godot/modules/gdnavigation/nav_map.cpp

781 lines
25 KiB
C++

/*************************************************************************/
/* nav_map.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/*************************************************************************/
#include "nav_map.h"
#include "core/os/threaded_array_processor.h"
#include "nav_region.h"
#include "rvo_agent.h"
#include <algorithm>
/**
@author AndreaCatania
*/
#define USE_ENTRY_POINT
void NavMap::set_up(Vector3 p_up) {
up = p_up;
regenerate_polygons = true;
}
void NavMap::set_cell_size(float p_cell_size) {
cell_size = p_cell_size;
regenerate_polygons = true;
}
void NavMap::set_edge_connection_margin(float p_edge_connection_margin) {
edge_connection_margin = p_edge_connection_margin;
regenerate_links = true;
}
gd::PointKey NavMap::get_point_key(const Vector3 &p_pos) const {
const int x = int(Math::floor(p_pos.x / cell_size));
const int y = int(Math::floor(p_pos.y / cell_size));
const int z = int(Math::floor(p_pos.z / cell_size));
gd::PointKey p;
p.key = 0;
p.x = x;
p.y = y;
p.z = z;
return p;
}
Vector<Vector3> NavMap::get_path(Vector3 p_origin, Vector3 p_destination, bool p_optimize) const {
const gd::Polygon *begin_poly = nullptr;
const gd::Polygon *end_poly = nullptr;
Vector3 begin_point;
Vector3 end_point;
float begin_d = 1e20;
float end_d = 1e20;
// Find the initial poly and the end poly on this map.
for (size_t i(0); i < polygons.size(); i++) {
const gd::Polygon &p = polygons[i];
// For each point cast a face and check the distance between the origin/destination
for (size_t point_id = 2; point_id < p.points.size(); point_id++) {
Face3 f(p.points[point_id - 2].pos, p.points[point_id - 1].pos, p.points[point_id].pos);
Vector3 spoint = f.get_closest_point_to(p_origin);
float dpoint = spoint.distance_to(p_origin);
if (dpoint < begin_d) {
begin_d = dpoint;
begin_poly = &p;
begin_point = spoint;
}
spoint = f.get_closest_point_to(p_destination);
dpoint = spoint.distance_to(p_destination);
if (dpoint < end_d) {
end_d = dpoint;
end_poly = &p;
end_point = spoint;
}
}
}
if (!begin_poly || !end_poly) {
// No path
return Vector<Vector3>();
}
if (begin_poly == end_poly) {
Vector<Vector3> path;
path.resize(2);
path.write[0] = begin_point;
path.write[1] = end_point;
return path;
}
std::vector<gd::NavigationPoly> navigation_polys;
navigation_polys.reserve(polygons.size() * 0.75);
// The elements indices in the `navigation_polys`.
int least_cost_id(-1);
List<uint32_t> open_list;
bool found_route = false;
navigation_polys.push_back(gd::NavigationPoly(begin_poly));
{
least_cost_id = 0;
gd::NavigationPoly *least_cost_poly = &navigation_polys[least_cost_id];
least_cost_poly->self_id = least_cost_id;
least_cost_poly->entry = begin_point;
}
open_list.push_back(0);
const gd::Polygon *reachable_end = nullptr;
float reachable_d = 1e30;
bool is_reachable = true;
while (found_route == false) {
{
// Takes the current least_cost_poly neighbors and compute the traveled_distance of each
for (size_t i = 0; i < navigation_polys[least_cost_id].poly->edges.size(); i++) {
gd::NavigationPoly *least_cost_poly = &navigation_polys[least_cost_id];
const gd::Edge &edge = least_cost_poly->poly->edges[i];
if (!edge.other_polygon) {
continue;
}
#ifdef USE_ENTRY_POINT
Vector3 edge_line[2] = {
least_cost_poly->poly->points[i].pos,
least_cost_poly->poly->points[(i + 1) % least_cost_poly->poly->points.size()].pos
};
const Vector3 new_entry = Geometry3D::get_closest_point_to_segment(least_cost_poly->entry, edge_line);
const float new_distance = least_cost_poly->entry.distance_to(new_entry) + least_cost_poly->traveled_distance;
#else
const float new_distance = least_cost_poly->poly->center.distance_to(edge.other_polygon->center) + least_cost_poly->traveled_distance;
#endif
auto it = std::find(
navigation_polys.begin(),
navigation_polys.end(),
gd::NavigationPoly(edge.other_polygon));
if (it != navigation_polys.end()) {
// Oh this was visited already, can we win the cost?
