The Battle for Wesnoth  1.19.1+dev
pathfind.cpp
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1 /*
2  Copyright (C) 2005 - 2024
3  by Guillaume Melquiond <guillaume.melquiond@gmail.com>
4  Copyright (C) 2003 by David White <dave@whitevine.net>
5  Part of the Battle for Wesnoth Project https://www.wesnoth.org/
6 
7  This program is free software; you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation; either version 2 of the License, or
10  (at your option) any later version.
11  This program is distributed in the hope that it will be useful,
12  but WITHOUT ANY WARRANTY.
13 
14  See the COPYING file for more details.
15 */
16 
17 /**
18  * @file
19  * Various pathfinding functions and utilities.
20  */
21 
22 #include "pathfind/pathfind.hpp"
23 #include "pathfind/teleport.hpp"
24 
25 #include "display.hpp"
26 #include "game_board.hpp"
27 #include "gettext.hpp"
28 #include "log.hpp"
29 #include "map/map.hpp"
30 #include "resources.hpp"
31 #include "team.hpp"
32 #include "units/unit.hpp"
33 #include "units/map.hpp"
34 #include "wml_exception.hpp"
35 
36 #include <vector>
37 #include <algorithm>
38 
39 static lg::log_domain log_engine("engine");
40 #define ERR_PF LOG_STREAM(err, log_engine)
41 
42 namespace pathfind {
43 
44 
45 /**
46  * Function that will find a location on the board that is as near
47  * to @a loc as possible, but which is unoccupied by any units.
48  * If no valid location can be found, it will return a null location.
49  * If @a pass_check is provided, the found location must have a terrain
50  * that this unit can enter.
51  * If @a shroud_check is provided, only locations not covered by this
52  * team's shroud will be considered.
53  */
55  const unit* pass_check, const team* shroud_check, const game_board* board)
56 {
57  if (!board) {
58  board = resources::gameboard;
59  assert(board);
60  }
61  const gamemap & map = board->map();
62  const unit_map & units = board->units();
63 
64  if (!map.on_board(loc)) return map_location();
65 
66  const bool do_shroud = shroud_check && shroud_check->uses_shroud();
67  std::set<map_location> pending_tiles_to_check, tiles_checked;
68  pending_tiles_to_check.insert(loc);
69  // Iterate out 50 hexes from loc
70  for (int distance = 0; distance < 50; ++distance) {
71  if (pending_tiles_to_check.empty())
72  return map_location();
73  //Copy over the hexes to check and clear the old set
74  std::set<map_location> tiles_checking;
75  tiles_checking.swap(pending_tiles_to_check);
76  //Iterate over all the hexes we need to check
77  for (const map_location &l : tiles_checking)
78  {
79  // Skip shrouded locations.
80  if ( do_shroud && shroud_check->shrouded(l) )
81  continue;
82  //If this area is not a castle but should, skip it.
83  if ( vacancy == VACANT_CASTLE && !map.is_castle(l) ) continue;
84  const bool pass_check_and_unreachable = pass_check
85  && pass_check->movement_cost(map[l]) == movetype::UNREACHABLE;
86  //If the unit can't reach the tile and we have searched
87  //an area of at least radius 10 (arbitrary), skip the tile.
88  //Necessary for cases such as an unreachable
89  //starting hex surrounded by 6 other unreachable hexes, in which case
90  //the algorithm would not even search distance==1
91  //even if there's a reachable hex for distance==2.
92  if (pass_check_and_unreachable && distance > 10) continue;
93  //If the hex is empty and we do either no pass check or the hex is reachable, return it.
94  if (units.find(l) == units.end() && !pass_check_and_unreachable) return l;
95 
96  for(const map_location& l2 : get_adjacent_tiles(l)) {
97  if (!map.on_board(l2)) continue;
98  // Add the tile to be checked if it hasn't already been and
99  // isn't being checked.
100  if (tiles_checked.find(l2) == tiles_checked.end() &&
101  tiles_checking.find(l2) == tiles_checking.end())
102  {
103  pending_tiles_to_check.insert(l2);
104  }
105  }
106  }
107  tiles_checked.swap(tiles_checking);
108  }
109  return map_location();
110 }
111 
112 /**
113  * Wrapper for find_vacant_tile() when looking for a vacant castle tile
114  * near a leader.
115  * If no valid location can be found, it will return a null location.
116  */
118 {
120  nullptr, &resources::gameboard->get_team(leader.side()));
121 }
122 
123 
124 /**
125  * Determines if a given location is in an enemy zone of control.
126  *
127  * @param current_team The moving team (only ZoC of enemies of this team are considered).
128  * @param loc The location to check.
129  * @param viewing_team Only units visible to this team are considered.
130  * @param see_all If true, all units are considered (and viewing_team is ignored).
131  *
132  * @return true iff a visible enemy exerts zone of control over loc.
133  */
134 bool enemy_zoc(const team& current_team, const map_location& loc,
135  const team& viewing_team, bool see_all)
136 {
137  // Check the adjacent tiles.
138  for(const map_location& adj : get_adjacent_tiles(loc)) {
139  const unit *u = resources::gameboard->get_visible_unit(adj, viewing_team, see_all);
140  if ( u && current_team.is_enemy(u->side()) && u->emits_zoc() )
141  return true;
142  }
143 
144  // No adjacent tiles had an enemy exerting ZoC over loc.
145  return false;
146 }
147 
148 
149 namespace {
150  /**
151  * Nodes used by find_routes().
152  * These store the information necessary for extending the path
153  * and for tracing the route back to the source.
154  */
155  struct findroute_node {
158  // search_num is used to detect which nodes have been collected
159  // in the current search. (More than just a boolean value so
160  // that nodes can be stored between searches.)
161  unsigned search_num;
162 
163  // Constructors.
164  findroute_node(int moves, int turns, const map_location &prev_loc, unsigned search_count)
165  : moves_left(moves)
166  , turns_left(turns)
167  , prev(prev_loc)
168  , search_num(search_count)
169  { }
170  findroute_node()
171  : moves_left(0)
172  , turns_left(0)
173  , prev()
174  , search_num(0)
175  { }
176 
177  // Compare these nodes based on movement consumed.
