seek_path.h

/* 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 NUVIE_PATHFINDER_SEEK_PATH_H
#define NUVIE_PATHFINDER_SEEK_PATH_H

#include "ultima/shared/std/containers.h"
#include "ultima/nuvie/pathfinder/path.h"

namespace Ultima {
namespace Nuvie {

/* Provides routines for building short paths around obstacles and seeking a
 * target. Much of the work doesn't involve finding a path at all, but instead
 * finding the direction closest to the target.
 */
class SeekPath: public Path {
protected:
    Std::vector<MapCoord> A_scan, B_scan; // nodes of a line scanned by trace_obstacle()

    void create_path(const MapCoord &start, const MapCoord &goal);
    Std::vector<MapCoord> *get_best_scan(const MapCoord &start, const MapCoord &goal);
    void delete_nodes();
    bool trace_check_obstacle(bool &turned, MapCoord &line, sint32 &deltax, sint32 &deltay, sint32 &xdir, sint32 &ydir, Std::vector<MapCoord> *scan);
    void trace_around_corner(MapCoord &line, sint32 &deltax, sint32 &deltay, sint32 &xdir, sint32 &ydir, Std::vector<MapCoord> *scan);

public:
    SeekPath();
    ~SeekPath() override;
    sint32 step_cost(const MapCoord &c1, const MapCoord &c2) override {
        return -1;
    }
    bool path_search(const MapCoord &start, const MapCoord &goal) override;
    void delete_path() {
        Path::delete_path();
        delete_nodes();
    }

    /* Trace obstacle towards xdir,ydir for a possible opening. */
    bool trace_obstacle(MapCoord line, sint32 deltax, sint32 deltay, sint32 xdir, sint32 ydir, Std::vector<MapCoord> *scan);
    /* Get two relative directions that a line can travel to trace around an
       obstacle towards `xdir',`ydir'. */
    bool get_obstacle_tracer(const MapCoord &start, sint32 xdir, sint32 ydir,
                             sint32 &Axdir, sint32 &Aydir,
                             sint32 &Bxdir, sint32 &Bydir);
};

} // End of namespace Nuvie
} // End of namespace Ultima

#endif