if (it->traveled_distance > new_distance) {
it->prev_navigation_poly_id = least_cost_id;
it->back_navigation_edge = edge.other_edge;
it->traveled_distance = new_distance;
#ifdef USE_ENTRY_POINT
it->entry = new_entry;
#endif
}
} else {
// Add to open neighbours
navigation_polys.push_back(gd::NavigationPoly(edge.other_polygon));
gd::NavigationPoly *np = &navigation_polys[navigation_polys.size() - 1];
np->self_id = navigation_polys.size() - 1;
np->prev_navigation_poly_id = least_cost_id;
np->back_navigation_edge = edge.other_edge;
np->traveled_distance = new_distance;
#ifdef USE_ENTRY_POINT
np->entry = new_entry;
#endif
open_list.push_back(navigation_polys.size() - 1);
}
}
}
// Removes the least cost polygon from the open list so we can advance.
open_list.erase(least_cost_id);
if (open_list.size() == 0) {
// When the open list is empty at this point the End Polygon is not reachable
// so use the further reachable polygon
ERR_BREAK_MSG(is_reachable == false, "It's not expect to not find the most reachable polygons");
is_reachable = false;
if (reachable_end == nullptr) {
// The path is not found and there is not a way out.
break;
}
// Set as end point the furthest reachable point.
end_poly = reachable_end;
end_d = 1e20;
for (size_t point_id = 2; point_id < end_poly->points.size(); point_id++) {
Face3 f(end_poly->points[point_id - 2].pos, end_poly->points[point_id - 1].pos, end_poly->points[point_id].pos);
Vector3 spoint = f.get_closest_point_to(p_destination);
float dpoint = spoint.distance_to(p_destination);
if (dpoint < end_d) {
end_point = spoint;
end_d = dpoint;
}
}
// Reset open and navigation_polys
gd::NavigationPoly np = navigation_polys[0];
navigation_polys.clear();
navigation_polys.push_back(np);
open_list.clear();
open_list.push_back(0);
reachable_end = nullptr;
continue;
}
// Now take the new least_cost_poly from the open list.
least_cost_id = -1;
float least_cost = 1e30;
for (auto element = open_list.front(); element != nullptr; element = element->next()) {
gd::NavigationPoly *np = &navigation_polys[element->get()];
float cost = np->traveled_distance;
#ifdef USE_ENTRY_POINT
cost += np->entry.distance_to(end_point);
#else
cost += np->poly->center.distance_to(end_point);
#endif
if (cost < least_cost) {
least_cost_id = np->self_id;
least_cost = cost;
}
}
// Stores the further reachable end polygon, in case our goal is not reachable.
if (is_reachable) {
float d = navigation_polys[least_cost_id].entry.distance_to(p_destination);
if (reachable_d > d) {
reachable_d = d;
reachable_end = navigation_polys[least_cost_id].poly;
}
}
ERR_BREAK(least_cost_id == -1);
// Check if we reached the end
if (navigation_polys[least_cost_id].poly == end_poly) {
// Yep, done!!
