fly/terragear
1
0
Fork 0
Code Activity

Initial revision.

Browse source
This commit is contained in:
curt 2000-11-13 19:15:09 +00:00
parent 9162b789f5
commit 5982e567fd
1 changed files with 282 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

282
src/Lib/Polygon/split-bin.cxx Normal file
View file

@ -0,0 +1,282 @@
// split.cxx -- polygon splitting utils
//
// Written by Curtis 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.
//
// $Id$
#include <simgear/compiler.h>
#include STL_STRING
#include <simgear/bucket/newbucket.hxx>
#include <simgear/debug/logstream.hxx>
#ifdef _MSC_VER
# include <win32/mkdir.hpp>
#endif
#include "index.hxx"
#include "names.hxx"
#include "simple_clip.hxx"
#include "split.hxx"
FG_USING_STD(cout);
static void clip_and_write_poly( string root, long int p_index, AreaType area,
FGBucket b, const FGPolygon& shape ) {
Point3D c, min, max, p;
c = Point3D( b.get_center_lon(), b.get_center_lat(), 0 );
double span = bucket_span( c.y() );
FGPolygon base, result;
char tile_name[256], poly_index[256];
// calculate bucket dimensions
if ( (c.y() >= -89.0) && (c.y() < 89.0) ) {
min.setx( c.x() - span / 2.0 );
max.setx( c.x() + span / 2.0 );
min.sety( c.y() - FG_HALF_BUCKET_SPAN );
max.sety( c.y() + FG_HALF_BUCKET_SPAN );
} else if ( c.y() < -89.0) {
min.setx( -90.0 );
max.setx( -89.0 );
min.sety( -180.0 );
max.sety( 180.0 );
} else if ( c.y() >= 89.0) {
min.setx( 89.0 );
max.setx( 90.0 );
min.sety( -180.0 );
max.sety( 180.0 );
} else {
FG_LOG ( FG_GENERAL, FG_ALERT,
"Out of range latitude in clip_and_write_poly() = " << c.y() );
}
FG_LOG( FG_GENERAL, FG_DEBUG, " (" << min << ") (" << max << ")" );
// set up clipping tile
base.add_node( 0, Point3D(min.x(), min.y(), 0) );
base.add_node( 0, Point3D(max.x(), min.y(), 0) );
base.add_node( 0, Point3D(max.x(), max.y(), 0) );
base.add_node( 0, Point3D(min.x(), max.y(), 0) );
// FG_LOG( FG_GENERAL, FG_DEBUG, "base = 4 vertices" );
/*
FILE *bfp= fopen("base", "w");
gpc_write_polygon(bfp, &base);
fclose(bfp);
*/
result = polygon_int( base, shape );
if ( result.contours() > 0 ) {
long int t_index = b.gen_index();
string path = root + "/" + b.gen_base_path();
#ifdef _MSC_VER
fg_mkdir( path.c_str() );
#else
string command = "mkdir -p " + path;
system( command.c_str() );
#endif
sprintf( tile_name, "%ld", t_index );
string polyfile = path + "/" + tile_name;
sprintf( poly_index, "%ld", p_index );
polyfile += ".";
polyfile += poly_index;
string poly_type = get_area_name( area );
if ( poly_type == "Unknown" ) {
cout << "unknown area type in clip_and_write_poly()!" << endl;
exit(-1);
}
FILE *rfp= fopen( polyfile.c_str(), "w" );
fprintf( rfp, "%s\n", poly_type.c_str() );
fprintf( rfp, "%d\n", result.contours() );
for ( int i = 0; i < result.contours(); ++i ) {
fprintf( rfp, "%d\n", result.contour_size(i) );
fprintf( rfp, "%d\n", result.get_hole_flag(i) );
for ( int j = 0; j < result.contour_size(i); ++j ) {
p = result.get_pt( i, j );
fprintf( rfp, "%.15f %.15f\n", p.x(), p.y() );
}
}
fclose( rfp );
}
}
// process shape (write polygon to all intersecting tiles)
void split_polygon(const string& path, AreaType area, const FGPolygon& shape) {
Point3D min, max, p;
// point2d min, max;
long int index;
int i, j;
// bail out immediately if polygon is empty
if ( shape.contours() == 0 ) {
return;
}
min = Point3D( 200.0 );
max = Point3D( -200.0 );
// find min/max of polygon
for ( i = 0; i < shape.contours(); i++ ) {
