godot/scene/resources/polygon_path_finder.cpp
Rémi Verschelde a7f49ac9a1 Update copyright statements to 2020
Happy new year to the wonderful Godot community!

We're starting a new decade with a well-established, non-profit, free
and open source game engine, and tons of further improvements in the
pipeline from hundreds of contributors.

Godot will keep getting better, and we're looking forward to all the
games that the community will keep developing and releasing with it.
2020-01-01 11:16:22 +01:00

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/*************************************************************************/
/* polygon_path_finder.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 */
/* 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 "polygon_path_finder.h"
#include "core/math/geometry.h"
bool PolygonPathFinder::_is_point_inside(const Vector2 &p_point) const {
int crosses = 0;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
Vector2 a = points[e.points[0]].pos;
Vector2 b = points[e.points[1]].pos;
if (Geometry::segment_intersects_segment_2d(a, b, p_point, outside_point, NULL)) {
crosses++;
}
}
return crosses & 1;
}
void PolygonPathFinder::setup(const Vector<Vector2> &p_points, const Vector<int> &p_connections) {
ERR_FAIL_COND(p_connections.size() & 1);
points.clear();
edges.clear();
//insert points
int point_count = p_points.size();
points.resize(point_count + 2);
bounds = Rect2();
for (int i = 0; i < p_points.size(); i++) {
points.write[i].pos = p_points[i];
points.write[i].penalty = 0;
outside_point.x = i == 0 ? p_points[0].x : (MAX(p_points[i].x, outside_point.x));
outside_point.y = i == 0 ? p_points[0].y : (MAX(p_points[i].y, outside_point.y));
if (i == 0) {
bounds.position = points[i].pos;
} else {
bounds.expand_to(points[i].pos);
}
}
outside_point.x += 20.451 + Math::randf() * 10.2039;
outside_point.y += 21.193 + Math::randf() * 12.5412;
//insert edges (which are also connetions)
for (int i = 0; i < p_connections.size(); i += 2) {
Edge e(p_connections[i], p_connections[i + 1]);
ERR_FAIL_INDEX(e.points[0], point_count);
ERR_FAIL_INDEX(e.points[1], point_count);
points.write[p_connections[i]].connections.insert(p_connections[i + 1]);
points.write[p_connections[i + 1]].connections.insert(p_connections[i]);
edges.insert(e);
}
//fill the remaining connections based on visibility
for (int i = 0; i < point_count; i++) {
for (int j = i + 1; j < point_count; j++) {
if (edges.has(Edge(i, j)))
continue; //if in edge ignore
Vector2 from = points[i].pos;
Vector2 to = points[j].pos;
if (!_is_point_inside(from * 0.5 + to * 0.5)) //connection between points in inside space
continue;
bool valid = true;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
if (e.points[0] == i || e.points[1] == i || e.points[0] == j || e.points[1] == j)
continue;
Vector2 a = points[e.points[0]].pos;
Vector2 b = points[e.points[1]].pos;
if (Geometry::segment_intersects_segment_2d(a, b, from, to, NULL)) {
valid = false;
break;
}
}
if (valid) {
points.write[i].connections.insert(j);
points.write[j].connections.insert(i);
}
}
}
}
Vector<Vector2> PolygonPathFinder::find_path(const Vector2 &p_from, const Vector2 &p_to) {
Vector<Vector2> path;
Vector2 from = p_from;
Vector2 to = p_to;
Edge ignore_from_edge(-1, -1);
Edge ignore_to_edge(-1, -1);
if (!_is_point_inside(from)) {
float closest_dist = 1e20;
Vector2 closest_point;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
Vector2 seg[2] = {
points[e.points[0]].pos,
points[e.points[1]].pos
};
Vector2 closest = Geometry::get_closest_point_to_segment_2d(from, seg);
float d = from.distance_squared_to(closest);
if (d < closest_dist) {
ignore_from_edge = E->get();
closest_dist = d;
closest_point = closest;
}
}
from = closest_point;
};
if (!_is_point_inside(to)) {
float closest_dist = 1e20;
Vector2 closest_point;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
Vector2 seg[2] = {
points[e.points[0]].pos,
points[e.points[1]].pos
};
Vector2 closest = Geometry::get_closest_point_to_segment_2d(to, seg);
float d = to.distance_squared_to(closest);
if (d < closest_dist) {
ignore_to_edge = E->get();
closest_dist = d;
closest_point = closest;
}
}
to = closest_point;
};
//test direct connection
{
bool can_see_eachother = true;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
if (e.points[0] == ignore_from_edge.points[0] && e.points[1] == ignore_from_edge.points[1])
continue;
