Called when computing the cost between two connected points. Note that this function is hidden in the default AStar class.
Called when estimating the cost between a point and the path's ending point. Note that this function is hidden in the default AStar class.
Adds a new point at the given position with the given identifier. The id must be 0 or larger, and the weight_scale must be 1 or larger. The weight_scale is multiplied by the result of _computeCost when determining the overall cost of traveling across a segment from a neighboring point to this point. Thus, all else being equal, the algorithm prefers points with lower weight_scales to form a path.
Returns whether the two given points are directly connected by a segment. If bidirectional is false, returns whether movement from id to to_id is possible through this segment.
Clears all the points and segments.
Creates a segment between the given points. If bidirectional is false, only movement from id to to_id is allowed, not the reverse direction.
Deletes the segment between the given points. If bidirectional is false, only movement from id to to_id is prevented, and a unidirectional segment possibly remains.
Returns the next available point ID with no point associated to it.
Returns the ID of the closest point to to_position, optionally taking disabled points into account. Returns -1 if there are no points in the points pool. Note: If several points are the closest to to_position, the one with the smallest ID will be returned, ensuring a deterministic result.
Returns the closest position to to_position that resides inside a segment between two connected points.
Returns an array with the IDs of the points that form the path found by AStar between the given points. The array is ordered from the starting point to the ending point of the path.
Returns the capacity of the structure backing the points, useful in conjunction with reserve_space.
Returns an array with the IDs of the points that form the connection with the given point.
Returns the number of points currently in the points pool.
Returns an array with the points that are in the path found by AStar between the given points. The array is ordered from the starting point to the ending point of the path. Note: This method is not thread-safe. If called from a Thread, it will return an empty PoolVector3Array and will print an error message.
Returns the position of the point associated with the given id.
Returns the weight scale of the point associated with the given id.
Returns an array of all points.
Returns whether a point associated with the given id exists.
Returns whether a point is disabled or not for pathfinding. By default, all points are enabled.
Removes the point associated with the given id from the points pool.
Reserves space internally for num_nodes points, useful if you're adding a known large number of points at once, for a grid for instance. New capacity must be greater or equals to old capacity.
Disables or enables the specified point for pathfinding. Useful for making a temporary obstacle.
Sets the position for the point with the given id.
Sets the weight_scale for the point with the given id. The weight_scale is multiplied by the result of _computeCost when determining the overall cost of traveling across a segment from a neighboring point to this point.
Construct a new instance of AStar. Note: use memnew!AStar instead.
class MyAStar: extends AStar
func _compute_cost(u, v): return abs(u - v)
func _estimate_cost(u, v): return min(0, abs(u - v) - 1)
_estimateCost should return a lower bound of the distance, i.e. _estimate_cost(u, v) <= _compute_cost(u, v). This serves as a hint to the algorithm because the custom _compute_cost might be computation-heavy. If this is not the case, make _estimateCost return the same value as _computeCost to provide the algorithm with the most accurate information. If the default _estimateCost and _computeCost methods are used, or if the supplied _estimateCost method returns a lower bound of the cost, then the paths returned by A* will be the lowest-cost paths. Here, the cost of a path equals the sum of the _computeCost results of all segments in the path multiplied by the weight_scales of the endpoints of the respective segments. If the default methods are used and the weight_scales of all points are set to 1.0, then this equals the sum of Euclidean distances of all segments in the path.
An implementation of A* to find the shortest paths among connected points in space.
A* (A star) is a computer algorithm that is widely used in pathfinding and graph traversal, the process of plotting short paths among vertices (points), passing through a given set of edges (segments). It enjoys widespread use due to its performance and accuracy. Godot's A* implementation uses points in three-dimensional space and Euclidean distances by default. You must add points manually with addPoint and create segments manually with connectPoints. Then you can test if there is a path between two points with the arePointsConnected function, get a path containing indices by getIdPath, or one containing actual coordinates with getPointPath. It is also possible to use non-Euclidean distances. To do so, create a class that extends AStar and override methods _computeCost and _estimateCost. Both take two indices and return a length, as is shown in the following example.