mirror of https://github.com/OpenTTD/OpenTTD
(svn r20890) -Doc: Make documentation accessible to doxygen.
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@ -7,14 +7,12 @@
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* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file aystar.cpp Implementation of A*. */
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/*
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* This file has the core function for AyStar
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* AyStar is a fast pathfinding routine and is used for things like
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* AI_pathfinding and Train_pathfinding.
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* For more information about AyStar (A* Algorithm), you can look at
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* http://en.wikipedia.org/wiki/A-star_search_algorithm
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/** @file aystar.cpp Implementation of A*.
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*
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* This file has the core function for %AyStar.
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* %AyStar is a fast path finding routine and is used for things like AI path finding and Train path finding.
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* For more information about %AyStar (A* Algorithm), you can look at
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* <A HREF='http://en.wikipedia.org/wiki/A-star_search_algorithm'>http://en.wikipedia.org/wiki/A-star_search_algorithm</A>.
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*/
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/*
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@ -29,15 +27,21 @@
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#include "../../core/alloc_func.hpp"
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#include "aystar.h"
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/* This looks in the Hash if a node exists in ClosedList
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* If so, it returns the PathNode, else NULL */
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/**
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* This looks in the hash whether a node exists in the closed list.
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* @param node Node to search.
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* @return The #PathNode if it is available, else \c NULL
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*/
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PathNode *AyStar::ClosedListIsInList(const AyStarNode *node)
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{
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return (PathNode*)this->closedlist_hash.Get(node->tile, node->direction);
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}
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/* This adds a node to the ClosedList
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* It makes a copy of the data */
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/**
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* This adds a node to the closed list.
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* It makes a copy of the data.
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* @param node Node to add to the closed list.
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*/
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void AyStar::ClosedListAdd(const PathNode *node)
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{
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/* Add a node to the ClosedList */
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@ -46,16 +50,21 @@ void AyStar::ClosedListAdd(const PathNode *node)
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this->closedlist_hash.Set(node->node.tile, node->node.direction, new_node);
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}
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/* Checks if a node is in the OpenList
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* If so, it returns the OpenListNode, else NULL */
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/**
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* Check whether a node is in the open list.
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* @param node Node to search.
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* @return If the node is available, it is returned, else \c NULL is returned.
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*/
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OpenListNode *AyStar::OpenListIsInList(const AyStarNode *node)
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{
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return (OpenListNode*)this->openlist_hash.Get(node->tile, node->direction);
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}
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/* Gets the best node from OpenList
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* returns the best node, or NULL of none is found
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* Also it deletes the node from the OpenList */
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/**
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* Gets the best node from the open list.
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* It deletes the returned node from the open list.
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* @returns the best node available, or \c NULL of none is found.
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*/
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OpenListNode *AyStar::OpenListPop()
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{
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/* Return the item the Queue returns.. the best next OpenList item. */
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@ -67,8 +76,10 @@ OpenListNode *AyStar::OpenListPop()
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return res;
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}
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/* Adds a node to the OpenList
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* It makes a copy of node, and puts the pointer of parent in the struct */
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/**
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* Adds a node to the open list.
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* It makes a copy of node, and puts the pointer of parent in the struct.
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*/
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void AyStar::OpenListAdd(PathNode *parent, const AyStarNode *node, int f, int g)
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{
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/* Add a new Node to the OpenList */
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@ -82,8 +93,8 @@ void AyStar::OpenListAdd(PathNode *parent, const AyStarNode *node, int f, int g)
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this->openlist_queue.Push(new_node, f);
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}
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/*
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* Checks one tile and calculate his f-value
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/**
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* Checks one tile and calculate its f-value
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*/
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void AyStar::CheckTile(AyStarNode *current, OpenListNode *parent)
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{
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@ -138,16 +149,14 @@ void AyStar::CheckTile(AyStarNode *current, OpenListNode *parent)
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}
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}
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/*
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* This function is the core of AyStar. It handles one item and checks
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* his neighbour items. If they are valid, they are added to be checked too.
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* return values:
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* AYSTAR_EMPTY_OPENLIST : indicates all items are tested, and no path
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* has been found.
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* AYSTAR_LIMIT_REACHED : Indicates that the max_nodes limit has been
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* reached.
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* AYSTAR_FOUND_END_NODE : indicates we found the end. Path_found now is true, and in path is the path found.
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* AYSTAR_STILL_BUSY : indicates we have done this tile, did not found the path yet, and have items left to try.
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/**
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* This function is the core of %AyStar. It handles one item and checks
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* his neighbour items. If they are valid, they are added to be checked too.
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* @return Possible values:
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* - #AYSTAR_EMPTY_OPENLIST : indicates all items are tested, and no path has been found.
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* - #AYSTAR_LIMIT_REACHED : Indicates that the max_nodes limit has been reached.
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* - #AYSTAR_FOUND_END_NODE : indicates we found the end. Path_found now is true, and in path is the path found.
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* - #AYSTAR_STILL_BUSY : indicates we have done this tile, did not found the path yet, and have items left to try.
