> ## Documentation Index
> Fetch the complete documentation index at: https://docs.summerengine.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Guide: Making A 2D Game Multiplayer

> Integrate Crafty into a 2D game by extending CraftyPlayer and syncing your own state.

## Platform Framing

You are not building a “Crafty game type.”\
You are building a 2D game in Summer/Godot and integrating the Crafty platform layer:

* multiplayer runtime,
* server authority,
* data/economy/teams/score modules.

## Recommended Player Model

For 2D games, create your own 2D player class that extends `CraftyPlayer`.

```gdscript theme={null}
extends CraftyPlayer

@export var speed := 220.0
var local_position := Vector2.ZERO
var is_alive := true

func _ready() -> void:
    set_synced("x", local_position.x)
    set_synced("y", local_position.y)
    set_synced("anim", "idle")
```

## Server Authority Loop

```gdscript theme={null}
extends CraftyGame

func _process(delta: float) -> void:
    super._process(delta)
    if not Crafty.is_server():
        return

    for p in get_players():
        _step_2d_player(p, delta)

func _step_2d_player(player, delta: float) -> void:
    var move: Vector2 = player.input.movement
    player.local_position += move.normalized() * player.speed * delta

    player.set_synced("x", player.local_position.x)
    player.set_synced("y", player.local_position.y)
    player.set_synced("anim", "run" if move.length() > 0 else "idle")
```

## Client Render Pattern

On clients, render from synced state:

```gdscript theme={null}
func _process(_delta: float) -> void:
    var x = get_synced("x")
    var y = get_synced("y")
    if x != null and y != null:
        $Sprite2D.global_position = Vector2(float(x), float(y))
```

## Joining / Leaving

```gdscript theme={null}
func _player_joined(player) -> void:
    player.set_synced("x", 0.0)
    player.set_synced("y", 0.0)
    player.set_synced("hp", 100)

func _player_left(player) -> void:
    pass
```

## Optional Subsystems

Use only what you need:

* `Crafty.score` for score/rank,
* `Crafty.teams` for team modes,
* `Crafty.data` for persistent inventory/progress,
* `Crafty.economy` for currency.

## Common Mistakes

* Running movement authority on clients.
* Mutating score/economy from client paths.
* Treating `set_synced` as client-owned state.

## Production Checklist (2D)

* [ ] `Crafty.is_server()` gates all authoritative state updates.
* [ ] 2D state is synced via `set_synced`.
* [ ] Client only renders synced values.
* [ ] Required manifest fields valid.
* [ ] Local test runner flow passes.