AStar3D

Documentation

Overview

Package AStar3D provides methods for working with AStar3D object instances.

Index

• type Advanced
• type Any
• type Implementation
• type Instance
  • func New() Instance
  • func (self Instance) AddPoint(id int, position Vector3.XYZ)
  • func (self Instance) ArePointsConnected(id int, to_id int) bool
  • func (self Instance) AsAStar3D() Instance
  • func (self Instance) AsObject() [1]gd.Object
  • func (self Instance) AsRefCounted() [1]gd.RefCounted
  • func (self Instance) Clear()
  • func (self Instance) ConnectPoints(id int, to_id int)
  • func (self Instance) DisconnectPoints(id int, to_id int)
  • func (self Instance) GetAvailablePointId() int
  • func (self Instance) GetClosestPoint(to_position Vector3.XYZ) int
  • func (self Instance) GetClosestPositionInSegment(to_position Vector3.XYZ) Vector3.XYZ
  • func (self Instance) GetIdPath(from_id int, to_id int) []int64
  • func (self Instance) GetPointCapacity() int
  • func (self Instance) GetPointConnections(id int) []int64
  • func (self Instance) GetPointCount() int
  • func (self Instance) GetPointIds() []int64
  • func (self Instance) GetPointPath(from_id int, to_id int) []Vector3.XYZ
  • func (self Instance) GetPointPosition(id int) Vector3.XYZ
  • func (self Instance) GetPointWeightScale(id int) Float.X
  • func (self Instance) HasPoint(id int) bool
  • func (self Instance) IsPointDisabled(id int) bool
  • func (self Instance) RemovePoint(id int)
  • func (self Instance) ReserveSpace(num_nodes int)
  • func (self Instance) SetPointDisabled(id int)
  • func (self Instance) SetPointPosition(id int, position Vector3.XYZ)
  • func (self Instance) SetPointWeightScale(id int, weight_scale Float.X)
  • func (self *Instance) UnsafePointer() unsafe.Pointer
  • func (self Instance) Virtual(name string) reflect.Value
• type Interface

Types

type Advanced

type Advanced = class

Advanced exposes a 1:1 low-level instance of the class, undocumented, for those who know what they are doing.

type Any

type Any interface {
	gd.IsClass
	AsAStar3D() Instance
}

type Implementation

type Implementation = implementation

Implementation implements Interface with empty methods.

type Instance

type Instance [1]gdclass.AStar3D

A* (A star) is a computer algorithm 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 3D space and Euclidean distances by default. You must add points manually with [method add_point] and create segments manually with [method connect_points]. Once done, you can test if there is a path between two points with the [method are_points_connected] function, get a path containing indices by [method get_id_path], or one containing actual coordinates with [method get_point_path]. It is also possible to use non-Euclidean distances. To do so, create a class that extends [AStar3D] and override methods [method _compute_cost] and [method _estimate_cost]. Both take two indices and return a length, as is shown in the following example. [codeblocks] [gdscript] class MyAStar:

extends AStar3D

func _compute_cost(u, v):
    return abs(u - v)

func _estimate_cost(u, v):
    return min(0, abs(u - v) - 1)

[/gdscript] [csharp] public partial class MyAStar : AStar3D

{
    public override float _ComputeCost(long fromId, long toId)
    {
        return Mathf.Abs((int)(fromId - toId));
    }

    public override float _EstimateCost(long fromId, long toId)
    {
        return Mathf.Min(0, Mathf.Abs((int)(fromId - toId)) - 1);
    }
}

[/csharp] [/codeblocks] [method _estimate_cost] should return a lower bound of the distance, i.e. [code]_estimate_cost(u, v) <= _compute_cost(u, v)[/code]. This serves as a hint to the algorithm because the custom [method _compute_cost] might be computation-heavy. If this is not the case, make [method _estimate_cost] return the same value as [method _compute_cost] to provide the algorithm with the most accurate information. If the default [method _estimate_cost] and [method _compute_cost] methods are used, or if the supplied [method _estimate_cost] 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 [method _compute_cost] results of all segments in the path multiplied by the [code]weight_scale[/code]s of the endpoints of the respective segments. If the default methods are used and the [code]weight_scale[/code]s of all points are set to [code]1.0[/code], then this equals the sum of Euclidean distances of all segments in the path.

See [Interface] for methods that can be overridden by a [Class] that extends it.

