156 lines
4.1 KiB
C++
156 lines
4.1 KiB
C++
/**************************************************************************
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* newbucket.hxx -- new bucket routines for better world modeling
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*
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* Written by Curtis L. Olson, started February 1999.
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*
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* Copyright (C) 1999 Curtis L. Olson - curt@flightgear.org
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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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#include "newbucket.hxx"
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// Build the path name for this bucket
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string FGBucket::gen_base_path() {
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long int index;
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int top_lon, top_lat, main_lon, main_lat;
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char hem, pole;
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char path[256];
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index = gen_index();
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path[0] = '\0';
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top_lon = lon / 10;
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main_lon = lon;
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if ( (lon < 0) && (top_lon * 10 != lon) ) {
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top_lon -= 1;
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}
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top_lon *= 10;
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if ( top_lon >= 0 ) {
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hem = 'e';
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} else {
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hem = 'w';
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top_lon *= -1;
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}
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if ( main_lon < 0 ) {
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main_lon *= -1;
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}
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top_lat = lat / 10;
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main_lat = lat;
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if ( (lat < 0) && (top_lat * 10 != lat) ) {
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top_lat -= 1;
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}
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top_lat *= 10;
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if ( top_lat >= 0 ) {
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pole = 'n';
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} else {
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pole = 's';
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top_lat *= -1;
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}
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if ( main_lat < 0 ) {
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main_lat *= -1;
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}
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sprintf(path, "%c%03d%c%02d/%c%03d%c%02d",
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hem, top_lon, pole, top_lat,
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hem, main_lon, pole, main_lat);
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return path;
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}
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// find the bucket which is offset by the specified tile units in the
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// X & Y direction. We need the current lon and lat to resolve
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// ambiguities when going from a wider tile to a narrower one above or
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// below. This assumes that we are feeding in
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FGBucket fgBucketOffset( double dlon, double dlat, int dx, int dy ) {
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FGBucket result( dlon, dlat );
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double clat = result.get_center_lat() + dy * FG_BUCKET_SPAN;
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// walk dy units in the lat direction
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result.set_bucket( dlon, clat );
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// find the lon span for the new latitude
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double span = bucket_span( clat );
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// walk dx units in the lon direction
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result.set_bucket( dlon + dx * span, clat );
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return result;
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}
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// calculate the offset between two buckets
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void fgBucketDiff( const FGBucket& b1, const FGBucket& b2, int *dx, int *dy ) {
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// Latitude difference
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double c1_lat = b1.get_center_lat();
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double c2_lat = b2.get_center_lat();
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double diff_lat = c2_lat - c1_lat;
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#ifdef HAVE_RINT
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*dy = (int)rint( diff_lat / FG_BUCKET_SPAN );
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#else
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if ( diff_lat > 0 ) {
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*dy = (int)( diff_lat / FG_BUCKET_SPAN + 0.5 );
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} else {
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*dy = (int)( diff_lat / FG_BUCKET_SPAN - 0.5 );
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}
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#endif
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// longitude difference
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double c1_lon = b1.get_center_lon();
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double c2_lon = b2.get_center_lon();
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double diff_lon = c2_lon - c1_lon;
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double span;
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if ( bucket_span(c1_lat) <= bucket_span(c2_lat) ) {
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span = bucket_span(c1_lat);
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} else {
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span = bucket_span(c2_lat);
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}
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#ifdef HAVE_RINT
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*dx = (int)rint( diff_lon / span );
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#else
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if ( diff_lon > 0 ) {
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*dx = (int)( diff_lon / span + 0.5 );
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} else {
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*dx = (int)( diff_lon / span - 0.5 );
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}
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#endif
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}
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// $Log$
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// Revision 1.2 1999/02/11 01:09:33 curt
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// Added a routine to calculate the offset in bucket units between two buckets.
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//
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// Revision 1.1 1999/02/08 23:52:16 curt
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// Added a new "newbucket.[ch]xx" FGBucket class to replace the old
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// fgBUCKET struct and C routines. This FGBucket class adjusts the tile
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// width towards the poles to ensure the tiles are at least 8 miles wide.
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//
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