/usr/include/SFCGAL/algorithm/differencePrimitives.h is in libsfcgal-dev 1.2.2-1.
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* SFCGAL
*
* Copyright (C) 2012-2013 Oslandia <infos@oslandia.com>
* Copyright (C) 2012-2013 IGN (http://www.ign.fr)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _SFCGAL_ALGORITHM_DIFFERENCEPRIMITIVES_H_
#define _SFCGAL_ALGORITHM_DIFFERENCEPRIMITIVES_H_
#include <SFCGAL/Exception.h>
#include <SFCGAL/triangulate/triangulatePolygon.h>
#include <SFCGAL/Polygon.h>
#include <SFCGAL/TriangulatedSurface.h>
#include <SFCGAL/detail/GeometrySet.h>
#include <CGAL/Boolean_set_operations_2.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/box_intersection_d.h>
#include <CGAL/corefinement_operations.h>
#include <SFCGAL/detail/Point_inside_polyhedron.h>
namespace SFCGAL {
namespace algorithm {
typedef CGAL::Vector_2<Kernel> Vector_2;
typedef CGAL::Point_2<Kernel> Point_2;
typedef CGAL::Segment_2<Kernel> Segment_2;
typedef CGAL::Triangle_2<Kernel> Triangle_2;
typedef CGAL::Polygon_2<Kernel> Polygon_2;
typedef CGAL::Polygon_with_holes_2<Kernel> PolygonWH_2;
typedef detail::NoVolume NoVolume;
typedef CGAL::Vector_3<Kernel> Vector_3;
typedef CGAL::Point_3<Kernel> Point_3;
typedef CGAL::Segment_3<Kernel> Segment_3;
typedef CGAL::Triangle_3<Kernel> Triangle_3;
typedef CGAL::Plane_3<Kernel> Plane_3;
typedef detail::MarkedPolyhedron MarkedPolyhedron;
CGAL::Object intersection( const CGAL::Triangle_3<Kernel>& a, const CGAL::Triangle_3<Kernel>& b );
inline
bool do_intersect( const Point_2& point, const PolygonWH_2& polygon )
{
// point intersects if it's inside the ext ring and outside all holes
if ( CGAL::bounded_side_2( polygon.outer_boundary().vertices_begin(),
polygon.outer_boundary().vertices_end(), point, Kernel() )
== CGAL::ON_UNBOUNDED_SIDE ) {
return false;
}
for ( PolygonWH_2::Hole_const_iterator hit = polygon.holes_begin();
hit != polygon.holes_end();
++hit ) {
if ( CGAL::bounded_side_2( hit->vertices_begin(),
hit->vertices_end(), point, Kernel() )
!= CGAL::ON_UNBOUNDED_SIDE ) {
return false;
}
}
return true;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_2& a, const Point_2& b, PointOutputIteratorType out )
{
if ( a != b ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_2& a, const Segment_2& b, PointOutputIteratorType out )
{
if ( ! CGAL::do_intersect( a, b ) ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_2& a, const PolygonWH_2& b, PointOutputIteratorType out )
{
if ( ! do_intersect( a, b ) ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_2&, const NoVolume& , PointOutputIteratorType out )
{
BOOST_ASSERT( false );
return out;
}
template < typename SegmentOutputIteratorType>
SegmentOutputIteratorType difference( const Segment_2&, const NoVolume& , SegmentOutputIteratorType out )
{
BOOST_ASSERT( false );
return out;
}
template < typename SurfaceOutputIteratorType>
SurfaceOutputIteratorType difference( const PolygonWH_2&, const NoVolume& , SurfaceOutputIteratorType out )
{
BOOST_ASSERT( false );
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_3& a, const Point_3& b, PointOutputIteratorType out )
{
if ( a != b ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_3& a, const Segment_3& b, PointOutputIteratorType out )
{
if ( ! b.has_on( a ) ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_3& a, const Triangle_3& b, PointOutputIteratorType out )