found_route = true;
break;
}
}
if (found_route) {
Vector<Vector3> path;
if (p_optimize) {
// String pulling
gd::NavigationPoly *apex_poly = &navigation_polys[least_cost_id];
Vector3 apex_point = end_point;
Vector3 portal_left = apex_point;
Vector3 portal_right = apex_point;
gd::NavigationPoly *left_poly = apex_poly;
gd::NavigationPoly *right_poly = apex_poly;
gd::NavigationPoly *p = apex_poly;
path.push_back(end_point);
while (p) {
Vector3 left;
Vector3 right;
#define CLOCK_TANGENT(m_a, m_b, m_c) (((m_a) - (m_c)).cross((m_a) - (m_b)))
if (p->poly == begin_poly) {
left = begin_point;
right = begin_point;
} else {
int prev = p->back_navigation_edge;
int prev_n = (p->back_navigation_edge + 1) % p->poly->points.size();
left = p->poly->points[prev].pos;
right = p->poly->points[prev_n].pos;
if (p->poly->clockwise) {
SWAP(left, right);
}
}
bool skip = false;
if (CLOCK_TANGENT(apex_point, portal_left, left).dot(up) >= 0) {
//process
if (portal_left == apex_point || CLOCK_TANGENT(apex_point, left, portal_right).dot(up) > 0) {
left_poly = p;
portal_left = left;
} else {
clip_path(navigation_polys, path, apex_poly, portal_right, right_poly);
apex_point = portal_right;
p = right_poly;
left_poly = p;
apex_poly = p;
portal_left = apex_point;
portal_right = apex_point;
path.push_back(apex_point);
skip = true;
}
}
if (!skip && CLOCK_TANGENT(apex_point, portal_right, right).dot(up) <= 0) {
//process
if (portal_right == apex_point || CLOCK_TANGENT(apex_point, right, portal_left).dot(up) < 0) {
right_poly = p;
portal_right = right;
} else {
clip_path(navigation_polys, path, apex_poly, portal_left, left_poly);
apex_point = portal_left;
p = left_poly;
right_poly = p;
apex_poly = p;
portal_right = apex_point;
portal_left = apex_point;
path.push_back(apex_point);
}
}
if (p->prev_navigation_poly_id != -1) {
p = &navigation_polys[p->prev_navigation_poly_id];
} else {
// The end
p = nullptr;
}
}
if (path[path.size() - 1] != begin_point) {
path.push_back(begin_point);
}
path.invert();
} else {
path.push_back(end_point);
// Add mid points
int np_id = least_cost_id;
while (np_id != -1) {
#ifdef USE_ENTRY_POINT
Vector3 point = navigation_polys[np_id].entry;
#else
int prev = navigation_polys[np_id].back_navigation_edge;
int prev_n = (navigation_polys[np_id].back_navigation_edge + 1) % navigation_polys[np_id].poly->points.size();
Vector3 point = (navigation_polys[np_id].poly->points[prev].pos + navigation_polys[np_id].poly->points[prev_n].pos) * 0.5;
#endif
path.push_back(point);
np_id = navigation_polys[np_id].prev_navigation_poly_id;
}
path.invert();
}
return path;
}
return Vector<Vector3>();
}
Vector3 NavMap::get_closest_point_to_segment(const Vector3 &p_from, const Vector3 &p_to, const bool p_use_collision) const {
bool use_collision = p_use_collision;
Vector3 closest_point;
real_t closest_point_d = 1e20;
// Find the initial poly and the end poly on this map.
for (size_t i(0); i < polygons.size(); i++) {
const gd::Polygon &p = polygons[i];
// For each point cast a face and check the distance to the segment
for (size_t point_id = 2; point_id < p.points.size(); point_id += 1) {
const Face3 f(p.points[point_id - 2].pos, p.points[point_id - 1].pos, p.points[point_id].pos);
Vector3 inters;
if (f.intersects_segment(p_from, p_to, &inters)) {
const real_t d = closest_point_d = p_from.distance_to(inters);
if (use_collision == false) {
closest_point = inters;
use_collision = true;
closest_point_d = d;
} else if (closest_point_d > d) {
closest_point = inters;
closest_point_d = d;
}
}
}
if (use_collision == false) {
for (size_t point_id = 0; point_id < p.points.size(); point_id += 1) {
Vector3 a, b;
Geometry3D::get_closest_points_between_segments(
p_from,
p_to,
p.points[point_id].pos,
p.points[(point_id + 1) % p.points.size()].pos,
a,
b);
const real_t d = a.distance_to(b);
if (d < closest_point_d) {
closest_point_d = d;
closest_point = b;
}
}
}
}
return closest_point;
}
Vector3 NavMap::get_closest_point(const Vector3 &p_point) const {
// TODO this is really not optimal, please redesign the API to directly return all this data
Vector3 closest_point;
real_t closest_point_d = 1e20;
// Find the initial poly and the end poly on this map.