178  bool operator<(const findroute_node& o) const
179  {
180  return std::tie(turns_left, moves_left) > std::tie(o.turns_left, o.moves_left);
181  }
182  };
183 
184  /**
185  * Converts map locations to and from integer indices.
186  */
187  struct findroute_indexer {
188  int w, h; // Width and height of the map.
189 
190  // Constructor:
191  findroute_indexer(int a, int b) : w(a), h(b) { }
192  // Convert to an index: (throws on out of bounds)
193  unsigned operator()(int x, int y) const {
194  VALIDATE(this->on_board(x,y),
195  "Pathfind: Location not on board");
196  return x + static_cast<unsigned>(y)*w;
197  }
198  unsigned operator()(const map_location& loc) const {
199  return (*this)(loc.x, loc.y);
200  }
201  // Convert from an index:
202  map_location operator()(unsigned index) const {
203  return map_location(
204  static_cast<int>(index%w),
205  static_cast<int>(index/w));
206  }
207  // Check if location is on board
208  inline bool on_board(const map_location& loc) const {
209  return this->on_board(loc.x, loc.y);
210  }
211  inline bool on_board(int x, int y) const {
212  return (x >= 0) && (x < w) && (y >= 0) && (y < h);
213  }
214  };
215 
216  /**
217  * A function object for comparing indices.
218  */
219  struct findroute_comp {
220  const std::vector<findroute_node>& nodes;
221 
222  // Constructor:
223  findroute_comp(const std::vector<findroute_node>& n) : nodes(n) { }
224  // Binary predicate evaluating the order of its arguments:
225  bool operator()(int l, int r) const {
226  return nodes[r] < nodes[l];
227  }
228  };
229 }
230 
231 /**
232  * Creates a list of routes that a unit can traverse from the provided location.
233  * (This is called when creating pathfind::paths and descendant classes.)
234  *
235  * @param[in] origin The location at which to begin the routes.
236  * @param[in] costs The costs to use for route finding.
237  * @param[in] slowed Whether or not to use the slowed costs.
238  * @param[in] moves_left The number of movement points left for the current turn.
239  * @param[in] max_moves The number of movement points in each future turn.
240  * @param[in] turns_left The number of future turns of movement to calculate.
241  * @param[out] destinations The traversable routes.
242  * @param[out] edges The hexes (possibly off-map) adjacent to those in
243  * destinations. (It is permissible for this to contain
244  * some hexes that are also in destinations.)
245  *
246  * @param[in] teleporter If not nullptr, teleportation will be considered, using
247  * this unit's abilities.
248  * @param[in] current_team If not nullptr, enemies of this team can obstruct routes
249  * both by occupying hexes and by exerting zones of control.
250  * In addition, the presence of units can affect
251  * teleportation options.
252  * @param[in] skirmisher If not nullptr, use this to determine where ZoC can and
253  * cannot be ignored (due to this unit having or not
254  * having the skirmisher ability).
255  * If nullptr, then ignore all zones of control.
256  * (No effect if current_team is nullptr).
257  * @param[in] viewing_team If not nullptr, use this team's vision when detecting
258  * enemy units and teleport destinations.
259  * If nullptr, then "see all".
260  * (No effect if teleporter and current_team are both nullptr.)
261  * @param[in] jamming_map The relevant "jamming" of the costs being used
262  * (currently only used with vision costs).
263  * @param[out] full_cost_map If not nullptr, build a cost_map instead of destinations.
264  * Destinations is ignored.
265  * full_cost_map is a vector of pairs. The first entry is the
266  * cost itself, the second how many units already visited this hex
267  * @param[in] check_vision If true, use vision check for teleports, that is, ignore
268  * units potentially blocking the teleport exit
269  */
270 static void find_routes(
271  const map_location & origin, const movetype::terrain_costs & costs,
272  bool slowed, int moves_left, int max_moves, int turns_left,
273  paths::dest_vect & destinations, std::set<map_location> * edges,
274  const unit * teleporter, const team * current_team,
275  const unit * skirmisher, const team * viewing_team,
276  const std::map<map_location, int> * jamming_map=nullptr,
277  std::vector<std::pair<int, int>> * full_cost_map=nullptr, bool check_vision=false)
278 {
279  const gamemap& map = resources::gameboard->map();
280 
281  const bool see_all = viewing_team == nullptr;
282  // When see_all is true, the viewing team never matters, but we still
283  // need to supply one to some functions.
284  if ( viewing_team == nullptr )
285  viewing_team = &resources::gameboard->teams().front();
286 
287  // Build a teleport map, if needed.
288  const teleport_map teleports = teleporter ?
289  get_teleport_locations(*teleporter, *viewing_team, see_all, current_team == nullptr, check_vision) :
290  teleport_map();
291 
292  // Since this is called so often, keep memory reserved for the node list.
293  static std::vector<findroute_node> nodes;
294  static unsigned search_counter = 0;
295  // Incrementing search_counter means we ignore results from earlier searches.
296  ++search_counter;
297  // Whenever the counter cycles, trash the contents of nodes and restart at 1.
298  if ( search_counter == 0 ) {
299  nodes.resize(0);
300  search_counter = 1;
301  }
302  // Initialize the nodes for this search.
303  nodes.resize(static_cast<size_t>(map.w()) * map.h());
304  findroute_comp node_comp(nodes);
305  findroute_indexer index(map.w(), map.h());
306 
307  assert(index.on_board(origin));
308 
309  // Check if full_cost_map has the correct size.
310  // If not, ignore it. If yes, initialize the start position.
311  if ( full_cost_map ) {
312  if ( full_cost_map->size() != static_cast<unsigned>(map.w() * map.h()) )
313  full_cost_map = nullptr;
314  else {
315  if ( (*full_cost_map)[index(origin)].second == 0 )
316  (*full_cost_map)[index(origin)].first = 0;
317  (*full_cost_map)[index(origin)].second += 1;
318  }
319  }
320 
321  // Used to optimize the final collection of routes.
322  int xmin = origin.x, xmax = origin.x, ymin = origin.y, ymax = origin.y;
323  int nb_dest = 1;
324 
325  // Record the starting location.
