diff --git a/doc/classes/AStar3D.xml b/doc/classes/AStar3D.xml index 2e8ae37a20b..31ee6d8e3c4 100644 --- a/doc/classes/AStar3D.xml +++ b/doc/classes/AStar3D.xml @@ -6,29 +6,42 @@ 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. + It is also possible to use non-Euclidean distances. To do so, create a script that extends [AStar3D] and override the methods [method _compute_cost] and [method _estimate_cost]. Both should take two point IDs and return the distance between the corresponding points. + [b]Example:[/b] Use Manhattan distance instead of Euclidean distance: [codeblocks] [gdscript] - class MyAStar: - extends AStar3D + class_name MyAStar3D + extends AStar3D - func _compute_cost(u, v): - return abs(u - v) + func _compute_cost(u, v): + var u_pos = get_point_position(u) + var v_pos = get_point_position(v) + return abs(u_pos.x - v_pos.x) + abs(u_pos.y - v_pos.y) + abs(u_pos.z - v_pos.z) - func _estimate_cost(u, v): - return min(0, abs(u - v) - 1) + func _estimate_cost(u, v): + var u_pos = get_point_position(u) + var v_pos = get_point_position(v) + return abs(u_pos.x - v_pos.x) + abs(u_pos.y - v_pos.y) + abs(u_pos.z - v_pos.z) [/gdscript] [csharp] - public partial class MyAStar : AStar3D + using Godot; + + [GlobalClass] + public partial class MyAStar3D : AStar3D { public override float _ComputeCost(long fromId, long toId) { - return Mathf.Abs((int)(fromId - toId)); + Vector3 fromPoint = GetPointPosition(fromId); + Vector3 toPoint = GetPointPosition(toId); + + return Mathf.Abs(fromPoint.X - toPoint.X) + Mathf.Abs(fromPoint.Y - toPoint.Y) + Mathf.Abs(fromPoint.Z - toPoint.Z); } public override float _EstimateCost(long fromId, long toId) { - return Mathf.Min(0, Mathf.Abs((int)(fromId - toId)) - 1); + Vector3 fromPoint = GetPointPosition(fromId); + Vector3 toPoint = GetPointPosition(toId); + return Mathf.Abs(fromPoint.X - toPoint.X) + Mathf.Abs(fromPoint.Y - toPoint.Y) + Mathf.Abs(fromPoint.Z - toPoint.Z); } } [/csharp]