--- /dev/null
+/**************************************************************************
+ * 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.
+//
--- /dev/null
+/**************************************************************************
+ * 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)
+ **************************************************************************/
+
+
+#ifndef _NEWBUCKET_HXX
+#define _NEWBUCKET_HXX
+
+#include <Include/compiler.h>
+
+#include <string>
+
+FG_USING_STD(string);
+FG_USING_NAMESPACE(std);
+
+#include <stdio.h> // sprintf()
+
+#include <Include/fg_constants.h>
+
+
+#define FG_BUCKET_SPAN 0.125 // 1/8 of a degree
+#define FG_HALF_BUCKET_SPAN 0.0625 // 1/2 of 1/8 of a degree = 1/16 = 0.0625
+
+
+class FGBucket {
+
+private:
+ double cx, cy; // centerpoint (lon, lat) in degrees of bucket
+ int lon; // longitude index (-180 to 179)
+ int lat; // latitude index (-90 to 89)
+ int x; // x subdivision (0 to 7)
+ int y; // y subdivision (0 to 7)
+
+public:
+
+ // default constructor
+ FGBucket();
+
+ // create a bucket which would contain the specified lon/lat
+ FGBucket(const double lon, const double lat);
+
+ // create a bucket based on "long int" index
+ FGBucket(const long int bindex);
+
+ ~FGBucket();
+
+ // Set the bucket params for the specified lat and lon
+ void set_bucket( double dlon, double dlat );
+
+ // Generate the unique scenery tile index for this bucket
+ long int gen_index();
+
+ // Build the path name for this bucket
+ string gen_base_path();
+
+ // return the center lon of a tile
+ double get_center_lon();
+
+ // return the center lat of a tile
+ double get_center_lat();
+
+ // friends
+ friend ostream& operator<< ( ostream&, const FGBucket& );
+};
+
+
+// return the horizontal tile span factor based on latitude
+inline double bucket_span( double l ) {
+ if ( l >= 89.0 ) {
+ return 0.0;
+ } else if ( l >= 88.0 ) {
+ return 8.0;
+ } else if ( l >= 86.0 ) {
+ return 4.0;
+ } else if ( l >= 83.0 ) {
+ return 2.0;
+ } else if ( l >= 76.0 ) {
+ return 1.0;
+ } else if ( l >= 62.0 ) {
+ return 0.5;
+ } else if ( l >= 22.0 ) {
+ return 0.25;
+ } else if ( l >= -22.0 ) {
+ return 0.125;
+ } else if ( l >= -62.0 ) {
+ return 0.25;
+ } else if ( l >= -76.0 ) {
+ return 0.5;
+ } else if ( l >= -83.0 ) {
+ return 1.0;
+ } else if ( l >= -86.0 ) {
+ return 2.0;
+ } else if ( l >= -88.0 ) {
+ return 4.0;
+ } else if ( l >= -89.0 ) {
+ return 8.0;
+ } else {
+ return 0.0;
+ }
+}
+
+
+// Set the bucket params for the specified lat and lon
+inline void FGBucket::set_bucket( double dlon, double dlat ) {
+ //
+ // latitude first
+ //
+ double span = bucket_span( dlat );
+ double diff = dlon - (double)(int)dlon;
+
+ // cout << "diff = " << diff << " span = " << span << endl;
+
+ if ( (dlon >= 0) || (fabs(diff) < FG_EPSILON) ) {
+ lon = (int)dlon;
+ } else {
+ lon = (int)dlon - 1;
+ }
+
+ // find subdivision or super lon if needed
+ if ( span < FG_EPSILON ) {
+ // polar cap
+ lon = 0;
+ x = 0;
+ } else if ( span <= 1.0 ) {
+ x = (int)((dlon - lon) / span);
+ } else {
+ if ( (dlon >= 0) || (fabs(diff) < FG_EPSILON) ) {
+ lon = (int)( (int)(lon / span) * span);
+ } else {
+ // cout << " lon = " << lon
+ // << " tmp = " << (int)((lon-1) / span) << endl;
+ lon = (int)( (int)((lon + 1) / span) * span - span);
+ if ( lon < -180 ) {
+ lon = -180;
+ }
+ }
+ x = 0;
+ }
+
+ //
+ // then latitude
+ //
+ diff = dlat - (double)(int)dlat;
+
+ if ( (dlat >= 0) || (fabs(diff) < FG_EPSILON) ) {
+ lat = (int)dlat;
+ } else {
+ lat = (int)dlat - 1;
+ }
+ y = (int)((dlat - lat) * 8);
+}
+
+
+// default constructor
+inline FGBucket::FGBucket() {}
+
+
+// constructor for specified location
+inline FGBucket::FGBucket(const double dlon, const double dlat) {
+ set_bucket(dlon, dlat);
+}
+
+
+// Parse a unique scenery tile index and find the lon, lat, x, and y
+inline FGBucket::FGBucket(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;
+}
+
+
+// default destructor
+inline FGBucket::~FGBucket() {}
+
+
+// Generate the unique scenery tile index for this bucket
+//
+// The index is constructed as follows:
+//
+// 9 bits - to represent 360 degrees of longitude (-180 to 179)
+// 8 bits - to represent 180 degrees of latitude (-90 to 89)
+//
+// Each 1 degree by 1 degree tile is further broken down into an 8x8
+// grid. So we also need:
+//
+// 3 bits - to represent x (0 to 7)
+// 3 bits - to represent y (0 to 7)
+
+inline long int FGBucket::gen_index() {
+ return ((lon + 180) << 14) + ((lat + 90) << 6) + (y << 3) + x;
+}
+
+
+// return the center lon of a tile
+inline double FGBucket::get_center_lon() {
+ double span = bucket_span( lat + y / 8.0 + FG_HALF_BUCKET_SPAN );
+
+ if ( span >= 1.0 ) {
+ return lon + span / 2.0;
+ } else {
+ return lon + x * span + span / 2.0;
+ }
+}
+
+
+// return the center lat of a tile
+inline double FGBucket::get_center_lat() {
+ return lat + y / 8.0 + FG_HALF_BUCKET_SPAN;
+}
+
+
+// offset a bucket struct by the specified tile units in the X & Y
+// direction
+FGBucket fgBucketOffset( double dlon, double dlat, int x, int y );
+
+
+/*
+// Given a lat/lon, fill in the local tile index array
+void fgBucketGenIdxArray(fgBUCKET *p1, fgBUCKET *tiles, int width, int height);
+
+
+
+inline bool
+operator== ( const fgBUCKET& b1, const fgBUCKET& b2 )
+{
+ return ( b1.lon == b2.lon &&
+ b1.lat == b2.lat &&
+ b1.x == b2.x &&
+ b1.y == b2.y );
+}
+
+inline string
+fgBucketGenIndex( const fgBUCKET& p )
+{
+ char index_str[256];
+ sprintf( index_str, "%ld", fgBucketGenIndex( &p ) );
+ return string( index_str );
+}
+
+inline string
+fgBucketGenBasePath( const fgBUCKET& p )
+{
+ char base_path[256];
+ fgBucketGenBasePath( &p, base_path );
+ return string( base_path );
+}
+
+*/
+
+inline ostream&
+operator<< ( ostream& out, const FGBucket& b )
+{
+ return out << b.lon << ":" << b.x << ", " << b.lat << ":" << b.y;
+}
+
+
+#endif // _NEWBUCKET_HXX
+
+
+// $Log$
+// 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.
+//
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