AyStar Class Reference

An AyStar implementation. More...

Classes
class	Path
	The path of the AyStar algorithm. More...

Public Member Functions
function	GetAuthor ()
function	GetName ()
function	GetShortName ()
function	GetDescription ()
function	GetVersion ()
function	GetDate ()
function	CreateInstance ()
function	GetCategory ()
constructor	AyStar (pf_instance, cost_callback, estimate_callback, neighbours_callback, check_direction_callback)
function	InitializePath (sources, goals, ignored_tiles=[])
	Initialize a path search between sources and goals.
function	FindPath (iterations)
	Try to find the path as indicated with InitializePath with the lowest cost.
function	_CleanPath ()

Public Attributes
	_queue_class = "queue.binary_heap"
	_pf_instance = null
	_cost_callback = null
	_estimate_callback = null
	_neighbours_callback = null
	_check_direction_callback = null
	_open = null
	_closed = null
	_goals = null

Detailed Description

An AyStar implementation.

It solves graphs by finding the fastest route from one point to the other.

Constructor & Destructor Documentation

constructor AyStar::AyStar ( pf_instance  , cost_callback  , estimate_callback  , neighbours_callback  , check_direction_callback    )

inline

Parameters

pf_instance	An instance that'll be used as 'this' for all the callback functions.
cost_callback	A function that returns the cost of a path. It should accept four parameters, old_path, new_tile, new_direction and cost_callback_param. old_path is an instance of AyStar.Path, and new_node is the new node that is added to that path. It should return the cost of the path including new_node.
estimate_callback	A function that returns an estimate from a node to the goal node. It should accept four parameters, tile, direction, goal_nodes and estimate_callback_param. It should return an estimate to the cost from the lowest cost between node and any node out of goal_nodes. Note that this estimate is not allowed to be higher than the real cost between node and any of goal_nodes. A lower value is fine, however the closer it is to the real value, the better the performance.
neighbours_callback	A function that returns all neighbouring nodes from a given node. It should accept three parameters, current_path, node and neighbours_callback_param. It should return an array containing all neighbouring nodes, which are an array in the form [tile, direction].
check_direction_callback	A function that returns either false or true. It should accept four parameters, tile, existing_direction, new_direction and check_direction_callback_param. It should check if both directions can go together on a single tile.

Member Function Documentation

function AyStar::FindPath

(

iterations

)

Try to find the path as indicated with InitializePath with the lowest cost.

Parameters

iterations

After how many iterations it should abort for a moment. This value should either be -1 for infinite, or > 0. Any other value aborts immediatly and will never find a path.

Returns

A route if one was found, or false if the amount of iterations was reached, or null if no path was found. You can call this function over and over as long as it returns false, which is an indication it is not yet done looking for a route.

function AyStar::InitializePath	(	sources	,
		goals	,
		ignored_tiles	= []
	)

Initialize a path search between sources and goals.

Parameters

sources	The source nodes. This can an array of either [tile, direction]-pairs or AyStar.Path-instances.
goals	The target tiles. This can be an array of either tiles or [tile, next_tile]-pairs.
ignored_tiles	An array of tiles that cannot occur in the final path.

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The documentation for this class was generated from the following files:

• library.nut
• main.nut