// Computes the intersection C+uV of the planes M*x+D=0 and N*x+E=0.
// Returns -1 if there are no intersections (parallel), 0 for a line
// intersection and 1 for co-planarity.
// precondition: A, B are normalized (hessian form)
int plane_plane_intersection(const Vector_3& M, const double D,
const Vector_3& N, const double E,
Point_3& C, Vector_3& V)
{
typedef CGAL::Cartesian<double> K;
typedef CGAL::Plane_3<K> Plane_3;
typedef CGAL::Line_3<K> Line_3;
Plane_3 P1(M.x(), M.y(), M.z(), D);
Plane_3 P2(N.x(), N.y(), N.z(), E);
CGAL::Object result = CGAL::intersection(P1, P2);
if (const Line_3 *iline = CGAL::object_cast<Line_3>(&result)) {
CGAL::Point_3<K> p = iline->point(0);
CGAL::Vector_3<K> v = iline->to_vector();
C = Point_3(p.x(), p.y(), p.z());
V = Vector_3(v.x(), v.y(), v.z());
return 0;
}
else if (const Plane_3 *iplane = CGAL::object_cast<Plane_3>(&result)) {
return 1;
}
else {
return -1;
}
}
std::size_t hash_value(const CGAL::Point_3<Kernel>& point)
{
std::size_t seed = 0;
boost::hash_combine(seed, to_double(point.x()));
boost::hash_combine(seed, to_double(point.y()));
boost::hash_combine(seed, to_double(point.z()));
return seed;
}
bool MeshEx::findClosestIntersection( const math::Vec3f &position, const math::Vec3f &p1, const math::Vec3f &p2, math::Vec3f &intersection, math::Vec3f &normal, Triangle *&t )
{
int count = 0;
struct IntersectionHelper
{
IntersectionHelper( math::Vec3f intersection, Triangle *triangle, float sqDistance ) : m_intersection(intersection), m_triangle(triangle), m_sqDistance(sqDistance)
{
}
// used for sorting
bool operator<( const IntersectionHelper &rhs )
{
return m_sqDistance < rhs.m_sqDistance;
}
math::Vec3f m_intersection; // point of intersection
Triangle *m_triangle; // triangle in which the intersection point lies
float m_sqDistance; // distance to the near point
};
std::vector<IntersectionHelper> intersections;
// test every triangle (TODO: do some spatial subdivision)
for( std::vector<Triangle *>::iterator it = m_triangles.begin(); it != m_triangles.end(); ++it )
{
Triangle *tri = *it;
Triangle_3 cgalTri( Point_3(tri->v0->position), Point_3(tri->v1->position), Point_3(tri->v2->position) );
Segment_3 seg( Point_3(p1), Point_3(p2) );
if( CGAL::do_intersect( cgalTri, seg ) )
{
CGAL::Point_3<K> tempIntersection;
CGAL::Object o = CGAL::intersection(CGAL::Plane_3<K>( Point_3(tri->v0->position), Point_3(tri->v1->position), Point_3(tri->v2->position) ), seg);
if( CGAL::assign(tempIntersection, o) )
{
float sd = CGAL::squared_distance( Point_3(position), tempIntersection );
// intersection results in a point
intersections.push_back( IntersectionHelper( math::Vec3f(tempIntersection.x(), tempIntersection.y(), tempIntersection.z()), tri, sd ) );
}else
{
// segment!
printf( "error : intersection during vertex movement is a line\n" );
}
//printf( "intersection\n" );
}
}
// if we have found any intersection
if( intersections.size() )
{
std::sort( intersections.begin(), intersections.end() );
// find the closest one
intersection = intersections[0].m_intersection;
t = intersections[0].m_triangle;
normal = t->normal;
// and indicate success
return true;
}
return false;
}
