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Work around skip functor 

We cannot support a skip functor in ray_intersection and we have to work
around the issue of the ray starting inside a facet. To do that we shift
the source of the ray by the epsilon of a floating point number. We have
to consider if we really want to keep it that way.

Add assertions to make sure the new and old code give the same results.
This commit is contained in:
Philipp Möller 2015-11-11 10:59:46 +01:00 committed by Sébastien Loriot
parent 5f2ea0c9f4
commit de28e712f4
1 changed files with 26 additions and 11 deletions
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37
Surface_mesh_segmentation/include/CGAL/internal/Surface_mesh_segmentation/SDF_calculation.h
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@ -55,6 +55,12 @@ struct FirstIntersectionVisitor {
}
};
template<typename FT>
struct Epsilon {
static /* CGAL_CONSTEXPR */ FT epsilon() { return std::numeric_limits<double>::epsilon(); }
};
/**
* @brief Responsible for calculating Shape Diameter Function over surface of the mesh.
*
@ -305,15 +311,18 @@ public:
boost::tie(is_intersected, intersection_is_acute, min_distance, closest_id)
= cast_and_return_minimum_1(segment, skip, accept_if_acute);
} else {
Ray ray(center, ray_direction);
// shift the center along the normal by epsilon
Point center_shifted = translated_point_functor(center, scale_functor(ray_direction, internal::Epsilon<FT>::epsilon()));
Ray ray_1(center, ray_direction);
Ray ray_2(center_shifted, ray_direction);
if(traits.is_degenerate_3_object()(ray)) {
if(traits.is_degenerate_3_object()(ray_1) || traits.is_degenerate_3_object()(ray_2)) {
CGAL_warning(false &&
"A degenerate ray is constructed. Most probable reason is using CGAL_PI as cone_angle parameter and also picking center of disk as a sample.");
}
boost::tie(is_intersected, intersection_is_acute, min_distance, closest_id)
= cast_and_return_minimum(ray, skip, accept_if_acute);
= cast_and_return_minimum(ray_1, ray_2, skip, accept_if_acute);
}
if(!intersection_is_acute) {
@ -374,12 +383,14 @@ private:
template <class Query, class SkipPrimitiveFunctor> // Query can be templated for just Ray and Segment types.
boost::tuple<bool, bool, double, Primitive_id> cast_and_return_minimum(
const Query& query, SkipPrimitiveFunctor skip, bool accept_if_acute) const {
const Query& query_1, const Query& query_2, SkipPrimitiveFunctor skip, bool accept_if_acute) const {
boost::tuple<bool, bool, double, Primitive_id>
one = cast_and_return_minimum_1(query, skip, accept_if_acute);
one = cast_and_return_minimum_1(query_1, skip, accept_if_acute);
boost::tuple<bool, bool, double, Primitive_id>
two = cast_and_return_minimum_2(query, skip, accept_if_acute);
(void)one;(void)two;
two = cast_and_return_minimum_2(query_2, skip, accept_if_acute);
assert(boost::get<3>(one) == boost::get<3>(two));
assert(boost::get<0>(one) == boost::get<0>(two));
assert(boost::get<1>(one) == boost::get<1>(two));
return one;
}
@ -460,19 +471,22 @@ private:
return min_distance;
}
template <class Query, class SkipPrimitiveFunctor> // Query can be templated for just Ray and Segment types.
template <class SkipPrimitiveFunctor>
boost::tuple<bool, bool, double, Primitive_id> cast_and_return_minimum_2(
const Query& query, SkipPrimitiveFunctor, bool accept_if_acute) const {
const Ray& query, SkipPrimitiveFunctor /* skip*/, bool accept_if_acute) const {
boost::tuple<bool, bool, double, Primitive_id>
min_distance(false, false, 0.0, Primitive_id());
boost::optional< typename Tree::template Intersection_and_primitive_id<Query>::Type >
boost::optional< typename Tree::template Intersection_and_primitive_id<Ray>::Type >
min_intersection = tree.ray_intersection(query);
if(!min_intersection)
return min_distance;
min_distance.template get<0>() = true;
min_distance.template get<3>() = min_intersection->second;
Vector min_i_ray(NULL_VECTOR);
Primitive_id min_id(min_intersection->second);
Primitive_id& min_id = min_distance.template get<3>();
if(const Point* i_point = boost::get<const Point>(&(min_intersection->first))) {
min_i_ray = Vector(*i_point, query.source());
@ -497,6 +511,7 @@ private:
min_distance.template get<1>() = true; // founded intersection is acceptable.
min_distance.template get<2>() = std::sqrt(min_distance.template get<2>());
return min_distance;
}