diff options
Diffstat (limited to 'src/pathfinder/npf/aystar.h')
| -rw-r--r-- | src/pathfinder/npf/aystar.h | 119 |
1 files changed, 62 insertions, 57 deletions
diff --git a/src/pathfinder/npf/aystar.h b/src/pathfinder/npf/aystar.h index 3c346a80c..df6e59593 100644 --- a/src/pathfinder/npf/aystar.h +++ b/src/pathfinder/npf/aystar.h @@ -9,11 +9,10 @@ /** * @file aystar.h - * This file has the header for AyStar - * AyStar is a fast pathfinding routine and is used for things like - * AI_pathfinding and Train_pathfinding. - * For more information about AyStar (A* Algorithm), you can look at - * http://en.wikipedia.org/wiki/A-star_search_algorithm + * This file has the header for %AyStar. + * %AyStar is a fast path finding routine and is used for things like AI path finding and Train path finding. + * For more information about AyStar (A* Algorithm), you can look at + * <A HREF='http://en.wikipedia.org/wiki/A-star_search_algorithm'>http://en.wikipedia.org/wiki/A-star_search_algorithm</A>. */ #ifndef AYSTAR_H @@ -24,87 +23,98 @@ #include "../../track_type.h" //#define AYSTAR_DEBUG + +/** Return status of #AyStar methods. */ enum AystarStatus { - AYSTAR_FOUND_END_NODE, - AYSTAR_EMPTY_OPENLIST, - AYSTAR_STILL_BUSY, - AYSTAR_NO_PATH, - AYSTAR_LIMIT_REACHED, - AYSTAR_DONE + AYSTAR_FOUND_END_NODE, ///< An end node was found. + AYSTAR_EMPTY_OPENLIST, ///< All items are tested, and no path has been found. + AYSTAR_STILL_BUSY, ///< Some checking was done, but no path found yet, and there are still items left to try. + AYSTAR_NO_PATH, ///< No path to the goal was found. + AYSTAR_LIMIT_REACHED, ///< The #max_nodes limit has been reached, aborting search. + AYSTAR_DONE, ///< Not an end-tile, or wrong direction. }; -static const int AYSTAR_INVALID_NODE = -1; +static const int AYSTAR_INVALID_NODE = -1; ///< Item is not valid (for example, not walkable). +/** Node in the search. */ struct AyStarNode { TileIndex tile; Trackdir direction; uint user_data[2]; }; -/* The resulting path has nodes looking like this. */ +/** A path of nodes. */ struct PathNode { AyStarNode node; - /* The parent of this item */ - PathNode *parent; + PathNode *parent; ///< The parent of this item. }; -/* For internal use only - * We do not save the h-value, because it is only needed to calculate the f-value. - * h-value should _always_ be the distance left to the end-tile. */ +/** + * Internal node. + * @note We do not save the h-value, because it is only needed to calculate the f-value. + * h-value should \em always be the distance left to the end-tile. + */ struct OpenListNode { int g; PathNode path; }; struct AyStar; -/* - * This function is called to check if the end-tile is found - * return values can be: - * AYSTAR_FOUND_END_NODE : indicates this is the end tile - * AYSTAR_DONE : indicates this is not the end tile (or direction was wrong) - */ -/* - * The 2nd parameter should be OpenListNode, and NOT AyStarNode. AyStarNode is - * part of OpenListNode and so it could be accessed without any problems. - * The good part about OpenListNode is, and how AIs use it, that you can + +/** + * Check whether the end-tile is found. + * @param aystar %AyStar search algorithm data. + * @param current Node to examone. + * @note The 2nd parameter should be #OpenListNode, and \em not #AyStarNode. #AyStarNode is + * part of #OpenListNode and so it could be accessed without any problems. + * The good part about #OpenListNode is, and how AIs use it, that you can * access the parent of the current node, and so check if you, for example * don't try to enter the file tile with a 90-degree curve. So please, leave - * this an OpenListNode, it works just fine -- TrueLight + * this an #OpenListNode, it works just fine -- TrueLight + * @return Status of the node: + * - #AYSTAR_FOUND_END_NODE : indicates this is the end tile + * - #AYSTAR_DONE : indicates this is not the end tile (or direction was wrong) */ typedef int32 AyStar_EndNodeCheck(AyStar *aystar, OpenListNode *current); -/* - * This function is called to calculate the G-value for AyStar