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Docs: Update AStar3D examples
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@@ -6,29 +6,42 @@
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<description>
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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.
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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].
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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.
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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.
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[b]Example:[/b] Use Manhattan distance instead of Euclidean distance:
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[codeblocks]
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[gdscript]
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class MyAStar:
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extends AStar3D
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class_name MyAStar3D
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extends AStar3D
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func _compute_cost(u, v):
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return abs(u - v)
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func _compute_cost(u, v):
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var u_pos = get_point_position(u)
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var v_pos = get_point_position(v)
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return abs(u_pos.x - v_pos.x) + abs(u_pos.y - v_pos.y) + abs(u_pos.z - v_pos.z)
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func _estimate_cost(u, v):
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return min(0, abs(u - v) - 1)
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func _estimate_cost(u, v):
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var u_pos = get_point_position(u)
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var v_pos = get_point_position(v)
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return abs(u_pos.x - v_pos.x) + abs(u_pos.y - v_pos.y) + abs(u_pos.z - v_pos.z)
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[/gdscript]
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[csharp]
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public partial class MyAStar : AStar3D
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using Godot;
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[GlobalClass]
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public partial class MyAStar3D : AStar3D
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{
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public override float _ComputeCost(long fromId, long toId)
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{
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return Mathf.Abs((int)(fromId - toId));
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Vector3 fromPoint = GetPointPosition(fromId);
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Vector3 toPoint = GetPointPosition(toId);
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return Mathf.Abs(fromPoint.X - toPoint.X) + Mathf.Abs(fromPoint.Y - toPoint.Y) + Mathf.Abs(fromPoint.Z - toPoint.Z);
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}
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public override float _EstimateCost(long fromId, long toId)
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{
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return Mathf.Min(0, Mathf.Abs((int)(fromId - toId)) - 1);
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Vector3 fromPoint = GetPointPosition(fromId);
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Vector3 toPoint = GetPointPosition(toId);
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return Mathf.Abs(fromPoint.X - toPoint.X) + Mathf.Abs(fromPoint.Y - toPoint.Y) + Mathf.Abs(fromPoint.Z - toPoint.Z);
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}
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}
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[/csharp]
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