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This commit is contained in:
Sébastien Loriot 2023-06-06 15:31:19 +02:00
parent 3d6c0da44c
commit 854aacd671
1 changed files with 31 additions and 17 deletions
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48
Intersections_3/include/CGAL/Intersections_3/internal/Triangle_3_Triangle_3_intersection.h
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@ -59,6 +59,19 @@ coplanar_segment_segment_alpha_intersection(const typename K::Point_3& p1, const
template <class Kernel>
struct Point_on_triangle
{
// triangle points are not stored in this class but are expected
// to always be passed in the same order. For a triangle pqr,
// edge 0 is pq, edge 1 qr and edge 2 rp. Point 0 is p, 1 is q and 2 is r.
//
// (id, -1) point on t1
// (-1, id) point on t2
// (id1, id2) intersection of edges
std::pair<int, int> t1_t2_ids;
boost::container::flat_set<int> extra_t1; // store other ids of edges containing the point
typename Kernel::FT alpha; //
//////
static
inline
const typename Kernel::Point_3&
@ -83,13 +96,7 @@ struct Point_on_triangle
, alpha(alpha)
{}
// (id, -1) point on t1
// (-1, id) point on t2
// (id1, id2) intersection of edges
std::pair<int, int> t1_t2_ids;
boost::container::flat_set<int> extra_t1;
typename Kernel::FT alpha;
// orientation of the current point wrt to edge id1 (p1q1)
Orientation
orientation (const typename Kernel::Point_3& p1, // source of edge edge_id1
const typename Kernel::Point_3& q1, // target of edge edge_id1
@ -116,7 +123,7 @@ struct Point_on_triangle
CGAL_assertion((t1_t2_ids.first+1)%3==edge_id1);
if (alpha==1) return ZERO;
return alpha<=1?POSITIVE:NEGATIVE;
}
}
else
{
//this is an input point of t2
@ -129,6 +136,7 @@ struct Point_on_triangle
int id1() const { return t1_t2_ids.first; }
int id2() const { return t1_t2_ids.second; }
// construct the intersection point from the info stored
typename Kernel::Point_3
point(const typename Kernel::Point_3& p1,
const typename Kernel::Point_3& q1,
@ -147,6 +155,12 @@ struct Point_on_triangle
}
};
// the intersection of two triangles is computed by interatively intersection t2
// with halfspaces defined by edges of t1. The following function is called
// for each each on t1 on edge of the current intersection.
// pq is such an edge and p1q1 from t1 defines the halfspace intersection
// we are currently interseted in. We return the intersection point of
// pq with p1q1
template <class Kernel>
Point_on_triangle<Kernel>
intersection(const Point_on_triangle<Kernel>& p,
@ -172,7 +186,7 @@ intersection(const Point_on_triangle<Kernel>& p,
{
switch(q.id1())
{
case -1: // (-1, ip2) - (-1, iq2)
case -1: // A: (-1, ip2) - (-1, iq2)
{
CGAL_assertion((p.id2()+1)%3 == q.id2() || (q.id2()+1)%3 == p.id2());
// CGAL_assertion(p.extra_t1.empty() && q.extra_t1.empty()); // TMP to see if it's worth implementing special case
@ -187,7 +201,7 @@ intersection(const Point_on_triangle<Kernel>& p,
return Point_on_triangle<Kernel>(edge_id_t1, id2, alpha); // intersection with an original edge of t2
}
default:
if (q.id2()!=-1) // (-1, ip2) - (iq1, iq2)
if (q.id2()!=-1) // B: (-1, ip2) - (iq1, iq2)
{
if (p.id2() == q.id2() || p.id2() == (q.id2()+1)%3)
{
@ -210,7 +224,7 @@ intersection(const Point_on_triangle<Kernel>& p,
int eid1 = p.extra_t1.count(q.id1())!=0 ? q.id1() : 3-q.id1()-edge_id_t1;
return Point_on_triangle<Kernel>((eid1+1)%3==edge_id_t1?edge_id_t1:(edge_id_t1+1)%3, -1); // vertex of t1
}
// (-1, ip2) - (iq1, -1)
// C: (-1, ip2) - (iq1, -1)
//vertex of t1, special case t1 edge passed thru a vertex of t2
CGAL_assertion(edge_id_t1 == 2);
#ifdef CGAL_DEBUG_COPLANAR_T3_T3_INTERSECTION
@ -229,7 +243,7 @@ intersection(const Point_on_triangle<Kernel>& p,
{
switch(q.id1())
{
case -1: // (ip1, -1) - (-1, iq2)
case -1: // G: (ip1, -1) - (-1, iq2)
//vertex of t1, special case t1 edge passed thru a vertex of t2
#ifdef CGAL_DEBUG_COPLANAR_T3_T3_INTERSECTION
std::cout << " -- case 5\n";
@ -243,8 +257,8 @@ intersection(const Point_on_triangle<Kernel>& p,
#ifdef CGAL_DEBUG_COPLANAR_T3_T3_INTERSECTION
std::cout << " -- case 6\n";
#endif
CGAL_assertion(q.id2()!=-1); // (ip1, -1) - (iq2, -1)
//(ip1,-1), (iq1, iq2)
CGAL_assertion(q.id2()!=-1); // I: (ip1, -1) - (iq2, -1)
//H: (ip1,-1), (iq1, iq2)
CGAL_assertion(edge_id_t1==2);
// p and q are on the same edge of t1
CGAL_assertion(p.id1()==q.id1() || p.id1()==(q.id1()+1)%3);
@ -256,7 +270,7 @@ intersection(const Point_on_triangle<Kernel>& p,
{
switch(q.id1())
{
case -1: // (ip1, ip2) - (-1, iq2)
case -1: // D: (ip1, ip2) - (-1, iq2)
{
if (q.id2() == p.id2() || q.id2() == (p.id2()+1)%3)
{
@ -284,7 +298,7 @@ intersection(const Point_on_triangle<Kernel>& p,
{
switch(q.id2())
{
case -1: // (ip1, ip2) - (iq1, -1)
case -1: // F: (ip1, ip2) - (iq1, -1)
{
// p and q are on the same edge of t1
CGAL_assertion(q.id1()==p.id1() || q.id1()==(p.id1()+1)%3);
@ -293,7 +307,7 @@ intersection(const Point_on_triangle<Kernel>& p,
#endif
return Point_on_triangle<Kernel>((p.id1()+1)%3==edge_id_t1?edge_id_t1:(edge_id_t1+1)%3 , -1);
}
default: // (ip1, ip2) - (iq1, iq2)
default: // E: (ip1, ip2) - (iq1, iq2)
{
if (p.id2()==q.id2())
{