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author | rubidium <rubidium@openttd.org> | 2007-01-02 19:19:48 +0000 |
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committer | rubidium <rubidium@openttd.org> | 2007-01-02 19:19:48 +0000 |
commit | 66bbf336c6af7353ef0aeed58002c46543b30635 (patch) | |
tree | ad4a63860df2626b22f77e7dac712e958bea54cb /src/aystar.c | |
parent | ccc0a3f4dbf58c005b22341ac8874252924690cd (diff) | |
download | openttd-66bbf336c6af7353ef0aeed58002c46543b30635.tar.xz |
(svn r7759) -Merge: makefile rewrite. This merge features:
- A proper ./configure, so everything needs to be configured only once, not for every make.
- Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
- A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
- Proper support for OSX universal binaries.
- Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
- Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.
Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.
Diffstat (limited to 'src/aystar.c')
-rw-r--r-- | src/aystar.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/src/aystar.c b/src/aystar.c new file mode 100644 index 000000000..0000d584c --- /dev/null +++ b/src/aystar.c @@ -0,0 +1,296 @@ +/* $Id$ */ + +/* + * This file has the core function 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 + */ + +/* + * Friendly reminder: + * Call (AyStar).free() when you are done with Aystar. It reserves a lot of memory + * And when not free'd, it can cause system-crashes. + * Also remember that when you stop an algorithm before it is finished, your + * should call clear() yourself! + */ + +#include "stdafx.h" +#include "openttd.h" +#include "aystar.h" + +int _aystar_stats_open_size; +int _aystar_stats_closed_size; + +// This looks in the Hash if a node exists in ClosedList +// If so, it returns the PathNode, else NULL +static PathNode* AyStarMain_ClosedList_IsInList(AyStar *aystar, const AyStarNode *node) +{ + return (PathNode*)Hash_Get(&aystar->ClosedListHash, node->tile, node->direction); +} + +// This adds a node to the ClosedList +// It makes a copy of the data +static void AyStarMain_ClosedList_Add(AyStar *aystar, const PathNode *node) +{ + // Add a node to the ClosedList + PathNode *new_node = malloc(sizeof(*new_node)); + *new_node = *node; + Hash_Set(&aystar->ClosedListHash, node->node.tile, node->node.direction, new_node); +} + +// Checks if a node is in the OpenList +// If so, it returns the OpenListNode, else NULL +static OpenListNode *AyStarMain_OpenList_IsInList(AyStar *aystar, const AyStarNode *node) +{ + return (OpenListNode*)Hash_Get(&aystar->OpenListHash, node->tile, node->direction); +} + +// Gets the best node from OpenList +// returns the best node, or NULL of none is found +// Also it deletes the node from the OpenList +static OpenListNode *AyStarMain_OpenList_Pop(AyStar *aystar) +{ + // Return the item the Queue returns.. the best next OpenList item. + OpenListNode *res = (OpenListNode*)aystar->OpenListQueue.pop(&aystar->OpenListQueue); + if (res != NULL) { + Hash_Delete(&aystar->OpenListHash, res->path.node.tile, res->path.node.direction); + } + + return res; +} + +// Adds a node to the OpenList +// It makes a copy of node, and puts the pointer of parent in the struct +static void AyStarMain_OpenList_Add(AyStar *aystar, PathNode *parent, const AyStarNode *node, int f, int g) +{ + // Add a new Node to the OpenList + OpenListNode *new_node = malloc(sizeof(*new_node)); + new_node->g = g; + new_node->path.parent = parent; + new_node->path.node = *node; + Hash_Set(&aystar->OpenListHash, node->tile, node->direction, new_node); + + // Add it to the queue + aystar->OpenListQueue.push(&aystar->OpenListQueue, new_node, f); +} + +/* + * Checks one tile and calculate his f-value + * return