AStar2D cannot override _estimate_cost or _compute_cost in GDScript

[Adinimys]

Godot version : 3.2.1, also present in 4.0

Issue description :
AStar provides a way to override its cost calculation from GDScript. Since AStar2D is a wrapper around it with an AStar astar member there is no way to override the _evaluate_cost() and _compute_cost() inside of it

Steps to reproduce :

`class CustomAStar2D :
extends AStar2D

func _estimate_cost(u, v):
	print("this isn't called")
	var dist = (get_point_position(u) - get_point_position(v)).abs()
	return dist.x + dist.y

func _compute_cost(u, v):
            print("not called either")
	return _estimate_cost(u, v)`

I'm not sure if the best would be to rewrite AStar2D to use its own _solve() which might also slightly improve performance by removing useless calculations. Or completly rewrite AStar2D to not be a wrapper ? Or maybe there is a way to reach astar._estimate_cost() from its wrapper class ?

At least if it's intended that advance uses needing to overwrite those methods should use AStar regardless of 2D/3D, it should be documented here : https://docs.godotengine.org/en/3.2/classes/class_astar2d.html

[bojidar-bg]

CC @Chaosus ( #27237 (comment) ).

[Adinimys]

Wouldn't the best approach be using templates ? With AStar<Vector3> and AStar<Vector2> exposed as AStar and AStar2D ?
It would also mean that it would be easier to then expand to other datat types to support non-spatial pathfinding (such as in GOAP)

[Chaosus]

You cannot use templates with GDScript so this is not a correct way to solve a problem. I will try to use function pointer instead...

[Adinimys]

Thanks ! @Chaosus