Stop variables resetting when changing scenes

ProbablyTooAmbitious

In my game there are enemies which will chase the player if they get too close. If the player is hit, the scene will change to a turn based battle. However when the player wins and the scene switches back, the variables have been reset and so the enemy is still there. I've tried using autoloads to fix this problem but I end up getting "invalid get index on base previously freed instance" errors.

cybereality

Yes, autoload is the answer. But you'll need to reapply the variables to the objects after the scene changes.

ProbablyTooAmbitious

I tried autoloads again and I don't get the error anymore - a good sign! However, autoloads end up causing another issue for me. The variables in the script for the battle system don't seem to be changing properly anymore. For example, this is what I get when I print the variable that signals when the player has had their turn:

cybereality

I'm not sure. Can you post some code or explain what you are doing?

ProbablyTooAmbitious

I'm still new so this is probably quite bad code

extends Node2D

var spell_selected
var battle_menu_number = 1
var battle_spell_select = 1
var battle_state
enum {
	neutral,
	fight,
	healing,
	attacking,
	enemy_attacking,
	won_battle,
	out_of_battle
}
var battle_key
onready var Player
onready var Enemy
onready var Menu
onready var Spell_Code
onready var spell1
var at_start_of_battle = true
var select_battle_option = true
var attacked: bool
var spell_in_use
var damage = 0
var enemy_attacked = false
var health = 60
func _process(delta):
	if health <= 0:
		health = 0
	if health == 0:
		battle_state = won_battle
		get_tree().change_scene(get_node("/root/Node2D").data_to_save["scene_path"])
	if get_tree().current_scene.filename == "res://battlesystem.tscn":
		if at_start_of_battle == true:
			battle_state = neutral
			at_start_of_battle = false
		Player = get_node("/root/Node2D/KinematicBody2D")
		Enemy = get_node("/root/Node2D/KinematicBody2D2")
		Menu = get_node("/root/Node2D/CanvasLayer3/NinePatchRect")
		Spell_Code = get_node("/root/Node2D/Node2D3")
		spell1 = get_node("/root/Node2D/RichTextLabel2")
		Player.movement_state = Player.player_in_battle
	match battle_state:
		neutral:
			if battle_menu_number == 1:
				if Input.is_action_just_pressed("ui_enter"):
					battle_state = fight
		fight:
			spell1.visible = true
			spell1.text = Menu.down_key_spell["name"]
			if battle_spell_select == 1:
				if Input.is_action_just_pressed("ui_enter"):
					select_battle_option = false
					spell_in_use = Menu.down_key_spell
					battle_key = "ui_downarrow"
					battle_state = attacking
			elif battle_spell_select == 1:
				if Input.is_action_just_pressed("ui_enter"):
					select_battle_option = false
					spell_in_use = Menu.up_key_spell
					battle_state = attacking
					battle_key = "ui_uparrow"
			elif battle_spell_select == 3:
				if Input.is_action_just_pressed("ui_enter"):
					select_battle_option = false
					spell_in_use = Menu.left_key_spell
					battle_state = attacking
					battle_key = "ui_leftarrow"
			elif battle_spell_select == 4:
				if Input.is_action_just_pressed("ui_enter"):
					select_battle_option = false
					spell_in_use = Menu.right_key_spell
					battle_state = attacking
					battle_key = "ui_rightarrow"
		attacking:
			if Player.position == Vector2(381, 197):
				Spell_Code.spells = spell_in_use["effect"]
			if attacked == false:
				Player.position = Player.position.move_toward(Vector2(381, 197), 6)
			else:
				Player.position = Player.position.move_toward(Vector2(225, 198), 6)
			if attacked == true:
				if Player.position == Vector2(225, 198):
					if damage > 0:
						if Enemy.bonus > 0: # bonus = extra damage to enemy if attacks are timed correctly
							damage += Enemy.bonus
							Enemy.bonus = 0
							health -= damage
							Enemy.bonus = 0
							damage = 0
						else:
							health -= damage
							damage = 0
					if health > 0:
						battle_state = enemy_attacking
		enemy_attacking:
			if enemy_attacked == false:
				Enemy.position = Enemy.position.move_toward(Vector2(-157, -1), 6)
				if Enemy.position == Vector2(-157, -1):
					Player.health -= 15
					enemy_attacked = true
			if enemy_attacked == true:
				Enemy.position = Enemy.position.move_toward(Vector2(0, 0), 6)
			if Enemy.position == Vector2(0, 0):
				enemy_attacked = false
				attacked = false
				battle_state = neutral
		won_battle:
			Enemy.dead = true
		out_of_battle:
			pass
func _on_AnimationPlayer2_animation_finished(anim_name):
	attacked = true
func _ready():
	battle_state = out_of_battle

bunnydefluff

This line , Player = get_node("/root/Node2D/KinematicBody2D"), and a few other lines that are similar below it, try to put that segment in func ready(): instead of the func process(delta):.

ProbablyTooAmbitious

When I put those lines in _ready(), the error I had previously shows up again (the "invalid get index on base previously freed instance" one). I'm still not entirely sure why it happens, but I appreciate the help regardless

I've looked and I can't seem to find anything about the "true and false" issue, which is strange since I've had the same issue numerous times before. It only happens when I try to change variables in autoloads, I haven't seen it happen with any other script.

TwistedTwigleg

Looking at the script, I wonder if the issue is after calling change_scene the rest of the code in _process is being called and that is causing the issue. Does adding return after change_scene on line 34 help?

ProbablyTooAmbitious

Return stopped the crashes from happening, thank you! Also, I solved the autoload problem - since the variables weren't having problems outside of the autoload script, I created two scripts - the autoload stores the variables whilst the other has the battle system. This seems to have fixed the problem. Thank you for your help!