tippecanoe/mapbox/geometry/wagyu/intersect_util.hpp
2018-07-31 17:47:52 -07:00

373 lines
12 KiB
C++

#pragma once
#include <mapbox/geometry/wagyu/active_bound_list.hpp>
#include <mapbox/geometry/wagyu/bound.hpp>
#include <mapbox/geometry/wagyu/bubble_sort.hpp>
#include <mapbox/geometry/wagyu/config.hpp>
#include <mapbox/geometry/wagyu/intersect.hpp>
#include <mapbox/geometry/wagyu/ring_util.hpp>
#include <mapbox/geometry/wagyu/util.hpp>
#include <algorithm>
namespace mapbox {
namespace geometry {
namespace wagyu {
template <typename T>
struct intersect_list_sorter {
inline bool operator()(intersect_node<T> const& node1, intersect_node<T> const& node2) {
if (!values_are_equal(node2.pt.y, node1.pt.y)) {
return node2.pt.y < node1.pt.y;
} else {
return (node2.bound1->winding_count2 + node2.bound2->winding_count2) >
(node1.bound1->winding_count2 + node1.bound2->winding_count2);
}
}
};
template <typename T>
inline mapbox::geometry::point<T> round_point(mapbox::geometry::point<double> const& pt) {
return mapbox::geometry::point<T>(round_towards_max<T>(pt.x), round_towards_max<T>(pt.y));
}
template <typename T>
inline void swap_rings(bound<T>& b1, bound<T>& b2) {
ring_ptr<T> ring = b1.ring;
b1.ring = b2.ring;
b2.ring = ring;
}
template <typename T>
inline void swap_sides(bound<T>& b1, bound<T>& b2) {
edge_side side = b1.side;
b1.side = b2.side;
b2.side = side;
}
template <typename T1, typename T2>
bool get_edge_intersection(edge<T1> const& e1,
edge<T1> const& e2,
mapbox::geometry::point<T2>& pt) {
T2 p0_x = static_cast<T2>(e1.bot.x);
T2 p0_y = static_cast<T2>(e1.bot.y);
T2 p1_x = static_cast<T2>(e1.top.x);
T2 p1_y = static_cast<T2>(e1.top.y);
T2 p2_x = static_cast<T2>(e2.bot.x);
T2 p2_y = static_cast<T2>(e2.bot.y);
T2 p3_x = static_cast<T2>(e2.top.x);
T2 p3_y = static_cast<T2>(e2.top.y);
T2 s1_x, s1_y, s2_x, s2_y;
s1_x = p1_x - p0_x;
s1_y = p1_y - p0_y;
s2_x = p3_x - p2_x;
s2_y = p3_y - p2_y;
T2 s = (-s1_y * (p0_x - p2_x) + s1_x * (p0_y - p2_y)) / (-s2_x * s1_y + s1_x * s2_y);
T2 t = (s2_x * (p0_y - p2_y) - s2_y * (p0_x - p2_x)) / (-s2_x * s1_y + s1_x * s2_y);
if (s >= 0.0 && s <= 1.0 && t >= 0.0 && t <= 1.0) {
pt.x = p0_x + (t * s1_x);
pt.y = p0_y + (t * s1_y);
return true;
}
// LCOV_EXCL_START
return false;
// LCOV_EXCL_END
}
template <typename T>
struct intersection_compare {
bool operator()(bound_ptr<T> const& b1, bound_ptr<T> const& b2) {
return !(b1->current_x > b2->current_x &&
!slopes_equal(*(b1->current_edge), *(b2->current_edge)));
}
};
template <typename T>
struct on_intersection_swap {
intersect_list<T>& intersects;
on_intersection_swap(intersect_list<T>& i) : intersects(i) {
}
void operator()(bound_ptr<T> const& b1, bound_ptr<T> const& b2) {
mapbox::geometry::point<double> pt;
if (!get_edge_intersection<T, double>(*(b1->current_edge), *(b2->current_edge), pt)) {
// LCOV_EXCL_START
throw std::runtime_error("Trying to find intersection of lines that do not intersect");
// LCOV_EXCL_END
}
intersects.emplace_back(b1, b2, pt);
}
};
template <typename T>
void build_intersect_list(active_bound_list<T>& active_bounds, intersect_list<T>& intersects) {
bubble_sort(active_bounds.begin(), active_bounds.end(), intersection_compare<T>(),
on_intersection_swap<T>(intersects));
}
template <typename T>
void intersect_bounds(bound<T>& b1,
bound<T>& b2,
mapbox::geometry::point<T> const& pt,
clip_type cliptype,
fill_type subject_fill_type,
fill_type clip_fill_type,
ring_manager<T>& rings,
active_bound_list<T>& active_bounds) {
bool b1Contributing = (b1.ring != nullptr);
bool b2Contributing = (b2.ring != nullptr);
// update winding counts...