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*/
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int AyStar::Loop()
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{
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@ -191,7 +200,7 @@ int AyStar::Loop()
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}
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}
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/*
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/**
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* This function frees the memory it allocated
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*/
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void AyStar::Free()
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#endif
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}
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/*
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* This function make the memory go back to zero
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* This function should be called when you are using the same instance again.
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/**
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* This function make the memory go back to zero.
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* This function should be called when you are using the same instance again.
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*/
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void AyStar::Clear()
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{
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#endif
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}
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/*
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/**
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* This is the function you call to run AyStar.
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* return values:
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* AYSTAR_FOUND_END_NODE : indicates we found an end node.
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* AYSTAR_NO_PATH : indicates that there was no path found.
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* AYSTAR_STILL_BUSY : indicates we have done some checked, that we did not found the path yet, and that we still have items left to try.
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* When the algorithm is done (when the return value is not AYSTAR_STILL_BUSY)
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* this->Clear() is called. Note that when you stop the algorithm halfway,
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* you should still call Clear() yourself!
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* @return Possible values:
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* - #AYSTAR_FOUND_END_NODE : indicates we found an end node.
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* - #AYSTAR_NO_PATH : indicates that there was no path found.
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* - #AYSTAR_STILL_BUSY : indicates we have done some checked, that we did not found the path yet, and that we still have items left to try.
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* @note When the algorithm is done (when the return value is not #AYSTAR_STILL_BUSY) #Clear() is called automatically.
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* When you stop the algorithm halfway, you should call #Clear() yourself!
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*/
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int AyStar::Main()
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{
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}
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}
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/*
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/**
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* Adds a node from where to start an algorithm. Multiple nodes can be added
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* if wanted. You should make sure that clear() is called before adding nodes
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* if the AyStar has been used before (though the normal main loop calls
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* clear() automatically when the algorithm finishes
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* g is the cost for starting with this node.
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* if wanted. You should make sure that #Clear() is called before adding nodes
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* if the #AyStar has been used before (though the normal main loop calls
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* #Clear() automatically when the algorithm finishes.
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* @param start_node Node to start with.
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* @param g the cost for starting with this node.
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*/
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void AyStar::AddStartNode(AyStarNode *start_node, uint g)
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{
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@ -279,8 +288,7 @@ void AyStar::AddStartNode(AyStarNode *start_node, uint g)
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/**
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* Initialize an #AyStar. You should fill all appropriate fields before
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* calling #Init (see the declaration of #AyStar for which fields are
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* internal.
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* calling #Init (see the declaration of #AyStar for which fields are internal).
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*/
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void AyStar::Init(Hash_HashProc hash, uint num_buckets)
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{
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@ -9,11 +9,10 @@
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/**
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* @file aystar.h
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* This file has the header for AyStar
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* AyStar is a fast pathfinding routine and is used for things like
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* AI_pathfinding and Train_pathfinding.
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* For more information about AyStar (A* Algorithm), you can look at
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* http://en.wikipedia.org/wiki/A-star_search_algorithm
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* This file has the header for %AyStar.
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* %AyStar is a fast path finding routine and is used for things like AI path finding and Train path finding.
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* For more information about AyStar (A* Algorithm), you can look at
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* <A HREF='http://en.wikipedia.org/wiki/A-star_search_algorithm'>http://en.wikipedia.org/wiki/A-star_search_algorithm</A>.
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*/
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#ifndef AYSTAR_H
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#include "../../track_type.h"
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//#define AYSTAR_DEBUG
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/** Return status of #AyStar methods. */
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enum AystarStatus {
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AYSTAR_FOUND_END_NODE,
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AYSTAR_EMPTY_OPENLIST,
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AYSTAR_STILL_BUSY,
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AYSTAR_NO_PATH,
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AYSTAR_LIMIT_REACHED,
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AYSTAR_DONE
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AYSTAR_FOUND_END_NODE, ///< An end node was found.
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AYSTAR_EMPTY_OPENLIST, ///< All items are tested, and no path has been found.
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AYSTAR_STILL_BUSY, ///< Some checking was done, but no path found yet, and there are still items left to try.
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AYSTAR_NO_PATH, ///< No path to the goal was found.
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AYSTAR_LIMIT_REACHED, ///< The #max_nodes limit has been reached, aborting search.
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AYSTAR_DONE, ///< Not an end-tile, or wrong direction.
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};
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static const int AYSTAR_INVALID_NODE = -1;
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static const int AYSTAR_INVALID_NODE = -1; ///< Item is not valid (for example, not walkable).
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/** Node in the search. */
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struct AyStarNode {
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TileIndex tile;
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Trackdir direction;
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uint user_data[2];
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};
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/* The resulting path has nodes looking like this. */
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/** A path of nodes. */
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struct PathNode {
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AyStarNode node;
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/* The parent of this item */
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PathNode *parent;
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PathNode *parent; ///< The parent of this item.
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};
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/* For internal use only
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* We do not save the h-value, because it is only needed to calculate the f-value.
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* h-value should _always_ be the distance left to the end-tile. */
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/**
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* Internal node.
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* @note We do not save the h-value, because it is only needed to calculate the f-value.
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* h-value should \em always be the distance left to the end-tile.