values: + * AYSTAR_DONE : indicates we are done + */ +int AyStarMain_CheckTile(AyStar *aystar, AyStarNode *current, OpenListNode *parent) +{ + int new_f, new_g, new_h; + PathNode *closedlist_parent; + OpenListNode *check; + + // Check the new node against the ClosedList + if (AyStarMain_ClosedList_IsInList(aystar, current) != NULL) return AYSTAR_DONE; + + // Calculate the G-value for this node + new_g = aystar->CalculateG(aystar, current, parent); + // If the value was INVALID_NODE, we don't do anything with this node + if (new_g == AYSTAR_INVALID_NODE) return AYSTAR_DONE; + + // There should not be given any other error-code.. + assert(new_g >= 0); + // Add the parent g-value to the new g-value + new_g += parent->g; + if (aystar->max_path_cost != 0 && (uint)new_g > aystar->max_path_cost) return AYSTAR_DONE; + + // Calculate the h-value + new_h = aystar->CalculateH(aystar, current, parent); + // There should not be given any error-code.. + assert(new_h >= 0); + + // The f-value if g + h + new_f = new_g + new_h; + + // Get the pointer to the parent in the ClosedList (the currentone is to a copy of the one in the OpenList) + closedlist_parent = AyStarMain_ClosedList_IsInList(aystar, &parent->path.node); + + // Check if this item is already in the OpenList + check = AyStarMain_OpenList_IsInList(aystar, current); + if (check != NULL) { + uint i; + // Yes, check if this g value is lower.. + if (new_g > check->g) return AYSTAR_DONE; + aystar->OpenListQueue.del(&aystar->OpenListQueue, check, 0); + // It is lower, so change it to this item + check->g = new_g; + check->path.parent = closedlist_parent; + /* Copy user data, will probably have changed */ + for (i = 0; i < lengthof(current->user_data); i++) { + check->path.node.user_data[i] = current->user_data[i]; + } + // Readd him in the OpenListQueue + aystar->OpenListQueue.push(&aystar->OpenListQueue, check, new_f); + } else { + // A new node, add him to the OpenList + AyStarMain_OpenList_Add(aystar, closedlist_parent, current, new_f, new_g); + } + + return AYSTAR_DONE; +} + +/* + * This function is the core of AyStar. It handles one item and checks + * his neighbour items. If they are valid, they are added to be checked too. + * return values: + * AYSTAR_EMPTY_OPENLIST : indicates all items are tested, and no path + * has been found. + * AYSTAR_LIMIT_REACHED : Indicates that the max_nodes limit has been + * reached. + * AYSTAR_FOUND_END_NODE : indicates we found the end. Path_found now is true, and in path is the path found. + * AYSTAR_STILL_BUSY : indicates we have done this tile, did not found the path yet, and have items left to try. + */ +int AyStarMain_Loop(AyStar *aystar) +{ + int i, r; + + // Get the best node from OpenList + OpenListNode *current = AyStarMain_OpenList_Pop(aystar); + // If empty, drop an error + if (current == NULL) return AYSTAR_EMPTY_OPENLIST; + + // Check for end node and if found, return that code + if (aystar->EndNodeCheck(aystar, current) == AYSTAR_FOUND_END_NODE) { + if (aystar->FoundEndNode != NULL) + aystar->FoundEndNode(aystar, current); + free(current); + return AYSTAR_FOUND_END_NODE; + } + + // Add the node to the ClosedList + AyStarMain_ClosedList_Add(aystar, ¤t->path); + + // Load the neighbours + aystar->GetNeighbours(aystar, current); + + // Go through all neighbours + for (i = 0; i < aystar->num_neighbours; i++) { + // Check and add them to the OpenList if needed + r = aystar->checktile(aystar, &aystar->neighbours[i], current); + } + + // Free the node + free(current); + + if (aystar->max_search_nodes != 0 && Hash_Size(&aystar->ClosedListHash) >= aystar->max_search_nodes) { + /* We've expanded enough nodes */ + return AYSTAR_LIMIT_REACHED; + } else { + // Return that we are still busy + return AYSTAR_STILL_BUSY; + } +} + +/* + * This