godot/core/math/a_star.cpp
2017-04-01 16:36:22 +10:30

428 lines
11 KiB
C++

/*************************************************************************/
/* a_star.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* */
/* 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 */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "a_star.h"
#include "geometry.h"
#include "scene/scene_string_names.h"
#include "script_language.h"
int AStar::get_available_point_id() const {
if (points.empty()) {
return 1;
}
return points.back()->key() + 1;
}
void AStar::add_point(int p_id, const Vector3 &p_pos, real_t p_weight_scale) {
ERR_FAIL_COND(p_id < 0);
if (!points.has(p_id)) {
Point *pt = memnew(Point);
pt->id = p_id;
pt->pos = p_pos;
pt->weight_scale = p_weight_scale;
pt->prev_point = NULL;
pt->last_pass = 0;
points[p_id] = pt;
} else {
points[p_id]->pos = p_pos;
points[p_id]->weight_scale = p_weight_scale;
}
}
Vector3 AStar::get_point_pos(int p_id) const {
ERR_FAIL_COND_V(!points.has(p_id), Vector3());
return points[p_id]->pos;
}
real_t AStar::get_point_weight_scale(int p_id) const {
ERR_FAIL_COND_V(!points.has(p_id), 0);
return points[p_id]->weight_scale;
}
void AStar::remove_point(int p_id) {
ERR_FAIL_COND(!points.has(p_id));
Point *p = points[p_id];
for (int i = 0; i < p->neighbours.size(); i++) {
Segment s(p_id, p->neighbours[i]->id);
segments.erase(s);
p->neighbours[i]->neighbours.erase(p);
}
memdelete(p);
points.erase(p_id);
}
void AStar::connect_points(int p_id, int p_with_id) {
ERR_FAIL_COND(!points.has(p_id));
ERR_FAIL_COND(!points.has(p_with_id));
ERR_FAIL_COND(p_id == p_with_id);
Point *a = points[p_id];
Point *b = points[p_with_id];
a->neighbours.push_back(b);
b->neighbours.push_back(a);
Segment s(p_id, p_with_id);
if (s.from == p_id) {
s.from_point = a;
s.to_point = b;
} else {
s.from_point = b;
s.to_point = a;
}
segments.insert(s);
}
void AStar::disconnect_points(int p_id, int p_with_id) {
Segment s(p_id, p_with_id);
ERR_FAIL_COND(!segments.has(s));
segments.erase(s);
Point *a = points[p_id];
Point *b = points[p_with_id];
a->neighbours.erase(b);
b->neighbours.erase(a);
}
bool AStar::are_points_connected(int p_id, int p_with_id) const {
Segment s(p_id, p_with_id);
return segments.has(s);
}
void AStar::clear() {
for (const Map<int, Point *>::Element *E = points.front(); E; E = E->next()) {
memdelete(E->get());
}
segments.clear();
points.clear();
}
int AStar::get_closest_point(const Vector3 &p_point) const {
int closest_id = -1;
real_t closest_dist = 1e20;
for (const Map<int, Point *>::Element *E = points.front(); E; E = E->next()) {
real_t d = p_point.distance_squared_to(E->get()->pos);
if (closest_id < 0 || d < closest_dist) {
closest_dist = d;
closest_id = E->key();
}
}
return closest_id;
}
Vector3 AStar::get_closest_pos_in_segment(const Vector3 &p_point) const {
real_t closest_dist = 1e20;
bool found = false;
Vector3 closest_point;
for (const Set<Segment>::Element *E = segments.front(); E; E = E->next()) {
Vector3 segment[2] = {
E->get().from_point->pos,
E->get().to_point->pos,
};
Vector3 p = Geometry::get_closest_point_to_segment(p_point, segment);
real_t d = p_point.distance_squared_to(p);
if (!found || d < closest_dist) {
closest_point = p;
closest_dist = d;
found = true;
}
}
return closest_point;
}
bool AStar::_solve(Point *begin_point, Point *end_point) {
pass++;
SelfList<Point>::List open_list;
bool found_route = false;
for (int i = 0; i < begin_point->neighbours.size(); i++) {
Point *n = begin_point->neighbours[i];
n->prev_point = begin_point;
n->distance = _compute_cost(n->id, begin_point->id);
n->distance *= n->weight_scale;
n->last_pass = pass;
open_list.add(&n->list);
if (end_point == n) {
found_route = true;
break;
}
}
while (!found_route) {
if (open_list.first() == NULL) {
//could not find path sadly
break;
}
//check open list
SelfList<Point> *least_cost_point = NULL;
real_t least_cost = 1e30;
//this could be faster (cache previous results)
for (SelfList<Point> *E = open_list.first(); E; E = E->next()) {
Point *p = E->self();
real_t cost = p->distance;
cost += _estimate_cost(p->id, end_point->id);
cost *= p->weight_scale;
if (cost < least_cost) {
least_cost_point = E;
least_cost = cost;
}
}
Point *p = least_cost_point->self();
//open the neighbours for search
int es = p->neighbours.size();
for (int i = 0; i < es; i++) {
Point *e = p->neighbours[i];
real_t distance = _compute_cost(p->id, e->id) + p->distance;
distance *= e->weight_scale;
if (e->last_pass == pass) {
//oh this was visited already, can we win the cost?
