xglScalef (1400, 1400, 1400);
+  
+    glutSolidSphere (1.0, 10, 10);
+    xglPopMatrix ();
+    xglEndList ();
 }
 
 
 /* Draw the moon */
 void fgMoonRender( void ) {
-    /* struct fgLIGHT *l; */
-
-    /* printf("Rendering moon\n"); */
-
-    /* l = &cur_light_params; */
-
-    /* xglMaterialfv(GL_FRONT, GL_AMBIENT, l->sky_color ); */
-    /* xglMaterialfv(GL_FRONT, GL_DIFFUSE, white); */
-
-    xglPushMatrix();
-    xglTranslatef(xMoon, yMoon, zMoon);
-    xglScalef(1400, 1400, 1400);
-
     xglCallList(moon);
-
-    xglPopMatrix();
 }
 
 
 /* $Log$
-/* Revision 1.6  1998/02/07 15:29:32  curt
-/* Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
-/* <chotchkiss@namg.us.anritsu.com>
+/* Revision 1.7  1998/02/23 19:07:54  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.6  1998/02/07 15:29:32  curt
+ * Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
+ * <chotchkiss@namg.us.anritsu.com>
+ *
  * Revision 1.5  1998/02/02 20:53:21  curt
  * To version 0.29
  *
diff --git a/Astro/moon.h b/Astro/moon.h
index 1b4121a7..f43820ae 100644
--- a/Astro/moon.h
+++ b/Astro/moon.h
@@ -31,11 +31,8 @@
 #include <Time/fg_time.h>
 #include <math.h>
 
-/* #define X .525731112119133606 */
-/* #define Z .850650808352039932 */
 
-
- /* Initialize the Moon Display management Subsystem */
+/* Initialize the Moon Display management Subsystem */
 void fgMoonInit( void );
 
 /* Draw the Moon */
@@ -51,9 +48,14 @@ extern struct OrbElements pltOrbElements[9];
 
 
 /* $Log$
-/* Revision 1.5  1998/02/02 20:53:21  curt
-/* To version 0.29
+/* Revision 1.6  1998/02/23 19:07:54  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.5  1998/02/02 20:53:21  curt
+ * To version 0.29
+ *
  * Revision 1.4  1998/01/22 02:59:27  curt
  * Changed #ifdef FILE_H to #ifdef _FILE_H
  *
diff --git a/Astro/orbits.c b/Astro/orbits.c
index 50da7450..fe5208c4 100644
--- a/Astro/orbits.c
+++ b/Astro/orbits.c
@@ -36,48 +36,12 @@
 struct OrbElements pltOrbElements[9];
 
 
-//double fgCalcActTime(struct fgTIME t)
-//{
-//   double
-//         actTime, UT;
-//   int year;
-//
-//   /* a hack. This one introduces the 2000 problem into the program */
-//   year = t.gmt->tm_year + 1900;
-//
-//   /* calculate the actual time, remember to add 1 to tm_mon! */
-//   actTime = 367 * year - 7 *
-//	          (year + ((t.gmt->tm_mon+1) + 9) / 12) / 4 + 275 *
-//	           (t.gmt->tm_mon+1) / 9 + t.gmt->tm_mday - 730530;
-//
-//    UT = t.gmt->tm_hour + ((double) t.gmt->tm_min / 60);
-//    /*printf("UT = %f\n", UT); */
-//    actTime += (UT / 24.0);
-//    #define DEBUG 1
-//    #ifdef DEBUG
-//    /* printf("  Actual Time:\n"); */
-//    /* printf("  current day = %f\t", actTime); */
-//    /* printf("  GMT = %d, %d, %d, %d, %d, %d\n",
-//	   year, t.gmt->tm_mon, t.gmt->tm_mday,
-//	   t.gmt->tm_hour, t.gmt->tm_min, t.gmt->tm_sec); */
-//    #endif
-//    return actTime;
-//}
-
-
 double fgCalcActTime(struct fgTIME t)
 {
   return (t.mjd - 36523.5);
 }
 
 
-/* convert degrees to radians */
-/*
-double fgDegToRad(double angle)
-{
-	return (angle * PIOVER180);
-}
-*/
 double fgCalcEccAnom(double M, double e)
 {
     double
@@ -101,16 +65,26 @@ double fgCalcEccAnom(double M, double e)
 }
 
