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engines/crab/PathfindingAgent.h

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+/* 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/>.
+ *
+ */
+
+/*
+ * This code is based on the CRAB engine
+ *
+ * Copyright (c) Arvind Raja Yadav
+ *
+ * Licensed under MIT
+ *
+ */
+
+#ifndef CRAB_PATHFINDINGAGENT_H
+#define CRAB_PATHFINDINGAGENT_H
+
+#include "common/stablemap.h"
+#include "crab/PathfindingGrid.h"
+#include "crab/PriorityQueue.h"
+#include "crab/vectors.h"
+
+namespace Crab {
+
+// This class represents the actual pathfinding and following agent that utilizes
+// the pathfinding grid
+class PlannerNode {
+	PlannerNode *_parent;
+	PlannerNode *_child;
+
+	double _cost;      // Heuristic cost equivalent to cost to reach goal from planner node's position.
+	double _finalCost; // Final cost of route through the planner node. Used to determine optimal path.
+	double _givenCost; // The current distance of the route.
+
+public:
+	PathfindingGraphNode *_location;
+
+	PlannerNode() {
+		_location = nullptr;
+		_parent = nullptr;
+		_child = nullptr;
+		_cost = 0;
+		_finalCost = 0;
+		_givenCost = 0;
+	}
+	~PlannerNode() {}
+
+	PathfindingGraphNode *getLocation() {
+		return _location;
+	}
+
+	PlannerNode *getParent() {
+		return _parent;
+	}
+
+	PlannerNode *getChild() {
+		return _child;
+	}
+
+	double getHCost() const {
+		return _cost;
+	}
+
+	double getFinalCost() const {
+		return _finalCost;
+	}
+
+	double getGivenCost() const {
+		return _givenCost;
+	}
+
+	void setLocation(PathfindingGraphNode *loc) {
+		_location = loc;
+	}
+
+	void setParent(PlannerNode *p) {
+		_parent = p;
+	}
+
+	void setChild(PlannerNode *c) {
+		_child = c;
+	}
+
+	void setHCost(double c) {
+		_cost = c;
+	}
+
+	void setFinalCost(double c) {
+		_finalCost = c;
+	}
+
+	void setGivenCost(double c) {
+		_givenCost = c;
+	}
+};
+
+class PathfindingAgent {
+	Vector2f _position;
+	Vector2f _prevPosition;  // Used to determine that we are making progress toward the goal
+	Vector2i _immediateDest; // The next stop on the AI's path
+
+	bool _destinationSet;       // Was a destination specified.
+	bool _destinationReachable; // Can the agent actually get to the destination?
+
+	float _nodeBufferDistance; // How much leeway is there for reaching the destination
+
+public:
+	PathfindingAgent();
+	~PathfindingAgent();
+
+	PathfindingGrid *_grid;
+
+	Vector2f _destination;
+
+	PathfindingGraphNode *_startTile;   // The system originally used tiles, but this one uses discreet points.
+	PathfindingGraphNode *_goalTile;    // The tile we are trying to reach. May not be the tile that was clicked if the clicked tile is blocked.
+	PathfindingGraphNode *_clickedTile; // The tile that was clicked. If it is open, it will be the goal node.
+
+	bool _solutionFound;
+	bool _noSolution;
+
+	Common::Array<PathfindingGraphNode const *> _vSolution;
+
+	void setNodeBufferDistance(float w) {
+		_nodeBufferDistance = w;
+	}
+
+	float getNodeBufferDistance() {
+		return _nodeBufferDistance;
+	}
+
+	// Added for Greedy search
+	double distSquared(PathfindingGraphNode *tileA, PathfindingGraphNode *tileB);
+	// Added for A* search
+	double distExact(PathfindingGraphNode *tileA, PathfindingGraphNode *tileB);
+
+	PriorityQueue<PlannerNode> _nodeQueue;
+
+	Common::StableMap<PathfindingGraphNode *, PlannerNode *> _createdList;
+
+	// void SetSprite(pyrodactyl::anim::Sprite* s){entitySprite = s;}
+
+	//! \brief Sets the tile map.
+	//!
+	//! Invoked when the user opens a tile map file.
+	//!
+	//! \param   _tileMap  the data structure that this algorithm will use
+	//!                    to access each tile's location and weight data.
+	void initialize(PathfindingGrid *g);
+
+	void setDestination(Vector2f d);
+	void setDestination(Vector2f d, bool r);
+	void setDestination(Vector2i d);
+	void setDestination(Vector2i d, bool r);
+
+	void setPosition(Vector2f p) {
+		_position = p;
+	}
+
+	void setPrevPosition(Vector2f p) {
+		_prevPosition = p;
+	}
+
+	Vector2f getPosition() {
+		return _position;
+	}
+
+	bool positionChanged() {
+		return _position != _prevPosition;
+	}
+
+	Vector2i getImmediateDest() {
+		return _immediateDest;
+	}
+
+	//! \brief Performs the main part of the algorithm until the specified time has elapsed or
+	//! no nodes are left open.
+	void update(uint32 timeslice);
+
+	//! \brief Returns <code>true</code> if and only if no nodes are left open.
+	//!
+	//! \return  <code>true</code> if no nodes are left open, <code>false</code> otherwise.
+	bool isDone() const;
+
+	//! \brief Returns an unmodifiable view of the solution path found by this algorithm.
+	Common::Array<PathfindingGraphNode const *> const getSolution(PathfindingGraphNode *destNode) const;
+
+	// Get the solution removing any nodes that are completely surrounded by open space.
+	// This will result in a more linear path to the goal.
+	Common::Array<PathfindingGraphNode const *> const getPrunedSolution(PathfindingGraphNode *destNode);
+
+	//! \brief Resets the algorithm.
+	void reset();
+
+	//! \brief Uninitializes the algorithm before the tile map is unloaded.
+	void shutdown();
+
+	// Returns true if the node connects to the goal node
+	bool adjacentToGoal(PathfindingGraphNode *node);
+};
+
+} // End of namespace Crab
+
+#endif // CRAB_PATHFINDINGAGENT_H