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346 lines
9.6 KiB
C++
346 lines
9.6 KiB
C++
/*
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Minetest
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Copyright (C) 2013 sapier, sapier at gmx dot net
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef PATHFINDER_H_
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#define PATHFINDER_H_
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/******************************************************************************/
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/* Includes */
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/******************************************************************************/
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#include <vector>
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#include "server.h"
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#include "irr_v3d.h"
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/******************************************************************************/
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/* Typedefs and macros */
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/******************************************************************************/
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//#define PATHFINDER_DEBUG
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typedef enum {
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DIR_XP,
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DIR_XM,
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DIR_ZP,
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DIR_ZM
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} path_directions;
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/** List of supported algorithms */
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typedef enum {
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DIJKSTRA, /**< Dijkstra shortest path algorithm */
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A_PLAIN, /**< A* algorithm using heuristics to find a path */
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A_PLAIN_NP /**< A* algorithm without prefetching of map data */
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} algorithm;
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/******************************************************************************/
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/* declarations */
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/******************************************************************************/
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/** c wrapper function to use from scriptapi */
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std::vector<v3s16> get_Path(ServerEnvironment* env,
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v3s16 source,
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v3s16 destination,
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unsigned int searchdistance,
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unsigned int max_jump,
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unsigned int max_drop,
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algorithm algo);
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/** representation of cost in specific direction */
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class path_cost {
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public:
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/** default constructor */
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path_cost();
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/** copy constructor */
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path_cost(const path_cost& b);
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/** assignment operator */
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path_cost& operator= (const path_cost& b);
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bool valid; /**< movement is possible */
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int value; /**< cost of movement */
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int direction; /**< y-direction of movement */
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bool updated; /**< this cost has ben calculated */
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};
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/** representation of a mapnode to be used for pathfinding */
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class path_gridnode {
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public:
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/** default constructor */
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path_gridnode();
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/** copy constructor */
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path_gridnode(const path_gridnode& b);
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/**
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* assignment operator
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* @param b node to copy
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*/
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path_gridnode& operator= (const path_gridnode& b);
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/**
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* read cost in a specific direction
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* @param dir direction of cost to fetch
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*/
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path_cost get_cost(v3s16 dir);
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/**
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* set cost value for movement
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* @param dir direction to set cost for
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* @cost cost to set
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*/
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void set_cost(v3s16 dir,path_cost cost);
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bool valid; /**< node is on surface */
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bool target; /**< node is target position */
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bool source; /**< node is stating position */
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int totalcost; /**< cost to move here from starting point */
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v3s16 sourcedir; /**< origin of movement for current cost */
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int surfaces; /**< number of surfaces with same x,z value*/
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v3s16 pos; /**< real position of node */
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path_cost directions[4]; /**< cost in different directions */
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/* debug values */
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bool is_element; /**< node is element of path detected */
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char type; /**< type of node */
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};
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/** class doing pathfinding */
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class pathfinder {
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public:
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/**
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* default constructor
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*/
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pathfinder();
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/**
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* path evaluation function
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* @param env environment to look for path
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* @param source origin of path
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* @param destination end position of path
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* @param searchdistance maximum number of nodes to look in each direction
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* @param max_jump maximum number of blocks a path may jump up
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* @param max_drop maximum number of blocks a path may drop
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* @param algo algorithm to use for finding a path
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*/
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std::vector<v3s16> get_Path(ServerEnvironment* env,
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v3s16 source,
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v3s16 destination,
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unsigned int searchdistance,
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unsigned int max_jump,
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unsigned int max_drop,
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algorithm algo);
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private:
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/** data struct for storing internal information */
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struct limits {
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struct limit {
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int min;
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int max;
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};
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limit X;
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limit Y;
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limit Z;
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};
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/* helper functions */
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/**
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* transform index pos to mappos
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* @param ipos a index position
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* @return map position
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*/
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v3s16 getRealPos(v3s16 ipos);
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/**
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* transform mappos to index pos
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* @param pos a real pos
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* @return index position
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*/
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v3s16 getIndexPos(v3s16 pos);