for ( j = 0; j < shape.contour_size(i); j++ ) {
p = shape.get_pt( i, j );
if ( p.x() < min.x() ) { min.setx( p.x() ); }
if ( p.y() < min.y() ) { min.sety( p.y() ); }
if ( p.x() > max.x() ) { max.setx( p.x() ); }
if ( p.y() > max.y() ) { max.sety( p.y() ); }
}
}
// get next polygon index
index = poly_index_next();
FG_LOG( FG_GENERAL, FG_INFO, " min = " << min << " max = " << max );
// find buckets for min, and max points of convex hull.
// note to self: self, you should think about checking for
// polygons that span the date line
FGBucket b_min( min.x(), min.y() );
FGBucket b_max( max.x(), max.y() );
FG_LOG( FG_GENERAL, FG_INFO, " Bucket min = " << b_min );
FG_LOG( FG_GENERAL, FG_INFO, " Bucket max = " << b_max );
if ( b_min == b_max ) {
// shape entirely contained in a single bucket, write and bail
clip_and_write_poly( path, index, area, b_min, shape );
return;
}
FGBucket b_cur;
int dx, dy;
fgBucketDiff(b_min, b_max, &dx, &dy);
FG_LOG( FG_GENERAL, FG_INFO,
" polygon spans tile boundaries" );
FG_LOG( FG_GENERAL, FG_INFO, " dx = " << dx
<< " dy = " << dy );
if ( (dx > 2880) || (dy > 1440) ) {
FG_LOG( FG_GENERAL, FG_ALERT,
"something is really wrong in split_polygon()!!!!" );
exit(-1);
}
if ( dy <= 1 ) {
// we are down to at most two rows, write each column and then
// bail
for ( j = 0; j <= 1; ++j ) {
for ( i = 0; i <= dx; ++i ) {
b_cur = fgBucketOffset(min.x(), min.y(), i, j);
clip_and_write_poly( path, index, area, b_cur, shape );
}
}
return;
}
// we have more than one row left, split in half and recurse with
// each chunk
// find mid point (integer math)
int mid = (dy + 1) / 2 - 1;
// determine horizontal clip line
FGBucket b_clip = fgBucketOffset(min.x(), min.y(), 0, mid);
double clip_line = b_clip.get_center_lat();
if ( (clip_line >= -89.0) && (clip_line < 89.0) ) {
clip_line += FG_HALF_BUCKET_SPAN;
} else if ( clip_line < -89.0 ) {
clip_line = -89.0;
} else if ( clip_line >= 89.0 ) {
clip_line = 90.0;
} else {
FG_LOG ( FG_GENERAL, FG_ALERT,
"Out of range latitude in clip_and_write_poly() = "
<< clip_line );
}
{
//
// Crop bottom area (hopefully by putting this in it's own
// scope we can shorten the life of some really large data
// structures to reduce memory use)
//
FG_LOG ( FG_GENERAL, FG_INFO,
"Generating bottom half (" << min.y() << "-" <<
clip_line << ")" );
FGPolygon bottom, bottom_clip;
if ( shape.total_size() < 50000 ) {
bottom.erase();
bottom_clip.erase();
bottom.add_node( 0, Point3D(-180.0, min.y(), 0) );
bottom.add_node( 0, Point3D(180.0, min.y(), 0) );
bottom.add_node( 0, Point3D(180.0, clip_line, 0) );
bottom.add_node( 0, Point3D(-180.0, clip_line, 0) );
bottom_clip = polygon_int( bottom, shape );
} else {
bottom_clip = horizontal_clip( shape, clip_line, Below );
}
split_polygon(path, area, bottom_clip);
}
{
//
// Crop top area (hopefully by putting this in it's own scope
// we can shorten the life of some really large data
// structures to reduce memory use)
//
FG_LOG ( FG_GENERAL, FG_INFO,
"Generating top half (" << clip_line << "-" <<
max.y() << ")" );
FGPolygon top, top_clip;
if ( shape.total_size() < 50000 ) {
top.erase();
top_clip.erase();
top.add_node( 0, Point3D(-180.0, clip_line, 0) );
top.add_node( 0, Point3D(180.0, clip_line, 0) );
top.add_node( 0, Point3D(180.0, max.y(), 0) );
top.add_node( 0, Point3D(-180.0, max.y(), 0) );
top_clip = polygon_int( top, shape );
} else {
top_clip = horizontal_clip( shape, clip_line, Above );
}
split_polygon(path, area, top_clip);
}
}