326  nodes[index(origin)] = findroute_node(moves_left, turns_left,
328  search_counter);
329  // Begin the search at the starting location.
330  std::vector<unsigned> hexes_to_process(1, index(origin)); // Will be maintained as a heap.
331 
332  while ( !hexes_to_process.empty() ) {
333  // Process the hex closest to the origin.
334  const unsigned cur_index = hexes_to_process.front();
335  const map_location cur_hex = index(cur_index);
336  const findroute_node& current = nodes[cur_index];
337  // Remove from the heap.
338  std::pop_heap(hexes_to_process.begin(), hexes_to_process.end(), node_comp);
339  hexes_to_process.pop_back();
340 
341  // Get the locations adjacent to current.
342  std::vector<map_location> adj_locs(6);
343  get_adjacent_tiles(cur_hex, adj_locs.data());
344 
345  // Sort adjacents by on-boardness
346  auto off_board_it = std::partition(adj_locs.begin(), adj_locs.end(), [&index](map_location loc){
347  return index.on_board(loc);
348  });
349  // Store off-board edges if needed
350  if(edges != nullptr){
351  edges->insert(off_board_it, adj_locs.end());
352  }
353  // Remove off-board map locations
354  adj_locs.erase(off_board_it, adj_locs.end());
355 
356  if ( teleporter ) {
357  auto allowed_teleports = teleports.get_adjacents(cur_hex);
358  adj_locs.insert(adj_locs.end(), allowed_teleports.begin(), allowed_teleports.end());
359  }
360  for ( int i = adj_locs.size()-1; i >= 0; --i ) {
361  // Get the node associated with this location.
362  const map_location & next_hex = adj_locs[i];
363  const unsigned next_index = index(next_hex);
364  findroute_node & next = nodes[next_index];
365 
366  // Skip nodes we have already collected.
367  // (Since no previously checked routes were longer than
368  // the current one, the current route cannot be shorter.)
369  // (Significant difference from classic Dijkstra: we have
370  // vertex weights, not edge weights.)
371  if ( next.search_num == search_counter )
372  continue;
373 
374  // If we go to next, it will be from current.
375  next.prev = cur_hex;
376 
377  // Calculate the cost of entering next_hex.
378  int cost = costs.cost(map[next_hex], slowed);
379  if ( jamming_map ) {
380  const std::map<map_location, int>::const_iterator jam_it =
381  jamming_map->find(next_hex);
382  if ( jam_it != jamming_map->end() )
383  cost += jam_it->second;
384  }
385 
386  // Calculate movement remaining after entering next_hex.
387  next.moves_left = current.moves_left - cost;
388  next.turns_left = current.turns_left;
389  if ( next.moves_left < 0 ) {
390  // Have to delay until the next turn.
391  next.turns_left--;
392  next.moves_left = max_moves - cost;
393  }
394  if ( next.moves_left < 0 || next.turns_left < 0 ) {
395  // Either can never enter this hex or out of turns.
396  if ( edges != nullptr )
397  edges->insert(next_hex);
398  continue;
399  }
400 
401  if ( current_team ) {
402  // Account for enemy units.
403  const unit *v = resources::gameboard->get_visible_unit(next_hex, *viewing_team, see_all);
404  if ( v && current_team->is_enemy(v->side()) ) {
405  // Cannot enter enemy hexes.
406  if ( edges != nullptr )
407  edges->insert(next_hex);
408  continue;
409  }
410 
411  if ( skirmisher && next.moves_left > 0 &&
412  enemy_zoc(*current_team, next_hex, *viewing_team, see_all) &&
413  !skirmisher->get_ability_bool("skirmisher", next_hex) ) {
414  next.moves_left = 0;
415  }
416  }
417 
418  if ( !see_all && viewing_team && current_team && viewing_team != current_team && viewing_team->shrouded(next_hex) ) {
419  // bug #2199: in "Show Enemy Moves", don't pathfind enemy units through the player's shroud
420  continue;
421  }
422 
423  // Update full_cost_map
424  if ( full_cost_map ) {
425  if ( (*full_cost_map)[next_index].second == 0 )
426  (*full_cost_map)[next_index].first = 0;
427  int summed_cost = (turns_left - next.turns_left + 1) * max_moves - next.moves_left;
428  (*full_cost_map)[next_index].first += summed_cost;
429  (*full_cost_map)[next_index].second += 1;
430  }
431 
432  // Mark next as being collected.
433  next.search_num = search_counter;
434 
435  // Add this node to the heap.
436  hexes_to_process.push_back(next_index);
437  std::push_heap(hexes_to_process.begin(), hexes_to_process.end(), node_comp);
438 
439  // Bookkeeping (for later).
440  ++nb_dest;
441  if ( next_hex.x < xmin )
442  xmin = next_hex.x;
443  else if ( xmax < next_hex.x )
444  xmax = next_hex.x;
445  if ( next_hex.y < ymin )
446  ymin = next_hex.y;
447  else if ( ymax < next_hex.y )
448  ymax = next_hex.y;
449  }//for (i)
450  }//while (hexes_to_process)
451 
452  // Currently the only caller who uses full_cost_map doesn't need the
453  // destinations. We can skip this part.
454  if ( full_cost_map ) {
455  return;
456  }
457 
458  // Build the routes for every map_location that we reached.
459  // The ordering must be compatible with map_location::operator<.
460  destinations.reserve(nb_dest);
461  for (int x = xmin; x <= xmax; ++x) {
462  for (int y = ymin; y <= ymax; ++y)
463  {
464  const findroute_node &n = nodes[index(x,y)];
465  if ( n.search_num == search_counter ) {
466  paths::step s =
467  { map_location(x,y), n.prev, n.moves_left + n.turns_left*max_moves };
468  destinations.push_back(s);
469  }
470  }
471  }
472 }
473 
474 static bool step_compare(const paths::step& a, const map_location& b) {
475  return a.curr < b;
476 }
477 
478 paths::dest_vect::const_iterator paths::dest_vect::find(const map_location &loc) const
479 {
480  const_iterator i = std::lower_bound(begin(), end(), loc, step_compare);
481  if (i != end() && i->curr != loc) return end();
482  return i;
483 }
484 
486 {
487  iterator i = std::lower_bound(begin(), end(), loc, step_compare);
488  if (i != end() && i->curr == loc) return;
489  paths::step s { loc, map_location(), 0 };
491 }
492 
493 /**
494  * Returns the path going from the source point (included) to the
495  * destination point @a j (excluded).
