PathFinder.h

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/*
 *  Copyright (C) 2000-2001  The Exult Team
 *
 *  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 2 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef PATHFINDER_H
#define PATHFINDER_H

#include "tiles.h"

/*
 *  This class provides A* cost methods.
 */
class Pathfinder_client
  {
private:
  int   move_flags;
public:
          // Figure when to give up.
  virtual int get_max_cost(int cost_to_goal);
          // Figure cost for a single step.
  virtual int get_step_cost(Tile_coord from, Tile_coord& to) = 0;
          // Estimate cost between two points.
  virtual int estimate_cost(Tile_coord& from, Tile_coord& to) = 0;
          // Is tile at the goal?
  virtual int at_goal(Tile_coord& tile, Tile_coord& goal);

  int get_move_flags() { return move_flags; }
  void set_move_flags(int m) { move_flags = m;}
  };

/*
 *  Base class for all PathFinders.
 */
class PathFinder
  {
protected:
  Tile_coord src;     // Source tile.
  Tile_coord dest;    // Destination.
public:
  // Find a path from sx,sy,sz to dx,dy,dz
  // Return 0 if no path can be traced.
  // Return !0 if path found
  PathFinder() : src(),dest()
    {  }
  virtual int NewPath(Tile_coord s, Tile_coord d, 
          Pathfinder_client *client)=0;
  // Retrieve starting point (set by subclasses).
  Tile_coord get_src()
    { return src; }
  // Retrieve current destination (set by subclasses).
  Tile_coord get_dest()
    { return dest; }
  // Retrieve the coordinates of the next step on the path
  virtual int GetNextStep(Tile_coord& n, bool& done)=0;
  int GetNextStep(Tile_coord& n)
    {     // If you don't care about last step.
    bool d;
    return GetNextStep(n, d);
    }
  // Set to retrieve in opposite order.
  virtual int set_backwards()
    { return 0; }   // Default: Can't do it.
  virtual int following_smart_path()  // Astar?
    { return 0; }
  virtual int get_num_steps() = 0;// # of steps left to take.
  virtual ~PathFinder();
  };

#endif

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