diff options
Diffstat (limited to 'boost/geometry/algorithms/detail/overlay/get_turn_info.hpp')
| -rw-r--r-- | boost/geometry/algorithms/detail/overlay/get_turn_info.hpp | 204 |
1 files changed, 171 insertions, 33 deletions
diff --git a/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp b/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp index 663d70d9af..b8320d9b7b 100644 --- a/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp +++ b/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp @@ -250,9 +250,15 @@ struct touch : public base_turn_handler int const side_pk_q2 = SideStrategy::apply(qj, qk, pk); int const side_pk_p = SideStrategy::apply(pi, pj, pk); int const side_qk_q = SideStrategy::apply(qi, qj, qk); + + bool const both_continue = side_pk_p == 0 && side_qk_q == 0; + bool const robustness_issue_in_continue = both_continue && side_pk_q2 != 0; + bool const q_turns_left = side_qk_q == 1; bool const block_q = side_qk_p1 == 0 - && ! same(side_qi_p1, side_qk_q); + && ! same(side_qi_p1, side_qk_q) + && ! robustness_issue_in_continue + ; // If Pk at same side as Qi/Qk // (the "or" is for collinear case) @@ -278,7 +284,7 @@ struct touch : public base_turn_handler if (side_pk_q1 == 0) { ti.operations[0].operation = operation_blocked; - // Q turns right -> union (both independant), + // Q turns right -> union (both independent), // Q turns left -> intersection ti.operations[1].operation = block_q ? operation_blocked : q_turns_left ? operation_intersection @@ -466,6 +472,45 @@ struct equal : public base_turn_handler template < typename TurnInfo, + typename AssignPolicy +> +struct equal_opposite : public base_turn_handler +{ + template + < + typename Point1, + typename Point2, + typename OutputIterator, + typename IntersectionInfo, + typename DirInfo + > + static inline void apply(Point1 const& pi, Point2 const& qi, + /* by value: */ TurnInfo tp, + OutputIterator& out, + IntersectionInfo const& intersection_info, + DirInfo const& dir_info) + { + // For equal-opposite segments, normally don't do anything. + if (AssignPolicy::include_opposite) + { + tp.method = method_equal; + for (int i = 0; i < 2; i++) + { + tp.operations[i].operation = operation_opposite; + } + for (unsigned int i = 0; i < intersection_info.count; i++) + { + geometry::convert(intersection_info.intersections[i], tp.point); + AssignPolicy::apply(tp, pi, qi, intersection_info, dir_info); + *out++ = tp; + } + } + } +}; + +template +< + typename TurnInfo, typename SideStrategy > struct collinear : public base_turn_handler @@ -494,6 +539,13 @@ struct collinear : public base_turn_handler - if P arrives and P turns right: intersection for P - if Q arrives and Q turns left: union for Q (=intersection for P) - if Q arrives and Q turns right: intersection for Q (=union for P) + + ROBUSTNESS: p and q are collinear, so you would expect + that side qk//p1 == pk//q1. But that is not always the case + in near-epsilon ranges. Then decision logic is different. + If p arrives, q is further, so the angle qk//p1 is (normally) + more precise than pk//p1 + */ template < @@ -516,12 +568,18 @@ struct collinear : public base_turn_handler // Should not be 0, this is checked before BOOST_ASSERT(arrival != 0); + int const side_p = SideStrategy::apply(pi, pj, pk); + int const side_q = SideStrategy::apply(qi, qj, qk); + // If p arrives, use p, else use q int const side_p_or_q = arrival == 1 - ? SideStrategy::apply(pi, pj, pk) - : SideStrategy::apply(qi, qj, qk) + ? side_p + : side_q ; + int const side_pk = SideStrategy::apply(qi, qj, pk); + int const side_qk = SideStrategy::apply(pi, pj, qk); + // See comments above, // resulting in a strange sort of mathematic rule here: // The arrival-info multiplied by the relevant side @@ -529,7 +587,15 @@ struct collinear : public base_turn_handler int const product = arrival * side_p_or_q; - if(product == 0) + // Robustness: side_p is supposed to be equal to side_pk (because p/q are collinear) + // and side_q to side_qk + bool const robustness_issue = side_pk != side_p || side_qk != side_q; + + if (robustness_issue) + { + handle_robustness(ti, arrival, side_p, side_q, side_pk, side_qk); + } + else if(product == 0) { both(ti, operation_continue); } @@ -538,6 +604,38 @@ struct collinear : public base_turn_handler ui_else_iu(product == 1, ti); } } + + static inline void handle_robustness(TurnInfo& ti, int arrival, + int side_p, int side_q, int side_pk, int side_qk) + { + // We take the longer one, i.e. if q arrives in p (arrival == -1), + // then p exceeds q and we should take p for a union... + + bool use_p_for_union = arrival == -1; + + // ... unless one of the sides consistently directs to the other side + int const consistent_side_p = side_p == side_pk ? side_p : 0; + int const consistent_side_q = side_q == side_qk ? side_q : 0; + if (arrival == -1 && (consistent_side_p == -1 || consistent_side_q == 1)) + { + use_p_for_union = false; + } + if (arrival == 1 && (consistent_side_p == 1 || consistent_side_q == -1)) + { + use_p_for_union = true; + } + + //std::cout << "ROBUSTNESS -> Collinear " + // << " arr: " << arrival + // << " dir: " << side_p << " " << side_q + // << " rev: " << side_pk << " " << side_qk + // << " cst: " << cside_p << " " << cside_q + // << std::boolalpha << " " << use_p_for_union + // << std::endl; + + ui_else_iu(use_p_for_union, ti); + } + }; template @@ -583,6 +681,7 @@ private : TurnInfo& tp, IntersectionInfo const& intersection_info) { int const side_rk_r = SideStrategy::apply(ri, rj, rk); + operation_type blocked = operation_blocked; switch(side_rk_r) { @@ -596,15 +695,24 @@ private : break; case 0 : // No turn on opposite collinear: block, do not traverse - // But this "xx" is ignored here, it is useless to include - // two operation blocked, so the whole point does not need + // But this "xx" is usually ignored, it is useless to include + // two operations blocked, so the whole point does not need // to be generated. // So return false to indicate nothing is to be done. - return false; + if (AssignPolicy::include_opposite) + { + tp.operations[Index].operation = operation_opposite; + blocked = operation_opposite; + } + else + { + return false; + } + break; } // The other direction is always blocked when collinear opposite - tp.operations[1 - Index].operation = operation_blocked; + tp.operations[1 - Index].operation = blocked; // If P arrives within Q, set info on P (which is done above, index=0), // this turn-info belongs to the second intersection point, index=1 @@ -633,32 +741,45 @@ public: IntersectionInfo const& intersection_info, DirInfo const& dir_info) { - /* - std::cout << "arrivals: " - << dir_info.arrival[0] - << "/" << dir_info.arrival[1] - << std::endl; - */ - TurnInfo tp = tp_model; tp.method = method_collinear; - // If P arrives within Q, there is a turn dependant on P + // If P arrives within Q, there is a turn dependent on P if (dir_info.arrival[0] == 1 && set_tp<0>(pi, pj, pk, tp, intersection_info)) { - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, intersection_info, dir_info); *out++ = tp; } - // If Q arrives within P, there is a turn dependant on Q + // If Q arrives within P, there is a turn dependent on Q if (dir_info.arrival[1] == 1 && set_tp<1>(qi, qj, qk, tp, intersection_info)) { - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, intersection_info, dir_info); *out++ = tp; } + + if (AssignPolicy::include_opposite) + { + // Handle cases not yet handled above + if ((dir_info.arrival[1] == -1 && dir_info.arrival[0] == 0) + || (dir_info.arrival[0] == -1 && dir_info.arrival[1] == 0)) + { + for (int i = 0; i < 2; i++) + { + tp.operations[i].operation = operation_opposite; + } + for (unsigned int i = 0; i < intersection_info.count; i++) + { + geometry::convert(intersection_info.intersections[i], tp.point); + AssignPolicy::apply(tp, pi, qi, intersection_info, dir_info); + *out++ = tp; + } + } + } + } }; @@ -722,9 +843,17 @@ struct assign_null_policy { static bool const include_no_turn = false; static bool const include_degenerate = false; - - template <typename Point1, typename Point2, typename Info> - static inline void apply(Info& , Point1 const& , Point2 const& ) + static bool const include_opposite = false; + + template + < + typename Info, + typename Point1, + typename Point2, + typename IntersectionInfo, + typename DirInfo + > + static inline void apply(Info& , Point1 const& , Point2 const&, IntersectionInfo const&, DirInfo const&) {} }; @@ -763,8 +892,9 @@ struct get_turn_info typedef typename si::segment_intersection_strategy_type strategy; - - + // Intersect pi-pj with qi-qj + // The points pk and qk are only used do determine more information + // about the turn. template <typename OutputIterator> static inline OutputIterator apply( Point1 const& pi, Point1 const& pj, Point1 const& pk, @@ -796,7 +926,7 @@ struct get_turn_info { only_convert<TurnInfo>::apply(tp, result.template get<0>()); - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } break; @@ -824,7 +954,7 @@ struct get_turn_info policy::template apply<1>(qi, qj, qk, pi, pj, pk, tp, result.template get<0>(), result.template get<1>()); } - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } break; @@ -838,7 +968,7 @@ struct get_turn_info policy::apply(pi, pj, pk, qi, qj, qk, tp, result.template get<0>(), result.template get<1>()); - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } break; @@ -853,7 +983,7 @@ struct get_turn_info policy::apply(pi, pj, pk, qi, qj, qk, tp, result.template get<0>(), result.template get<1>()); - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } break; @@ -871,10 +1001,18 @@ struct get_turn_info policy::apply(pi, pj, pk, qi, qj, qk, tp, result.template get<0>(), result.template get<1>()); - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } - // If they ARE opposite, don't do anything. + else + { + equal_opposite + < + TurnInfo, + AssignPolicy + >::apply(pi, qi, + tp, out, result.template get<0>(), result.template get<1>()); + } } break; case 'c' : @@ -906,7 +1044,7 @@ struct get_turn_info tp, result.template get<0>(), result.template get<1>()); } - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } else @@ -927,7 +1065,7 @@ struct get_turn_info if (AssignPolicy::include_degenerate) { only_convert<TurnInfo>::apply(tp, result.template get<0>()); - AssignPolicy::apply(tp, pi, qi); + AssignPolicy::apply(tp, pi, qi, result.template get<0>(), result.template get<1>()); *out++ = tp; } } |