for (size_t i(0); i < polygons.size(); i++) {
const gd::Polygon &p = polygons[i];
// For each point cast a face and check the distance to the point
for (size_t point_id = 2; point_id < p.points.size(); point_id += 1) {
const Face3 f(p.points[point_id - 2].pos, p.points[point_id - 1].pos, p.points[point_id].pos);
const Vector3 inters = f.get_closest_point_to(p_point);
const real_t d = inters.distance_to(p_point);
if (d < closest_point_d) {
closest_point = inters;
closest_point_d = d;
}
}
}
return closest_point;
}
Vector3 NavMap::get_closest_point_normal(const Vector3 &p_point) const {
// TODO this is really not optimal, please redesign the API to directly return all this data
Vector3 closest_point;
Vector3 closest_point_normal;
real_t closest_point_d = 1e20;
// Find the initial poly and the end poly on this map.
for (size_t i(0); i < polygons.size(); i++) {
const gd::Polygon &p = polygons[i];
// For each point cast a face and check the distance to the point
for (size_t point_id = 2; point_id < p.points.size(); point_id += 1) {
const Face3 f(p.points[point_id - 2].pos, p.points[point_id - 1].pos, p.points[point_id].pos);
const Vector3 inters = f.get_closest_point_to(p_point);
const real_t d = inters.distance_to(p_point);
if (d < closest_point_d) {
closest_point = inters;
closest_point_normal = f.get_plane().normal;
closest_point_d = d;
}
}
}
return closest_point_normal;
}
RID NavMap::get_closest_point_owner(const Vector3 &p_point) const {
// TODO this is really not optimal, please redesign the API to directly return all this data
Vector3 closest_point;
RID closest_point_owner;
real_t closest_point_d = 1e20;
// Find the initial poly and the end poly on this map.
for (size_t i(0); i < polygons.size(); i++) {
const gd::Polygon &p = polygons[i];
// For each point cast a face and check the distance to the point
for (size_t point_id = 2; point_id < p.points.size(); point_id += 1) {
const Face3 f(p.points[point_id - 2].pos, p.points[point_id - 1].pos, p.points[point_id].pos);
const Vector3 inters = f.get_closest_point_to(p_point);
const real_t d = inters.distance_to(p_point);
if (d < closest_point_d) {
closest_point = inters;
closest_point_owner = p.owner->get_self();
closest_point_d = d;
}
}
}
return closest_point_owner;
}
void NavMap::add_region(NavRegion *p_region) {
regions.push_back(p_region);
regenerate_links = true;
}
void NavMap::remove_region(NavRegion *p_region) {
std::vector<NavRegion *>::iterator it = std::find(regions.begin(), regions.end(), p_region);
if (it != regions.end()) {
regions.erase(it);
regenerate_links = true;
}
}
bool NavMap::has_agent(RvoAgent *agent) const {
return std::find(agents.begin(), agents.end(), agent) != agents.end();
}
void NavMap::add_agent(RvoAgent *agent) {
if (!has_agent(agent)) {
agents.push_back(agent);
agents_dirty = true;
}
}
void NavMap::remove_agent(RvoAgent *agent) {
remove_agent_as_controlled(agent);
auto it = std::find(agents.begin(), agents.end(), agent);
if (it != agents.end()) {
agents.erase(it);
agents_dirty = true;
}
}
void NavMap::set_agent_as_controlled(RvoAgent *agent) {
const bool exist = std::find(controlled_agents.begin(), controlled_agents.end(), agent) != controlled_agents.end();
if (!exist) {
ERR_FAIL_COND(!has_agent(agent));
controlled_agents.push_back(agent);
}
}
void NavMap::remove_agent_as_controlled(RvoAgent *agent) {
auto it = std::find(controlled_agents.begin(), controlled_agents.end(), agent);
if (it != controlled_agents.end()) {
controlled_agents.erase(it);
}
}
void NavMap::sync() {
if (regenerate_polygons) {
for (size_t r(0); r < regions.size(); r++) {
regions[r]->scratch_polygons();
}
regenerate_links = true;
}
for (size_t r(0); r < regions.size(); r++) {
if (regions[r]->sync()) {
regenerate_links = true;
}
}
if (regenerate_links) {
// Copy all region polygons in the map.
