*
* Written by Curtis L. Olson, started February 1999.
*
- * Copyright (C) 1999 Curtis L. Olson - curt@flightgear.org
+ * Copyright (C) 1999 Curtis L. Olson - http://www.flightgear.org/~curt/
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
**************************************************************************/
#ifdef HAVE_CONFIG_H
-# include <config.h>
+# include <simgear_config.h>
#endif
-
#include <math.h>
-#include <simgear/misc/fgpath.hxx>
+#include <simgear/misc/sg_path.hxx>
#include "newbucket.hxx"
+// default constructor
+SGBucket::SGBucket() {
+}
+
+
+// constructor for specified location
+SGBucket::SGBucket(const double dlon, const double dlat) {
+ set_bucket(dlon, dlat);
+}
+
+SGBucket::SGBucket(const SGGeod& geod) {
+ set_bucket(geod);
+}
+
+// create an impossible bucket if false
+SGBucket::SGBucket(const bool is_good) {
+ set_bucket(0.0, 0.0);
+ if ( !is_good ) {
+ lon = -1000;
+ }
+}
+
+
+// Parse a unique scenery tile index and find the lon, lat, x, and y
+SGBucket::SGBucket(const long int bindex) {
+ long int index = bindex;
+
+ lon = index >> 14;
+ index -= lon << 14;
+ lon -= 180;
+
+ lat = index >> 6;
+ index -= lat << 6;
+ lat -= 90;
+
+ y = index >> 3;
+ index -= y << 3;
+
+ x = index;
+}
+
+
+// Set the bucket params for the specified lat and lon
+void SGBucket::set_bucket( double *lonlat ) {
+ set_bucket( lonlat[0], lonlat[1] );
+}
+
+
+// Set the bucket params for the specified lat and lon
+void SGBucket::set_bucket( double dlon, double dlat ) {
+ //
+ // latitude first
+ //
+ double span = sg_bucket_span( dlat );
+ double diff = dlon - (double)(int)dlon;
+
+ // cout << "diff = " << diff << " span = " << span << endl;
+
+ /* Calculate the greatest integral longitude less than
+ * or equal to the given longitude (floor(dlon)),
+ * but attribute coordinates near the east border
+ * to the next tile.
+ */
+ if ( (dlon >= 0) || (fabs(diff) < SG_EPSILON) ) {
+ lon = (int)dlon;
+ } else {
+ lon = (int)dlon - 1;
+ }
+
+ // find subdivision or super lon if needed
+ if ( span < SG_EPSILON ) {
+ /* sg_bucket_span() never returns 0.0
+ * or anything near it, so this really
+ * should not occur at any time.
+ */
+ // polar cap
+ lon = 0;
+ x = 0;
+ } else if ( span <= 1.0 ) {
+ /* We have more than one tile per degree of
+ * longitude, so we need an x offset.
+ */
+ x = (int)((dlon - lon) / span);
+ } else {
+ /* We have one or more degrees per tile,
+ * so we need to find the base longitude
+ * of that tile.
+ *
+ * First we calculate the integral base longitude
+ * (e.g. -85.5 => -86) and then find the greatest
+ * multiple of span that is less than or equal to
+ * that longitude.
+ *
+ * That way, the Greenwich Meridian is always
+ * a tile border.
+ *
+ * This gets us into trouble with the polar caps,
+ * which have width 360 and thus either span
+ * the range from 0 to 360 or from -360 to 0
+ * degrees, depending on whether lon is positive
+ * or negative!
+ *
+ * We also get into trouble with the 8 degree tiles
+ * north of 88N and south of 88S, because the west-
+ * and east-most tiles in that range will cover 184W
+ * to 176W and 176E to 184E respectively, with their
+ * center at 180E/W!
+ */
+ lon=(int)floor(floor((lon+SG_EPSILON)/span)*span);
+ /* Correct the polar cap issue */
+ if ( lon < -180 ) {
+ lon = -180;
+ }
+ x = 0;
+ }
+
+ //
+ // then latitude
+ //
+ diff = dlat - (double)(int)dlat;
+
+ /* Again, a modified floor() function (see longitude) */
+ if ( (dlat >= 0) || (fabs(diff) < SG_EPSILON) ) {
+ lat = (int)dlat;
+ } else {
+ lat = (int)dlat - 1;
+ }
+ /* Latitude base and offset are easier, as
+ * tiles always are 1/8 degree of latitude wide.