496  */
497 std::vector<map_location> paths::dest_vect::get_path(const const_iterator &j) const
498 {
499  std::vector<map_location> path;
500  if (!j->prev.valid()) {
501  path.push_back(j->curr);
502  } else {
503  const_iterator i = j;
504  do {
505  i = find(i->prev);
506  assert(i != end());
507  path.push_back(i->curr);
508  } while (i->prev.valid());
509  }
510  std::reverse(path.begin(), path.end());
511  return path;
512 }
513 
515 {
516  return find(loc) != end();
517 }
518 
519 /**
520  * Construct a list of paths for the specified unit.
521  *
522  * This function is used for several purposes, including showing a unit's
523  * potential moves and generating currently possible paths.
524  * @param u The unit whose moves and movement type will be used.
525  * @param force_ignore_zoc Set to true to completely ignore zones of control.
526  * @param allow_teleport Set to true to consider teleportation abilities.
527  * @param viewing_team Usually the current team, except for "show enemy moves", etc.
528  * @param additional_turns The number of turns to account for, in addition to the current.
529  * @param see_all Set to true to remove unit visibility from consideration.
530  * @param ignore_units Set to true if units should never obstruct paths (implies ignoring ZoC as well).
531  */
532 paths::paths(const unit& u, bool force_ignore_zoc,
533  bool allow_teleport, const team &viewing_team,
534  int additional_turns, bool see_all, bool ignore_units)
535  : destinations()
536 {
537  try {
538  find_routes(
539  u.get_location(),
542  u.movement_left(),
543  u.total_movement(),
544  additional_turns,
545  destinations,
546  nullptr,
547  allow_teleport ? &u : nullptr,
548  ignore_units ? nullptr : &resources::gameboard->get_team(u.side()),
549  force_ignore_zoc ? nullptr : &u,
550  see_all ? nullptr : &viewing_team
551  );
552  } catch(const std::out_of_range&) {
553  // Invalid unit side.
554  }
555 }
556 
557 /**
558  * Virtual destructor to support child classes.
559  */
561 {
562 }
563 
564 /**
565  * Constructs a list of vision paths for a unit.
566  *
567  * This is used to construct a list of hexes that the indicated unit can see.
568  * It differs from pathfinding in that it will only ever go out one turn,
569  * and that it will also collect a set of border hexes (the "one hex beyond"
570  * movement to which vision extends).
571  * @param viewer The unit doing the viewing.
572  * @param loc The location from which the viewing occurs
573  * (does not have to be the unit's location).
574  * @param jamming_map The relevant "jamming" of the costs being used.
575  */
576 vision_path::vision_path(const unit& viewer, const map_location& loc,
577  const std::map<map_location, int>& jamming_map)
578  : paths(), edges()
579 {
580  const int sight_range = viewer.vision();
581 
582  // The three nullptr parameters indicate (in order):
583  // ignore units, ignore ZoC (no effect), and don't build a cost_map.
584  // The viewing team needs to be the unit's team here.
585  const team& viewing_team = resources::gameboard->get_team(viewer.side());
586  find_routes(loc, viewer.movement_type().get_vision(),
587  viewer.get_state(unit::STATE_SLOWED), sight_range, sight_range,
588  0, destinations, &edges, &viewer, nullptr, nullptr, &viewing_team, &jamming_map, nullptr, true);
589 }
590 
591 /**
592  * Constructs a list of vision paths for a unit.
593  *
594  * This constructor is provided so that only the relevant portion of a unit's
595  * data is required to construct the vision paths.
596  * @param view_costs The vision costs of the unit doing the viewing.
597  * @param slowed Whether or not the unit is slowed.
598  * @param sight_range The vision() of the unit.
599  * @param loc The location from which the viewing occurs
600  * (does not have to be the unit's location).
601  * @param jamming_map The relevant "jamming" of the costs being used.
602  */
604  int sight_range, const map_location & loc,
605  const std::map<map_location, int>& jamming_map)
606  : paths(), edges()
607 {
608  // The three nullptr parameters indicate (in order):
609  // ignore units, ignore ZoC (no effect), and don't build a cost_map.
611 
612  if(u.valid())
613  {
614  // The viewing team needs to be the unit's team here.
615  const team& viewing_team = resources::gameboard->get_team(u->side());
616  find_routes(loc, view_costs, slowed, sight_range, sight_range, 0,
617  destinations, &edges, &*u, nullptr, nullptr, &viewing_team, &jamming_map, nullptr, true);
618  }
619  else
620  {
621  find_routes(loc, view_costs, slowed, sight_range, sight_range, 0,
622  destinations, &edges, nullptr, nullptr, nullptr, nullptr, &jamming_map, nullptr, true);
623  }
624 }
625 
626 /** Default destructor */
628 {
629 }
630 
631 
632 /**
633  * Constructs a list of jamming paths for a unit.
634  *
635  * This is used to construct a list of hexes that the indicated unit can jam.
636  * It differs from pathfinding in that it will only ever go out one turn.
637  * @param jammer The unit doing the jamming.
638  * @param loc The location from which the jamming occurs
639  * (does not have to be the unit's location).
640  */
641 jamming_path::jamming_path(const unit& jammer, const map_location& loc)
642  : paths()
643 {
644  const int jamming_range = jammer.jamming();
645 
646  // The five nullptr parameters indicate (in order): no edges, no teleports,
647  // ignore units, ignore ZoC (no effect), and see all (no effect).