Algorithm. - * return values can be: - * AYSTAR_INVALID_NODE : indicates an item is not valid (e.g.: unwalkable) - * Any value >= 0 : the g-value for this tile +/** + * Calculate the G-value for the %AyStar algorithm. + * @return G value of the node: + * - #AYSTAR_INVALID_NODE : indicates an item is not valid (e.g.: unwalkable) + * - Any value >= 0 : the g-value for this tile */ typedef int32 AyStar_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent); -/* - * This function is called to calculate the H-value for AyStar Algorithm. - * Mostly, this must result the distance (Manhattan way) between the - * current point and the end point - * return values can be: - * Any value >= 0 : the h-value for this tile +/** + * Calculate the H-value for the %AyStar algorithm. + * Mostly, this must return the distance (Manhattan way) between the current point and the end point. + * @return The h-value for this tile (any value >= 0) */ typedef int32 AyStar_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent); -/* - * This function request the tiles around the current tile and put them in tiles_around - * tiles_around is never resetted, so if you are not using directions, just leave it alone. - * Warning: never add more tiles_around than memory allocated for it. +/** + * This function requests the tiles around the current tile and put them in #tiles_around. + * #tiles_around is never reset, so if you are not using directions, just leave it alone. + * \warning Never add more tiles_around than memory allocated for it. */ typedef void AyStar_GetNeighbours(AyStar *aystar, OpenListNode *current); -/* +/** * If the End Node is found, this function is called. - * It can do, for example, calculate the route and put that in an array + * It can do, for example, calculate the route and put that in an array. */ typedef void AyStar_FoundEndNode(AyStar *aystar, OpenListNode *current); +/** + * %AyStar search algorithm struct. + * Before calling #Init(), fill #CalculateG, #CalculateH, #GetNeighbours, #EndNodeCheck, and #FoundEndNode. + * If you want to change them after calling #Init(), first call #Free() ! + * + * The #user_path, #user_target, and #user_data[10] are intended to be used by the user routines. The data not accessed by the #AyStar code itself. + * The user routines can change any moment they like. + */ struct AyStar { -/* These fields should be filled before initting the AyStar, but not changed +/* These fields should be filled before initing the AyStar, but not changed * afterwards (except for user_data and user_path)! (free and init again to change them) */ /* These should point to the application specific routines that do the @@ -115,24 +125,19 @@ struct AyStar { AyStar_EndNodeCheck *EndNodeCheck; AyStar_FoundEndNode *FoundEndNode; - /* These are completely untouched by AyStar, they can be accesed by + /* These are completely untouched by AyStar, they can be accessed by * the application specific routines to input and output data. * user_path should typically contain data about the resulting path * afterwards, user_target should typically contain information about - * what where looking for, and user_data can contain just about + * what you where looking for, and user_data can contain just about * everything */ void *user_path; void *user_target; uint user_data[10]; - /* How many loops are there called before Main() gives - * control back to the caller. 0 = until done */ - byte loops_per_tick; - /* If the g-value goes over this number, it stops searching - * 0 = infinite */ - uint max_path_cost; - /* The maximum amount of nodes that will be expanded, 0 = infinite */ - uint max_search_nodes; + byte loops_per_tick; ///< How many loops are there called before Main() gives control back to the caller. 0 = until done. + uint max_path_cost; ///< If the g-value goes over this number, it stops searching, 0 = infinite. + uint max_search_nodes; ///< The maximum number of nodes that will be expanded, 0 = infinite. /* These should be filled with the neighbours of a tile by * GetNeighbours */ |