%!(EXTRA string=AStar3D)

var Nil Instance

Nil is a nil/null instance of the class. Equivalent to the zero value.

func New

func New() Instance

func (Instance) AddPoint

func (self Instance) AddPoint(id int, position Vector3.XYZ)

Adds a new point at the given position with the given identifier. The [param id] must be 0 or larger, and the [param weight_scale] must be 0.0 or greater. The [param weight_scale] is multiplied by the result of [method _compute_cost] 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 [param weight_scale]s to form a path. [codeblocks] [gdscript] var astar = AStar3D.new() astar.add_point(1, Vector3(1, 0, 0), 4) # Adds the point (1, 0, 0) with weight_scale 4 and id 1 [/gdscript] [csharp] var astar = new AStar3D(); astar.AddPoint(1, new Vector3(1, 0, 0), 4); // Adds the point (1, 0, 0) with weight_scale 4 and id 1 [/csharp] [/codeblocks] If there already exists a point for the given [param id], its position and weight scale are updated to the given values.

func (Instance) ArePointsConnected

func (self Instance) ArePointsConnected(id int, to_id int) bool

Returns whether the two given points are directly connected by a segment. If [param bidirectional] is [code]false[/code], returns whether movement from [param id] to [param to_id] is possible through this segment.

func (Instance) AsAStar3D

func (self Instance) AsAStar3D() Instance

func (Instance) AsObject

func (self Instance) AsObject() [1]gd.Object

func (Instance) AsRefCounted

func (self Instance) AsRefCounted() [1]gd.RefCounted

func (Instance) Clear

func (self Instance) Clear()

Clears all the points and segments.

func (Instance) ConnectPoints

func (self Instance) ConnectPoints(id int, to_id int)

Creates a segment between the given points. If [param bidirectional] is [code]false[/code], only movement from [param id] to [param to_id] is allowed, not the reverse direction. [codeblocks] [gdscript] var astar = AStar3D.new() astar.add_point(1, Vector3(1, 1, 0)) astar.add_point(2, Vector3(0, 5, 0)) astar.connect_points(1, 2, false) [/gdscript] [csharp] var astar = new AStar3D(); astar.AddPoint(1, new Vector3(1, 1, 0)); astar.AddPoint(2, new Vector3(0, 5, 0)); astar.ConnectPoints(1, 2, false); [/csharp] [/codeblocks]

func (Instance) DisconnectPoints

func (self Instance) DisconnectPoints(id int, to_id int)

Deletes the segment between the given points. If [param bidirectional] is [code]false[/code], only movement from [param id] to [param to_id] is prevented, and a unidirectional segment possibly remains.

func (Instance) GetAvailablePointId

func (self Instance) GetAvailablePointId() int

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

func (Instance) GetClosestPoint

func (self Instance) GetClosestPoint(to_position Vector3.XYZ) int

Returns the ID of the closest point to [param to_position], optionally taking disabled points into account. Returns [code]-1[/code] if there are no points in the points pool. [b]Note:[/b] If several points are the closest to [param to_position], the one with the smallest ID will be returned, ensuring a deterministic result.

func (Instance) GetClosestPositionInSegment

func (self Instance) GetClosestPositionInSegment(to_position Vector3.XYZ) Vector3.XYZ

Returns the closest position to [param to_position] that resides inside a segment between two connected points. [codeblocks] [gdscript] var astar = AStar3D.new() astar.add_point(1, Vector3(0, 0, 0)) astar.add_point(2, Vector3(0, 5, 0)) astar.connect_points(1, 2) var res = astar.get_closest_position_in_segment(Vector3(3, 3, 0)) # Returns (0, 3, 0) [/gdscript] [csharp] var astar = new AStar3D(); astar.AddPoint(1, new Vector3(0, 0, 0)); astar.AddPoint(2, new Vector3(0, 5, 0)); astar.ConnectPoints(1, 2); Vector3 res = astar.GetClosestPositionInSegment(new Vector3(3, 3, 0)); // Returns (0, 3, 0) [/csharp] [/codeblocks] The result is in the segment that goes from [code]y = 0[/code] to [code]y = 5[/code]. It's the closest position in the segment to the given point.

func (Instance) GetIdPath

func (self Instance) GetIdPath(from_id int, to_id int) []int64

Returns an array with the IDs of the points that form the path found by AStar3D between the given points. The array is ordered from the starting point to the ending point of the path. If there is no valid path to the target, and [param allow_partial_path] is [code]true[/code], returns a path to the point closest to the target that can be reached. [codeblocks] [gdscript] var astar = AStar3D.new() astar.add_point(1, Vector3(0, 0, 0)) astar.add_point(2, Vector3(0, 1, 0), 1) # Default weight is 1 astar.add_point(3, Vector3(1, 1, 0)) astar.add_point(4, Vector3(2, 0, 0))

astar.connect_points(1, 2, false) astar.connect_points(2, 3, false) astar.connect_points(4, 3, false) astar.connect_points(1, 4, false)

var res = astar.get_id_path(1, 3) # Returns [1, 2, 3] [/gdscript] [csharp] var astar = new AStar3D(); astar.AddPoint(1, new Vector3(0, 0, 0)); astar.AddPoint(2, new Vector3(0, 1, 0), 1); // Default weight is 1 astar.AddPoint(3, new Vector3(1, 1, 0)); astar.AddPoint(4, new Vector3(2, 0, 0)); astar.ConnectPoints(1, 2, false); astar.ConnectPoints(2, 3, false); astar.ConnectPoints(4, 3, false); astar.ConnectPoints(1, 4, false); int[] res = astar.GetIdPath(1, 3); // Returns [1, 2, 3] [/csharp] [/codeblocks] If you change the 2nd point's weight to 3, then the result will be [code][1, 4, 3][/code] instead, because now even though the distance is longer, it's "easier" to get through point 4 than through point 2.

