AStar class representation that uses vectors as edges.
``````    public class AStar : Reference
``````

A* (A star) is a computer algorithm that is widely used in pathfinding and graph traversal, the process of plotting an efficiently directed path between multiple points. It enjoys widespread use due to its performance and accuracy. Godot’s A* implementation make use of vectors as points.

You must add points manually with AddPoint(int, Godot.Vector3, float) and create segments manually with ConnectPoints(int, int, bool). So you can test if there is a path between two points with the ArePointsConnected(int, int) function, get the list of existing ids in the found path with GetIdPath(int, int), or the points list with GetPointPath(int, int).

### Constructors

``````    public AStar()
``````

### Methods

``````    public virtual float _ComputeCost(int fromId, int toId)
``````

Called when computing the cost between two connected points.

``````    public virtual float _EstimateCost(int fromId, int toId)
``````

Called when estimating the cost between a point and the path’s ending point.

``````    public void AddPoint(int id, Vector3 position, float weightScale = 1f)
``````

Adds a new point at the given position with the given identifier. The algorithm prefers points with lower `weightScale` to form a path. The `id` must be 0 or larger, and the `weightScale` must be 1 or larger.

[codeblock]

var as = AStar.new()

as.add_point(1, Vector3(1,0,0), 4) # Adds the point (1,0,0) with weight_scale=4 and id=1

[/codeblock]

If there already exists a point for the given id, its position and weight scale are updated to the given values.

``````    public bool ArePointsConnected(int id, int toId)
``````

Returns whether there is a connection/segment between the given points.

``````    public void Clear()
``````

Clears all the points and segments.

``````    public void ConnectPoints(int id, int toId, bool bidirectional = true)
``````

Creates a segment between the given points.

[codeblock]

var as = AStar.new()

as.add_point(1, Vector3(1,1,0))

as.add_point(2, Vector3(0,5,0))

as.connect_points(1, 2, false) # If bidirectional=false it’s only possible to go from point 1 to point 2

# and not from point 2 to point 1.

[/codeblock]

``````    public void DisconnectPoints(int id, int toId)
``````

Deletes the segment between the given points.

``````    public int GetAvailablePointId()
``````

Returns the next available point id with no point associated to it.

``````    public int GetClosestPoint(Vector3 toPosition)
``````

Returns the id of the closest point to `toPosition`. Returns -1 if there are no points in the points pool.

``````    public Vector3 GetClosestPositionInSegment(Vector3 toPosition)
``````

Returns the closest position to `toPosition` that resides inside a segment between two connected points.

[codeblock]

var as = AStar.new()

as.add_point(1, Vector3(0,0,0))

as.add_point(2, Vector3(0,5,0))

as.connect_points(1, 2)

var res = as.get_closest_position_in_segment(Vector3(3,3,0)) # returns (0, 3, 0)

[/codeblock]

The result is in the segment that goes from `y=0` to `y=5`. It’s the closest position in the segment to the given point.

``````    public int[] GetIdPath(int fromId, int toId)
``````

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.

[codeblock]

var as = AStar.new()

as.add_point(1, Vector3(0,0,0))

as.add_point(2, Vector3(0,1,0), 1) # default weight is 1

as.add_point(3, Vector3(1,1,0))

as.add_point(4, Vector3(2,0,0))

as.connect_points(1, 2, false)

as.connect_points(2, 3, false)

as.connect_points(4, 3, false)

as.connect_points(1, 4, false)

as.connect_points(5, 4, false)

var res = as.get_id_path(1, 3) # returns [1, 2, 3]

[/codeblock]

If you change the 2nd point’s weight to 3, then the result will be `[1, 4, 3]` instead, because now even though the distance is longer, it’s “easier” to get through point 4 than through point 2.

``````    public int[] GetPointConnections(int id)
``````

Returns an array with the ids of the points that form the connect with the given point.

[codeblock]

var as = AStar.new()

as.add_point(1, Vector3(0,0,0))

as.add_point(2, Vector3(0,1,0))

as.add_point(3, Vector3(1,1,0))

as.add_point(4, Vector3(2,0,0))

as.connect_points(1, 2, true)

as.connect_points(1, 3, true)

var neighbors = as.get_point_connections(1) # returns [2, 3]

[/codeblock]

``````    public Vector3[] GetPointPath(int fromId, int toId)
``````

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.

``````    public Vector3 GetPointPosition(int id)
``````

Returns the position of the point associated with the given id.

``````    public object[] GetPoints()
``````

Returns an array of all points.

``````    public float GetPointWeightScale(int id)
``````

Returns the weight scale of the point associated with the given id.

``````    public bool HasPoint(int id)
``````

Returns whether a point associated with the given id exists.

``````    public void RemovePoint(int id)
``````

Removes the point associated with the given id from the points pool.

``````    public void SetPointPosition(int id, Vector3 position)
``````

Sets the position for the point with the given id.

``````    public void SetPointWeightScale(int id, float weightScale)
``````

Sets the `weightScale` for the point with the given id.

Tags: