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/**
* Copyright (C) 2014 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/geo/big_polygon.h"
#include <map>
#include "mongo/base/owned_pointer_vector.h"
#include "mongo/util/assert_util.h"
namespace mongo {
using boost::scoped_ptr;
using std::auto_ptr;
using std::vector;
BigSimplePolygon::BigSimplePolygon() {
}
// Caller should ensure loop is valid.
BigSimplePolygon::BigSimplePolygon(S2Loop* loop) :
_loop(loop), _isNormalized(loop->IsNormalized()) {
}
BigSimplePolygon::~BigSimplePolygon() {
}
void BigSimplePolygon::Init(S2Loop* loop) {
_loop.reset(loop);
_isNormalized = loop->IsNormalized();
_borderLine.reset();
_borderPoly.reset();
}
double BigSimplePolygon::GetArea() const {
return _loop->GetArea();
}
bool BigSimplePolygon::Contains(const S2Polygon& polygon) const {
const S2Polygon& polyBorder = GetPolygonBorder();
if (_isNormalized) {
// Polygon border is the same as the loop
return polyBorder.Contains(&polygon);
}
// Polygon border is the complement of the loop
//
// Return true iff big polygon's complement (polyBorder) doesn't intersect with polygon.
// We don't guarantee whether the points on border are contained or not.
return !polyBorder.Intersects(&polygon);
}
bool BigSimplePolygon::Contains(const S2Polyline& line) const {
//
// A line is contained within a loop if the result of subtracting the loop from the line is
// nothing.
//
// Also, a line is contained within a loop if the result of clipping the line to the
// complement of the loop is nothing.
//
// If we can't subtract the loop itself using S2, we clip (intersect) to the inverse. Every
// point in S2 is contained in exactly one of these loops.
//
// TODO: Polygon borders are actually kind of weird, and this is somewhat inconsistent with
// Intersects(). A point might Intersect() a boundary exactly, but not be Contain()ed
// within the Polygon. Think the right thing to do here is custom intersection functions.
//
const S2Polygon& polyBorder = GetPolygonBorder();
OwnedPointerVector<S2Polyline> clippedOwned;
vector<S2Polyline*>& clipped = clippedOwned.mutableVector();
if (_isNormalized) {
// Polygon border is the same as the loop
polyBorder.SubtractFromPolyline(&line, &clipped);
return clipped.size() == 0;
}
else {
// Polygon border is the complement of the loop
polyBorder.IntersectWithPolyline(&line, &clipped);
return clipped.size() == 0;
}
}
bool BigSimplePolygon::Contains(S2Point const& point) const {
return _loop->Contains(point);
}
bool BigSimplePolygon::Intersects(const S2Polygon& polygon) const {
// If the loop area is at most 2*Pi, treat it as a simple Polygon.
if (_isNormalized) {
const S2Polygon& polyBorder = GetPolygonBorder();
return polyBorder.Intersects(&polygon);
}
// The loop area is greater than 2*Pi, so it intersects a polygon (even with holes) if it
// intersects any of the top-level polygon loops, since any valid polygon is less than
// a hemisphere.
//
// Intersecting a polygon hole requires that the loop must have intersected the containing
// loop - topology ftw.
//
// Another approach is to check polyBorder doesn't contain polygon, but the following
// approach is cheaper.
// Iterate over all the top-level polygon loops
for (int i = 0; i < polygon.num_loops(); i = polygon.GetLastDescendant(i) + 1) {
const S2Loop* polyLoop = polygon.loop(i);
if (_loop->Intersects(polyLoop))
return true;
}
return false;
}
bool BigSimplePolygon::Intersects(const S2Polyline& line) const {
//
// A loop intersects a line if line intersects the loop border or, if it doesn't, either
// line is contained in the loop, or line is disjoint with the loop. So checking any
// vertex of the line is sufficient.
//
// TODO: Make a general Polygon/Line relation tester which uses S2 primitives
//
return GetLineBorder().Intersects(&line) || _loop->Contains(line.vertex(0));
}
bool BigSimplePolygon::Intersects(S2Point const& point) const {
return Contains(point);
}
void BigSimplePolygon::Invert() {
_loop->Invert();
_isNormalized = _loop->IsNormalized();
}
const S2Polygon& BigSimplePolygon::GetPolygonBorder() const {
if (_borderPoly)
return *_borderPoly;
auto_ptr<S2Loop> cloned(_loop->Clone());
// Any loop in polygon should be than a hemisphere (2*Pi).
cloned->Normalize();
OwnedPointerVector<S2Loop> loops;
loops.mutableVector().push_back(cloned.release());
_borderPoly.reset(new S2Polygon(&loops.mutableVector()));
return *_borderPoly;
}
const S2Polyline& BigSimplePolygon::GetLineBorder() const {
if (_borderLine)
return *_borderLine;
vector<S2Point> points;
int numVertices = _loop->num_vertices();
for (int i = 0; i <= numVertices; ++i) {
// vertex() maps "numVertices" to 0 internally, so we don't have to deal with
// the index out of range.
points.push_back(_loop->vertex(i));
}
_borderLine.reset(new S2Polyline(points));
return *_borderLine;
}
BigSimplePolygon* BigSimplePolygon::Clone() const {
return new BigSimplePolygon(_loop->Clone());
}
S2Cap BigSimplePolygon::GetCapBound() const {
return _loop->GetCapBound();
}
S2LatLngRect BigSimplePolygon::GetRectBound() const {
return _loop->GetRectBound();
}
bool BigSimplePolygon::Contains(const S2Cell& cell) const {
return _loop->Contains(cell);
}
bool BigSimplePolygon::MayIntersect(const S2Cell& cell) const {
return _loop->MayIntersect(cell);
}
bool BigSimplePolygon::VirtualContainsPoint(const S2Point& p) const {
return _loop->VirtualContainsPoint(p);
}
void BigSimplePolygon::Encode(Encoder* const encoder) const {
invariant(false);
}
bool BigSimplePolygon::Decode(Decoder* const decoder) {
invariant(false);
}
bool BigSimplePolygon::DecodeWithinScope(Decoder* const decoder) {
invariant(false);
}
}
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