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[buffer] add cheap check using the new robust_offsetted_envelope

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This safes about 1% performance
It is only applicable for convex joins, we will add this distinction later
(currently all joins are convex)
This commit is contained in:
Barend Gehrels
2014-11-23 12:57:50 +01:00
parent bbc8c605e6
commit 899f308890
1 changed files with 36 additions and 11 deletions
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47
include/boost/geometry/algorithms/detail/buffer/turn_in_piece_visitor.hpp
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@@ -139,7 +139,7 @@ class analyse_turn_wrt_piece
template <typename Point>
static inline analyse_result check_helper_segment(Point const& s1,
Point const& s2, Point const& point,
analyse_result return_if_collinear,
bool is_original,
Point const& offsetted)
{
typedef typename strategy::side::services::default_strategy
@@ -164,7 +164,7 @@ class analyse_turn_wrt_piece
if (geometry::covered_by(point, box))
{
// It is on the segment
if (return_if_collinear == analyse_within
if (! is_original
&& geometry::comparable_distance(point, offsetted) <= 1)
{
// It is close to the offsetted-boundary, take
@@ -172,11 +172,18 @@ class analyse_turn_wrt_piece
return analyse_near_offsetted;
}
return return_if_collinear;
// Points on helper-segments are considered as within
// Points on original boundary are processed differently
return is_original
? analyse_on_original_boundary
: analyse_within;
}
// It is not on the segment
return analyse_continue;
// It is collinear but not on the segment. Because these
// segments are convex, it is outside
// Unless the offsetted ring is collinear or concave w.r.t.
// helper-segment but that scenario is not yet supported
return analyse_disjoint;
}
break;
}
@@ -226,18 +233,18 @@ class analyse_turn_wrt_piece
return analyse_on_original_boundary;
}
// Right side
// Right side of the piece
analyse_result result
= check_helper_segment(points[0], points[1], point,
analyse_within, points[0]);
false, points[0]);
if (result != analyse_continue)
{
return result;
}
// Left side
// Left side of the piece
result = check_helper_segment(points[2], points[3], point,
analyse_within, points[3]);
false, points[3]);
if (result != analyse_continue)
{
return result;
@@ -245,15 +252,33 @@ class analyse_turn_wrt_piece
if (! comparator(points[1], points[2]))
{
// Side at original
// Side of the piece at side of original geometry
result = check_helper_segment(points[1], points[2], point,
analyse_on_original_boundary, point);
true, point);
if (result != analyse_continue)
{
return result;
}
}
// We are within the \/ or |_| shaped piece, where the top is the
// offsetted ring.
if (! geometry::covered_by(point, piece.robust_offsetted_envelope))
{
// Not in offsetted-area. This makes a cheap check possible
typedef typename strategy::side::services::default_strategy
<
typename cs_tag<Point>::type
>::type side_strategy;
switch(side_strategy::apply(points[3], points[0], point))
{
case 1 : return analyse_disjoint;
case -1 : return analyse_within;
case 0 : return analyse_disjoint;
}
}
return analyse_continue;
}