:truck: Import scene replication example project

Imported from https://godotengine.org/article/multiplayer-in-godot-4-0-scene-replication/

netnet/level.gd

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+extends Node3D
+
+const SPAWN_RANDOM := 5.0
+
+func _ready():
+	# We only need to spawn players on the server.
+	if not multiplayer.is_server():
+		return
+
+	multiplayer.peer_connected.connect(add_player)
+	multiplayer.peer_disconnected.connect(del_player)
+
+	# Spawn already connected players
+	for id in multiplayer.get_peers():
+		add_player(id)
+
+	# Spawn the local player unless this is a dedicated server export.
+	if not OS.has_feature("dedicated_server"):
+		add_player(1)
+
+
+func _exit_tree():
+	if not multiplayer.is_server():
+		return
+	multiplayer.peer_connected.disconnect(add_player)
+	multiplayer.peer_disconnected.disconnect(del_player)
+
+
+func add_player(id: int):
+	var character = preload("res://player.tscn").instantiate()
+	# Set player id.
+	character.player = id
+	# Randomize character position.
+	var pos := Vector2.from_angle(randf() * 2 * PI)
+	character.position = Vector3(pos.x * SPAWN_RANDOM * randf(), 0, pos.y * SPAWN_RANDOM * randf())
+	character.name = str(id)
+	$Players.add_child(character, true)
+
+
+func del_player(id: int):
+	if not $Players.has_node(str(id)):
+		return
+	$Players.get_node(str(id)).queue_free()

netnet/level.tscn

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+[gd_scene load_steps=6 format=3 uid="uid://efwjm4hfeqf2"]
+
+[ext_resource type="PackedScene" uid="uid://c6br8h3si2ypg" path="res://sphere.tscn" id="1_8awbr"]
+[ext_resource type="Script" path="res://level.gd" id="1_p4gvl"]
+
+[sub_resource type="WorldBoundaryShape3D" id="WorldBoundaryShape3D_s66iy"]
+
+[sub_resource type="PlaneMesh" id="PlaneMesh_7cbpt"]
+size = Vector2(20, 20)
+
+[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_kgp6f"]
+albedo_color = Color(0.164706, 0.478431, 1, 1)
+
+[node name="World" type="Node3D"]
+script = ExtResource("1_p4gvl")
+
+[node name="Camera3D" type="Camera3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1.35697, 3.4425)
+
+[node name="Floor" type="StaticBody3D" parent="."]
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="Floor"]
+shape = SubResource("WorldBoundaryShape3D_s66iy")
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="Floor"]
+mesh = SubResource("PlaneMesh_7cbpt")
+surface_material_override/0 = SubResource("StandardMaterial3D_kgp6f")
+
+[node name="OmniLight3D" type="OmniLight3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 10.4214, 0)
+light_energy = 10.0
+omni_range = 20.2379
+
+[node name="Objects" type="Node3D" parent="."]
+
+[node name="Sphere" parent="Objects" instance=ExtResource("1_8awbr")]
+
+[node name="Sphere2" parent="Objects" instance=ExtResource("1_8awbr")]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3.09399, 4.03106, 0)
+
+[node name="Players" type="Node3D" parent="."]
+
+[node name="MultiplayerSpawner" type="MultiplayerSpawner" parent="."]
+_spawnable_scenes = PackedStringArray("res://player.tscn")
+spawn_path = NodePath("../Players")
+spawn_limit = 4

netnet/multiplayer.gd

@@ -0,0 +1,67 @@
+extends Node
+
+const PORT = 4433
+
+func _ready():
+	# Start paused
+	get_tree().paused = true
+	# You can save bandwith by disabling server relay and peer notifications.
+	multiplayer.server_relay = false
+
+	# Automatically start the server in headless mode.
+	if DisplayServer.get_name() == "headless":
+		print("Automatically starting dedicated server")
+		_on_host_pressed.call_deferred()
+
+
+func _on_host_pressed():
+	# Start as server
+	var peer = ENetMultiplayerPeer.new()
+	peer.create_server(PORT)
+	if peer.get_connection_status() == MultiplayerPeer.CONNECTION_DISCONNECTED:
+		OS.alert("Failed to start multiplayer server")
+		return
+	multiplayer.multiplayer_peer = peer
+	start_game()
+
+
+func _on_connect_pressed():
+	# Start as client
+	var txt : String = $UI/Net/Options/Remote.text
+	if txt == "":
+		OS.alert("Need a remote to connect to.")
+		return
+	var peer = ENetMultiplayerPeer.new()
+	peer.create_client(txt, PORT)
+	if peer.get_connection_status() == MultiplayerPeer.CONNECTION_DISCONNECTED:
+		OS.alert("Failed to start multiplayer client")
+		return
+	multiplayer.multiplayer_peer = peer
+	start_game()
+
+func start_game():
+	# Hide the UI and unpause to start the game.
+	$UI.hide()
+	get_tree().paused = false
+	# Only change level on the server.
+	# Clients will instantiate the level via the spawner.
+	if multiplayer.is_server():
+		change_level.call_deferred(load("res://level.tscn"))
+
+
+# Call this function deferred and only on the main authority (server).
+func change_level(scene: PackedScene):
+	# Remove old level if any.
+	var level = $Level
+	for c in level.get_children():
+		level.remove_child(c)
+		c.queue_free()
+	# Add new level.
+	level.add_child(scene.instantiate())
+
+# The server can restart the level by pressing HOME.
+func _input(event):
+	if not multiplayer.is_server():
+		return
+	if event.is_action("ui_home") and Input.is_action_just_pressed("ui_home"):
+		change_level.call_deferred(load("res://level.tscn"))