{
if ( ! b.has_on( a ) ) {
*out++ = a;
}
return out;
}
template < typename PointOutputIteratorType>
PointOutputIteratorType difference( const Point_3& a, const MarkedPolyhedron& b, PointOutputIteratorType out )
{
Point_inside_polyhedron<MarkedPolyhedron, Kernel> is_in_poly( b );
if ( CGAL::ON_UNBOUNDED_SIDE == is_in_poly( a ) ) {
*out++ = a;
}
return out;
}
template < typename SegmentType , typename SegmentOrSurfaceType, typename SegmentOutputIteratorType>
SegmentOutputIteratorType difference( const SegmentType& a, const SegmentOrSurfaceType& b, SegmentOutputIteratorType out )
{
CGAL::Object inter = CGAL::intersection( a, b );
const SegmentType* s = CGAL::object_cast< SegmentType >( &inter );
if ( s ) { // there maybe zero, one or two segments as a result
if ( CGAL::squared_distance( a.source(), s->source() ) < CGAL::squared_distance( a.source(), s->target() ) ) {
if ( a.source() != s->source() ) {
*out++ = SegmentType( a.source(), s->source() );
}
if ( s->target() != a.target() ) {
*out++ = SegmentType( s->target(), a.target() );
}
}
else {
if ( a.source() != s->target() ) {
*out++ = SegmentType( a.source(), s->target() );
}
if ( s->source() != a.target() ) {
*out++ = SegmentType( s->source(), a.target() );
}
}
}
else { // intersection is a point or nothing, leave a unchanged
*out++ = a;
}
return out;
}
template<typename PointType>
struct Nearer {
Nearer( const PointType& reference ) :_ref( reference ) {}
bool operator()( const PointType& lhs, const PointType& rhs ) const {
return CGAL::squared_distance( _ref, lhs ) < CGAL::squared_distance( _ref, rhs );
}
private:
const PointType _ref;
};
template < typename SegmentOutputIteratorType>
SegmentOutputIteratorType difference( const Segment_2& segment, const PolygonWH_2& polygon, SegmentOutputIteratorType out )
{
// we could triangulate the polygon and substract each triangle
//
// we could also cut the line by polygon contours and test if the middle of the segment is inside
// but if the segment lies on the contour it's a special case
// we first substract the contours to take care of this
// special case, we obtain a vector of segments,
// for each segment of this vector, we subdivide it with the intersection
// points with the rings
// once done, we check, for each subdivision that has distinct end-points
// if the middle is in or out.
std::vector< Segment_2 > result( 1, segment );
std::vector< Polygon_2 > rings( 1, polygon.outer_boundary() );
rings.insert( rings.end(), polygon.holes_begin(), polygon.holes_end() );
for ( std::vector< Polygon_2 >::iterator ring = rings.begin(); ring != rings.end(); ++ring ) {
for ( Polygon_2::Vertex_const_iterator target = ring->vertices_begin();
target != ring->vertices_end(); ++target ) {
const Segment_2 sc( target == ring->vertices_begin()
? *( ring->vertices_end() - 1 )
: *( target - 1 )
,
*target );
std::vector< Segment_2 > tmp;
for ( std::vector< Segment_2 >::const_iterator s = result.begin(); s != result.end(); ++s ) {
difference( *s, sc, std::back_inserter( tmp ) );
}
tmp.swap( result );
}
}
for ( std::vector< Segment_2 >::const_iterator s = result.begin(); s != result.end(); ++s ) {
std::vector< Point_2 > points( 1, s->source() );
for ( std::vector< Polygon_2 >::iterator ring = rings.begin(); ring != rings.end(); ++ring ) {