int count = 0;
for (size_t r(0); r < regions.size(); r++) {
count += regions[r]->get_polygons().size();
}
polygons.resize(count);
count = 0;
for (size_t r(0); r < regions.size(); r++) {
std::copy(
regions[r]->get_polygons().data(),
regions[r]->get_polygons().data() + regions[r]->get_polygons().size(),
polygons.begin() + count);
count += regions[r]->get_polygons().size();
}
// Connects the `Edges` of all the `Polygons` of all `Regions` each other.
Map<gd::EdgeKey, gd::Connection> connections;
for (size_t poly_id(0); poly_id < polygons.size(); poly_id++) {
gd::Polygon &poly(polygons[poly_id]);
for (size_t p(0); p < poly.points.size(); p++) {
int next_point = (p + 1) % poly.points.size();
gd::EdgeKey ek(poly.points[p].key, poly.points[next_point].key);
Map<gd::EdgeKey, gd::Connection>::Element *connection = connections.find(ek);
if (!connection) {
// Nothing yet
gd::Connection c;
c.A = &poly;
c.A_edge = p;
c.B = nullptr;
c.B_edge = -1;
connections[ek] = c;
} else if (connection->get().B == nullptr) {
CRASH_COND(connection->get().A == nullptr); // Unreachable
// Connect the two Polygons by this edge
connection->get().B = &poly;
connection->get().B_edge = p;
connection->get().A->edges[connection->get().A_edge].this_edge = connection->get().A_edge;
connection->get().A->edges[connection->get().A_edge].other_polygon = connection->get().B;
connection->get().A->edges[connection->get().A_edge].other_edge = connection->get().B_edge;
connection->get().B->edges[connection->get().B_edge].this_edge = connection->get().B_edge;
connection->get().B->edges[connection->get().B_edge].other_polygon = connection->get().A;
connection->get().B->edges[connection->get().B_edge].other_edge = connection->get().A_edge;
} else {
// The edge is already connected with another edge, skip.
ERR_PRINT("Attempted to merge a navigation mesh triangle edge with another already-merged edge. This happens when the Navigation3D's `cell_size` is different from the one used to generate the navigation mesh. This will cause navigation problem.");
}
}
}
// Takes all the free edges.
std::vector<gd::FreeEdge> free_edges;
free_edges.reserve(connections.size());
for (auto connection_element = connections.front(); connection_element; connection_element = connection_element->next()) {
if (connection_element->get().B == nullptr) {
CRASH_COND(connection_element->get().A == nullptr); // Unreachable
CRASH_COND(connection_element->get().A_edge < 0); // Unreachable
// This is a free edge
uint32_t id(free_edges.size());
free_edges.push_back(gd::FreeEdge());
free_edges[id].is_free = true;
free_edges[id].poly = connection_element->get().A;
free_edges[id].edge_id = connection_element->get().A_edge;
uint32_t point_0(free_edges[id].edge_id);
uint32_t point_1((free_edges[id].edge_id + 1) % free_edges[id].poly->points.size());
Vector3 pos_0 = free_edges[id].poly->points[point_0].pos;
Vector3 pos_1 = free_edges[id].poly->points[point_1].pos;
Vector3 relative = pos_1 - pos_0;
free_edges[id].edge_center = (pos_0 + pos_1) / 2.0;
free_edges[id].edge_dir = relative.normalized();
free_edges[id].edge_len_squared = relative.length_squared();
}
}
const float ecm_squared(edge_connection_margin * edge_connection_margin);
#define LEN_TOLLERANCE 0.1
#define DIR_TOLLERANCE 0.9
// In front of tolerance
#define IFO_TOLLERANCE 0.5
// Find the compatible near edges.
