tron@2186: /* $Id$ */
tron@2186: 
truelight@110: /*
truelight@110:  * This file has the core function for AyStar
truelight@110:  *  AyStar is a fast pathfinding routine and is used for things like
truelight@110:  *  AI_pathfinding and Train_pathfinding.
truelight@110:  *  For more information about AyStar (A* Algorithm), you can look at
truelight@110:  *    http://en.wikipedia.org/wiki/A-star_search_algorithm
truelight@110:  */
truelight@193: 
truelight@110: /*
truelight@110:  * Friendly reminder:
truelight@110:  *  Call (AyStar).free() when you are done with Aystar. It reserves a lot of memory
truelight@110:  *  And when not free'd, it can cause system-crashes.
truelight@110:  * Also remember that when you stop an algorithm before it is finished, your
truelight@110:  * should call clear() yourself!
truelight@110:  */
truelight@110: 
truelight@110: #include "stdafx.h"
Darkvater@1891: #include "openttd.h"
truelight@110: #include "aystar.h"
truelight@110: // This looks in the Hash if a node exists in ClosedList
truelight@110: //  If so, it returns the PathNode, else NULL
tron@1095: static PathNode *AyStarMain_ClosedList_IsInList(AyStar *aystar, AyStarNode *node)
tron@1095: {
truelight@110: 	return (PathNode*)Hash_Get(&aystar->ClosedListHash, node->tile, node->direction);
truelight@110: }
truelight@110: 
truelight@110: // This adds a node to the ClosedList
truelight@110: //  It makes a copy of the data
tron@1095: static void AyStarMain_ClosedList_Add(AyStar *aystar, PathNode *node)
tron@1095: {
truelight@110: 	// Add a node to the ClosedList
truelight@110: 	PathNode *new_node = malloc(sizeof(PathNode));
truelight@110: 	*new_node = *node;
truelight@110: 	Hash_Set(&aystar->ClosedListHash, node->node.tile, node->node.direction, new_node);
truelight@110: }
truelight@110: 
truelight@110: // Checks if a node is in the OpenList
truelight@110: //   If so, it returns the OpenListNode, else NULL
tron@1095: static OpenListNode *AyStarMain_OpenList_IsInList(AyStar *aystar, AyStarNode *node)
tron@1095: {
truelight@110: 	return (OpenListNode*)Hash_Get(&aystar->OpenListHash, node->tile, node->direction);
truelight@110: }
truelight@110: 
truelight@110: // Gets the best node from OpenList
truelight@110: //  returns the best node, or NULL of none is found
truelight@110: // Also it deletes the node from the OpenList
tron@1095: static OpenListNode *AyStarMain_OpenList_Pop(AyStar *aystar)
tron@1095: {
truelight@110: 	// Return the item the Queue returns.. the best next OpenList item.
truelight@110: 	OpenListNode* res = (OpenListNode*)aystar->OpenListQueue.pop(&aystar->OpenListQueue);
truelight@110: 	if (res != NULL)
truelight@110: 		Hash_Delete(&aystar->OpenListHash, res->path.node.tile, res->path.node.direction);
truelight@193: 
truelight@110: 	return res;
truelight@110: }
truelight@110: 
truelight@110: // Adds a node to the OpenList
truelight@110: //  It makes a copy of node, and puts the pointer of parent in the struct
matthijs@1777: static void AyStarMain_OpenList_Add(AyStar *aystar, PathNode *parent, AyStarNode *node, int f, int g)
tron@1095: {
truelight@110: 	// Add a new Node to the OpenList
truelight@110: 	OpenListNode* new_node = malloc(sizeof(OpenListNode));
truelight@110: 	new_node->g = g;
truelight@110: 	new_node->path.parent = parent;
truelight@110: 	new_node->path.node = *node;
truelight@110: 	Hash_Set(&aystar->OpenListHash, node->tile, node->direction, new_node);
truelight@110: 
truelight@110: 	// Add it to the queue
truelight@110: 	aystar->OpenListQueue.push(&aystar->OpenListQueue, new_node, f);
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * Checks one tile and calculate his f-value
truelight@110:  *  return values:
truelight@110:  *	AYSTAR_DONE : indicates we are done
truelight@110:  */
truelight@110: int AyStarMain_CheckTile(AyStar *aystar, AyStarNode *current, OpenListNode *parent) {
truelight@110: 	int new_f, new_g, new_h;
truelight@110: 	PathNode *closedlist_parent;
truelight@110: 	OpenListNode *check;
truelight@110: 
truelight@110: 	// Check the new node against the ClosedList
truelight@110: 	if (AyStarMain_ClosedList_IsInList(aystar, current) != NULL) return AYSTAR_DONE;
truelight@193: 
truelight@110: 	// Calculate the G-value for this node
truelight@110: 	new_g = aystar->CalculateG(aystar, current, parent);
truelight@110: 	// If the value was INVALID_NODE, we don't do anything with this node
truelight@110: 	if (new_g == AYSTAR_INVALID_NODE) return AYSTAR_DONE;
truelight@193: 
truelight@110: 	// There should not be given any other error-code..
truelight@110: 	assert(new_g >= 0);
truelight@110: 	// Add the parent g-value to the new g-value
truelight@110: 	new_g += parent->g;
truelight@110: 	if (aystar->max_path_cost != 0 && (uint)new_g > aystar->max_path_cost) return AYSTAR_DONE;
truelight@193: 
truelight@110: 	// Calculate the h-value
truelight@110: 	new_h = aystar->CalculateH(aystar, current, parent);
truelight@110: 	// There should not be given any error-code..
truelight@110: 	assert(new_h >= 0);
truelight@193: 
truelight@110: 	// The f-value if g + h
truelight@110: 	new_f = new_g + new_h;
truelight@193: 
truelight@110: 	// Get the pointer to the parent in the ClosedList (the currentone is to a copy of the one in the OpenList)
truelight@110: 	closedlist_parent = AyStarMain_ClosedList_IsInList(aystar, &parent->path.node);
truelight@193: 
truelight@110: 	// Check if this item is already in the OpenList
truelight@110: 	if ((check = AyStarMain_OpenList_IsInList(aystar, current)) != NULL) {
tron@959: 		uint i;
truelight@110: 		// Yes, check if this g value is lower..
truelight@110: 		if (new_g > check->g) return AYSTAR_DONE;
truelight@110: 		aystar->OpenListQueue.del(&aystar->OpenListQueue, check, 0);
truelight@110: 		// It is lower, so change it to this item
truelight@110: 		check->g = new_g;
truelight@110: 		check->path.parent = closedlist_parent;
truelight@110: 		/* Copy user data, will probably have changed */
truelight@110: 		for (i=0;i<lengthof(current->user_data);i++)
truelight@110: 			check->path.node.user_data[i] = current->user_data[i];
truelight@110: 		// Readd him in the OpenListQueue
truelight@110: 		aystar->OpenListQueue.push(&aystar->OpenListQueue, check, new_f);
truelight@110: 	} else {
truelight@110: 		// A new node, add him to the OpenList
matthijs@1777: 		AyStarMain_OpenList_Add(aystar, closedlist_parent, current, new_f, new_g);
truelight@110: 	}
truelight@193: 
truelight@110: 	return AYSTAR_DONE;
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * This function is the core of AyStar. It handles one item and checks
truelight@110:  *  his neighbour items. If they are valid, they are added to be checked too.
truelight@110:  *  return values:
truelight@110:  *	AYSTAR_EMPTY_OPENLIST : indicates all items are tested, and no path
truelight@110:  *	has been found.
truelight@110:  *	AYSTAR_LIMIT_REACHED : Indicates that the max_nodes limit has been
truelight@110:  *	reached.
truelight@110:  *	AYSTAR_FOUND_END_NODE : indicates we found the end. Path_found now is true, and in path is the path found.
truelight@110:  *	AYSTAR_STILL_BUSY : indicates we have done this tile, did not found the path yet, and have items left to try.
