Search code examples
godotgodot4

Child node attribute is null

I have a scene 'DragonSelector' which extends Area2D. The scene has a Sprite2D node called 'DragonSprite'.

DragonSelector.gd

class_name DragonSelector
extends Area2D

@onready var dragon_sprite = $DragonSprite

func _ready():
    pass 

func _process(delta):
    pass

func set_texture(dragon_texture: Texture):
    dragon_sprite.Texture = dragon_texture

I want to instantiate this scene in 'Main' scene and set the Texture on 'DragonSprite' in runtime.

Main.gd

class_name Main
extends Node2D

var dragon_selector_scene = preload("res://dragon_selector/dragon_selector.tscn")

func _ready():
    var dragon_selector_instance = dragon_selector_scene.instantiate()
    var texture = preload("res://dragon/flying_dragon-gold.png")
    dragon_selector_instance.set_texture(texture)
    add_child(dragon_selector_instance)
    dragon_selector_instance.position = Vector2(100, 100) 
    
func _process(delta):
    pass

This yields an error: Invalid set index 'Texture' (on base: 'Nil') with value of type 'CompressedTexture2D'. This is associated with the texture assignment line in set_texture:

enter image description here

To validate that the texture is where I think it is, I changed function set_texture to load the texture directly from within DragonSelector.gd:

func set_texture(dragon_texture: Texture):
    dragon_sprite.Texture = preload("res://dragon/flying_dragon-gold.png")
    #dragon_sprite.Texture = dragon_texture

This works as expected. Apologies for the vague title, I have no idea what to refer this to. Suggestions for correction are welcome. Using godot 4.2.1

Solution

  • The issue is that I was trying to set the texture before I added the dragon_selector to the scene tree:

    var texture = preload("res://dragon/flying_dragon-gold.png")
dragon_selector_instance.set_texture(texture)
add_child(dragon_selector_instance)

    Inside the dragon_selector script, dragon_sprite is only available after Ready() was executed which only happens after dragon_selector is added. Switching the order solved the issue.