648  find_routes(loc, jammer.movement_type().get_jamming(),
649  jammer.get_state(unit::STATE_SLOWED), jamming_range, jamming_range,
650  0, destinations, nullptr, nullptr, nullptr, nullptr, nullptr);
651 }
652 
653 /** Default destructor */
655 {
656 }
657 
658 marked_route mark_route(const plain_route &rt, bool update_move_cost)
659 {
660  marked_route res;
661 
662  if (rt.steps.empty()) return marked_route();
663  res.route = rt;
664 
666  if (it == resources::gameboard->units().end()) return marked_route();
667  const unit& u = *it;
668 
669  int turns = 0;
670  int total_costs = 0;
671  int movement = u.movement_left();
672  const team& unit_team = resources::gameboard->get_team(u.side());
673  bool zoc = false;
674 
675  std::vector<map_location>::const_iterator i = rt.steps.begin();
676 
677  for (; i !=rt.steps.end(); ++i) {
678  bool last_step = (i+1 == rt.steps.end());
679 
680  // move_cost of the next step is irrelevant for the last step
681  assert(last_step || resources::gameboard->map().on_board(*(i+1)));
682  const int move_cost = last_step ? 0 : u.movement_cost(static_cast<const game_board*>(resources::gameboard)->map()[*(i+1)]);
683 
684  const team& viewing_team = resources::gameboard->teams()[display::get_singleton()->viewing_team()];
685 
686  if (last_step || zoc || move_cost > movement) {
687  // check if we stop an a village and so maybe capture it
688  // if it's an enemy unit and a fogged village, we assume a capture
689  // (if he already owns it, we can't know that)
690  // if it's not an enemy, we can always know if he owns the village
691  bool capture = resources::gameboard->map().is_village(*i) && ( !unit_team.owns_village(*i)
692  || (viewing_team.is_enemy(u.side()) && viewing_team.fogged(*i)) );
693 
694  ++turns;
695 
696  bool invisible = u.invisible(*i, false);
697 
698  res.marks[*i] = marked_route::mark(turns, zoc, capture, invisible);
699 
700  if(last_step) {
701  if(capture) {
702  total_costs += movement;
703  }
704  break; // finished and we used dummy move_cost
705  }
706 
707  total_costs += movement;
708  movement = u.total_movement();
709  if(move_cost > movement) {
710  return res; //we can't reach destination
711  }
712  }
713 
714  zoc = enemy_zoc(unit_team, *(i + 1), viewing_team)
715  && !u.get_ability_bool("skirmisher", *(i+1));
716 
717  if (zoc) {
718  total_costs += movement;
719  movement = 0;
720  } else {
721  movement -= move_cost;
722  total_costs += move_cost;
723  }
724  }
725 
726  if(update_move_cost) {
727  res.move_cost = total_costs;
728  }
729  return res;
730 }
731 
733  const std::vector<team>& teams, const gamemap& map,
734  bool ignore_unit, bool ignore_defense, bool see_all)
735  : unit_(u), viewing_team_(t), teams_(teams), map_(map),
736  movement_left_(unit_.movement_left()),
737  total_movement_(unit_.total_movement()),
738  ignore_unit_(ignore_unit), ignore_defense_(ignore_defense),
739  see_all_(see_all)
740 {}
741 
742 double shortest_path_calculator::cost(const map_location& loc, const double so_far) const
743 {
744  assert(map_.on_board(loc));
745 
746  // loc is shrouded, consider it impassable
747  // NOTE: This is why AI must avoid to use shroud
748  if (!see_all_ && viewing_team_.shrouded(loc))
749  return getNoPathValue();
750 
751  const t_translation::terrain_code terrain = map_[loc];
752  const int terrain_cost = unit_.movement_cost(terrain);
753  // Pathfinding heuristic: the cost must be at least 1
754  VALIDATE(terrain_cost >= 1, _("Terrain with a movement cost less than 1 encountered."));
755 
756  // Compute how many movement points are left in the game turn
757  // needed to reach the previous hex.
758  // total_movement_ is not zero, thanks to the pathfinding heuristic
759  int remaining_movement = movement_left_ - static_cast<int>(so_far);
760  if (remaining_movement < 0) {
761  remaining_movement = total_movement_ - (-remaining_movement) % total_movement_;
762  }
763 
764  if (terrain_cost >= movetype::UNREACHABLE || (total_movement_ < terrain_cost && remaining_movement < terrain_cost)) {
765  return getNoPathValue();
766  }
767 
768  int other_unit_subcost = 0;
769  if (!ignore_unit_) {
770  const unit *other_unit =
772 
773  // We can't traverse visible enemy and we also prefer empty hexes
774  // (less blocking in multi-turn moves and better when exploring fog,
775  // because we can't stop on a friend)
776 
777  if (other_unit)
778  {
779  if (teams_[unit_.side() - 1].is_enemy(other_unit->side()))
780  return getNoPathValue();
781  else
782  // This value will be used with the defense_subcost (see below)
783  // The 1 here means: consider occupied hex as a -1% defense
784  // (less important than 10% defense because friends may move)
785  other_unit_subcost = 1;
786  }
787  }
788 
789  // this will sum all different costs of this move
790  int move_cost = 0;
791 
792  // Suppose that we have only 2 remaining MP and want to move onto a hex
793  // costing 3 MP. We don't have enough MP now, so we must end our turn here,
794  // thus spend our remaining MP by waiting (next turn, with full MP, we will
795  // be able to move on that hex)
796  if (remaining_movement < terrain_cost) {
797  move_cost += remaining_movement;
798  remaining_movement = total_movement_; // we consider having full MP now
799  }
800 
801  // check ZoC
802  if (!ignore_unit_ && remaining_movement != terrain_cost
804  && !unit_.get_ability_bool("skirmisher", loc)) {
805  // entering ZoC cost all remaining MP
806  move_cost += remaining_movement;
807  } else {
808  // empty hex, pay only the terrain cost
809  move_cost += terrain_cost;
810  }
811 
812  // We will add a tiny cost based on terrain defense, so the pathfinding
813  // will prefer good terrains between 2 with the same MP cost
814  // Keep in mind that defense_modifier is inverted (= 100 - defense%)
815  const int defense_subcost = ignore_defense_ ? 0 : unit_.defense_modifier(terrain);
816 
817  // We divide subcosts by 100 * 100, because defense is 100-based and
818  // we don't want any impact on move cost for less then 100-steps path
819  // (even ~200 since mean defense is around ~50%)
820  return move_cost + (defense_subcost + other_unit_subcost) / 10000.0;
821 }
822 
823 move_type_path_calculator::move_type_path_calculator(const movetype& mt, int movement_left, int total_movement, const team& t, const gamemap& map)
824  : movement_type_(mt), movement_left_(movement_left),
825  total_movement_(total_movement), viewing_team_(t), map_(map)
826 {}
827 
828 // This is an simplified version of shortest_path_calculator (see above for explanation)
829 double move_type_path_calculator::cost(const map_location& loc, const double so_far) const
830 {
831  assert(map_.on_board(loc));
832  if (viewing_team_.shrouded(loc))
833  return getNoPathValue();
834 
835  const t_translation::terrain_code terrain = map_[loc];
836  const int terrain_cost = movement_type_.movement_cost(terrain);
837 
838  if (total_movement_ < terrain_cost)
839  return getNoPathValue();
840 
841  int remaining_movement = movement_left_ - static_cast<int>(so_far);
842  if (remaining_movement < 0)
843  remaining_movement = total_movement_ - (-remaining_movement) % total_movement_;
844 
845  int move_cost = 0;
846 
847  if (remaining_movement < terrain_cost) {
848  move_cost += remaining_movement;
849  }
850 
851  move_cost += terrain_cost;
852 
853  return move_cost;
854 }
855 
856 
858  : unit_(u), map_(map)
859 {}
860 
861 double emergency_path_calculator::cost(const map_location& loc, const double) const
862 {
863  assert(map_.on_board(loc));
864 
865  return unit_.movement_cost(map_[loc]);
866 }
867 
869 {}
870 
871 double dummy_path_calculator::cost(const map_location&, const double) const
872 {
873  return 1.0;
874 }
875 
876 /**
877  * Constructs a cost-map. For a unit each hex is mapped to the cost the
878  * unit will need to reach this hex. Considers movement-loss caused by
879  * turn changes.