 
-// This function assumes that if the FILE ptr is valid that the contents
-// will be valid. Should we check the file for validity?
+/* This function assumes that if the FILE ptr is valid that the
+   contents will be valid. Should we check the file for validity? */
+  
+/* Sounds like a good idea to me. What type of checks are you thinking
+   of, other than feof(FILE*)? That's currently the only check I can
+   think of (Durk) */
 
-void fgReadOrbElements(struct OrbElements *dest, FILE *src)
+int fgReadOrbElements(struct OrbElements *dest, FILE *src)
 {
 	char line[256];
     int i,j;
     j = 0;
     do
     {
+ 	if (feof (src)) {
+	    fgPrintf (FG_ASTRO, FG_ALERT,
+		      "End of file found while reading planetary positions:\n");
+ 	    return 0;
+ 	}
+ 
     	fgets(line, 256,src);
         for (i = 0; i < 256; i++)
         {
@@ -127,6 +101,8 @@ void fgReadOrbElements(struct OrbElements *dest, FILE *src)
            &dest->aFirst, &dest->aSec,
            &dest->eFirst, &dest->eSec,
            &dest->MFirst, &dest->MSec);
+
+    return(1);
 }
 
 
@@ -159,7 +135,9 @@ int fgSolarSystemInit(struct fgTIME t)
 	for (i = 0; i < 9; i ++)
 	    {
 		/* ...read from the data file ... */
-		fgReadOrbElements(&pltOrbElements[i], data);
+		if (!(fgReadOrbElements (&pltOrbElements[i], data))) {
+		    ret_val = 0;
+		}
 		/* ...and calculate the actual values */
 		fgSolarSystemUpdate(&pltOrbElements[i], t);
 	    }
@@ -177,20 +155,25 @@ void fgSolarSystemUpdate(struct OrbElements *planet, struct fgTIME t)
    actTime = fgCalcActTime(t);
 
    /* calculate the actual orbital elements */
-    planet->M = DEG_TO_RAD * (planet->MFirst + (planet->MSec * actTime));	// angle in radians
-    planet->w = DEG_TO_RAD * (planet->wFirst + (planet->wSec * actTime));	// angle in radians
-    planet->N = DEG_TO_RAD * (planet->NFirst + (planet->NSec * actTime));	// angle in radians
-    planet->i = DEG_TO_RAD * (planet->iFirst + (planet->iSec * actTime));  // angle in radians
-    planet->e = planet->eFirst + (planet->eSec * actTime);
-    planet->a = planet->aFirst + (planet->aSec * actTime);
+   planet->M = DEG_TO_RAD * (planet->MFirst + (planet->MSec * actTime));
+   planet->w = DEG_TO_RAD * (planet->wFirst + (planet->wSec * actTime));
+   planet->N = DEG_TO_RAD * (planet->NFirst + (planet->NSec * actTime));
+   planet->i = DEG_TO_RAD * (planet->iFirst + (planet->iSec * actTime));
+   planet->e = planet->eFirst + (planet->eSec * actTime);
+   planet->a = planet->aFirst + (planet->aSec * actTime);
 }
 
 
 /* $Log$
-/* Revision 1.7  1998/02/12 21:59:33  curt
-/* Incorporated code changes contributed by Charlie Hotchkiss
-/* <chotchkiss@namg.us.anritsu.com>
+/* Revision 1.8  1998/02/23 19:07:55  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.7  1998/02/12 21:59:33  curt
+ * Incorporated code changes contributed by Charlie Hotchkiss
+ * <chotchkiss@namg.us.anritsu.com>
+ *
  * Revision 1.6  1998/02/03 23:20:11  curt
  * Lots of little tweaks to fix various consistency problems discovered by
  * Solaris' CC.  Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
diff --git a/Astro/orbits.h b/Astro/orbits.h
index 658edd31..377c4166 100644
--- a/Astro/orbits.h
+++ b/Astro/orbits.h
@@ -34,14 +34,17 @@
 
 
 
-#define STANDARDEPOCH 2000
-#define PIOVER180	1.74532925199433E-002
+//#define STANDARDEPOCH 2000
 
