How to make a first-person inventory system in Godot 4

1. Items as resources

A Resource is the Godot way to describe data you edit in the Inspector. One .tres file per item keeps names and icons out of your code:

class_name Item
extends Resource

@export var id := ""
@export var display_name := ""
@export var icon: Texture2D

2. An autoload that holds the slots

Add this script under Project Settings > Globals > Autoload as Inventory. A signal tells the UI to redraw:

extends Node

signal changed
const SIZE := 9
var slots: Array[Item] = []
var selected := 0

func _ready() -> void:
    slots.resize(SIZE)

func add(item: Item) -> bool:
    for i in SIZE:
        if slots[i] == null:
            slots[i] = item
            changed.emit()
            return true
    return false

func drop_selected() -> Item:
    var item := slots[selected]
    slots[selected] = null
    changed.emit()
    return item

3. Pick up what you look at

Put a RayCast3D on the camera, about 2 m long. When the player presses the interact action and the ray hits a pickup, add its item and free the node:

@onready var ray: RayCast3D = $Camera3D/RayCast3D

func _unhandled_input(event: InputEvent) -> void:
    if event.is_action_pressed("interact") and ray.is_colliding():
        var target := ray.get_collider()
        if target is Pickup and Inventory.add(target.item):
            target.queue_free()
    if event is InputEventMouseButton and event.pressed:
        if event.button_index == MOUSE_BUTTON_WHEEL_UP:
            Inventory.selected = posmod(Inventory.selected - 1, Inventory.SIZE)
        elif event.button_index == MOUSE_BUTTON_WHEEL_DOWN:
            Inventory.selected = posmod(Inventory.selected + 1, Inventory.SIZE)
        Inventory.changed.emit()

Pickup is a small script on a StaticBody3D or RigidBody3D with an exported item: Item. For the hotbar, an HBoxContainer of TextureRects that redraws on Inventory.changed is enough.

4. Save the inventory

Save item ids, not the resources themselves, so a save keeps working when you change an icon:

func save_inventory() -> void:
    var ids := Inventory.slots.map(func(i): return i.id if i else "")
    var file := FileAccess.open("user://inventory.json", FileAccess.WRITE)
    file.store_string(JSON.stringify(ids))

On load, read the ids and map each one back to its .tres with a dictionary of items. The same pattern saves doors, coins and checkpoints.

5. Or start from working systems

The 10 Game Systems collection for Godot 4 ships this inventory together with save and load, doors with keys and keypads, a shop, a starter RPG and five more, each with a demo scene and typed GDScript. The Door System is free.

FREE EDITION

10 Game Systems for Godot 4: Doors, Inventory, Save, Shop & RPG

Unity 6 · URP · C# source + demo

Freepaid editions from $7.99

FREE EDITION

Horror Essentials: PSX Horror Template for Unity 6 & Godot 4

Unity 6 · URP · C# source + demo

Freepaid editions from $7.99