truelight@110:  */
truelight@110: int AyStarMain_Loop(AyStar *aystar) {
truelight@110: 	int i, r;
truelight@193: 
truelight@110: 	// Get the best node from OpenList
truelight@110: 	OpenListNode *current = AyStarMain_OpenList_Pop(aystar);
truelight@110: 	// If empty, drop an error
truelight@110: 	if (current == NULL) return AYSTAR_EMPTY_OPENLIST;
truelight@193: 
truelight@110: 	// Check for end node and if found, return that code
truelight@1617: 	if (aystar->EndNodeCheck(aystar, current) == AYSTAR_FOUND_END_NODE) {
truelight@110: 		if (aystar->FoundEndNode != NULL)
truelight@110: 			aystar->FoundEndNode(aystar, current);
truelight@110: 		free(current);
truelight@110: 		return AYSTAR_FOUND_END_NODE;
truelight@110: 	}
truelight@193: 
truelight@110: 	// Add the node to the ClosedList
truelight@110: 	AyStarMain_ClosedList_Add(aystar, &current->path);
truelight@110: 
truelight@110: 	// Load the neighbours
truelight@110: 	aystar->GetNeighbours(aystar, current);
truelight@193: 
truelight@110: 	// Go through all neighbours
truelight@110: 	for (i=0;i<aystar->num_neighbours;i++) {
truelight@110: 		// Check and add them to the OpenList if needed
truelight@110: 		r = aystar->checktile(aystar, &aystar->neighbours[i], current);
truelight@110: 	}
truelight@193: 
truelight@110: 	// Free the node
truelight@110: 	free(current);
truelight@193: 
truelight@110: 	if (aystar->max_search_nodes != 0 && Hash_Size(&aystar->ClosedListHash) >= aystar->max_search_nodes)
truelight@110: 		/* We've expanded enough nodes */
truelight@110: 		return AYSTAR_LIMIT_REACHED;
truelight@110: 	else
truelight@110: 		// Return that we are still busy
truelight@110: 		return AYSTAR_STILL_BUSY;
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * This function frees the memory it allocated
truelight@110:  */
truelight@110: void AyStarMain_Free(AyStar *aystar) {
truelight@110: 	aystar->OpenListQueue.free(&aystar->OpenListQueue, false);
truelight@110: 	/* 2nd argument above is false, below is true, to free the values only
truelight@110: 	 * once */
truelight@110: 	delete_Hash(&aystar->OpenListHash, true);
truelight@110: 	delete_Hash(&aystar->ClosedListHash, true);
truelight@110: #ifdef AYSTAR_DEBUG
truelight@110: 	printf("[AyStar] Memory free'd\n");
truelight@110: #endif
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * This function make the memory go back to zero
truelight@110:  *  This function should be called when you are using the same instance again.
truelight@110:  */
truelight@110: void AyStarMain_Clear(AyStar *aystar) {
truelight@110: 	// Clean the Queue, but not the elements within. That will be done by
truelight@110: 	// the hash.
truelight@110: 	aystar->OpenListQueue.clear(&aystar->OpenListQueue, false);
truelight@110: 	// Clean the hashes
truelight@110: 	clear_Hash(&aystar->OpenListHash, true);
truelight@110: 	clear_Hash(&aystar->ClosedListHash, true);
truelight@110: 
truelight@110: #ifdef AYSTAR_DEBUG
truelight@110: 	printf("[AyStar] Cleared AyStar\n");
truelight@110: #endif
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * This is the function you call to run AyStar.
truelight@110:  *  return values:
truelight@110:  *	AYSTAR_FOUND_END_NODE : indicates we found an end node.
truelight@110:  *	AYSTAR_NO_PATH : indicates that there was no path found.
truelight@110:  *	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.
truelight@110:  * When the algorithm is done (when the return value is not AYSTAR_STILL_BUSY)
truelight@110:  * aystar->clear() is called. Note that when you stop the algorithm halfway,
truelight@110:  * you should still call clear() yourself!