-struct SunPos {
+typedef struct {
     double xs;
     double ys;
     double dist;
-};
+    double lonSun;
+} fgSUNPOS;
+
+extern fgSUNPOS solarPosition;
+
 
 struct OrbElements {
     double NFirst;		/* longitude of the ascending node first part */
@@ -68,11 +71,10 @@ struct CelestialCoord {
 };
 
 
-/* double fgDegToRad(double angle); */
 double fgCalcEccAnom(double M, double e);
 double fgCalcActTime(struct fgTIME t);
 
-void fgReadOrbElements(struct OrbElements *dest, FILE *src);
+int fgReadOrbElements (struct OrbElements *dest, FILE * src);
 int  fgSolarSystemInit(struct fgTIME t);
 void fgSolarSystemUpdate(struct OrbElements *planets, struct fgTIME t);
 
@@ -81,10 +83,15 @@ void fgSolarSystemUpdate(struct OrbElements *planets, struct fgTIME t);
 
 
 /* $Log$
-/* Revision 1.5  1998/02/12 21:59:35  curt
-/* Incorporated code changes contributed by Charlie Hotchkiss
-/* <chotchkiss@namg.us.anritsu.com>
+/* Revision 1.6  1998/02/23 19:07:55  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.5  1998/02/12 21:59:35  curt
+ * Incorporated code changes contributed by Charlie Hotchkiss
+ * <chotchkiss@namg.us.anritsu.com>
+ *
  * Revision 1.4  1998/02/02 20:53:22  curt
  * To version 0.29
  *
diff --git a/Astro/planets.c b/Astro/planets.c
index 0def3af7..552547a8 100644
--- a/Astro/planets.c
+++ b/Astro/planets.c
@@ -43,46 +43,37 @@ struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
                                         struct OrbElements theSun,
                                         struct fgTIME t, int idx)
 {
-   struct CelestialCoord
-		result;
+    struct CelestialCoord result;
 
-    struct SunPos
-    	SolarPosition;
+    fgSUNPOS SolarPosition;
 
-	double
-        eccAnom, r, v, ecl, actTime, R, s, ir, Nr, B, FV, ring_magn,
+    double eccAnom, r, v, ecl, actTime, R, s, ir, Nr, B, FV, ring_magn,
         xv, yv, xh, yh, zh, xg, yg, zg, xe, ye, ze;
 
-      actTime = fgCalcActTime(t);
-      /* calculate the angle between ecliptic and equatorial coordinate system */
-      /* ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); */
-      ecl = 0.409093 - 6.2186E-9 * actTime;
+    actTime = fgCalcActTime(t);
+    /*calculate the angle between ecliptic and equatorial coordinate system */
+    ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime);
 
     /* calculate the eccentric anomaly */
-	eccAnom  = fgCalcEccAnom(planet.M, planet.e);
+    eccAnom  = fgCalcEccAnom(planet.M, planet.e);
 
     /* calculate the planets distance (r) and true anomaly (v) */
     xv = planet.a * (cos(eccAnom) - planet.e);
     yv = planet.a * (sqrt(1.0 - planet.e*planet.e) * sin(eccAnom));
     v = atan2(yv, xv);
     r = sqrt ( xv*xv + yv*yv);
-
+    
     /* calculate the planets position in 3-dimensional space */
-    xh = r * ( cos(planet.N) * cos(v+planet.w) - sin(planet.N) * sin(v+planet.w) * cos(planet.i));
-    yh = r * ( sin(planet.N) * cos(v+planet.w) + cos(planet.N) * sin(v+planet.w) * cos(planet.i));
+    xh = r * (cos (planet.N) * cos (v + planet.w) -
+ 	      sin (planet.N) * sin (v + planet.w) * cos (planet.i));
+    yh = r * (sin (planet.N) * cos (v + planet.w) +
+ 	      cos (planet.N) * sin (v + planet.w) * cos (planet.i));
     zh = r * ( sin(v+planet.w) * sin(planet.i));
 
