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flightgear/Bucket/newbucket.cxx
curt 91efc5ad87 Added a new "newbucket.[ch]xx" FGBucket class to replace the old
fgBUCKET struct and C routines.  This FGBucket class adjusts the tile
width towards the poles to ensure the tiles are at least 8 miles wide.
1999-02-08 23:52:13 +00:00

107 lines
2.9 KiB
C++

/**************************************************************************
* newbucket.hxx -- new bucket routines for better world modeling
*
* Written by Curtis L. Olson, started February 1999.
*
* Copyright (C) 1999 Curtis L. Olson - curt@flightgear.org
*
* 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 "newbucket.hxx"
// Build the path name for this bucket
string FGBucket::gen_base_path() {
long int index;
int top_lon, top_lat, main_lon, main_lat;
char hem, pole;
char path[256];
index = gen_index();
path[0] = '\0';
top_lon = lon / 10;
main_lon = lon;
if ( (lon < 0) && (top_lon * 10 != lon) ) {
top_lon -= 1;
}
top_lon *= 10;
if ( top_lon >= 0 ) {
hem = 'e';
} else {
hem = 'w';
top_lon *= -1;
}
if ( main_lon < 0 ) {
main_lon *= -1;
}
top_lat = lat / 10;
main_lat = lat;
if ( (lat < 0) && (top_lat * 10 != lat) ) {
top_lat -= 1;
}
top_lat *= 10;
if ( top_lat >= 0 ) {
pole = 'n';
} else {
pole = 's';
top_lat *= -1;
}
if ( main_lat < 0 ) {
main_lat *= -1;
}
sprintf(path, "%c%03d%c%02d/%c%03d%c%02d",
hem, top_lon, pole, top_lat,
hem, main_lon, pole, main_lat);
return path;
}
// find the bucket which is offset by the specified tile units in the
// 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;
// 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 );
// walk dx units in the lon direction
result.set_bucket( dlon + dx * span, clat );
return result;
}
// $Log$
// Revision 1.1 1999/02/08 23:52:16 curt
// Added a new "newbucket.[ch]xx" FGBucket class to replace the old
// fgBUCKET struct and C routines. This FGBucket class adjusts the tile
// width towards the poles to ensure the tiles are at least 8 miles wide.
//