godot/scene/resources/polygon_path_finder.cpp

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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;
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if (Geometry::segment_intersects_segment_2d(a, b, p_point, outside_point, nullptr)) {
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;
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if (Geometry::segment_intersects_segment_2d(a, b, from, to, nullptr)) {
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;
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if (Geometry::segment_intersects_segment_2d(a, b, from, to, nullptr)) {
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]) {
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if (Geometry::segment_intersects_segment_2d(a, b, from, points[i].pos, nullptr)) {
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]) {
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if (Geometry::segment_intersects_segment_2d(a, b, to, points[i].pos, nullptr)) {
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);
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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"));
Vector<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);
const Vector2 *pr = p.ptr();
for (int i = 0; i < pc; i++) {
points.write[i].pos = pr[i];
Vector<int> con = c[i];
const int *cr = con.ptr();
int cc = con.size();
for (int j = 0; j < cc; j++) {
points.write[i].connections.insert(cr[j]);
}
}
if (p_data.has("penalties")) {
Vector<float> penalties = p_data["penalties"];
if (penalties.size() == pc) {
const float *pr2 = penalties.ptr();
for (int i = 0; i < pc; i++) {
points.write[i].penalty = pr2[i];
}
}
}
Vector<int> segs = p_data["segments"];
int sc = segs.size();
ERR_FAIL_COND(sc & 1);
const int *sr = segs.ptr();
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;
Vector<Vector2> p;
Vector<int> ind;
Array connections;
p.resize(MAX(0, points.size() - 2));
connections.resize(MAX(0, points.size() - 2));
ind.resize(edges.size() * 2);
Vector<float> penalties;
penalties.resize(MAX(0, points.size() - 2));
{
Vector2 *wp = p.ptrw();
float *pw = penalties.ptrw();
for (int i = 0; i < points.size() - 2; i++) {
wp[i] = points[i].pos;
pw[i] = points[i].penalty;
Vector<int> c;
c.resize(points[i].connections.size());
{
int *cw = c.ptrw();
int idx = 0;
for (Set<int>::Element *E = points[i].connections.front(); E; E = E->next()) {
cw[idx++] = E->get();
}
}
connections[i] = c;
}
}
{
int *iw = ind.ptrw();
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;
}
}
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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() {
}