for ( Polygon_2::Vertex_const_iterator target = ring->vertices_begin();
target != ring->vertices_end(); ++target ) {
Segment_2 sc( target == ring->vertices_begin()
? *( ring->vertices_end() - 1 )
: *( target - 1 )
,
*target );
CGAL::Object inter = CGAL::intersection( *s, sc );
const Point_2* p = CGAL::object_cast< Point_2 >( &inter );
if ( p ) {
points.push_back( *p );
}
}
}
points.push_back( s->target() );
// order point according to the distance from source
const Nearer<Point_2> nearer( s->source() );
std::sort( points.begin()+1, points.end()-1, nearer );
// append segments that has length and wich midpoint is outside polygon to result
for ( std::vector< Point_2 >::const_iterator p = points.begin(); p != points.end()-1; ++p ) {
std::vector< Point_2 >::const_iterator q = p+1;
if ( *p != *q && !do_intersect( CGAL::midpoint( *p,*q ), polygon ) ) {
*out++ = Segment_2( *p, *q );
}
}
}
return out;
}
// assuming two disjoint (except at a point) polygon, test if the first a hole of the second
inline
bool isHoleOf( const Polygon_2& hole, const Polygon_2& poly )
{
return CGAL::bounded_side_2( poly.vertices_begin(),
poly.vertices_end(), *hole.vertices_begin(), Kernel() )
== CGAL::ON_BOUNDED_SIDE ||
CGAL::bounded_side_2( poly.vertices_begin(),
poly.vertices_end(), *( hole.vertices_begin()+1 ), Kernel() )
== CGAL::ON_BOUNDED_SIDE ;
}
template < typename PolygonOutputIteratorType>
PolygonOutputIteratorType fix_cgal_valid_polygon( const PolygonWH_2& p, PolygonOutputIteratorType out )
{
const Polygon_2& outer = p.outer_boundary();
//std::cerr << "in fix outer " << outer << "\n";
if ( !outer.is_simple() ) {
// the holes are simple, so we need to find the intersection points, then split
// the outer ring into simple components and put holes in the right one
// note that the hole may touch the outer boundary at a point,
// so if the tested hole point falls on the boundary, we test the next
std::vector< Polygon_2 > boundaries;
std::vector< std::vector<Point_2> > stack( 1 );
for ( Polygon_2::Vertex_const_iterator v = outer.vertices_begin();
v != outer.vertices_end(); ++v ) {
if ( stack.back().size() && stack.back()[0] == *v ) { // closing ring
boundaries.push_back( Polygon_2( stack.back().begin(), stack.back().end() ) );
stack.pop_back();
}
else if ( std::find( v+1, outer.vertices_end(), *v ) != outer.vertices_end() ) { //split point
stack.back().push_back( *v );
stack.resize( stack.size() + 1 );
stack.back().push_back( *v );
}
else {
stack.back().push_back( *v );
}
}
if ( stack.size() ) {
boundaries.push_back( Polygon_2( stack.back().begin(), stack.back().end() ) );
}
//std::cerr << "in fix boundaries " << boundaries.size() << "\n";
std::vector<Polygon_2> holes( p.holes_begin(), p.holes_end() );
// one of the boundaries may be a hole
std::vector< Polygon_2 > cw;
std::vector< Polygon_2 > ccw;
for ( std::vector< Polygon_2 >::const_iterator b = boundaries.begin();
b != boundaries.end(); ++b ) {
if ( b->orientation() == CGAL::CLOCKWISE ) {
cw.push_back( *b );
}
else {
ccw.push_back( *b );
}
}
//std::cerr << "in fix " << ccw.size() << " ccw and " << cw.size() << " cw\n";
// if we have holes, check the orientation of the first hole to see
// what is a hole orientation
// if we don't have holes, we test if the first ccw is a hole of any
// of the cw, if not, then the other are holes
bool holesAreCCW = false;
