Passing/connecting variables between scripts/scenes

Help Programming
1

4.3 Stable

Question
Hello! First post on the forum.
Currently, I am trying to figure out how to connect variables between scenes so that the value remains constant between scripts.
I have already heard of autoloads, but I am a little confused on how to use them for this purpose, and there appear to be multiple downsides to using them for a lot of variables, so I was wondering if there were other methods to connecting variables across scripts. I am also curious if dictionaries could be used to circumvent having to create a large amount of autoloads.
I also heard about the possibility of connecting them with functions, but I am unsure how to set this up so that the value of the variable could still be changed.

2

One option would be to create a class with static variables.
Example:

# foo.gd
class_name Foo

static var is_godot = true

# bar.gd
func _ready():
    print(Foo.is_godot) # true
3

I donā€™t quite know what you mean by ā€œconnecting them with functionsā€, but you can use setters and getters to run code whenever a property is set or accessed.
Example:

var two_plus_two = 4:
    set(value):
        if value != 4:
            OS.crash("Two plus two must equal 4!")
        two_plus_two = value

func _ready():
    two_plus_two = 5 # Would crash the game
4

The idea of connecting the variables with a function was something that I had heard of in a tutorial I watched. The basic idea, from what I understood, was that it was a function that simply returned the value of a variable when called, and could be called from another script because it was a function.

Also, I looked into autoloads a little more and they actually seem to be the best option for what Iā€™m trying to do, as I previously misunderstood autoloads for some reason only being able to store one variable per autoload. I donā€™t know why I thought this, but it resulted in me preferring to avoid them as I thought I would need a lot of autoloads instead of just one.

5

If I understand what you mean, this wouldnā€™t be hard to implement:

var foo = true

func get_foo():
    return foo

var foo = true

func get_foo():
    return foo

func set_foo(value):
    foo = value

However, I donā€™t see the point of this when you can get and set variables from another script without functions.

6

Sorry, to clarify, I meant that Iā€™m unsure of how to set the values for a variable that is contained inside of a dictionary, or if thatā€™s even possible.

7

Never mind on the adding to dictionaries question, I somehow managed to miss an entire section of the documentation.

8

I am currently having difficulties actually using a variable from an autoload. I am getting the error: ā€œInvalid access to property or key ā€˜global_1ā€™ on a base object of type ā€˜Node (global_variables.gd)ā€™.ā€ My code is as follows:

# In the script attempting to access the variable:
var global_1 = (global.global_1)

# On the autoload's script:
var global_1: int = 1

If it helps, as extra info, the autoload itself is just a free-floating script and not attached to any node.

9

Code like that works as intended for me. The problem may be elsewhere.
Can you show more of your code?

10

Sure, but the only other code I have written that I think could interact is just a function that prints the value for global_1 when a button is pressed in the scene thatā€™s attempting to use global_1.

# > used as a stand-in for indents
func on_print_example_pressed() -> void:
> print (global_1)

with a signal connecting said button to the function.
For a wider context to the scene itself, itā€™s a panel of buttons that I am using to test out methods of compiling multiple variables from across the project into a dictionary for saving to a JSON file, but none of the code for actually compiling the dictionary has been written yet as I realized I didnā€™t actually know how to grab the variables in the first place. Now, hereā€™s the entirety of the sceneā€™s script. (itā€™s moderately unorganized:)

extends Node2D


var example_value = 1
var file_number
var example_1
var path_dictionary
var var_path
var global_1 = (global.global_1)

# Called when the node enters the scene tree for the first time.
func _ready() -> void:
	pass

# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta: float) -> void:
	$RichTextLabel.set_text(str(example_value))

# This function will create the dictionary variable that will be saved to the JSON file.
func create_save_dict():
	for var_name in path_dictionary:
		var_path = path_dictionary[var_name]

# This function will be for the final process of saving to the file
func save_to_file(file_number):
	print(file_number)
	
	# 
	
	# learn about callables.
	return 
	pass



func _on_plus_one_to_value_pressed() -> void:
	# pass # Replace with function body.
	example_value += 1

func _on_minus_one_to_value_pressed() -> void:
	# pass # Replace with function body.
	example_value -= 1


func _on_print_example_pressed() -> void:
	print (global_1)
	


func _on_main_1_path_dictionary_signal(path_dictionary: Variant) -> void:
	pass # Replace with function body.

The function at the very bottom was me attempting an experiment with passing variables over signals, but that hasnā€™t gone anywhere.
Edit just after posting: I have no clue why that second block quote is entirely gray.

11

Also, the code in the autoload itself is as follows:

extends Node

var global_1: int = 1

# Called when the node enters the scene tree for the first time.
func _ready() -> void:
	pass # Replace with function body.


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta: float) -> void:
	pass
12

I donā€™t see anything wrong with your code, and it works perfectly fine for me. I hate to say it, but I simply donā€™t know what the problem could be. The one thing I would check would be the autoload configuration in the project settings.
For what itā€™s worth, I hope youā€™re able to find a solution.

13

Alright, thanks for the help! If I find a solution for my error, Iā€™ll post it and mark it as the solution the thread.

14

OK, oddly enough, just deleting the script and making a new one fixed it. I have no clue why it wasnā€™t working previously, but a fix is a fix. Again, thanks for the help!
(Since this is marked as the solution, please read through thread for actual info on topic.)

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