#include "sunsolver.hxx"
-const time_t day_secs = 86400;
+static const time_t day_secs = 86400;
+static const time_t half_day_secs = day_secs / 2;
+static const time_t step_secs = 60;
static double sun_angle( const SGTime &t, sgVec3 world_up,
double lon_rad, double lat_rad ) {
SG_LOG( SG_EVENT, SG_DEBUG, " Updating Sun position" );
SG_LOG( SG_EVENT, SG_DEBUG, " Gst = " << t.getGst() );
- double sun_lon, sun_gd_lat, sun_gc_lat, sl_radius;
+ double sun_lon, sun_gd_lat;
fgSunPositionGST( t.getGst(), &sun_lon, &sun_gd_lat );
-
- sgGeodToGeoc(sun_gd_lat, 0.0, &sl_radius, &sun_gc_lat);
-
- p = Point3D( sun_lon, sun_gc_lat, sl_radius );
- Point3D sunpos = sgPolarToCart3d(p);
+ Point3D sunpos = sgGeodToCart(Point3D(sun_lon, sun_gd_lat, 0));
SG_LOG( SG_EVENT, SG_DEBUG, " t.cur_time = " << t.get_cur_time() );
SG_LOG( SG_EVENT, SG_DEBUG,
- " Sun Geodetic lat = " << sun_gd_lat
- << " Geocentric lat = " << sun_gc_lat );
+ " Sun Geodetic lat = " << sun_gd_lat );
// calculate the sun's relative angle to local up
sgCopyVec3( nup, world_up );
/**
- * Given the current unix time in seconds, calculate seconds to noon
+ * Given the current unix time in seconds, calculate seconds to the
+ * specified sun angle (relative to straight up.) Also specify if we
+ * want the angle while the sun is ascending or descending. For
+ * instance noon is when the sun angle is 0 (or the closest it can
+ * get.) Dusk is when the sun angle is 90 and descending. Dawn is
+ * when the sun angle is 90 and ascending.
*/
-time_t fgTimeSecondsUntilNoon( time_t cur_time,
- double lon_rad,
- double lat_rad )
-{
- // cout << "location = " << lon_rad * SG_RADIANS_TO_DEGREES << ", "
- // << lat_rad * SG_RADIANS_TO_DEGREES << endl;
- Point3D geod( lon_rad, lat_rad, 0 );
- Point3D tmp = sgGeodToCart( geod );
- sgVec3 world_up;
- sgSetVec3( world_up, tmp.x(), tmp.y(), tmp.z() );
- SGTime t = SGTime( lon_rad, lat_rad, "", 0 );
-
- double best_angle = 180.0;
- time_t best_time = cur_time;
-
- for ( time_t secs = cur_time; secs < cur_time + day_secs; secs += 300 ) {
- t.update( lon_rad, lat_rad, secs, 0 );
- double angle = sun_angle( t, world_up, lon_rad, lat_rad );
- if ( angle < best_angle ) {
- // cout << "best angle = " << angle << " offset = "
- // << secs - cur_time << endl;
- best_angle = angle;
- best_time = secs;
- }
- }
-
- if ( best_time > day_secs / 2 ) {
- best_time -= day_secs;
- }
-
- return best_time - cur_time;
-}
-
-
-/**
- * Given the current unix time in seconds, calculate seconds to midnight
- */
-time_t fgTimeSecondsUntilMidnight( time_t cur_time,
+time_t fgTimeSecondsUntilSunAngle( time_t cur_time,
double lon_rad,
- double lat_rad )
+ double lat_rad,
+ double target_angle_deg,
+ bool ascending )
{
// cout << "location = " << lon_rad * SG_RADIANS_TO_DEGREES << ", "
// << lat_rad * SG_RADIANS_TO_DEGREES << endl;
sgSetVec3( world_up, tmp.x(), tmp.y(), tmp.z() );
SGTime t = SGTime( lon_rad, lat_rad, "", 0 );
- double best_angle = 0.0;
- time_t best_time = cur_time;
-
- for ( time_t secs = cur_time; secs < cur_time + day_secs; secs += 300 ) {