if ( !cw.size() ) {
holesAreCCW = false;
}
else if ( !ccw.size() ) {
holesAreCCW = true;
}
else if ( holes.size() ) {
holesAreCCW = holes[0].orientation() != CGAL::CLOCKWISE;
}
else {
for ( std::vector< Polygon_2 >::const_iterator b = cw.begin();
b != boundaries.end(); ++b ) {
if ( isHoleOf( ccw[0], *b ) ) {
holesAreCCW = true;
break;
}
}
}
if ( holesAreCCW ) {
holes.insert( holes.end(), ccw.begin(), ccw.end() );
boundaries.swap( cw );
}
else {
holes.insert( holes.end(), cw.begin(), cw.end() );
boundaries.swap( ccw );
}
std::vector< std::vector< Polygon_2 > > sortedHoles( boundaries.size() ); // 1/1 with boudaries
unsigned nbHoles = 0;
for ( std::vector< Polygon_2 >::const_iterator h = holes.begin(); h != holes.end(); ++h ) {
++nbHoles;
for ( std::vector< Polygon_2 >::const_iterator b = boundaries.begin();
b != boundaries.end(); ++b ) {
if ( isHoleOf( *h, *b ) ) {
sortedHoles[ b - boundaries.begin() ].push_back( *h );
}
}
}
for ( unsigned i = 0; i < boundaries.size(); i++ ) {
*out++ = PolygonWH_2( boundaries[i], sortedHoles[i].begin(), sortedHoles[i].end() );
}
//std::cerr << "extracted " << boundaries.size() << " boundaries, dispatched " << nbHoles << " holes \n";
}
else {
*out++ = p;
}
return out;
}
inline
PolygonWH_2
fix_sfs_valid_polygon( const PolygonWH_2& p )
{
CGAL::Gps_segment_traits_2<Kernel> traits;
if ( are_holes_and_boundary_pairwise_disjoint( p, traits ) ) {
return p;
}
// a polygon is valid for sfs and invalid for CGAL when two rings intersect
// on a point that is not a ring vertex
// we add this vertex to fix the polygon
// for each ring segment
// for every other ring point
// add point to segment
// put all rings in a vector to avoid distinction between outer and holes
std::vector< Polygon_2 > rings( 1, p.outer_boundary() );
rings.insert( rings.end(), p.holes_begin(), p.holes_end() );
std::vector< Polygon_2 > out;
for ( std::vector< Polygon_2 >::iterator ring = rings.begin(); ring != rings.end(); ++ring ) {
out.push_back( Polygon_2() );
for ( Polygon_2::Vertex_const_iterator target = ring->vertices_begin(); target != ring->vertices_end(); ++target ) {
Segment_2 segment(
target == ring->vertices_begin()
? *( ring->vertices_end() - 1 )
: *( target - 1 )
,
*target );
// for every other ring
for ( std::vector< Polygon_2 >::const_iterator other = rings.begin(); other != rings.end(); ++other ) {
if ( ring == other ) {
continue;
}
for ( Polygon_2::Vertex_const_iterator vertex = other->vertices_begin();
vertex != other->vertices_end(); ++vertex ) {
if ( CGAL::do_intersect( *vertex, segment ) ) {
out.back().push_back( *vertex );
}
}
}
out.back().push_back( *target );
}
}
return PolygonWH_2( out[0], out.begin()+1, out.end() );
}
template < typename OutputIteratorType >
OutputIteratorType difference( const Triangle_3& p, const Triangle_3& q, OutputIteratorType out )
{
const Plane_3 plane = p.supporting_plane();
if ( plane != q.supporting_plane() || !CGAL::do_intersect( p,q ) ) {
*out++ = p;
}
else {
// project on plane
// difference between polygons
// triangulate the result
PolygonWH_2 pProj, qProj;
for ( unsigned i=0; i<3; i++ ) {
pProj.outer_boundary().push_back( plane.to_2d( p.vertex( i ) ) );
qProj.outer_boundary().push_back( plane.to_2d( q.vertex( i ) ) );
}
std::vector< PolygonWH_2 > res;
difference( pProj, qProj, std::back_inserter( res ) );