// assumes that b1 will be to the Right of b2 ABOVE the intersection
if (b1.poly_type == b2.poly_type) {
if (is_even_odd_fill_type(b1, subject_fill_type, clip_fill_type)) {
std::swap(b1.winding_count, b2.winding_count);
} else {
if (b1.winding_count + b2.winding_delta == 0) {
b1.winding_count = -b1.winding_count;
} else {
b1.winding_count += b2.winding_delta;
}
if (b2.winding_count - b1.winding_delta == 0) {
b2.winding_count = -b2.winding_count;
} else {
b2.winding_count -= b1.winding_delta;
}
}
} else {
if (!is_even_odd_fill_type(b2, subject_fill_type, clip_fill_type)) {
b1.winding_count2 += b2.winding_delta;
} else {
b1.winding_count2 = (b1.winding_count2 == 0) ? 1 : 0;
}
if (!is_even_odd_fill_type(b1, subject_fill_type, clip_fill_type)) {
b2.winding_count2 -= b1.winding_delta;
} else {
b2.winding_count2 = (b2.winding_count2 == 0) ? 1 : 0;
}
}
fill_type b1FillType, b2FillType, b1FillType2, b2FillType2;
if (b1.poly_type == polygon_type_subject) {
b1FillType = subject_fill_type;
b1FillType2 = clip_fill_type;
} else {
b1FillType = clip_fill_type;
b1FillType2 = subject_fill_type;
}
if (b2.poly_type == polygon_type_subject) {
b2FillType = subject_fill_type;
b2FillType2 = clip_fill_type;
} else {
b2FillType = clip_fill_type;
b2FillType2 = subject_fill_type;
}
std::int32_t b1Wc, b2Wc;
switch (b1FillType) {
case fill_type_positive:
b1Wc = b1.winding_count;
break;
case fill_type_negative:
b1Wc = -b1.winding_count;
break;
case fill_type_even_odd:
case fill_type_non_zero:
default:
b1Wc = std::abs(static_cast<int>(b1.winding_count));
}
switch (b2FillType) {
case fill_type_positive:
b2Wc = b2.winding_count;
break;
case fill_type_negative:
b2Wc = -b2.winding_count;
break;
case fill_type_even_odd:
case fill_type_non_zero:
default:
b2Wc = std::abs(static_cast<int>(b2.winding_count));
}
if (b1Contributing && b2Contributing) {
if ((b1Wc != 0 && b1Wc != 1) || (b2Wc != 0 && b2Wc != 1) ||
(b1.poly_type != b2.poly_type && cliptype != clip_type_x_or)) {
add_local_maximum_point(b1, b2, pt, rings, active_bounds);
} else {
add_point(b1, active_bounds, pt, rings);
add_point(b2, active_bounds, pt, rings);
swap_sides(b1, b2);
swap_rings(b1, b2);
}
} else if (b1Contributing) {
if (b2Wc == 0 || b2Wc == 1) {
add_point(b1, active_bounds, pt, rings);
b2.last_point = pt;
swap_sides(b1, b2);
swap_rings(b1, b2);
}
} else if (b2Contributing) {
if (b1Wc == 0 || b1Wc == 1) {
b1.last_point = pt;
add_point(b2, active_bounds, pt, rings);
swap_sides(b1, b2);
swap_rings(b1, b2);
}
} else if ((b1Wc == 0 || b1Wc == 1) && (b2Wc == 0 || b2Wc == 1)) {
// neither bound is currently contributing ...