     /* calculate the ecliptic longitude and latitude */
 
-    /*
-    lonecl = atan2(yh, xh);
-    latecl = atan2(zh, sqrt ( xh*xh + yh*yh));
-    */
-    /* calculate the solar position */
-
-    SolarPosition = fgCalcSunPos(theSun);
-    xg = xh + SolarPosition.xs;
-    yg = yh + SolarPosition.ys;
+    xg = xh + solarPosition.xs;
+    yg = yh + solarPosition.ys;
     zg = zh;
 
     xe = xg;
@@ -91,7 +82,6 @@ struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
 
     result.RightAscension = atan2(ye,xe);
     result.Declination = atan2(ze, sqrt(xe*xe + ye*ye));
-
 	 
     /* Let's calculate the brightness of the planet */
     R = sqrt ( xg*xg + yg*yg + zg*zg);
@@ -117,7 +107,9 @@ struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
 	ir = 0.4897394;
 	Nr = 2.9585076 + 6.6672E-7*actTime;
 	
-	B = asin ( sin (result.Declination) * cos(ir) - cos(result.Declination) * sin (ir) * sin (result.RightAscension - Nr));
+	B = asin (sin (result.Declination) * cos (ir) -
+		  cos (result.Declination) * sin (ir) *
+		  sin (result.RightAscension - Nr));
 	ring_magn = -2.6 * sin (fabs(B)) + 1.2 * pow(sin(B),2);
 	result.magnitude = -9.0 + 5*log10( r*R ) + 0.044 * FV + ring_magn;
 	break;
@@ -145,15 +137,18 @@ struct CelestialCoord fgCalculatePlanet(struct OrbElements planet,
 
 void fgPlanetsInit( void )
 {
+  struct fgLIGHT *l;
   int i;
   struct CelestialCoord pltPos;
   double magnitude;
 
+  l = &cur_light_params;
   /* if the display list was already built during a previous init,
-     recycle it */
+     then recycle it */
 
-  if (planets)
+  if (planets) {
       xglDeleteLists(planets, 1);
+  }
 
   planets = xglGenLists(1);
   xglNewList( planets, GL_COMPILE );
@@ -166,10 +161,6 @@ void fgPlanetsInit( void )
     pltPos = fgCalculatePlanet(pltOrbElements[i], 
 			       pltOrbElements[0], cur_time_params, i);
     
-    /* give the planets a temporary color, for testing purposes */
-    /* xglColor3f( 1.0, 0.0, 0.0); */
-    /* scale magnitudes to (0.0 - 1.0) */
-    
     magnitude = (0.0 - pltPos.magnitude) / 5.0 + 1.0;
     
     /* scale magnitudes again so they look ok */
@@ -182,15 +173,24 @@ void fgPlanetsInit( void )
     if ( magnitude > 1.0 ) { magnitude = 1.0; }
     if ( magnitude < 0.0 ) { magnitude = 0.0; }
     
-    
-    xglColor3f(magnitude, magnitude, magnitude);
-    /* xglColor3f(1.0, 1.0,1.0); */
-    
-    xglVertex3f( 50000.0 * cos(pltPos.RightAscension) * 
-		           cos(pltPos.Declination),
-		 50000.0 * sin(pltPos.RightAscension) *
-		           cos(pltPos.Declination),
-		 50000.0 * sin(pltPos.Declination) );
+    /* Add planets to the display list, based on sun_angle and current
+       magnitude It's pretty experimental... */
+
+    if ((double) (l->sun_angle - FG_PI_2) > 
+	((magnitude - 1.0) * -20 * DEG_TO_RAD))
+ 	{
+ 	    xglColor3f (magnitude, magnitude, magnitude);
+ 	    printf ("Sun Angle to Horizon (in Rads) = %f\n", 
+		    (double) (l->sun_angle - FG_PI_2));
+ 	    printf ("Transformed Magnitude is :%f  %f\n", 
+		    magnitude, (magnitude - 1.0) * -20 * DEG_TO_RAD);
+ 
+ 	    xglVertex3f (50000.0 * cos (pltPos.RightAscension) *
+ 			 cos (pltPos.Declination),
+ 			 50000.0 * sin (pltPos.RightAscension) *
+ 			 cos (pltPos.Declination),
+ 			 50000.0 * sin (pltPos.Declination));
+ 	}
   }
   xglEnd();
   xglEndList();
@@ -204,10 +204,15 @@ void fgPlanetsRender( void ) {
 