if (e.points[0] == ignore_to_edge.points[0] && e.points[1] == ignore_to_edge.points[1])
continue;
Vector2 a = points[e.points[0]].pos;
Vector2 b = points[e.points[1]].pos;
if (Geometry::segment_intersects_segment_2d(a, b, from, to, NULL)) {
can_see_eachother = false;
break;
}
}
if (can_see_eachother) {
path.push_back(from);
path.push_back(to);
return path;
}
}
//add to graph
int aidx = points.size() - 2;
int bidx = points.size() - 1;
points.write[aidx].pos = from;
points.write[bidx].pos = to;
points.write[aidx].distance = 0;
points.write[bidx].distance = 0;
points.write[aidx].prev = -1;
points.write[bidx].prev = -1;
points.write[aidx].penalty = 0;
points.write[bidx].penalty = 0;
for (int i = 0; i < points.size() - 2; i++) {
bool valid_a = true;
bool valid_b = true;
points.write[i].prev = -1;
points.write[i].distance = 0;
if (!_is_point_inside(from * 0.5 + points[i].pos * 0.5)) {
valid_a = false;
}
if (!_is_point_inside(to * 0.5 + points[i].pos * 0.5)) {
valid_b = false;
}
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
if (e.points[0] == i || e.points[1] == i)
continue;
Vector2 a = points[e.points[0]].pos;
Vector2 b = points[e.points[1]].pos;
if (valid_a) {
if (e.points[0] != ignore_from_edge.points[1] &&
e.points[1] != ignore_from_edge.points[1] &&
e.points[0] != ignore_from_edge.points[0] &&
e.points[1] != ignore_from_edge.points[0]) {
if (Geometry::segment_intersects_segment_2d(a, b, from, points[i].pos, NULL)) {
valid_a = false;
}
}
}
if (valid_b) {
if (e.points[0] != ignore_to_edge.points[1] &&
e.points[1] != ignore_to_edge.points[1] &&
e.points[0] != ignore_to_edge.points[0] &&
e.points[1] != ignore_to_edge.points[0]) {
if (Geometry::segment_intersects_segment_2d(a, b, to, points[i].pos, NULL)) {
valid_b = false;
}
}
}
if (!valid_a && !valid_b)
break;
}
if (valid_a) {
points.write[i].connections.insert(aidx);
points.write[aidx].connections.insert(i);
}
if (valid_b) {
points.write[i].connections.insert(bidx);
points.write[bidx].connections.insert(i);
}
}
//solve graph
Set<int> open_list;
points.write[aidx].distance = 0;
points.write[aidx].prev = aidx;
for (Set<int>::Element *E = points[aidx].connections.front(); E; E = E->next()) {
open_list.insert(E->get());
points.write[E->get()].distance = from.distance_to(points[E->get()].pos);
points.write[E->get()].prev = aidx;
}
bool found_route = false;
while (true) {
if (open_list.size() == 0) {
printf("open list empty\n");
break;
}
//check open list
int least_cost_point = -1;
float least_cost = 1e30;
//this could be faster (cache previous results)
for (Set<int>::Element *E = open_list.front(); E; E = E->next()) {
const Point &p = points[E->get()];
float cost = p.distance;
cost += p.pos.distance_to(to);
cost += p.penalty;
if (cost < least_cost) {
least_cost_point = E->get();
least_cost = cost;
}
}
const Point &np = points[least_cost_point];
//open the neighbours for search
for (Set<int>::Element *E = np.connections.front(); E; E = E->next()) {
Point &p = points.write[E->get()];
float distance = np.pos.distance_to(p.pos) + np.distance;
if (p.prev != -1) {
//oh this was visited already, can we win the cost?
if (p.distance > distance) {
p.prev = least_cost_point; //reasign previous
p.distance = distance;
}
} else {
//add to open neighbours
p.prev = least_cost_point;
p.distance = distance;
open_list.insert(E->get());
if (E->get() == bidx) {
//oh my reached end! stop algorithm
found_route = true;
break;
}
}
}
if (found_route)
break;
open_list.erase(least_cost_point);
}
if (found_route) {
int at = bidx;
path.push_back(points[at].pos);
do {
at = points[at].prev;
path.push_back(points[at].pos);
} while (at != aidx);
path.invert();
}
for (int i = 0; i < points.size() - 2; i++) {
points.write[i].connections.erase(aidx);
points.write[i].connections.erase(bidx);
points.write[i].prev = -1;
points.write[i].distance = 0;
}
points.write[aidx].connections.clear();
points.write[aidx].prev = -1;
points.write[aidx].distance = 0;
points.write[bidx].connections.clear();
points.write[bidx].prev = -1;
points.write[bidx].distance = 0;
return path;
}
void PolygonPathFinder::_set_data(const Dictionary &p_data) {
ERR_FAIL_COND(!p_data.has("points"));
ERR_FAIL_COND(!p_data.has("connections"));
ERR_FAIL_COND(!p_data.has("segments"));
ERR_FAIL_COND(!p_data.has("bounds"));
PoolVector<Vector2> p = p_data["points"];
Array c = p_data["connections"];
ERR_FAIL_COND(c.size() != p.size());
if (c.size())
return;