880  * Can also used with multiple units to accumulate their costs efficiently.
881  * Will also count how many units could reach a hex for easy normalization.
882  * @param u the unit
883  * @param force_ignore_zoc Set to true to completely ignore zones of control.
884  * @param allow_teleport Set to true to consider teleportation abilities.
885  * @param viewing_team Usually the current team, except for "show enemy moves", etc.
886  * @param see_all Set to true to remove unit visibility from consideration.
887  * @param ignore_units Set to true if units should never obstruct paths (implies ignoring ZoC as well).
888  */
889 full_cost_map::full_cost_map(const unit& u, bool force_ignore_zoc,
890  bool allow_teleport, const team &viewing_team,
891  bool see_all, bool ignore_units)
892  :force_ignore_zoc_(force_ignore_zoc), allow_teleport_(allow_teleport),
893  viewing_team_(viewing_team), see_all_(see_all), ignore_units_(ignore_units)
894 {
895  const gamemap& map = resources::gameboard->map();
896  cost_map = std::vector<std::pair<int, int>>(static_cast<size_t>(map.w()) * map.h(), std::pair(-1, 0));
897  add_unit(u);
898 }
899 
900 /**
901  * Same as other constructor but without unit. Use this when working
902  * with add_unit().
903  */
904 full_cost_map::full_cost_map(bool force_ignore_zoc,
905  bool allow_teleport, const team &viewing_team,
906  bool see_all, bool ignore_units)
907  :force_ignore_zoc_(force_ignore_zoc), allow_teleport_(allow_teleport),
908  viewing_team_(viewing_team), see_all_(see_all), ignore_units_(ignore_units)
909 {
910  const gamemap& map = resources::gameboard->map();
911  cost_map = std::vector<std::pair<int, int>>(static_cast<size_t>(map.w()) * map.h(), std::pair(-1, 0));
912 }
913 
914 /**
915  * Adds a units cost map to cost_map (increments the elements in cost_map)
916  * @param u a real existing unit on the map
917  * @param use_max_moves whether to use the unit's max movement or the unit's remaining movement
918  */
919 void full_cost_map::add_unit(const unit& u, bool use_max_moves)
920 {
921  try {
922  // We don't need the destinations, but find_routes() wants to have this parameter
924 
925  find_routes(
926  u.get_location(),
929  (use_max_moves) ? u.total_movement() : u.movement_left(),
930  u.total_movement(),
931  99,
932  dummy,
933  nullptr,
934  allow_teleport_ ? &u : nullptr,
935  ignore_units_ ? nullptr : &resources::gameboard->get_team(u.side()),
936  force_ignore_zoc_ ? nullptr : &u,
937  see_all_ ? nullptr : &viewing_team_,
938  nullptr,
939  &cost_map
940  );
941  } catch(const std::out_of_range&) {
942  // Invalid unit side.
943  }
944 }
945 
946 /**
947  * Adds a units cost map to cost_map (increments the elements in cost_map)
948  * This function can be used to generate a cost_map with a non existing unit.
949  * @param origin the location on the map from where the calculations shall start
950  * @param ut the unit type we are interested in
951  * @param side the side of the unit. Important for zocs.
952  */
953 void full_cost_map::add_unit(const map_location& origin, const unit_type* const ut, int side)
954 {
955  if (!ut) {
956  return;
957  }
958  unit_ptr u = unit::create(*ut, side, false);
959  u->set_location(origin);
960  add_unit(*u);
961 }
962 
963 /**
964  * Accessor for the cost/reach-amount pairs.
965  * Read comment in pathfind.hpp to cost_map.
966  *
967  * @return the entry of the cost_map at (x, y)
968  * or (-1, 0) if value is not set or (x, y) is invalid.
969  */
970 std::pair<int, int> full_cost_map::get_pair_at(map_location loc) const
971 {
972  const gamemap& map = resources::gameboard->map();
973  assert(cost_map.size() == static_cast<unsigned>(map.w() * map.h()));
974 
975  if (!map.on_board(loc)) {
976  return std::pair(-1, 0); // invalid
977  }
978 
979  return cost_map[loc.x + (loc.y * map.w())];
980 }
981 
982 /**
983  * Accessor for the costs.
984  *
985  * @return the value of the cost_map at (x, y)
986  * or -1 if value is not set or (x, y) is invalid.
987  */
989 {
990  return get_pair_at(loc).first;
991 }
992 
993 /**
994  * Accessor for the costs.
995  *
996  * @return The average cost of all added units for this hex
997  * or -1 if no unit can reach the hex.