for ( std::vector< PolygonWH_2 >::const_iterator i = res.begin(); i != res.end(); ++i ) {
const Polygon poly( *i );
TriangulatedSurface ts;
triangulate::triangulatePolygon3D( poly, ts );
for ( TriangulatedSurface::iterator t = ts.begin(); t != ts.end(); ++t ) {
*out++ = Triangle_3( plane.to_3d( t->vertex( 0 ).toPoint_2() ),
plane.to_3d( t->vertex( 1 ).toPoint_2() ),
plane.to_3d( t->vertex( 2 ).toPoint_2() ) ) ;
}
}
}
return out;
}
template < typename VolumeOutputIteratorType>
VolumeOutputIteratorType difference( const MarkedPolyhedron& a, const MarkedPolyhedron& b, VolumeOutputIteratorType out )
{
MarkedPolyhedron& p = const_cast<MarkedPolyhedron&>( a );
MarkedPolyhedron& q = const_cast<MarkedPolyhedron&>( b );
typedef CGAL::Polyhedron_corefinement<MarkedPolyhedron> Corefinement;
Corefinement coref;
CGAL::Emptyset_iterator no_polylines;
typedef std::vector<std::pair<MarkedPolyhedron*, int> > ResultType;
ResultType result;
coref( p, q, no_polylines, std::back_inserter( result ), Corefinement::P_minus_Q_tag );
for ( ResultType::iterator it = result.begin(); it != result.end(); it++ ) {
*out++ = *it->first;
delete it->first;
}
return out;
}
typedef CGAL::Box_intersection_d::Box_with_handle_d<double,3,MarkedPolyhedron::Halfedge_around_facet_const_circulator> FaceBboxBase;
struct FaceBbox: FaceBboxBase {
struct Bbox: CGAL::Bbox_3 {
Bbox( MarkedPolyhedron::Halfedge_around_facet_const_circulator handle )
: CGAL::Bbox_3( handle->vertex()->point().bbox() ) {
const MarkedPolyhedron::Halfedge_around_facet_const_circulator end = handle;
do {
// @note with CGAL 4.5 you would write simply
// *this += (++handle)->vertex()->point().bbox();
this->CGAL::Bbox_3::operator=( *this + ( ++handle )->vertex()->point().bbox() );
}
while ( handle != end );
}
};
FaceBbox( const MarkedPolyhedron::Facet& facet )
: FaceBboxBase( Bbox( facet.facet_begin() ), facet.facet_begin() ) {
}
};
struct FaceSegmentCollide {
typedef std::vector< MarkedPolyhedron::Halfedge_around_facet_const_circulator > CollisionVector;
FaceSegmentCollide( CollisionVector& list ): _list( list ) {}
void operator()( const FaceBboxBase&, const FaceBboxBase& face ) {
_list.push_back( face.handle() );
}
private:
CollisionVector& _list;
};
template < typename TriangleOutputIteratorType>
TriangleOutputIteratorType collidingTriangles( const FaceSegmentCollide::CollisionVector& collisions, TriangleOutputIteratorType out )
{
for ( FaceSegmentCollide::CollisionVector::const_iterator cit = collisions.begin();
cit != collisions.end(); ++cit ) {
MarkedPolyhedron::Halfedge_around_facet_const_circulator it = *cit;
std::vector< Point > points( 1, it->vertex()->point() );
do {
points.push_back( ( ++it )->vertex()->point() );
}
while ( it != *cit );
if ( points.size() == 3 ) {
*out++ = Triangle_3( points[0].toPoint_3(), points[1].toPoint_3(), points[2].toPoint_3() ) ;
}
else {
const Polygon poly( points );
TriangulatedSurface ts;
triangulate::triangulatePolygon3D( poly, ts );
for ( TriangulatedSurface::iterator t = ts.begin(); t != ts.end(); ++t ) {
*out++ = Triangle_3( t->vertex( 0 ).toPoint_3(),
t->vertex( 1 ).toPoint_3(),
t->vertex( 2 ).toPoint_3() );
}
}
}
return out;
}
template < typename SegmentOutputIteratorType>
SegmentOutputIteratorType difference( const Segment_3& segment, const MarkedPolyhedron& polyhedron, SegmentOutputIteratorType out )
{
