Trying to override _compute_cost() and _estimate_cost() in my AStar2D subclass

system · November 19, 2020, 1:41am


	Attention	Topic was automatically imported from the old Question2Answer platform.
	Asked By	mason

Hey all,

I’ve created a subclass of AStar2D and tried to override the _compute_cost() and _estimate_cost() functions. I’m trying to make it so A* sees the distance between any two connected nodes as 1. That way, the shortest path is determined only by the number of connections.

Here’s my code: extends Nodeclass HyperAStar2D: extends AStar2D func _compute_cost( - Pastebin.com

It seems to be ignoring the functions I’ve written. Firstly, it fails to calculate the shortest path, and secondly, it doesn’t print “blamo” to the console when computing distance.

Anybody know what I’m doing wrong?

Thanks!

system · November 19, 2020, 3:52am


	Reply From:	jgodfrey

What version of Godot are you using? Poking around, it seems that AStar2D didn’t used to allow those methods to be overridden (even though AStar did). However, reading this…

github.com/godotengine/godot

AStar2D cannot override _estimate_cost or _compute_cost in GDScript

opened 07:25PM - 11 Mar 20 UTC

closed 07:20AM - 19 Mar 20 UTC

Adinimys

discussion topic:core

Godot version : 3.2.1, also present in 4.0 Issue description : AStar provide…s 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

and

…makes me think the necessary changes were implemented in AStar2D and were cherry-picked into both 3.2.3 and 3.2.2.

Ah, perfect. Upgrading fixed the problem. I was running 3.2.1 I think. Thanks for looking into this for me!

mason | 2020-11-19 04:01

system · November 19, 2020, 4:02am


	Reply From:	mason

Upgrading fixed the problem. I was running 3.2.1.