//
// Note:
// Considering that the edges must be compatible (for obvious reasons)
// to be connected, create new polygons to remove that small gap is
// not really useful and would result in wasteful computation during
// connection, integration and path finding.
for (size_t i(0); i < free_edges.size(); i++) {
if (!free_edges[i].is_free) {
continue;
}
gd::FreeEdge &edge = free_edges[i];
for (size_t y(0); y < free_edges.size(); y++) {
gd::FreeEdge &other_edge = free_edges[y];
if (i == y || !other_edge.is_free || edge.poly->owner == other_edge.poly->owner) {
continue;
}
Vector3 rel_centers = other_edge.edge_center - edge.edge_center;
if (ecm_squared > rel_centers.length_squared() // Are enough closer?
&& ABS(edge.edge_len_squared - other_edge.edge_len_squared) < LEN_TOLLERANCE // Are the same length?
&& ABS(edge.edge_dir.dot(other_edge.edge_dir)) > DIR_TOLLERANCE // Are aligned?
&& ABS(rel_centers.normalized().dot(edge.edge_dir)) < IFO_TOLLERANCE // Are one in front the other?
) {
// The edges can be connected
edge.is_free = false;
other_edge.is_free = false;
edge.poly->edges[edge.edge_id].this_edge = edge.edge_id;
edge.poly->edges[edge.edge_id].other_edge = other_edge.edge_id;
edge.poly->edges[edge.edge_id].other_polygon = other_edge.poly;
other_edge.poly->edges[other_edge.edge_id].this_edge = other_edge.edge_id;
other_edge.poly->edges[other_edge.edge_id].other_edge = edge.edge_id;
other_edge.poly->edges[other_edge.edge_id].other_polygon = edge.poly;
}
}
}
}
if (regenerate_links) {
map_update_id = (map_update_id + 1) % 9999999;
}
if (agents_dirty) {
std::vector<RVO::Agent *> raw_agents;
raw_agents.reserve(agents.size());
for (size_t i(0); i < agents.size(); i++) {
raw_agents.push_back(agents[i]->get_agent());
}
rvo.buildAgentTree(raw_agents);
}
regenerate_polygons = false;
regenerate_links = false;
agents_dirty = false;
}
void NavMap::compute_single_step(uint32_t index, RvoAgent **agent) {
(*(agent + index))->get_agent()->computeNeighbors(&rvo);
(*(agent + index))->get_agent()->computeNewVelocity(deltatime);
}
void NavMap::step(real_t p_deltatime) {
deltatime = p_deltatime;
if (controlled_agents.size() > 0) {
thread_process_array(
controlled_agents.size(),
this,
&NavMap::compute_single_step,
controlled_agents.data());
}
}
void NavMap::dispatch_callbacks() {
for (int i(0); i < static_cast<int>(controlled_agents.size()); i++) {
controlled_agents[i]->dispatch_callback();
}
}
void NavMap::clip_path(const std::vector<gd::NavigationPoly> &p_navigation_polys, Vector<Vector3> &path, const gd::NavigationPoly *from_poly, const Vector3 &p_to_point, const gd::NavigationPoly *p_to_poly) const {
Vector3 from = path[path.size() - 1];
if (from.distance_to(p_to_point) < CMP_EPSILON) {
return;
}
Plane cut_plane;
cut_plane.normal = (from - p_to_point).cross(up);
if (cut_plane.normal == Vector3()) {
return;
}
cut_plane.normal.normalize();
cut_plane.d = cut_plane.normal.dot(from);
while (from_poly != p_to_poly) {
int back_nav_edge = from_poly->back_navigation_edge;
Vector3 a = from_poly->poly->points[back_nav_edge].pos;
Vector3 b = from_poly->poly->points[(back_nav_edge + 1) % from_poly->poly->points.size()].pos;
ERR_FAIL_COND(from_poly->prev_navigation_poly_id == -1);
from_poly = &p_navigation_polys[from_poly->prev_navigation_poly_id];
if (a.distance_to(b) > CMP_EPSILON) {
Vector3 inters;
if (cut_plane.intersects_segment(a, b, &inters)) {
if (inters.distance_to(p_to_point) > CMP_EPSILON && inters.distance_to(path[path.size() - 1]) > CMP_EPSILON) {
path.push_back(inters);
}
}
}
}
}