Add multiplayer version compatibility check

menu/components/alerter.gd

@@ -0,0 +1,19 @@
+extends Node
+
+
+func show_simple_alert(text: String, title: String = "Alert") -> void:
+	var dialog = AcceptDialog.new()
+	dialog.dialog_text = text
+	dialog.window_title = title
+	dialog.connect("modal_closed", dialog, "queue_free")
+	var scene_tree = Engine.get_main_loop()
+	scene_tree.current_scene.add_child(dialog)
+	dialog.popup_centered()
+
+
+func create_simple_alert(text: String, title: String = "Alert") -> AcceptDialog:
+	var dialog = AcceptDialog.new()
+	dialog.dialog_text = text
+	dialog.window_title = title
+	dialog.connect("modal_closed", dialog, "queue_free")
+	return dialog

network/multiplayer_controller.gd

@@ -6,6 +6,7 @@ const GUI_SCENE = "res://player/gui.tscn"
 
 var enet_peer = NetworkedMultiplayerENet.new()
 var peers = {}
+var version_checked = []
 
 var current_track: Node = null
 var current_track_path: String
@@ -102,6 +103,7 @@ func _peer_connected(peer_id):
 	)
 	emit_signal("peers_updated")
 	if get_tree().get_network_unique_id() == 1:
+		if version_checked.has(peer_id):
 			rpc_id(peer_id, "select_track", current_track_path)
 
 
@@ -111,7 +113,9 @@ func _peer_disconnected(peer_id):
 
 
 func _connected_to_server():
-	pass
+	rpc_id(
+		1, "check_version", get_tree().get_network_unique_id(), GlobalSettings.get_version_string()
+	)
 
 
 func _connection_failed():
@@ -125,6 +129,13 @@ func _server_disconnected():
 	peers.clear()
 	get_tree().network_peer = null
 	get_tree().root.get_child(get_tree().root.get_child_count() - 1).queue_free()
+	var alert = Alerter.create_simple_alert("Connection to the host has been lost.")
+	get_tree().root.add_child(alert)
+	alert.connect("popup_hide", self, "_on_disconnect_confirmed")
+	alert.popup_centered()
+
+
+func _on_disconnect_confirmed():
 	get_tree().change_scene("res://menu/main_menu.tscn")
 
 
@@ -184,6 +195,15 @@ remote func add_player(peer_id, peer_info: Array):
 		emit_signal("peers_updated")
 
 
+remote func check_version(peer_id: int, version: String) -> void:
+	if version != GlobalSettings.get_version_string():
+		enet_peer.disconnect_peer(peer_id)
+		return
+
+	version_checked.append(peer_id)
+	rpc_id(peer_id, "select_track", current_track_path)
+
+
 remote func select_track(track_path):
 	current_track = load(track_path).instance()
 	get_tree().root.call_deferred("add_child", current_track)

project.godot

@@ -59,6 +59,7 @@ config/icon="res://icon.png"
 
 GlobalSettings="*res://settings/global_settings.gd"
 MultiplayerController="*res://network/multiplayer_controller.gd"
+Alerter="*res://menu/components/alerter.gd"
 
 [editor_plugins]