Restrict Sophisticated Backpacks

# Restrict Sophisticated Backpacks

A server-side addon that restricts access to [Sophisticated Backpacks](https://www.curseforge.com/minecraft/mc-mods/sophisticated-backpacks) until it has been explicitly unlocked using a scoreboard value.

## What It Does

This mod blocks Sophisticated Backpacks interactions until it is unlocked.

It covers:
- opening a placed backpack by right-clicking it
- opening a backpack item by right-clicking it in-hand
- opening a backpack through the Sophisticated Backpacks hotkey

You unlock the ability to interact with Sophisticated Backpacks when the player's scoreboard value for `sophisticated_backpack_unlocked` is greater than `0`.

## How It Works

The mod uses a server-side scoreboard objective named:

`sophisticated_backpack_unlocked`

If the score is:
- `0` or missing: backpack use is blocked
- `1` or higher: backpack use is allowed

The objective is created automatically when the server starts.

## Installation

This mod is intended for server-side only installation but can be installed on clients as well. Clients do not need this mod installed for the restriction to work.

## Scoreboard Usage

Unlock the ability to interact with backpacks:

```mcfunction
/scoreboard players set <player> sophisticated_backpack_unlocked 1
```

Lock the ability to interact with backpacks:

```mcfunction
/scoreboard players set <player> sophisticated_backpack_unlocked 0
```

## Performance

This mod has minimal performance impact.

It does not tick players, scan inventories continuously or run world searches. It only performs lightweight checks when a player tries to interact with a Sophisticated Backpack or when the backpack container opens.

## Notes

- The restriction is enforced server-side, so players cannot bypass it by rebinding keys or using the backpack hotkey.
- Shift-right-click pickup of a placed backpack with an empty main hand is still allowed.