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flightgear/Tools/Prep/ShapeFile/shape.cxx

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C++

// shape.cxx -- shape/gpc 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 <Include/compiler.h>
#include STL_STRING
#include <Bucket/newbucket.hxx>
#include <Debug/logstream.hxx>
#include <Polygon/index.hxx>
#include <Polygon/names.hxx>
#include "shape.hxx"
#define FG_MAX_VERTICES 100000
static gpc_vertex_list v_list;
class point2d {
public:
double x, y;
};
static void clip_and_write_poly( string root, long int p_index, AreaType area,
FGBucket b, gpc_polygon *shape ) {
point2d c, min, max;
c.x = b.get_center_lon();
c.y = b.get_center_lat();
double span = bucket_span(c.y);
gpc_polygon base, result;
char tile_name[256], poly_index[256];
// calculate bucket dimensions
if ( (c.y >= -89.0) && (c.y < 89.0) ) {
min.x = c.x - span / 2.0;
max.x = c.x + span / 2.0;
min.y = c.y - FG_HALF_BUCKET_SPAN;
max.y = c.y + FG_HALF_BUCKET_SPAN;
} else if ( c.y < -89.0) {
min.x = -90.0;
max.x = -89.0;
min.y = -180.0;
max.y = 180.0;
} else if ( c.y >= 89.0) {
min.x = 89.0;
max.x = 90.0;
min.y = -180.0;
max.y = 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_INFO, " (" << min.x << "," << min.y << ") ("
<< max.x << "," << max.y << ")" );
// set up clipping tile
v_list.vertex[0].x = min.x;
v_list.vertex[0].y = min.y;
v_list.vertex[1].x = max.x;
v_list.vertex[1].y = min.y;
v_list.vertex[2].x = max.x;
v_list.vertex[2].y = max.y;
v_list.vertex[3].x = min.x;
v_list.vertex[3].y = max.y;
v_list.num_vertices = 4;
base.num_contours = 0;
base.contour = NULL;
gpc_add_contour( &base, &v_list, 0 );
// FG_LOG( FG_GENERAL, FG_DEBUG, "base = 4 vertices" );
/*
FILE *bfp= fopen("base", "w");
gpc_write_polygon(bfp, &base);
fclose(bfp);
*/
gpc_polygon_clip(GPC_INT, &base, shape, &result);
if ( result.num_contours > 0 ) {
long int t_index = b.gen_index();
string path = root + "/Scenery/" + b.gen_base_path();
string command = "mkdir -p " + path;
system( command.c_str() );
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() );
gpc_write_polygon( rfp, 1, &result );
fclose( rfp );
// only free result if it is not empty
gpc_free_polygon(&result);
}
gpc_free_polygon(&base);
}
// Initialize structure we use to create polygons for the gpc library
bool shape_utils_init() {
v_list.num_vertices = 0;
v_list.vertex = new gpc_vertex[FG_MAX_VERTICES];;
return true;
}
// initialize a gpc_polygon
void init_shape(gpc_polygon *shape) {
shape->num_contours = 0;
shape->contour = NULL;
}
// make a gpc_polygon, first contour is outline, remaining contours
// are holes
void add_to_shape(int count, double *coords, gpc_polygon *shape) {
for ( int i = 0; i < count; i++ ) {
v_list.vertex[i].x = coords[i*2+0];
v_list.vertex[i].y = coords[i*2+1];
}
v_list.num_vertices = count;
if ( shape->num_contours == 0 ) {
// outline
gpc_add_contour( shape, &v_list, 0 );
} else {
// hole
gpc_add_contour( shape, &v_list, 1 );
}
}
// process shape (write polygon to all intersecting tiles)
void process_shape(string path, AreaType area, gpc_polygon *gpc_shape) {
point2d min, max;
long int index;
int i, j;
min.x = min.y = 200.0;
max.x = max.y = -200.0;
// find min/max of polygon
for ( i = 0; i < gpc_shape->num_contours; i++ ) {
for ( j = 0; j < gpc_shape->contour[i].num_vertices; j++ ) {
double x = gpc_shape->contour[i].vertex[j].x;
double y = gpc_shape->contour[i].vertex[j].y;
if ( x < min.x ) { min.x = x; }
if ( y < min.y ) { min.y = y; }
if ( x > max.x ) { max.x = x; }
if ( y > max.y ) { max.y = y; }
}
}
/*
FILE *sfp= fopen("shape", "w");
gpc_write_polygon(sfp, gpc_shape);
fclose(sfp);
exit(-1);
*/
// get next polygon index
index = poly_index_next();
FG_LOG( FG_GENERAL, FG_INFO, " min = " << min.x << "," << min.y
<< " max = " << max.x << "," << max.y );
// 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 ) {
clip_and_write_poly( path, index, area, b_min, gpc_shape );
} else {
FGBucket b_cur;
int dx, dy, i, j;
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 > 100) || (dy > 100) ) {
FG_LOG( FG_GENERAL, FG_ALERT,
"somethings really wrong!!!!" );
exit(-1);
}
for ( j = 0; j <= dy; 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, gpc_shape );
}
}
// string answer; cin >> answer;
}
}
// free a gpc_polygon
void free_shape(gpc_polygon *shape) {
gpc_free_polygon(shape);
}