I am trying to have a TextureRect update with an input. The child has the script below.

Question

extends KinematicBody2D

var charge = 0

func ready():
pass
func _physicsprocess(delta):
chargeFunc()
func chargeFunc():
if Input.isactionpressed("attack") and charge > 4:
charge = charge + 0.5

var chargeBar = get_parent()
if charge == 4:
    chargeBar.texture = load("res://UI/FullCharge.png")
if charge == 3:
    chargeBar.texture = load("res://UI/Charged3.png")
if charge == 2:
    chargeBar.texture = load("res://UI/Charged2.png")
if charge == 1:
    chargeBar.texture = load("res://UI/Charged1.png")
if charge == 0:
    chargeBar.texture = load("res://UI/EmptyCharge.png")

if Input.is_action_just_released("attack"):
    charge = 0

Answer 1

It looks like it's impossible for charge to ever be greater than 0 since it's only incremented when charge is greater than 4.

Also, I think you should look into using match statements instead of having many separate if statements. Also, I'm not sure if you want to run this code in _physics_process. It sounds like it might increment the charge counter too quickly? Maybe consider using a Timer?