function frees the memory it allocated + */ +void AyStarMain_Free(AyStar *aystar) +{ + aystar->OpenListQueue.free(&aystar->OpenListQueue, false); + /* 2nd argument above is false, below is true, to free the values only + * once */ + delete_Hash(&aystar->OpenListHash, true); + delete_Hash(&aystar->ClosedListHash, true); +#ifdef AYSTAR_DEBUG + printf("[AyStar] Memory free'd\n"); +#endif +} + +/* + * This function make the memory go back to zero + * This function should be called when you are using the same instance again. + */ +void AyStarMain_Clear(AyStar *aystar) +{ + // Clean the Queue, but not the elements within. That will be done by + // the hash. + aystar->OpenListQueue.clear(&aystar->OpenListQueue, false); + // Clean the hashes + clear_Hash(&aystar->OpenListHash, true); + clear_Hash(&aystar->ClosedListHash, true); + +#ifdef AYSTAR_DEBUG + printf("[AyStar] Cleared AyStar\n"); +#endif +} + +/* + * This is the function you call to run AyStar. + * return values: + * AYSTAR_FOUND_END_NODE : indicates we found an end node. + * AYSTAR_NO_PATH : indicates that there was no path found. + * 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. + * When the algorithm is done (when the return value is not AYSTAR_STILL_BUSY) + * aystar->clear() is called. Note that when you stop the algorithm halfway, + * you should still call clear() yourself! + */ +int AyStarMain_Main(AyStar *aystar) { + int r, i = 0; + // Loop through the OpenList + // Quit if result is no AYSTAR_STILL_BUSY or is more than loops_per_tick + while ((r = aystar->loop(aystar)) == AYSTAR_STILL_BUSY && (aystar->loops_per_tick == 0 || ++i < aystar->loops_per_tick)) { } +#ifdef AYSTAR_DEBUG + switch (r) { + case AYSTAR_FOUND_END_NODE: printf("[AyStar] Found path!\n"); break; + case AYSTAR_EMPTY_OPENLIST: printf("[AyStar] OpenList run dry, no path found\n"); break; + case AYSTAR_LIMIT_REACHED: printf("[AyStar] Exceeded search_nodes, no path found\n"); break; + default: break; + } +#endif + if (r != AYSTAR_STILL_BUSY) { + /* We're done, clean up */ + _aystar_stats_open_size = aystar->OpenListHash.size; + _aystar_stats_closed_size = aystar->ClosedListHash.size; + aystar->clear(aystar); + } + + switch (r) { + case AYSTAR_FOUND_END_NODE: return AYSTAR_FOUND_END_NODE; + case AYSTAR_EMPTY_OPENLIST: + case AYSTAR_LIMIT_REACHED: return AYSTAR_NO_PATH; + default: return AYSTAR_STILL_BUSY; + } +} + +/* + * Adds a node from where to start an algorithm. Multiple nodes can be added + * if wanted. You should make sure that clear() is called before adding nodes + * if the AyStar has been used before (though the normal main loop calls + * clear() automatically when the algorithm finishes + * g is the cost for starting with this node. + */ +void AyStarMain_AddStartNode(AyStar *aystar, AyStarNode *start_node, uint g) +{ +#ifdef AYSTAR_DEBUG + printf("[AyStar] Starting A* Algorithm from node (%d, %d, %d)\n", + TileX(start_node->tile), TileY(start_node->tile), start_node->direction); +#endif + AyStarMain_OpenList_Add(aystar, NULL, start_node, 0, g); +} + +void init_AyStar(AyStar *aystar, Hash_HashProc hash, uint num_buckets) +{ + // Allocated the Hash for the OpenList and ClosedList + init_Hash(&aystar->OpenListHash, hash, num_buckets); + init_Hash(&aystar->ClosedListHash, hash, num_buckets); + + // Set up our sorting queue + // BinaryHeap allocates a block of 1024 nodes + // When thatone gets full it reserves an otherone, till this number + // That is why it can stay this high + init_BinaryHeap(&aystar->OpenListQueue, 102400); + + aystar->addstart = AyStarMain_AddStartNode; + aystar->main = AyStarMain_Main; + aystar->loop = AyStarMain_Loop; + aystar->free = AyStarMain_Free; + aystar->clear = AyStarMain_Clear; + aystar->checktile = AyStarMain_CheckTile; +} |