 
 /* $Log$
-/* Revision 1.6  1998/02/12 21:59:36  curt
-/* Incorporated code changes contributed by Charlie Hotchkiss
-/* <chotchkiss@namg.us.anritsu.com>
+/* Revision 1.7  1998/02/23 19:07:55  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.6  1998/02/12 21:59:36  curt
+ * Incorporated code changes contributed by Charlie Hotchkiss
+ * <chotchkiss@namg.us.anritsu.com>
+ *
  * Revision 1.5  1998/02/03 23:20:12  curt
  * Lots of little tweaks to fix various consistency problems discovered by
  * Solaris' CC.  Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
diff --git a/Astro/sun.c b/Astro/sun.c
index 673fea64..2a04057b 100644
--- a/Astro/sun.c
+++ b/Astro/sun.c
@@ -25,26 +25,23 @@
 #include <GL/glut.h>
 #include <XGL/xgl.h>
 
-#include <Time/fg_time.h>
-#include <Main/views.h>
 #include <Astro/orbits.h>
 #include <Astro/sun.h>
-#include <Main/fg_debug.h>
 #include <Include/fg_constants.h>
+#include <Main/fg_debug.h>
+#include <Main/views.h>
+#include <Time/fg_time.h>
+#include <Time/sunpos.h>
 
 GLint sun_obj = 0;
 
 static struct CelestialCoord sunPos;
 
-float xSun, ySun, zSun;
+fgSUNPOS solarPosition;
 
-struct SunPos fgCalcSunPos(struct OrbElements params)
+void fgCalcSunPos(struct OrbElements params)
 {
-    double
-    	EccAnom, lonSun,
-        xv, yv, v, r;
-    struct SunPos
-    	solarPosition;
+    double EccAnom, xv, yv, v, r;
 
     /* calculate the eccentric anomaly */
     EccAnom = fgCalcEccAnom(params.M, params.e);
@@ -56,37 +53,31 @@ struct SunPos fgCalcSunPos(struct OrbElements params)
     r = sqrt(xv*xv + yv*yv);
 
     /* calculate the the Sun's true longitude (lonsun) */
-    lonSun = v + params.w;
+    solarPosition.lonSun = v + params.w;
 
-	/* convert true longitude and distance to ecliptic rectangular geocentric
-      coordinates (xs, ys) */
-    solarPosition.xs = r * cos(lonSun);
-    solarPosition.ys = r * sin(lonSun);
+    /* convert true longitude and distance to ecliptic rectangular
+      geocentric coordinates (xs, ys) */
+    solarPosition.xs = r * cos (solarPosition.lonSun);
+    solarPosition.ys = r * sin (solarPosition.lonSun);
     solarPosition.dist = r;
-    return solarPosition;
+    /* return solarPosition; */
 }
 
 
 struct CelestialCoord fgCalculateSun(struct OrbElements params, struct fgTIME t)
 {
-	struct CelestialCoord
-		result;
-    struct SunPos
-    	SolarPosition;
-    double
-    	xe, ye, ze, ecl, actTime;
+    struct CelestialCoord result;
+    double xe, ye, ze, ecl, actTime;
 
     /* calculate the angle between ecliptic and equatorial coordinate system */
     actTime = fgCalcActTime(t);
-    ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime);			// Angle now in Rads
+    ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime);	// Angle now in Rads
 
-    /* calculate the sun's ecliptic position */
-    SolarPosition = fgCalcSunPos(params);
-
-	/* convert ecliptic coordinates to equatorial rectangular geocentric coordinates */
-    xe = SolarPosition.xs;
-    ye = SolarPosition.ys * cos(ecl);
-    ze = SolarPosition.ys * sin(ecl);
+    /* convert ecliptic coordinates to equatorial rectangular
+       geocentric coordinates */
+    xe = solarPosition.xs;
+    ye = solarPosition.ys * cos (ecl);
+    ze = solarPosition.ys * sin (ecl);
 
     /* and finally... Calulate Right Ascention and Declination */
     result.RightAscension = atan2( ye, xe);
@@ -100,6 +91,7 @@ void fgSunInit( void ) {
     struct fgLIGHT *l;
     struct fgTIME *t;
     struct fgVIEW *v;  
+    float xSun, ySun, zSun;
 