- t.update( lon_rad, lat_rad, secs, 0 );
- double angle = sun_angle( t, world_up, lon_rad, lat_rad );
- if ( angle > best_angle ) {
- // cout << "best angle = " << angle << " offset = "
- // << secs - cur_time << endl;
- best_angle = angle;
- best_time = secs;
- }
- }
-
- if ( best_time > day_secs / 2 ) {
- best_time -= day_secs;
- }
-
- return best_time - cur_time;
-}
-
-
-/**
- * Given the current unix time in seconds, calculate seconds to dusk
- */
-time_t fgTimeSecondsUntilDusk( time_t cur_time,
- double lon_rad,
- double lat_rad )
-{
- // cout << "location = " << lon_rad * SG_RADIANS_TO_DEGREES << ", "
- // << lat_rad * SG_RADIANS_TO_DEGREES << endl;
- Point3D geod( lon_rad, lat_rad, 0 );
- Point3D tmp = sgGeodToCart( geod );
- sgVec3 world_up;
- sgSetVec3( world_up, tmp.x(), tmp.y(), tmp.z() );
- SGTime t = SGTime( lon_rad, lat_rad, "", 0 );
-
- double best_diff = 90.0;
+ double best_diff = 180.0;
double last_angle = -99999.0;
time_t best_time = cur_time;
- for ( time_t secs = cur_time; secs < cur_time + day_secs; secs += 300 ) {
+ for ( time_t secs = cur_time - half_day_secs;
+ secs < cur_time + half_day_secs;
+ secs += step_secs )
+ {
t.update( lon_rad, lat_rad, secs, 0 );
- double angle = sun_angle( t, world_up, lon_rad, lat_rad );
- double diff = fabs( angle - 90.0 );
+ double angle_deg = sun_angle( t, world_up, lon_rad, lat_rad );
+ double diff = fabs( angle_deg - target_angle_deg );
if ( diff < best_diff ) {
- if ( last_angle <= 180.0 && ( last_angle < angle ) ) {
+ if ( last_angle <= 180.0 && ascending
+ && ( last_angle > angle_deg ) ) {
// cout << "best angle = " << angle << " offset = "
// << secs - cur_time << endl;
best_diff = diff;
best_time = secs;
- }
- }
-
- last_angle = angle;
- }
-
- if ( best_time > day_secs / 2 ) {
- best_time -= day_secs;
- }
-
- return best_time - cur_time;
-}
-
-
-/**
- * Given the current unix time in seconds, calculate seconds to dawn
- */
-time_t fgTimeSecondsUntilDawn( time_t cur_time,
- double lon_rad,
- double lat_rad )
-{
- // cout << "location = " << lon_rad * SG_RADIANS_TO_DEGREES << ", "
- // << lat_rad * SG_RADIANS_TO_DEGREES << endl;
- Point3D geod( lon_rad, lat_rad, 0 );
- Point3D tmp = sgGeodToCart( geod );
- sgVec3 world_up;
- sgSetVec3( world_up, tmp.x(), tmp.y(), tmp.z() );
- SGTime t = SGTime( lon_rad, lat_rad, "", 0 );
-
- double best_diff = 90.0;
- double last_angle = -99999.0;
- time_t best_time = cur_time;
-
- for ( time_t secs = cur_time; secs < cur_time + day_secs; secs += 300 ) {
- t.update( lon_rad, lat_rad, secs, 0 );
- double angle = sun_angle( t, world_up, lon_rad, lat_rad );
- double diff = fabs( angle - 90.0 );
- if ( diff < best_diff ) {
- if ( last_angle <= 180.0 && ( last_angle > angle ) ) {
+ } else if ( last_angle <= 180.0 && !ascending
+ && ( last_angle < angle_deg ) ) {
// cout << "best angle = " << angle << " offset = "
// << secs - cur_time << endl;
best_diff = diff;
}
}
- last_angle = angle;
- }
-
- if ( best_time > day_secs / 2 ) {
- best_time -= day_secs;
+ last_angle = angle_deg;
}
return best_time - cur_time;
projects / flightgear.git / blobdiff