+ */
+ y = (int)((dlat - lat) * 8);
+}
+
+
+void SGBucket::set_bucket(const SGGeod& geod)
+{
+ set_bucket(geod.getLongitudeDeg(), geod.getLatitudeDeg());
+}
+
// Build the path name for this bucket
-string FGBucket::gen_base_path() const {
+std::string SGBucket::gen_base_path() const {
// long int index;
int top_lon, top_lat, main_lon, main_lat;
char hem, pole;
hem, top_lon, pole, top_lat,
hem, main_lon, pole, main_lat);
- FGPath path( raw_path );
+ SGPath path( raw_path );
return path.str();
}
+// return width of the tile in degrees
+double SGBucket::get_width() const {
+ return sg_bucket_span( get_center_lat() );
+}
+
+
+// return height of the tile in degrees
+double SGBucket::get_height() const {
+ return SG_BUCKET_SPAN;
+}
+
+
// return width of the tile in meters
-double FGBucket::get_width_m() const {
+double SGBucket::get_width_m() const {
double clat = (int)get_center_lat();
if ( clat > 0 ) {
clat = (int)clat + 0.5;
} else {
clat = (int)clat - 0.5;
}
- double clat_rad = clat * DEG_TO_RAD;
+ double clat_rad = clat * SGD_DEGREES_TO_RADIANS;
double cos_lat = cos( clat_rad );
- double local_radius = cos_lat * EQUATORIAL_RADIUS_M;
- double local_perimeter = 2.0 * local_radius * FG_PI;
+ double local_radius = cos_lat * SG_EQUATORIAL_RADIUS_M;
+ double local_perimeter = local_radius * SGD_2PI;
double degree_width = local_perimeter / 360.0;
- return bucket_span( get_center_lat() ) * degree_width;
+ return get_width() * degree_width;
}
// return height of the tile in meters
-double FGBucket::get_height_m() const {
- double perimeter = 2.0 * EQUATORIAL_RADIUS_M * FG_PI;
+double SGBucket::get_height_m() const {
+ double perimeter = SG_EQUATORIAL_RADIUS_M * SGD_2PI;
double degree_height = perimeter / 360.0;
- return FG_BUCKET_SPAN * degree_height;
+ return SG_BUCKET_SPAN * degree_height;
}
// X & Y direction. We need the current lon and lat to resolve
// ambiguities when going from a wider tile to a narrower one above or
// below. This assumes that we are feeding in
-FGBucket fgBucketOffset( double dlon, double dlat, int dx, int dy ) {
- FGBucket result( dlon, dlat );
- double clat = result.get_center_lat() + dy * FG_BUCKET_SPAN;
+SGBucket sgBucketOffset( double dlon, double dlat, int dx, int dy ) {
+ SGBucket result( dlon, dlat );
+ double clat = result.get_center_lat() + dy * SG_BUCKET_SPAN;
// walk dy units in the lat direction
result.set_bucket( dlon, clat );
// find the lon span for the new latitude
- double span = bucket_span( clat );
+ double span = sg_bucket_span( clat );
// walk dx units in the lon direction
double tmp = dlon + dx * span;
// calculate the offset between two buckets
-void fgBucketDiff( const FGBucket& b1, const FGBucket& b2, int *dx, int *dy ) {
+void sgBucketDiff( const SGBucket& b1, const SGBucket& b2, int *dx, int *dy ) {
// Latitude difference
double c1_lat = b1.get_center_lat();
double diff_lat = c2_lat - c1_lat;
#ifdef HAVE_RINT
- *dy = (int)rint( diff_lat / FG_BUCKET_SPAN );
+ *dy = (int)rint( diff_lat / SG_BUCKET_SPAN );
#else
if ( diff_lat > 0 ) {
- *dy = (int)( diff_lat / FG_BUCKET_SPAN + 0.5 );
+ *dy = (int)( diff_lat / SG_BUCKET_SPAN + 0.5 );
} else {
- *dy = (int)( diff_lat / FG_BUCKET_SPAN - 0.5 );
+ *dy = (int)( diff_lat / SG_BUCKET_SPAN - 0.5 );
}
#endif
// longitude difference
- double c1_lon = b1.get_center_lon();
- double c2_lon = b2.get_center_lon();
- double diff_lon = c2_lon - c1_lon;
- double span;
- if ( bucket_span(c1_lat) <= bucket_span(c2_lat) ) {
- span = bucket_span(c1_lat);
+ double diff_lon=0.0;
+ double span=0.0;
+
+ SGBucket tmp_bucket;
+ // To handle crossing the bucket size boundary
+ // we need to account for different size buckets.
+
+ if ( sg_bucket_span(c1_lat) <= sg_bucket_span(c2_lat) )
+ {
+ span = sg_bucket_span(c1_lat);
} else {
- span = bucket_span(c2_lat);
+ span = sg_bucket_span(c2_lat);
}
+ diff_lon = b2.get_center_lon() - b1.get_center_lon();
+
+ if (diff_lon <0.0)
+ {
+ diff_lon -= b1.get_width()*0.5 + b2.get_width()*0.5 - span;
+ }
+ else
+ {
+ diff_lon += b1.get_width()*0.5 + b2.get_width()*0.5 - span;
+ }
+
+
#ifdef HAVE_RINT
*dx = (int)rint( diff_lon / span );
#else
#endif
}
+void sgGetBuckets( const SGGeod& min, const SGGeod& max, std::vector<SGBucket>& list ) {
+ double lon, lat, span;
+ for (lat = min.getLatitudeDeg(); lat <= max.getLatitudeDeg(); lat += SG_BUCKET_SPAN) {
+ span = sg_bucket_span( lat );
+ for (lon = min.getLongitudeDeg(); lon <= max.getLongitudeDeg(); lon += span) {
+ list.push_back( SGBucket(lon , lat) );
+ }
+ }
+}