998  */
1000 {
1001  auto p = get_pair_at(loc);
1002  if (p.second == 0) {
1003  return -1;
1004  } else {
1005  return static_cast<double>(p.first) /p.second;
1006  }
1007 }
1008 }//namespace pathfind
double t
Definition: astarsearch.cpp:63
std::size_t viewing_team() const
The viewing team is the team currently viewing the game.
Definition: display.hpp:123
static display * get_singleton()
Returns the display object if a display object exists.
Definition: display.hpp:102
Game board class.
Definition: game_board.hpp:46
virtual const std::vector< team > & teams() const override
Definition: game_board.hpp:79
team & get_team(int i)
Definition: game_board.hpp:91
unit * get_visible_unit(const map_location &loc, const team &current_team, bool see_all=false)
Definition: game_board.cpp:213
virtual const unit_map & units() const override
Definition: game_board.hpp:106
virtual const gamemap & map() const override
Definition: game_board.hpp:96
int w() const
Effective map width.
Definition: map.hpp:50
int h() const
Effective map height.
Definition: map.hpp:53
bool on_board(const map_location &loc) const
Tell if a location is on the map.
Definition: map.cpp:384
Encapsulates the map of the game.
Definition: map.hpp:172
bool is_village(const map_location &loc) const
Definition: map.cpp:65
bool is_castle(const map_location &loc) const
Definition: map.cpp:69
A const-only interface for how many (movement, vision, or "jamming") points a unit needs for each hex...
Definition: movetype.hpp:53
int cost(const t_translation::terrain_code &terrain, bool slowed=false) const
Returns the cost associated with the given terrain.
Definition: movetype.hpp:68
The basic "size" of the unit - flying, small land, large land, etc.
Definition: movetype.hpp:44
static const int UNREACHABLE
Magic value that signifies a hex is unreachable.
Definition: movetype.hpp:174
const terrain_costs & get_jamming() const
Definition: movetype.hpp:268
int movement_cost(const t_translation::terrain_code &terrain, bool slowed=false) const
Returns the cost to move through the indicated terrain.
Definition: movetype.hpp:278
const terrain_costs & get_movement() const
Definition: movetype.hpp:266
const terrain_costs & get_vision() const
Definition: movetype.hpp:267
std::set< map_location > get_adjacents(map_location loc) const
Definition: teleport.cpp:234
This class stores all the data for a single 'side' (in game nomenclature).
Definition: team.hpp:74
bool uses_shroud() const
Definition: team.hpp:303
bool is_enemy(int n) const
Definition: team.hpp:229
bool owns_village(const map_location &loc) const
Definition: team.hpp:171
bool shrouded(const map_location &loc) const
Definition: team.cpp:650
bool fogged(const map_location &loc) const
Definition: team.cpp:659
Container associating units to locations.
Definition: map.hpp:98
unit_iterator end()
Definition: map.hpp:428
unit_iterator find(std::size_t id)
Definition: map.cpp:302
A single unit type that the player may recruit.
Definition: types.hpp:43
This class represents a single unit of a specific type.
Definition: unit.hpp:133
static unit_ptr create(const config &cfg, bool use_traits=false, const vconfig *vcfg=nullptr)
Initializes a unit from a config.
Definition: unit.hpp:201
map_display and display: classes which take care of displaying the map and game-data on the screen.
std::size_t i
Definition: function.cpp:968
const unit * unit_
static bool operator<(const placing_info &a, const placing_info &b)
Definition: game_state.cpp:108
static std::string _(const char *str)
Definition: gettext.hpp:93
bool get_ability_bool(const std::string &tag_name, const map_location &loc) const
Checks whether this unit currently possesses or is affected by a given ability.
Definition: abilities.cpp:180
bool invisible(const map_location &loc, bool see_all=true) const
Definition: unit.cpp:2636
bool get_state(const std::string &state) const
Check if the unit is affected by a status effect.
Definition: unit.cpp:1349
int side() const
The side this unit belongs to.
Definition: unit.hpp:343
@ STATE_SLOWED
Definition: unit.hpp:860
int defense_modifier(const t_translation::terrain_code &terrain) const
The unit's defense on a given terrain.
Definition: unit.cpp:1796
bool emits_zoc() const
Tests whether the unit has a zone-of-control, considering incapacitated.
Definition: unit.hpp:1370
int jamming() const
Gets the unit's jamming points.
Definition: unit.hpp:1438
const map_location & get_location() const
The current map location this unit is at.
Definition: unit.hpp:1389
int movement_cost(const t_translation::terrain_code &terrain) const
Get the unit's movement cost on a particular terrain.
Definition: unit.hpp:1472
const movetype & movement_type() const
Get the unit's movement type.
Definition: unit.hpp:1462
int movement_left() const
Gets how far a unit can move, considering the incapacitated flag.
Definition: unit.hpp:1314
int total_movement() const
The maximum moves this unit has.
Definition: unit.hpp:1298
int vision() const
Gets the unit's vision points.
Definition: unit.hpp:1432
void get_adjacent_tiles(const map_location &a, map_location *res)
Function which, given a location, will place all adjacent locations in res.
Definition: location.cpp:474
Standard logging facilities (interface).
std::string path
Definition: filesystem.cpp:89
static void find_routes(const map_location &origin, const movetype::terrain_costs &costs, bool slowed, int moves_left, int max_moves, int turns_left, paths::dest_vect &destinations, std::set< map_location > *edges, const unit *teleporter, const team *current_team, const unit *skirmisher, const team *viewing_team, const std::map< map_location, int > *jamming_map=nullptr, std::vector< std::pair< int, int >> *full_cost_map=nullptr, bool check_vision=false)
Creates a list of routes that a unit can traverse from the provided location.
Definition: pathfind.cpp:270
map_location find_vacant_castle(const unit &leader)
Wrapper for find_vacant_tile() when looking for a vacant castle tile near a leader.
Definition: pathfind.cpp:117
static bool step_compare(const paths::step &a, const map_location &b)
Definition: pathfind.cpp:474
VACANT_TILE_TYPE
Definition: pathfind.hpp:39
@ VACANT_CASTLE
Definition: pathfind.hpp:39
bool enemy_zoc(const team &current_team, const map_location &loc, const team &viewing_team, bool see_all)
Determines if a given location is in an enemy zone of control.