     /* GLfloat color[4] = { 1.00, 1.00, 1.00, 1.00 }; */
     double x_2, x_4, x_8, x_10;
@@ -112,9 +104,14 @@ void fgSunInit( void ) {
 
     fgPrintf( FG_ASTRO, FG_INFO, "  Initializing the Sun\n");
 
+    // Calculate basic sun position
     fgSolarSystemUpdate(&(pltOrbElements[0]), cur_time_params);
     sunPos = fgCalculateSun(pltOrbElements[0], cur_time_params);
 
+    // Calculate additional sun position parameters based on the above
+    // position that are needed by other parts of FG
+    fgUpdateSunPos();
+
     fgPrintf( FG_ASTRO, FG_INFO,
 	      "Sun found at %f (ra), %f (dec)\n",
 	      sunPos.RightAscension, sunPos.Declination);
@@ -162,29 +159,12 @@ void fgSunInit( void ) {
               "Sun Angle       : %f\n" ,
               amb[0], amb[1], amb[2], ambient, l->sun_angle);
 
-    /* set lighting parameters */
-    /*xglLightfv(GL_LIGHT0, GL_AMBIENT, color );
-      xglLightfv(GL_LIGHT0, GL_DIFFUSE, color );
-      xglMaterialfv(GL_FRONT, GL_AMBIENT, amb);
-      xglMaterialfv(GL_FRONT, GL_DIFFUSE, diff); 
-      xglMaterialfv(GL_FRONT, GL_SHININESS, diff);
-      xglMaterialfv(GL_FRONT, GL_EMISSION, diff);
-      xglMaterialfv(GL_FRONT, GL_SPECULAR, diff); */
-
-    /* xglDisable( GL_LIGHTING ); */
-
     xglPushMatrix();
     xglTranslatef(xSun, ySun, zSun);
     xglScalef(1400, 1400, 1400);
-
-    /*xglColor3f(0.85, 0.65, 0.05);*/
     xglColor3f(amb[0], amb[1], amb[2]); 
     glutSolidSphere(1.0, 10, 10);
-
     xglPopMatrix();
-
-    /* xglEnable( GL_LIGHTING ); */
-
     xglEndList();
 }
 
@@ -196,10 +176,15 @@ void fgSunRender( void ) {
 
 
 /* $Log$
-/* Revision 1.6  1998/02/12 21:59:39  curt
-/* Incorporated code changes contributed by Charlie Hotchkiss
-/* <chotchkiss@namg.us.anritsu.com>
+/* Revision 1.7  1998/02/23 19:07:56  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.6  1998/02/12 21:59:39  curt
+ * Incorporated code changes contributed by Charlie Hotchkiss
+ * <chotchkiss@namg.us.anritsu.com>
+ *
  * Revision 1.5  1998/02/02 20:53:24  curt
  * To version 0.29
  *
diff --git a/Astro/sun.h b/Astro/sun.h
index 4f4a7be3..0132f2a1 100644
--- a/Astro/sun.h
+++ b/Astro/sun.h
@@ -27,7 +27,10 @@
 #define _SUN_H
 
 
-struct SunPos fgCalcSunPos(struct OrbElements sunParams);
+extern struct fgSUNPOS solarPosition;
+
+
+void fgCalcSunPos (struct OrbElements sunParams);
 extern struct OrbElements pltOrbElements[9];
 
 /* Initialize the Sun */
@@ -41,9 +44,14 @@ void fgSunRender( void );
 
 
 /* $Log$
-/* Revision 1.3  1998/01/22 02:59:29  curt
-/* Changed #ifdef FILE_H to #ifdef _FILE_H
+/* Revision 1.4  1998/02/23 19:07:57  curt
+/* Incorporated Durk's Astro/ tweaks.  Includes unifying the sun position
+/* calculation code between sun display, and other FG sections that use this
+/* for things like lighting.
 /*
+ * Revision 1.3  1998/01/22 02:59:29  curt
+ * Changed #ifdef FILE_H to #ifdef _FILE_H
+ *
  * Revision 1.2  1998/01/19 18:40:19  curt
  * Tons of little changes to clean up the code and to remove fatal errors
  * when building with the c++ compiler.