// this is a bit of a pain
// the algo should follow the same lines as the Segment_2 - PolygonWH_2
// namely, remove the pieces of the segment were it touches facets,
// then compute the intersections with facets to cut the segments and
// create segments for output were the middle point is inside
//
// to speed thing up we put facets in AABB-Tree
std::vector< FaceBbox > bboxes( polyhedron.facets_begin(), polyhedron.facets_end() );
std::vector< FaceBboxBase > bbox( 1, FaceBboxBase( segment.bbox(),polyhedron.facets_begin()->facet_begin() ) ); // nevermind the facet handle, it's not used anyway
FaceSegmentCollide::CollisionVector collisions;
FaceSegmentCollide cb( collisions );
CGAL::box_intersection_d( bbox.begin(), bbox.end(),
bboxes.begin(), bboxes.end(),
cb );
if ( !collisions.size() ) {
// completely in or out, we just test one point
Point_inside_polyhedron<MarkedPolyhedron, Kernel> is_in_poly( polyhedron );
if ( CGAL::ON_UNBOUNDED_SIDE == is_in_poly( segment.source() ) ) {
*out++ = segment;
}
}
else {
std::vector< Triangle_3 > triangles;
collidingTriangles( collisions, std::back_inserter( triangles ) );
// first step, substract faces
std::vector< Segment_3 > res1( 1, segment );
for ( std::vector< Triangle_3 >::const_iterator tri=triangles.begin();
tri != triangles.end(); ++tri ) {
std::vector< Segment_3 > tmp;
for ( std::vector< Segment_3 >::const_iterator seg = res1.begin();
seg != res1.end(); ++seg ) {
difference( *seg, *tri, std::back_inserter( tmp ) );
}
res1.swap( tmp );
}
// second step, for each segment, add intersection points and test each middle point
// to know if it's in or out
for ( std::vector< Segment_3 >::const_iterator seg = res1.begin();
seg != res1.end(); ++seg ) {
std::vector< Point_3 > points( 1, seg->source() );
for ( std::vector< Triangle_3 >::const_iterator tri=triangles.begin();
tri != triangles.end(); ++tri ) {
CGAL::Object inter = CGAL::intersection( *seg, *tri );
const Point_3* p = CGAL::object_cast< Point_3 >( &inter );
if ( p ) {
points.push_back( *p );
}
}
points.push_back( seg->target() );
// order point according to the distance from source
const Nearer<Point_3> nearer( seg->source() );
std::sort( points.begin()+1, points.end()-1, nearer );
Point_inside_polyhedron<MarkedPolyhedron, Kernel> is_in_poly( polyhedron );
// append segments that has length and wich midpoint is outside polyhedron to result
for ( std::vector< Point_3 >::const_iterator p = points.begin(); p != points.end()-1; ++p ) {
std::vector< Point_3 >::const_iterator q = p+1;
if ( *p != *q && CGAL::ON_UNBOUNDED_SIDE == is_in_poly( CGAL::midpoint( *p,*q ) ) ) {
*out++ = Segment_3( *p, *q );
}
}
}
}
return out;
}
// @TODO put that in a proper header
void _intersection_solid_triangle( const MarkedPolyhedron& pa, const Triangle_3& tri, detail::GeometrySet<3>& output );
template < typename TriangleOutputIteratorType>
TriangleOutputIteratorType difference( const Triangle_3& triangle, const MarkedPolyhedron& polyhedron, TriangleOutputIteratorType out )
{
std::vector< Triangle_3 > inter;
// call _intersection_solid_triangle
detail::GeometrySet<3> interSet;
_intersection_solid_triangle( polyhedron, triangle, interSet );
for ( detail::GeometrySet<3>::SurfaceCollection::const_iterator it = interSet.surfaces().begin();
it != interSet.surfaces().end(); ++it ) {
inter.push_back( it->primitive() );