func (Instance) GetPointCapacity

func (self Instance) GetPointCapacity() int

Returns the capacity of the structure backing the points, useful in conjunction with [method reserve_space].

func (Instance) GetPointConnections

func (self Instance) GetPointConnections(id int) []int64

Returns an array with the IDs of the points that form the connection with the given point. [codeblocks] [gdscript] var astar = AStar3D.new() astar.add_point(1, Vector3(0, 0, 0)) astar.add_point(2, Vector3(0, 1, 0)) astar.add_point(3, Vector3(1, 1, 0)) astar.add_point(4, Vector3(2, 0, 0))

astar.connect_points(1, 2, true) astar.connect_points(1, 3, true)

var neighbors = astar.get_point_connections(1) # Returns [2, 3] [/gdscript] [csharp] var astar = new AStar3D(); astar.AddPoint(1, new Vector3(0, 0, 0)); astar.AddPoint(2, new Vector3(0, 1, 0)); astar.AddPoint(3, new Vector3(1, 1, 0)); astar.AddPoint(4, new Vector3(2, 0, 0)); astar.ConnectPoints(1, 2, true); astar.ConnectPoints(1, 3, true);

int[] neighbors = astar.GetPointConnections(1); // Returns [2, 3] [/csharp] [/codeblocks]

func (Instance) GetPointCount

func (self Instance) GetPointCount() int

Returns the number of points currently in the points pool.

func (Instance) GetPointIds

func (self Instance) GetPointIds() []int64

Returns an array of all point IDs.

func (Instance) GetPointPath

func (self Instance) GetPointPath(from_id int, to_id int) []Vector3.XYZ

Returns an array with the points that are in the path found by AStar3D between the given points. The array is ordered from the starting point to the ending point of the path. If there is no valid path to the target, and [param allow_partial_path] is [code]true[/code], returns a path to the point closest to the target that can be reached. [b]Note:[/b] This method is not thread-safe. If called from a [Thread], it will return an empty array and will print an error message.

func (Instance) GetPointPosition

func (self Instance) GetPointPosition(id int) Vector3.XYZ

Returns the position of the point associated with the given [param id].

func (Instance) GetPointWeightScale

func (self Instance) GetPointWeightScale(id int) Float.X

Returns the weight scale of the point associated with the given [param id].

func (Instance) HasPoint

func (self Instance) HasPoint(id int) bool

Returns whether a point associated with the given [param id] exists.

func (Instance) IsPointDisabled

func (self Instance) IsPointDisabled(id int) bool

Returns whether a point is disabled or not for pathfinding. By default, all points are enabled.

func (Instance) RemovePoint

func (self Instance) RemovePoint(id int)

Removes the point associated with the given [param id] from the points pool.

func (Instance) ReserveSpace

func (self Instance) ReserveSpace(num_nodes int)

Reserves space internally for [param num_nodes] points. Useful if you're adding a known large number of points at once, such as points on a grid. New capacity must be greater or equals to old capacity.

func (Instance) SetPointDisabled

func (self Instance) SetPointDisabled(id int)

Disables or enables the specified point for pathfinding. Useful for making a temporary obstacle.

func (Instance) SetPointPosition

func (self Instance) SetPointPosition(id int, position Vector3.XYZ)

Sets the [param position] for the point with the given [param id].

func (Instance) SetPointWeightScale

func (self Instance) SetPointWeightScale(id int, weight_scale Float.X)

Sets the [param weight_scale] for the point with the given [param id]. The [param weight_scale] is multiplied by the result of [method _compute_cost] when determining the overall cost of traveling across a segment from a neighboring point to this point.

func (*Instance) UnsafePointer

func (self *Instance) UnsafePointer() unsafe.Pointer

func (Instance) Virtual

func (self Instance) Virtual(name string) reflect.Value

type Interface

type Interface interface {
	//Called when estimating the cost between a point and the path's ending point.
	//Note that this function is hidden in the default [AStar3D] class.
	EstimateCost(from_id int, to_id int) Float.X
	//Called when computing the cost between two connected points.
	//Note that this function is hidden in the default [AStar3D] class.
	ComputeCost(from_id int, to_id int) Float.X
}