Grid Inventory System with Custom Patterns for Godot 4

---

Project Overview

This project implements a grid-based inventory system as seen in inventory management games using Godot 4, with features such as:

• Customizable Item Patterns: Items can have varying shapes defined by patterns.
• Rotatable Items: Items can rotate to fit within the grid.
• Item Stacking and Merging: Supports stacking of items and merging items with specific conditions.
• Dynamic Inventory Grid: Fully scalable and customizable inventory grid.
• Inventory Save/Load Support: States of the inventory and items can be saved and reloaded.
• Item Rarity System: Different rarities with associated probabilities and visual indicators.
• Interactive Inventory: Drag-and-drop functionality for item placement and repositioning.

---

How to Use

Setup

1. Include the apeloot folder in your addons directory, or download it from asset library.
2. Attach inventory_interface.gd to a PanelContainer node in your scene. This node represents the inventory grid. You can also drag and drop inventory_interface.tscn to your scene.

---

Features

Item Definitions

Define items in Apeloot.gd under the items dictionary:

const items := {
	"steak": {
		"name": "Steak",
		"desc": "Made from happy cows.",
		"price": 31,
		"rarity": Rarity.COMMON,
		"pattern": "3x1",
		"merge": true,
	}
}

• name: Display name.
• desc: Description.
• price: Price of the item.
• rarity: Rarity of the item (e.g., COMMON, UNCOMMON). Used for merging.
• pattern: The shape/pattern of the item on the grid (refer to item_patterns).
• merge: Whether the item can merge with another of the same type.
• stack: Maximum stack count for item, accepts int.

Grid Configuration

inventory_interface.gd allows customization:

• id: This is identifier for the inventory, should be unique.
• slot_count: Total number of slots in the inventory.
• columns: Number of columns in the grid.
• single_slot: Restrict items to single-slot grids.
• pickup_only: Disable item placement; inventory becomes read-only.
• slot_background: Texture for slot backgrounds.
• slot_separation: Defines spacing between slots.

---

API Reference

Signals

• item_placed(item: DraggableItem): Fired when an item is placed in the inventory.
• item_removed(item: DraggableItem): Fired when an item is removed.
• item_updated(item: DraggableItem): Fired when an item's state changes.

Functions

1. initialize_inventory(states: Array = item_states)

   • Initializes the inventory with predefined states.
   • Parameters:
     • states (optional): Array of saved states to load.

2. load_inventory(data: Dictionary)

   • Loads inventory from a saved dictionary.
   • Parameters:
     • data: Dictionary containing inventory data.

3. try_fit_and_place(item: DraggableItem) -> bool

   • Attempts to fit and place an item in the inventory.
   • Returns true if successful.

4. remove_item(item: DraggableItem)

   • Removes a specified item from the inventory.

5. find_valid_slot(item: DraggableItem) -> int

   • Finds the first valid slot where an item can fit.
   • Returns the slot index or -1 if no slot is valid.

6. get_item_at_slot(slot_id: int) -> DraggableItem

   • Retrieves the item at a specified slot index.

7. reconstruct_grid_from_states(saved_states: Array)

   • Reconstructs the grid layout from saved item states.

8. get_occupied_slots(item: DraggableItem, center_slot_id: int) -> Array

   • Returns a list of slots occupied by an item based on its center position.

---

Example Usage

You can also refer to example.tscn for example usages.

Adding Items

var item = inventory.spawn_item("steak")
if inventory.can_place_item(item, target_slot):
	inventory.snap_item_to_grid(item, target_slot)
else:
	item.queue_free()  # Cleanup if placement fails

Loading Inventory

var saved_inventory = {
	"inventories": {
		"main_inventory": [
			{"id": "steak", "stack_count": 1, "previous_center_slot": 5}
		]
	}
}
inventory.load_inventory(saved_inventory)

Saving Inventory

var saved_states = inventory.item_states
# Save `saved_states` externally

---

Item Patterns

Patterns define item shapes on the grid. Use square matrices, 1 defines occupied slots.

Examples:

const item_patterns = {
	"1x1": [[1]],
	"2x2": [
		[1, 1],
		[1, 1]
	],
	"T": [
		[1, 1, 1],
		[0, 1, 0],
		[0, 1, 0]
	]
}

---

Future Enhancements

• Advanced Sorting: Organize items by type, rarity, or other attributes.
• Multiplayer Synchronization: Real-time inventory updates across networked instances.
• Drag-and-Drop UI Refinements: Enhanced visual cues during item interactions.

---