Get_world_3d() results in an error due to null value

[ljlhouben]

Godot Version

4.3 Stable Steam

Question

Hi All

Same issue as HERE but I don’t understand the ‘solution’ or what I’m doing wrong in my code. So therefor I ask the question again (as I cannot reply to the existing topic)

The goal that I’m trying to perform:
I’m trying to get the position from my 3D scene were I click the left mouse button.

The long story
Within the project I have a singleton ‘Global’ which has multiple variables and functions, and were I’m trying to add the functionality for the ray casting. The ray casting is (at this moment) a separate script which I call with the following code:

extends Node

var RayCasting  : Node

func _ready():
	RayCasting = load("res://Content/Global/raycasting.gd").new()

The code from raycasting.gd looks like this:

extends Node3D

const CFG_RAY_LENGTH := 1000

func getCastInformation(CollisionMask: int = 0xFFFF_FFFF) -> Dictionary:
# Prepare environment information
	if get_world_3d() == null:
		return {}
	var SpaceState = get_world_3d().direct_space_state
	var Camera = get_viewport().get_camera_3d()
	var MousePos = get_viewport().get_mouse_position()
	
# Prepare ray positions
	var RayStartPos = Camera.project_ray_RayStartPos(MousePos)
	var RayEndPos = RayStartPos + Camera.project_ray_normal(MousePos) * CFG_RAY_LENGTH
	
# Prepare query parameters
	var Query = PhysicsRayQueryParameters3D.create(RayStartPos, RayEndPos)
	Query.collide_with_areas = true
	Query.collision_mask = CollisionMask
	
# Execute ray casting
	var result = SpaceState.intersect_ray(Query)
	return result

I call these scripts in my test scene which has its own script with following code:

extends Node3D
var StartPos : Vector3

func _unhandled_input(_event: InputEvent) -> void:
	if Input.is_action_just_pressed("mouse_btn_left"):
		var test = Global.RayCasting.getCastInformation()

I’m running the scene with F6 (current scene). Which results in the error.

I already figured out that the error is due to a null reference. But I’m lost how and what to check. What is the World3D? I looked in the official docu, but I do not know what they are referring to. I added a WorldEnvironment to my test scene, but that didn’t do the trick. Also it’s not the root, and ChatGPT could also not help me further

So I need some beginners course what the World3D is, and/or what additional parameters I should assign to the get_world_3d() method.

Many thanks already for any help/suggestions
Regards,

Ludo

PS I have reduced the code to only the relevant parts for my issue

[gertkeno]

@ljlhouben

var RayCasting  : Node

func _ready():
	RayCasting = load("res://Content/Global/raycasting.gd").new()

Your raycasting node is not added to the scene tree, so it cannot access the scene’s world3D. Could you add this raycasting.gd to your globals?

[ljlhouben]

Hi Gertkeno

The ‘RayCasting’ is the instance of ‘raycasting.gd’ that I create/add within the ‘Global’ node. In the tree the ‘Global’ node is present, so I would guess (from my C++/CoDeSys experience), that the code is running. If I call ‘Global.RayCasting.’ than the editor can find the info. Or does the ray casting need to be it’s own node (Node3D)??

Regards

Ludo

[gertkeno]

If you do not use add_child(RayCasting) then you only have a reference to RayCasting, but it is not part of the world/tree.

[ljlhouben]

As mentioned by @gertkeno there must be a node added within the tree. So in my singleton ‘Global’ I have updated the code to:

etends Node

var RayCasting  : Node

func _ready():
	RayCasting = load("res://Content/Global/raycasting.gd").new()
	RayCasting.name = "RayCasting"   #Name displayed in tree
	add_child(RayCasting)

The node is now added to the tree as a child from my node ‘Global’.

Then the function World3D works like a charm.
Thanks @gertkeno for your quick anwser

Regards

Ludo