Test value of exported var in ready()

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:bust_in_silhouette: Asked By Michael McCrickard

I have an exported String var called color. I want to specify the color with a string in the editor. If the var is “red”, I load a red texture into my TextureProgress. Or “blue” for my blue texture, etc.

I am able to see the exported var in the editor and enter the string. And I can set the texture in ready(), but for some reason, my if test on the exported var color is failing. The code is very simple:

export var color:String = ""

func _ready():
	var tx
	if color == "blue":
		tx = load("res://blueBar.png")


If I leave the if test out, then the texture gets set, but not with the if test.

:bust_in_silhouette: Reply From: Gluon

Try changing load to preload

tx = preload("res://blueBar.png")

That does it! In reading the docs about load vs. preload, I can’t see why this wouldn’t work but the lesson learned seems to be, Don’t use load() in the ready() function? Use preload() instead?

Michael McCrickard | 2022-03-09 14:57

Okay so what I am about to write is not 100% correct but it is a good way of thinking about it.

Load essentially means you are running the set up of the scene at that point, so in your original code you have a var which you are saying is a load of a scene. What happens effectively is the scene loads in the background but isnt added to your main running scene so it just runs silently in the background but a var cannot be a scene so the var is now null. It has already run the code to load the scene.

Preload on the other hand creates a scene silently but then adds effectively a link to the var which says load this scene I have now created.

In essence load runs straight away so if you use load you have to add it to the scene straight away, preload allows you to have a link to a scene but effectively actually load it later as you did in your code with


Gluon | 2022-03-09 15:14

Thanks very much for this detailed answer. This seems related to some of the info I was reading last night about “Applying Object Oriented Principles in Godot”, like “Scripts are not technically classes. Instead, they are resources that tell the engine a sequence of initializations to perform on one of the engine’s built-in classes”. Clearly, the initialization aspect is critical.

Michael McCrickard | 2022-03-09 17:05