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/**
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* get gridnode at a specific index position
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* @param ipos index position
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* @return gridnode for index
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*/
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path_gridnode& getIndexElement(v3s16 ipos);
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/**
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* invert a 3d position
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* @param pos 3d position
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* @return pos *-1
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*/
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v3s16 invert(v3s16 pos);
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/**
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* check if a index is within current search area
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* @param index position to validate
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* @return true/false
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*/
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bool valid_index(v3s16 index);
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/**
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* translate position to float position
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* @param pos integer position
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* @return float position
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*/
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v3f tov3f(v3s16 pos);
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/* algorithm functions */
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/**
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* calculate 2d manahttan distance to target
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* @param pos position to calc distance
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* @return integer distance
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*/
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int get_manhattandistance(v3s16 pos);
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/**
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* get best direction based uppon heuristics
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* @param directions list of unchecked directions
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* @param g_pos mapnode to start from
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* @return direction to check
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*/
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v3s16 get_dir_heuristic(std::vector<v3s16>& directions,path_gridnode& g_pos);
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/**
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* build internal data representation of search area
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* @return true/false if costmap creation was successfull
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*/
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bool build_costmap();
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/**
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* calculate cost of movement
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* @param pos real world position to start movement
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* @param dir direction to move to
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* @return cost information
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*/
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path_cost calc_cost(v3s16 pos,v3s16 dir);
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/**
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* recursive update whole search areas total cost information
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* @param ipos position to check next
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* @param srcdir positionc checked last time
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* @param total_cost cost of moving to ipos
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* @param level current recursion depth
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* @return true/false path to destination has been found
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*/
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bool update_all_costs(v3s16 ipos,v3s16 srcdir,int total_cost,int level);
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/**
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* recursive try to find a patrh to destionation
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* @param ipos position to check next
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* @param srcdir positionc checked last time
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* @param total_cost cost of moving to ipos
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* @param level current recursion depth
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* @return true/false path to destination has been found
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*/
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bool update_cost_heuristic(v3s16 ipos,v3s16 srcdir,int current_cost,int level);
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/**
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* recursive build a vector containing all nodes from source to destination
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* @param path vector to add nodes to
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* @param pos pos to check next
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* @param level recursion depth
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*/
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void build_path(std::vector<v3s16>& path,v3s16 pos, int level);
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/* variables */
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int m_max_index_x; /**< max index of search area in x direction */
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int m_max_index_y; /**< max index of search area in y direction */
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int m_max_index_z; /**< max index of search area in z direction */
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int m_searchdistance; /**< max distance to search in each direction */
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int m_maxdrop; /**< maximum number of blocks a path may drop */
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int m_maxjump; /**< maximum number of blocks a path may jump */
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int m_min_target_distance; /**< current smalest path to target */
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bool m_prefetch; /**< prefetch cost data */
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v3s16 m_start; /**< source position */
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v3s16 m_destination; /**< destination position */
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limits m_limits; /**< position limits in real map coordinates */
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/** 3d grid containing all map data already collected and analyzed */
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std::vector<std::vector<std::vector<path_gridnode> > > m_data;
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ServerEnvironment* m_env; /**< minetest environment pointer */
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#ifdef PATHFINDER_DEBUG
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/**
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* print collected cost information
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*/
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void print_cost();
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/**
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* print collected cost information in a specific direction
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* @param dir direction to print
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*/
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void print_cost(path_directions dir);
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/**
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* print type of node as evaluated
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*/
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void print_type();
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/**
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* print pathlenght for all nodes in search area
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*/
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void print_pathlen();
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/**
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* print a path
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* @param path path to show
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*/
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void print_path(std::vector<v3s16> path);
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/**
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* print y direction for all movements
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*/
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void print_ydir();
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/**
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* print y direction for moving in a specific direction
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* @param dir direction to show data
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*/
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void print_ydir(path_directions dir);
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/**
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* helper function to translate a direction to speaking text
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* @param dir direction to translate
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* @return textual name of direction
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*/
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std::string dir_to_name(path_directions dir);
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#endif
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};
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#endif /* PATHFINDER_H_ */
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