if (e->distance > distance) {
e->prev_point = p;
e->distance = distance;
}
} else {
//add to open neighbours
e->prev_point = p;
e->distance = distance;
e->last_pass = pass; //mark as used
open_list.add(&e->list);
if (e == end_point) {
//oh my reached end! stop algorithm
found_route = true;
break;
}
}
}
if (found_route)
break;
open_list.remove(least_cost_point);
}
//clear the openf list
while (open_list.first()) {
open_list.remove(open_list.first());
}
return found_route;
}
float AStar::_estimate_cost(int p_from_id, int p_to_id) {
if (get_script_instance() && get_script_instance()->has_method(SceneStringNames::get_singleton()->_estimate_cost))
return get_script_instance()->call(SceneStringNames::get_singleton()->_estimate_cost, p_from_id, p_to_id);
return points[p_from_id]->pos.distance_to(points[p_to_id]->pos);
}
float AStar::_compute_cost(int p_from_id, int p_to_id) {
if (get_script_instance() && get_script_instance()->has_method(SceneStringNames::get_singleton()->_compute_cost))
return get_script_instance()->call(SceneStringNames::get_singleton()->_compute_cost, p_from_id, p_to_id);
return points[p_from_id]->pos.distance_to(points[p_to_id]->pos);
}
PoolVector<Vector3> AStar::get_point_path(int p_from_id, int p_to_id) {
ERR_FAIL_COND_V(!points.has(p_from_id), PoolVector<Vector3>());
ERR_FAIL_COND_V(!points.has(p_to_id), PoolVector<Vector3>());
pass++;
Point *a = points[p_from_id];
Point *b = points[p_to_id];
if (a == b) {
PoolVector<Vector3> ret;
ret.push_back(a->pos);
return ret;
}
Point *begin_point = a;
Point *end_point = b;
bool found_route = _solve(begin_point, end_point);
if (!found_route)
return PoolVector<Vector3>();
//midpoints
Point *p = end_point;
int pc = 1; //begin point
while (p != begin_point) {
pc++;
p = p->prev_point;
}
PoolVector<Vector3> path;
path.resize(pc);
{
PoolVector<Vector3>::Write w = path.write();
Point *p = end_point;
int idx = pc - 1;
while (p != begin_point) {
w[idx--] = p->pos;
p = p->prev_point;
}
w[0] = p->pos; //assign first
}
return path;
}
PoolVector<int> AStar::get_id_path(int p_from_id, int p_to_id) {
ERR_FAIL_COND_V(!points.has(p_from_id), PoolVector<int>());
ERR_FAIL_COND_V(!points.has(p_to_id), PoolVector<int>());
pass++;
Point *a = points[p_from_id];
Point *b = points[p_to_id];
if (a == b) {
PoolVector<int> ret;
ret.push_back(a->id);
return ret;
}
Point *begin_point = a;
Point *end_point = b;
bool found_route = _solve(begin_point, end_point);
if (!found_route)
return PoolVector<int>();
//midpoints
Point *p = end_point;
int pc = 1; //begin point
while (p != begin_point) {
pc++;
p = p->prev_point;
}
PoolVector<int> path;
path.resize(pc);
{
PoolVector<int>::Write w = path.write();
p = end_point;
int idx = pc - 1;
while (p != begin_point) {
w[idx--] = p->id;
p = p->prev_point;
}
w[0] = p->id; //assign first
}
return path;
}
void AStar::_bind_methods() {
ClassDB::bind_method(D_METHOD("get_available_point_id"), &AStar::get_available_point_id);
ClassDB::bind_method(D_METHOD("add_point", "id", "pos", "weight_scale"), &AStar::add_point, DEFVAL(1.0));
ClassDB::bind_method(D_METHOD("get_point_pos", "id"), &AStar::get_point_pos);
ClassDB::bind_method(D_METHOD("get_point_weight_scale", "id"), &AStar::get_point_weight_scale);
ClassDB::bind_method(D_METHOD("remove_point", "id"), &AStar::remove_point);
ClassDB::bind_method(D_METHOD("connect_points", "id", "to_id"), &AStar::connect_points);
ClassDB::bind_method(D_METHOD("disconnect_points", "id", "to_id"), &AStar::disconnect_points);
ClassDB::bind_method(D_METHOD("are_points_connected", "id", "to_id"), &AStar::are_points_connected);
ClassDB::bind_method(D_METHOD("clear"), &AStar::clear);
ClassDB::bind_method(D_METHOD("get_closest_point", "to_pos"), &AStar::get_closest_point);
ClassDB::bind_method(D_METHOD("get_closest_pos_in_segment", "to_pos"), &AStar::get_closest_pos_in_segment);
ClassDB::bind_method(D_METHOD("get_point_path", "from_id", "to_id"), &AStar::get_point_path);
ClassDB::bind_method(D_METHOD("get_id_path", "from_id", "to_id"), &AStar::get_id_path);
BIND_VMETHOD(MethodInfo("_estimate_cost", PropertyInfo(Variant::INT, "from_id"), PropertyInfo(Variant::INT, "to_id")));
BIND_VMETHOD(MethodInfo("_compute_cost", PropertyInfo(Variant::INT, "from_id"), PropertyInfo(Variant::INT, "to_id")));
}
AStar::AStar() {
pass = 1;
}
AStar::~AStar() {
pass = 1;
}