scummvm/engines/twp/graph.h
2024-03-24 22:49:08 +01:00

134 lines
4.0 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef TWP_GRAPH_H
#define TWP_GRAPH_H
#include "common/array.h"
#include "math/vector2d.h"
#include "twp/util.h"
namespace Twp {
class IndexedPriorityQueue {
public:
explicit IndexedPriorityQueue(Common::Array<float> &keys);
void insert(int index);
int pop();
void reorderUp();
void reorderDown();
bool isEmpty();
private:
Common::Array<float> &_keys;
Common::Array<int> _data;
};
// An edge is a part of a walkable area, it is used by a Graph.
// See also:
// - PathFinder
// - Graph
struct GraphEdge {
GraphEdge(int start, int to, float cost);
int start; // Index of the node in the graph representing the start of the edge.
int to; // Index of the node in the graph representing the end of the edge.
float cost; // Cost of the edge in the graph.
};
// A graph helps to find a path between two points.
// This class has been ported from http://www.groebelsloot.com/2016/03/13/pathfinding-part-2/
// and modified
class Graph {
public:
Graph();
void addNode(const Math::Vector2d &node);
void addEdge(const GraphEdge &edge);
// Gets the edge from 'from' index to 'to' index.
GraphEdge *edge(int start, int to);
Common::Array<int> getPath(int source, int target);
Common::Array<Math::Vector2d> _nodes;
Common::Array<Common::Array<GraphEdge> > _edges;
Common::Array<Math::Vector2d> _concaveVertices;
};
class AStar {
public:
AStar(Graph *graph);
void search(int source, int target);
Graph *_graph = nullptr;
Common::Array<GraphEdge *> _spt; // The Shortest Path Tree
Common::Array<float> _gCost; // This array will store the G cost of each node
Common::Array<float> _fCost; // This array will store the F cost of each node
Common::Array<GraphEdge *> _sf; // The Search Frontier
};
// Represents an area where an actor can or cannot walk
class Walkbox {
public:
Walkbox(const Common::Array<Vector2i> &polygon, bool visible = true);
// Indicates whether or not the specified position is inside this walkbox.
bool contains(const Math::Vector2d &position, bool toleranceOnOutside = true) const;
bool concave(int vertex) const;
void setVisible(bool visible) { _visible = visible; }
bool isVisible() const { return _visible; }
const Common::Array<Vector2i> &getPoints() const { return _polygon; }
Math::Vector2d getClosestPointOnEdge(const Math::Vector2d &p) const;
public:
Common::String _name;
private:
Common::Array<Vector2i> _polygon;
bool _visible;
};
// A PathFinder is used to find a walkable path within one or several walkboxes.
class PathFinder {
public:
void setWalkboxes(const Common::Array<Walkbox> &walkboxes);
Common::Array<Walkbox> getWalkboxes() const { return _walkboxes; }
Common::Array<Math::Vector2d> calculatePath(const Math::Vector2d &start, const Math::Vector2d &to);
void setDirty(bool dirty) { _isDirty = dirty; }
bool isDirty() const { return _isDirty; }
const Graph &getGraph() const { return _walkgraph; }
private:
Common::SharedPtr<Graph> createGraph();
bool inLineOfSight(const Math::Vector2d &start, const Math::Vector2d &to);
private:
Common::Array<Walkbox> _walkboxes;
Common::SharedPtr<Graph> _graph;
Graph _walkgraph;
bool _isDirty = true;
};
} // namespace Twp
#endif