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*/
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struct OpenListNode {
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int g;
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PathNode path;
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};
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struct AyStar;
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/*
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* This function is called to check if the end-tile is found
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* return values can be:
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* AYSTAR_FOUND_END_NODE : indicates this is the end tile
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* AYSTAR_DONE : indicates this is not the end tile (or direction was wrong)
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*/
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/*
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* The 2nd parameter should be OpenListNode, and NOT AyStarNode. AyStarNode is
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* part of OpenListNode and so it could be accessed without any problems.
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* The good part about OpenListNode is, and how AIs use it, that you can
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/**
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* Check whether the end-tile is found.
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* @param aystar %AyStar search algorithm data.
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* @param current Node to examone.
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* @note The 2nd parameter should be #OpenListNode, and \em not #AyStarNode. #AyStarNode is
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* part of #OpenListNode and so it could be accessed without any problems.
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* The good part about #OpenListNode is, and how AIs use it, that you can
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* access the parent of the current node, and so check if you, for example
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* don't try to enter the file tile with a 90-degree curve. So please, leave
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* this an OpenListNode, it works just fine -- TrueLight
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* this an #OpenListNode, it works just fine -- TrueLight
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* @return Status of the node:
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* - #AYSTAR_FOUND_END_NODE : indicates this is the end tile
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* - #AYSTAR_DONE : indicates this is not the end tile (or direction was wrong)
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*/
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typedef int32 AyStar_EndNodeCheck(AyStar *aystar, OpenListNode *current);
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/*
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* This function is called to calculate the G-value for AyStar Algorithm.
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* return values can be:
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* AYSTAR_INVALID_NODE : indicates an item is not valid (e.g.: unwalkable)
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* Any value >= 0 : the g-value for this tile
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/**
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* Calculate the G-value for the %AyStar algorithm.
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* @return G value of the node:
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* - #AYSTAR_INVALID_NODE : indicates an item is not valid (e.g.: unwalkable)
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* - Any value >= 0 : the g-value for this tile
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*/
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typedef int32 AyStar_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
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/*
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* This function is called to calculate the H-value for AyStar Algorithm.
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* Mostly, this must result the distance (Manhattan way) between the
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* current point and the end point
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* return values can be:
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* Any value >= 0 : the h-value for this tile
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/**
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* Calculate the H-value for the %AyStar algorithm.
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* Mostly, this must return the distance (Manhattan way) between the current point and the end point.
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* @return The h-value for this tile (any value >= 0)
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*/
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typedef int32 AyStar_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
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/*
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* This function request the tiles around the current tile and put them in tiles_around
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* tiles_around is never resetted, so if you are not using directions, just leave it alone.
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* Warning: never add more tiles_around than memory allocated for it.
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/**
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* This function requests the tiles around the current tile and put them in #tiles_around.
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* #tiles_around is never reset, so if you are not using directions, just leave it alone.
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* \warning Never add more tiles_around than memory allocated for it.
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*/
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typedef void AyStar_GetNeighbours(AyStar *aystar, OpenListNode *current);
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/*
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/**
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* If the End Node is found, this function is called.
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* It can do, for example, calculate the route and put that in an array
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* It can do, for example, calculate the route and put that in an array.
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*/
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typedef void AyStar_FoundEndNode(AyStar *aystar, OpenListNode *current);
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/**
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* %AyStar search algorithm struct.
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* Before calling #Init(), fill #CalculateG, #CalculateH, #GetNeighbours, #EndNodeCheck, and #FoundEndNode.
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* If you want to change them after calling #Init(), first call #Free() !
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*
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* 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.
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* The user routines can change any moment they like.
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*/
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struct AyStar {
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/* These fields should be filled before initting the AyStar, but not changed
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/* These fields should be filled before initing the AyStar, but not changed
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* afterwards (except for user_data and user_path)! (free and init again to change them) */
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/* These should point to the application specific routines that do the
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AyStar_EndNodeCheck *EndNodeCheck;
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AyStar_FoundEndNode *FoundEndNode;
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/* These are completely untouched by AyStar, they can be accesed by
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/* These are completely untouched by AyStar, they can be accessed by
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* the application specific routines to input and output data.
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* user_path should typically contain data about the resulting path
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* afterwards, user_target should typically contain information about
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* what where looking for, and user_data can contain just about
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* what you where looking for, and user_data can contain just about
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* everything */
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void *user_path;
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void *user_target;
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uint user_data[10];
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/* How many loops are there called before Main() gives
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* control back to the caller. 0 = until done */
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byte loops_per_tick;
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/* If the g-value goes over this number, it stops searching
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* 0 = infinite */
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uint max_path_cost;
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/* The maximum amount of nodes that will be expanded, 0 = infinite */
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uint max_search_nodes;
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byte loops_per_tick; ///< How many loops are there called before Main() gives control back to the caller. 0 = until done.
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uint max_path_cost; ///< If the g-value goes over this number, it stops searching, 0 = infinite.
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uint max_search_nodes; ///< The maximum number of nodes that will be expanded, 0 = infinite.
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/* These should be filled with the neighbours of a tile by
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* GetNeighbours */
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