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calc_point_inside():

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- Fixed one-off bug.
	- Take care of the border-case where the line exactly overlaps a node.
This commit is contained in:
Ralf Gerlich 2008-01-03 15:56:10 +01:00
parent c5410c336d
commit d8539d5412
1 changed files with 29 additions and 11 deletions
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40
src/Lib/Geometry/poly_support.cxx
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@ -36,6 +36,7 @@
#include <Triangulate/trieles.hxx>
#include <algorithm>
#include <iterator>
#define REAL double
extern "C" {
@ -51,6 +52,8 @@ extern "C" {
SG_USING_STD(cout);
SG_USING_STD(endl);
SG_USING_STD(sort);
SG_USING_STD(copy);
SG_USING_STD(ostream_iterator);
// Given a line segment specified by two endpoints p1 and p2, return
// the slope of the line.
@ -821,7 +824,7 @@ static void intersect_yline_with_contour( double yline, TGContourNode *node, TGP
point_list::size_type count = pts.size();
cout << "intersect_yline_with_contour() yline=" << yline << endl;
// cout << "intersect_yline_with_contour() yline=" << yline << endl;
for ( int i = 0; i < count; ++i ) {
const Point3D &p0 = pts[ i ];
@ -834,24 +837,35 @@ static void intersect_yline_with_contour( double yline, TGContourNode *node, TGP
if (ymax<p1.y())
ymax=p1.y();
cout << "intersect_yline_with_contour() p0=(" << p0.x() << ", " << p0.y() << ") p1=(" << p1.x() << ", " << p1.y() << ") ymin=" << ymin << " ymax=" << ymax << " yline=" << yline << endl;
// cout << "intersect_yline_with_contour() p0=(" << p0.x() << ", " << p0.y() << ") p1=(" << p1.x() << ", " << p1.y() << ") ymin=" << ymin << " ymax=" << ymax << " yline=" << yline << endl;
if (yline<ymin || ymax<yline) {
cout << "intersect_yline_with_contour() does not intersect" << endl;
if ((yline+SG_EPSILON)<ymin || ymax<(yline-SG_EPSILON)) {
// cout << "intersect_yline_with_contour() does not intersect" << endl;
continue;
}
if (ymax-ymin<SG_EPSILON) {
cout << "intersect_yline_with_contour() line is nearly y-parallel" << endl;
// The line is nearly y-parallel, so add both ends
// cout << "intersect_yline_with_contour() line is nearly y-parallel" << endl;
/* The line is nearly y-parallel, so add both ends */
xcuts.push_back(p0.x());
xcuts.push_back(p1.x());
}
if (yline-ymin<SG_EPSILON) {
// cout << "intersect_yline_with_contour() line touches topmost node" << endl;
/*
* The line touches the topmost node.
* To avoid adding that node twice (thereby possibly
* creating an odd number of intersections), only add it
* when it is the lower of the two ends.
*/
continue;
}
double t=(yline-p0.y())/(p1.y()-p0.y());
double x=p0.x()+t*(p1.x()-p0.x());
cout << "intersect_yline_with_contour() intersection at x=" << x << endl;
// cout << "intersect_yline_with_contour() intersection at x=" << x << endl;
xcuts.push_back(x);
}
}
@ -869,7 +883,7 @@ static void calc_point_inside( TGContourNode *node, TGPolygon &p ) {
}
}
if ( contour_num <= 0 )
if ( contour_num < 0 )
return;
/*
@ -890,7 +904,7 @@ static void calc_point_inside( TGContourNode *node, TGPolygon &p ) {
ymax=pts[i].y();
}
cout << "calc_point_inside() contour_num=" << contour_num << " " << pts.size() << " points ymin=" << ymin << " ymax=" << ymax << endl;
// cout << "calc_point_inside() contour_num=" << contour_num << " " << pts.size() << " points ymin=" << ymin << " ymax=" << ymax << endl;
double yline=(ymin+ymax)/2.0;
vector < double > xcuts;
@ -903,10 +917,12 @@ static void calc_point_inside( TGContourNode *node, TGPolygon &p ) {
}
}
cout << "calc_point_inside() " << xcuts.size() << " intersections" << endl;
sort( xcuts.begin(), xcuts.end() );
// cout << "calc_point_inside() " << xcuts.size() << " intersections ";
copy(xcuts.begin(), xcuts.end(), ostream_iterator<double>(cout, " "));
cout << endl;
if ( xcuts.size() < 2 || (xcuts.size() % 2) != 0 ) {
throw sg_exception("Geometric inconsistency in calc_point_inside()");
}
@ -925,6 +941,8 @@ static void calc_point_inside( TGContourNode *node, TGPolygon &p ) {
double x = (xcuts[ longest ] + xcuts[ longest + 1 ])/2.0;
// cout << "calc_point_inside() found point inside x=" << x << " y=" << yline << endl;
p.set_point_inside( contour_num, Point3D(x, yline, -9999.0) );
}