Definition: pathfind.cpp:134
marked_route mark_route(const plain_route &rt, bool update_move_cost)
Add marks on a route rt assuming that the unit located at the first hex of rt travels along it.
Definition: pathfind.cpp:658
const teleport_map get_teleport_locations(const unit &u, const team &viewing_team, bool see_all, bool ignore_units, bool check_vision)
Definition: teleport.cpp:270
map_location find_vacant_tile(const map_location &loc, VACANT_TILE_TYPE vacancy, const unit *pass_check, const team *shroud_check, const game_board *board)
Function that will find a location on the board that is as near to loc as possible,...
Definition: pathfind.cpp:54
game_board * gameboard
Definition: resources.cpp:20
std::size_t index(const std::string &str, const std::size_t index)
Codepoint index corresponding to the nth character in a UTF-8 string.
Definition: unicode.cpp:70
std::string & insert(std::string &str, const std::size_t pos, const std::string &insert)
Insert a UTF-8 string at the specified position.
Definition: unicode.cpp:98
std::string::const_iterator iterator
Definition: tokenizer.hpp:25
int h
Definition: pathfind.cpp:188
static lg::log_domain log_engine("engine")
int turns_left
Definition: pathfind.cpp:156
int moves_left
Definition: pathfind.cpp:156
const std::vector< findroute_node > & nodes
Definition: pathfind.cpp:220
unsigned search_num
Definition: pathfind.cpp:161
int w
Definition: pathfind.cpp:188
map_location prev
Definition: pathfind.cpp:157
This module contains various pathfinding functions and utilities.
std::shared_ptr< unit > unit_ptr
Definition: ptr.hpp:26
Encapsulates the map of the game.
Definition: location.hpp:38
static const map_location & null_location()
Definition: location.hpp:81
static double getNoPathValue()
Definition: pathfind.hpp:65
virtual double cost(const map_location &loc, const double so_far) const
Definition: pathfind.cpp:871
dummy_path_calculator(const unit &u, const gamemap &map)
Definition: pathfind.cpp:868
emergency_path_calculator(const unit &u, const gamemap &map)
Definition: pathfind.cpp:857
virtual double cost(const map_location &loc, const double so_far) const
Definition: pathfind.cpp:861
Structure which uses find_routes() to build a cost map This maps each hex to a the movements a unit w...
Definition: pathfind.hpp:268
const bool force_ignore_zoc_
Definition: pathfind.hpp:299
full_cost_map(const unit &u, bool force_ignore_zoc, bool allow_teleport, const team &viewing_team, bool see_all=true, bool ignore_units=true)
Constructs a cost-map.
Definition: pathfind.cpp:889
double get_average_cost_at(map_location loc) const
Accessor for the costs.
Definition: pathfind.cpp:999
void add_unit(const unit &u, bool use_max_moves=true)
Adds a units cost map to cost_map (increments the elements in cost_map)
Definition: pathfind.cpp:919
const team & viewing_team_
Definition: pathfind.hpp:301
int get_cost_at(map_location loc) const
Accessor for the costs.
Definition: pathfind.cpp:988
std::pair< int, int > get_pair_at(map_location loc) const
Accessor for the cost/reach-amount pairs.
Definition: pathfind.cpp:970
const bool ignore_units_
Definition: pathfind.hpp:303
std::vector< std::pair< int, int > > cost_map
Definition: pathfind.hpp:296
const bool allow_teleport_
Definition: pathfind.hpp:300
jamming_path(const unit &jammer, const map_location &loc)
Construct a list of jammed hexes for a unit.
Definition: pathfind.cpp:641
virtual ~jamming_path()
Default destructor.
Definition: pathfind.cpp:654
Structure which holds a single route and marks for special events.
Definition: pathfind.hpp:142
virtual double cost(const map_location &loc, const double so_far) const
Definition: pathfind.cpp:829
move_type_path_calculator(const movetype &mt, int movement_left, int total_movement, const team &t, const gamemap &map)
Definition: pathfind.cpp:823
Ordered vector of possible destinations.
Definition: pathfind.hpp:95
std::vector< map_location > get_path(const const_iterator &) const
Returns the path going from the source point (included) to the destination point j (excluded).
Definition: pathfind.cpp:497
void insert(const map_location &)
Definition: pathfind.cpp:485
bool contains(const map_location &) const
Definition: pathfind.cpp:514
const_iterator find(const map_location &) const
Definition: pathfind.cpp:478
Object which contains all the possible locations a unit can move to, with associated best routes to t...
Definition: pathfind.hpp:73
virtual ~paths()
Virtual destructor (default processing).
Definition: pathfind.cpp:560
dest_vect destinations
Definition: pathfind.hpp:101
Structure which holds a single route between one location and another.
Definition: pathfind.hpp:133
std::vector< map_location > steps
Definition: pathfind.hpp:135
shortest_path_calculator(const unit &u, const team &t, const std::vector< team > &teams, const gamemap &map, bool ignore_unit=false, bool ignore_defense_=false, bool see_all=false)
Definition: pathfind.cpp:732
const std::vector< team > & teams_
Definition: pathfind.hpp:215
virtual double cost(const map_location &loc, const double so_far) const
Definition: pathfind.cpp:742
std::set< map_location > edges
The edges are the non-destination hexes bordering the destinations.
Definition: pathfind.hpp:117
virtual ~vision_path()
Default destructor.
Definition: pathfind.cpp:627
vision_path(const unit &viewer, const map_location &loc, const std::map< map_location, int > &jamming_map)
Constructs a list of vision paths for a unit.
Definition: pathfind.cpp:576
A terrain string which is converted to a terrain is a string with 1 or 2 layers the layers are separa...
Definition: translation.hpp:49
bool valid() const
Definition: map.hpp:273
mock_party p
static map_location::DIRECTION n
static map_location::DIRECTION s
static std::string mark
Definition: tstring.cpp:70
Add a special kind of assert to validate whether the input from WML doesn't contain any problems that...
#define VALIDATE(cond, message)
The macro to use for the validation of WML.
#define a
#define b