std::int32_t b1Wc2, b2Wc2;
switch (b1FillType2) {
case fill_type_positive:
b1Wc2 = b1.winding_count2;
break;
case fill_type_negative:
b1Wc2 = -b1.winding_count2;
break;
case fill_type_even_odd:
case fill_type_non_zero:
default:
b1Wc2 = std::abs(static_cast<int>(b1.winding_count2));
}
switch (b2FillType2) {
case fill_type_positive:
b2Wc2 = b2.winding_count2;
break;
case fill_type_negative:
b2Wc2 = -b2.winding_count2;
break;
case fill_type_even_odd:
case fill_type_non_zero:
default:
b2Wc2 = std::abs(static_cast<int>(b2.winding_count2));
}
if (b1.poly_type != b2.poly_type) {
add_local_minimum_point(b1, b2, active_bounds, pt, rings);
} else if (b1Wc == 1 && b2Wc == 1) {
switch (cliptype) {
case clip_type_intersection:
if (b1Wc2 > 0 && b2Wc2 > 0) {
add_local_minimum_point(b1, b2, active_bounds, pt, rings);
}
break;
default:
case clip_type_union:
if (b1Wc2 <= 0 && b2Wc2 <= 0) {
add_local_minimum_point(b1, b2, active_bounds, pt, rings);
}
break;
case clip_type_difference:
if (((b1.poly_type == polygon_type_clip) && (b1Wc2 > 0) && (b2Wc2 > 0)) ||
((b1.poly_type == polygon_type_subject) && (b1Wc2 <= 0) && (b2Wc2 <= 0))) {
add_local_minimum_point(b1, b2, active_bounds, pt, rings);
}
break;
case clip_type_x_or:
add_local_minimum_point(b1, b2, active_bounds, pt, rings);
}
} else {
swap_sides(b1, b2);
}
}
}
template <typename T>
bool bounds_adjacent(intersect_node<T> const& inode, bound_ptr<T> next) {
return (next == inode.bound2) || (next == inode.bound1);
}
template <typename T>
struct find_first_bound {
bound_ptr<T> b1;
bound_ptr<T> b2;
find_first_bound(intersect_node<T> const& inode) : b1(inode.bound1), b2(inode.bound2) {
}
bool operator()(bound_ptr<T> const& b) {
return b == b1 || b == b2;
}
};
template <typename T>
void process_intersect_list(intersect_list<T>& intersects,
clip_type cliptype,
fill_type subject_fill_type,
fill_type clip_fill_type,
ring_manager<T>& rings,
active_bound_list<T>& active_bounds) {
for (auto node_itr = intersects.begin(); node_itr != intersects.end(); ++node_itr) {
auto b1 = std::find_if(active_bounds.begin(), active_bounds.end(),
find_first_bound<T>(*node_itr));
auto b2 = std::next(b1);
if (!bounds_adjacent(*node_itr, *b2)) {
auto next_itr = std::next(node_itr);
while (next_itr != intersects.end()) {
auto n1 = std::find_if(active_bounds.begin(), active_bounds.end(),
find_first_bound<T>(*next_itr));
auto n2 = std::next(n1);
if (bounds_adjacent(*next_itr, *n2)) {
b1 = n1;
b2 = n2;
break;
}
++next_itr;
}
if (next_itr == intersects.end()) {
throw std::runtime_error("Could not properly correct intersection order.");
}
std::iter_swap(node_itr, next_itr);
}
mapbox::geometry::point<T> pt = round_point<T>(node_itr->pt);
intersect_bounds(*(node_itr->bound1), *(node_itr->bound2), pt, cliptype, subject_fill_type,
clip_fill_type, rings, active_bounds);
std::iter_swap(b1, b2);
}
}
template <typename T>
void update_current_x(active_bound_list<T>& active_bounds, T top_y) {
std::size_t pos = 0;
for (auto& bnd : active_bounds) {
bnd->pos = pos++;
bnd->current_x = get_current_x(*bnd->current_edge, top_y);
}
}
template <typename T>
void process_intersections(T top_y,
active_bound_list<T>& active_bounds,
clip_type cliptype,
fill_type subject_fill_type,
fill_type clip_fill_type,
ring_manager<T>& rings) {
if (active_bounds.empty()) {
return;
}
update_current_x(active_bounds, top_y);
intersect_list<T> intersects;
build_intersect_list(active_bounds, intersects);
if (intersects.empty()) {
return;
}
// Restore order of active bounds list
std::stable_sort(
active_bounds.begin(), active_bounds.end(),
[](bound_ptr<T> const& b1, bound_ptr<T> const& b2) { return b1->pos < b2->pos; });
// Sort the intersection list
std::stable_sort(intersects.begin(), intersects.end(), intersect_list_sorter<T>());
process_intersect_list(intersects, cliptype, subject_fill_type, clip_fill_type, rings,
active_bounds);
}
}
}
}