Authority And Security
Anti-Cheat Measures
Server-Side Validation
# server_validator.gd
extends Node
const MAX_SPEED = 300.0
const MAX_TELEPORT_DISTANCE = 50.0
@rpc("any_peer", "call_remote", "reliable")
func request_move(new_position: Vector2) -> void:
var sender_id := multiplayer.get_remote_sender_id()
var player := get_node("/root/World/" + str(sender_id))
# Validate movement
var distance := player.position.distance_to(new_position)
var delta := get_physics_process_delta_time()
var max_allowed := MAX_SPEED * delta
if distance > max_allowed:
push_warning("Player %d teleported %f units (max: %f)" % [sender_id, distance, max_allowed])
# Reject movement, force server position
rpc_id(sender_id, "force_position", player.position)
return
# Accept movement
player.position = new_position
@rpc("authority", "call_remote", "reliable")
func force_position(server_position: Vector2) -> void:
position = server_position
Bandwidth Optimization
Input Buffering
# ❌ BAD: Send input every frame (60 packets/s)
func _physics_process(delta: float) -> void:
var input := get_input()
rpc_id(1, "receive_input", input)
# ✅ GOOD: Send every 3rd frame (20 packets/s)
var input_timer := 0.0
const INPUT_SEND_RATE = 0.05 # 20 Hz
func _physics_process(delta: float) -> void:
input_timer += delta
if input_timer >= INPUT_SEND_RATE:
var input := get_input()
rpc_id(1, "receive_input", input)
input_timer = 0.0
Testing Multiplayer Locally
# Launch multiple instances for testing
# Run from command line:
# Windows:
# Server: Godot.exe --path . res://main.tscn -- --server
# Client 1: Godot.exe --path . res://main.tscn -- --client
# Client 2: Godot.exe --path . res://main.tscn -- --client
# Parse arguments in code:
func _ready() -> void:
var args := OS.get_cmdline_args()
if "--server" in args:
host_game()
elif "--client" in args:
join_game("127.0.0.1")