}
std::vector< Triangle_3 > res( 1, triangle );
// GOTCHA for intersection points (volume touching triangle) , need to retriangulate
for ( detail::GeometrySet<3>::PointCollection::const_iterator it = interSet.points().begin();
it != interSet.points().end(); ++it ) {
std::vector< Triangle_3 > tmp;
for ( std::vector< Triangle_3 >::const_iterator tri = res.begin(); tri != res.end(); ++tri ) {
const Point_3 p( it->primitive() );
for ( int s = 0; s<3; s++ ) {
if ( p != tri->vertex( s ) && p != tri->vertex( ( s+1 )%3 )
&& Segment_3( tri->vertex( s ), tri->vertex( ( s+1 )%3 ) ).has_on( p ) ) {
tmp.push_back( Triangle_3( tri->vertex( s ), p, tri->vertex( ( s+2 )%3 ) ) );
tmp.push_back( Triangle_3( p, tri->vertex( ( s+1 )%3 ), tri->vertex( ( s+2 )%3 ) ) );
}
}
}
tmp.swap( res );
}
for ( std::vector< Triangle_3 >::const_iterator it = inter.begin(); it != inter.end(); ++it ) {
std::vector< Triangle_3 > tmp;
for ( std::vector< Triangle_3 >::const_iterator tri = res.begin(); tri != res.end(); ++tri ) {
difference( *tri, *it, std::back_inserter( tmp ) );
}
tmp.swap( res );
}
for ( std::vector< Triangle_3 >::const_iterator tri = res.begin(); tri != res.end(); ++tri ) {
*out++ = *tri;
}
return out;
/*
std::vector< FaceBbox > bboxes(polyhedron.facets_begin(), polyhedron.facets_end() );
std::vector< FaceBboxBase > bbox( 1, FaceBboxBase(triangle.bbox(),polyhedron.facets_begin()->facet_begin()) ); // nevermind the facet handle, it's not used anyway
FaceSegmentCollide::CollisionVector collisions;
FaceSegmentCollide cb(collisions);
CGAL::box_intersection_d( bbox.begin(), bbox.end(),
bboxes.begin(), bboxes.end(),
cb );
if ( !collisions.size() ){
// completely in or out, we just test one point
CGAL::Point_inside_polyhedron_3<MarkedPolyhedron, Kernel> is_in_poly( polyhedron );
if ( CGAL::ON_UNBOUNDED_SIDE == is_in_poly( triangle.vertex(0) ) ) *out++ = triangle;
}
else {
// now we first transform bboxes colliding faces into triangles
// then we test for intersection and store resulting segments in a vector
// we also store resulting polygons as segments
//
// we need to convert the resulting segments to a multipolygon of sort
//
// finally we triangulate the result and substract those triangles
//
std::vector< Triangle_3 > interTriangles;
collidingTriangles( collisions, std::back_inserter( interTriangles ) );
std::vector< Segment_3 > intersectionCountours;
BOOST_THROW_EXCEPTION(NotImplementedException("Triangle_3 - Volume is not implemented") );
}
return out;
*/
}
template < typename PolygonOutputIteratorType>
PolygonOutputIteratorType difference( const PolygonWH_2& a, const PolygonWH_2& b, PolygonOutputIteratorType out )
{
CGAL::Gps_segment_traits_2<Kernel> traits;
std::vector< PolygonWH_2 > temp;
CGAL::difference(
are_holes_and_boundary_pairwise_disjoint( a, traits ) ? a : fix_sfs_valid_polygon( a ),
are_holes_and_boundary_pairwise_disjoint( b, traits ) ? b : fix_sfs_valid_polygon( b ),
std::back_inserter( temp ) );
// polygon outer rings from difference can self intersect at points
// therefore we need to split the generated polygons so that they are valid for SFS
for ( std::vector< PolygonWH_2 >::const_iterator poly=temp.begin(); poly!=temp.end(); ++poly ) {
out = fix_cgal_valid_polygon( *poly, out );
}
return out;
}
}
}
#endif
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