int pc = p.size();
points.resize(pc + 2);
PoolVector<Vector2>::Read pr = p.read();
for (int i = 0; i < pc; i++) {
points.write[i].pos = pr[i];
PoolVector<int> con = c[i];
PoolVector<int>::Read cr = con.read();
int cc = con.size();
for (int j = 0; j < cc; j++) {
points.write[i].connections.insert(cr[j]);
}
}
if (p_data.has("penalties")) {
PoolVector<float> penalties = p_data["penalties"];
if (penalties.size() == pc) {
PoolVector<float>::Read pr2 = penalties.read();
for (int i = 0; i < pc; i++) {
points.write[i].penalty = pr2[i];
}
}
}
PoolVector<int> segs = p_data["segments"];
int sc = segs.size();
ERR_FAIL_COND(sc & 1);
PoolVector<int>::Read sr = segs.read();
for (int i = 0; i < sc; i += 2) {
Edge e(sr[i], sr[i + 1]);
edges.insert(e);
}
bounds = p_data["bounds"];
}
Dictionary PolygonPathFinder::_get_data() const {
Dictionary d;
PoolVector<Vector2> p;
PoolVector<int> ind;
Array connections;
p.resize(MAX(0, points.size() - 2));
connections.resize(MAX(0, points.size() - 2));
ind.resize(edges.size() * 2);
PoolVector<float> penalties;
penalties.resize(MAX(0, points.size() - 2));
{
PoolVector<Vector2>::Write wp = p.write();
PoolVector<float>::Write pw = penalties.write();
for (int i = 0; i < points.size() - 2; i++) {
wp[i] = points[i].pos;
pw[i] = points[i].penalty;
PoolVector<int> c;
c.resize(points[i].connections.size());
{
PoolVector<int>::Write cw = c.write();
int idx = 0;
for (Set<int>::Element *E = points[i].connections.front(); E; E = E->next()) {
cw[idx++] = E->get();
}
}
connections[i] = c;
}
}
{
PoolVector<int>::Write iw = ind.write();
int idx = 0;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
iw[idx++] = E->get().points[0];
iw[idx++] = E->get().points[1];
}
}
d["bounds"] = bounds;
d["points"] = p;
d["penalties"] = penalties;
d["connections"] = connections;
d["segments"] = ind;
return d;
}
bool PolygonPathFinder::is_point_inside(const Vector2 &p_point) const {
return _is_point_inside(p_point);
}
Vector2 PolygonPathFinder::get_closest_point(const Vector2 &p_point) const {
float closest_dist = 1e20;
Vector2 closest_point;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
const Edge &e = E->get();
Vector2 seg[2] = {
points[e.points[0]].pos,
points[e.points[1]].pos
};
Vector2 closest = Geometry::get_closest_point_to_segment_2d(p_point, seg);
float d = p_point.distance_squared_to(closest);
if (d < closest_dist) {
closest_dist = d;
closest_point = closest;
}
}
ERR_FAIL_COND_V(closest_dist == 1e20, Vector2());
return closest_point;
}
Vector<Vector2> PolygonPathFinder::get_intersections(const Vector2 &p_from, const Vector2 &p_to) const {
Vector<Vector2> inters;
for (Set<Edge>::Element *E = edges.front(); E; E = E->next()) {
Vector2 a = points[E->get().points[0]].pos;
Vector2 b = points[E->get().points[1]].pos;
Vector2 res;
if (Geometry::segment_intersects_segment_2d(a, b, p_from, p_to, &res)) {
inters.push_back(res);
}
}
return inters;
}
Rect2 PolygonPathFinder::get_bounds() const {
return bounds;
}
void PolygonPathFinder::set_point_penalty(int p_point, float p_penalty) {
ERR_FAIL_INDEX(p_point, points.size() - 2);
points.write[p_point].penalty = p_penalty;
}
float PolygonPathFinder::get_point_penalty(int p_point) const {
ERR_FAIL_INDEX_V(p_point, points.size() - 2, 0);
return points[p_point].penalty;
}
void PolygonPathFinder::_bind_methods() {
ClassDB::bind_method(D_METHOD("setup", "points", "connections"), &PolygonPathFinder::setup);
ClassDB::bind_method(D_METHOD("find_path", "from", "to"), &PolygonPathFinder::find_path);
ClassDB::bind_method(D_METHOD("get_intersections", "from", "to"), &PolygonPathFinder::get_intersections);
ClassDB::bind_method(D_METHOD("get_closest_point", "point"), &PolygonPathFinder::get_closest_point);
ClassDB::bind_method(D_METHOD("is_point_inside", "point"), &PolygonPathFinder::is_point_inside);
ClassDB::bind_method(D_METHOD("set_point_penalty", "idx", "penalty"), &PolygonPathFinder::set_point_penalty);
ClassDB::bind_method(D_METHOD("get_point_penalty", "idx"), &PolygonPathFinder::get_point_penalty);
ClassDB::bind_method(D_METHOD("get_bounds"), &PolygonPathFinder::get_bounds);
ClassDB::bind_method(D_METHOD("_set_data"), &PolygonPathFinder::_set_data);
ClassDB::bind_method(D_METHOD("_get_data"), &PolygonPathFinder::_get_data);
ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NOEDITOR | PROPERTY_USAGE_INTERNAL), "_set_data", "_get_data");
}
PolygonPathFinder::PolygonPathFinder() {
}