truelight@110:  */
truelight@110: int AyStarMain_Main(AyStar *aystar) {
truelight@110: 	int r, i = 0;
truelight@110: 	// Loop through the OpenList
miham@826: 	//  Quit if result is no AYSTAR_STILL_BUSY or is more than loops_per_tick
truelight@110: 	while ((r = aystar->loop(aystar)) == AYSTAR_STILL_BUSY && (aystar->loops_per_tick == 0 || ++i < aystar->loops_per_tick)) { }
truelight@110: #ifdef AYSTAR_DEBUG
truelight@110: 	if (r == AYSTAR_FOUND_END_NODE)
truelight@110: 		printf("[AyStar] Found path!\n");
truelight@110: 	else if (r == AYSTAR_EMPTY_OPENLIST)
truelight@110: 		printf("[AyStar] OpenList run dry, no path found\n");
truelight@110: 	else if (r == AYSTAR_LIMIT_REACHED)
truelight@110: 		printf("[AyStar] Exceeded search_nodes, no path found\n");
truelight@110: #endif
hackykid@2008: 
hackykid@2008: 	if (aystar->BeforeExit != NULL)
hackykid@2008: 		aystar->BeforeExit(aystar);
hackykid@2008: 
truelight@110: 	if (r != AYSTAR_STILL_BUSY)
truelight@110: 		/* We're done, clean up */
truelight@110: 		aystar->clear(aystar);
truelight@193: 
truelight@110: 	// Check result-value
truelight@110: 	if (r == AYSTAR_FOUND_END_NODE) return AYSTAR_FOUND_END_NODE;
truelight@110: 	// Check if we have some left in the OpenList
truelight@110: 	if (r == AYSTAR_EMPTY_OPENLIST || r == AYSTAR_LIMIT_REACHED) return AYSTAR_NO_PATH;
truelight@110: 
truelight@110: 	// Return we are still busy
truelight@110: 	return AYSTAR_STILL_BUSY;
truelight@110: }
truelight@110: 
truelight@110: /*
truelight@110:  * Adds a node from where to start an algorithm. Multiple nodes can be added
truelight@110:  * if wanted. You should make sure that clear() is called before adding nodes
truelight@110:  * if the AyStar has been used before (though the normal main loop calls
truelight@193:  * clear() automatically when the algorithm finishes
matthijs@1777:  * g is the cost for starting with this node.
truelight@110:  */
matthijs@1777: void AyStarMain_AddStartNode(AyStar *aystar, AyStarNode *start_node, uint g) {
truelight@110: #ifdef AYSTAR_DEBUG
tron@926: 	printf("[AyStar] Starting A* Algorithm from node (%d, %d, %d)\n",
tron@926: 		TileX(start_node->tile), TileY(start_node->tile), start_node->direction);
truelight@110: #endif
matthijs@1777: 	AyStarMain_OpenList_Add(aystar, NULL, start_node, 0, g);
truelight@110: }
truelight@110: 
truelight@110: void init_AyStar(AyStar* aystar, Hash_HashProc hash, uint num_buckets) {
truelight@110: 	// Allocated the Hash for the OpenList and ClosedList
truelight@110: 	init_Hash(&aystar->OpenListHash, hash, num_buckets);
truelight@110: 	init_Hash(&aystar->ClosedListHash, hash, num_buckets);
truelight@110: 
truelight@110: 	// Set up our sorting queue
truelight@110: 	//  BinaryHeap allocates a block of 1024 nodes
truelight@110: 	//  When thatone gets full it reserves an otherone, till this number
truelight@110: 	//  That is why it can stay this high
truelight@110: 	init_BinaryHeap(&aystar->OpenListQueue, 102400);
truelight@110: 
truelight@110: 	aystar->addstart	= AyStarMain_AddStartNode;
truelight@110: 	aystar->main		= AyStarMain_Main;
truelight@110: 	aystar->loop		= AyStarMain_Loop;
truelight@110: 	aystar->free		= AyStarMain_Free;
truelight@110: 	aystar->clear		= AyStarMain_Clear;
truelight@110: 	aystar->checktile	= AyStarMain_CheckTile;
truelight@110: }