netnet/multiplayer.tscn

@@ -0,0 +1,56 @@
+[gd_scene load_steps=2 format=3 uid="uid://bvnwjpd0f3oa0"]
+
+[ext_resource type="Script" path="res://multiplayer.gd" id="1_jiv4u"]
+
+[node name="Multiplayer" type="Node"]
+script = ExtResource("1_jiv4u")
+
+[node name="Level" type="Node" parent="."]
+
+[node name="LevelSpawner" type="MultiplayerSpawner" parent="."]
+_spawnable_scenes = PackedStringArray("res://level.tscn")
+spawn_path = NodePath("../Level")
+spawn_limit = 1
+
+[node name="UI" type="Control" parent="."]
+process_mode = 3
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="Net" type="VBoxContainer" parent="UI"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="Options" type="HBoxContainer" parent="UI/Net"]
+layout_mode = 2
+
+[node name="Label" type="Label" parent="UI/Net/Options"]
+layout_mode = 2
+text = "Direct:"
+
+[node name="Host" type="Button" parent="UI/Net/Options"]
+layout_mode = 2
+text = "Host"
+
+[node name="Connect" type="Button" parent="UI/Net/Options"]
+layout_mode = 2
+text = "Connect"
+
+[node name="Remote" type="LineEdit" parent="UI/Net/Options"]
+layout_mode = 2
+size_flags_horizontal = 3
+text = "127.0.0.1"
+placeholder_text = "Remote Host"
+caret_blink = true
+caret_blink_interval = 0.5
+
+[connection signal="pressed" from="UI/Net/Options/Host" to="." method="_on_host_pressed"]
+[connection signal="pressed" from="UI/Net/Options/Connect" to="." method="_on_connect_pressed"]

netnet/player.gd

@@ -0,0 +1,49 @@
+extends CharacterBody3D
+
+const SPEED = 5.0
+const JUMP_VELOCITY = 4.5
+
+# Get the gravity from the project settings to be synced with RigidBody nodes.
+var gravity = ProjectSettings.get_setting("physics/3d/default_gravity")
+
+# Set by the authority, synchronized on spawn.
+@export var player := 1 :
+	set(id):
+		player = id
+		# Give authority over the player input to the appropriate peer.
+		$PlayerInput.set_multiplayer_authority(id)
+
+# Player synchronized input.
+@onready var input = $PlayerInput
+
+func _ready():
+	# Set the camera as current if we are this player.
+	if player == multiplayer.get_unique_id():
+		$Camera3D.current = true
+	# Only process on server.
+	# EDIT: Left the client simulate player movement too to compesate network latency.
+	# set_physics_process(multiplayer.is_server())
+
+
+func _physics_process(delta):
+	# Add the gravity.
+	if not is_on_floor():
+		velocity.y -= gravity * delta
+
+	# Handle Jump.
+	if input.jumping and is_on_floor():
+		velocity.y = JUMP_VELOCITY
+
+	# Reset jump state.
+	input.jumping = false
+
+	# Handle movement.
+	var direction = (transform.basis * Vector3(input.direction.x, 0, input.direction.y)).normalized()
+	if direction:
+		velocity.x = direction.x * SPEED
+		velocity.z = direction.z * SPEED
+	else:
+		velocity.x = move_toward(velocity.x, 0, SPEED)
+		velocity.z = move_toward(velocity.z, 0, SPEED)
+
+	move_and_slide()

netnet/player.tscn

@@ -0,0 +1,44 @@
+[gd_scene load_steps=7 format=3 uid="uid://cw8w6clmxedi6"]
+
+[ext_resource type="Script" path="res://player.gd" id="1_hwwnj"]
+[ext_resource type="Script" path="res://player_input.gd" id="2_ju3m6"]
+
+[sub_resource type="SceneReplicationConfig" id="SceneReplicationConfig_fb1vy"]
+properties/0/path = NodePath(".:player")
+properties/0/spawn = true
+properties/0/sync = false
+properties/1/path = NodePath(".:position")
+properties/1/spawn = true
+properties/1/sync = true
+properties/2/path = NodePath(".:velocity")
+properties/2/spawn = true
+properties/2/sync = true
+
+[sub_resource type="SceneReplicationConfig" id="SceneReplicationConfig_hoavk"]
+properties/0/path = NodePath(".:direction")
+properties/0/spawn = false
+properties/0/sync = true
+
+[sub_resource type="CapsuleShape3D" id="CapsuleShape3D_37qaq"]
+
+[sub_resource type="CapsuleMesh" id="CapsuleMesh_jab13"]
+
+[node name="Player" type="CharacterBody3D"]
+script = ExtResource("1_hwwnj")
+
+[node name="ServerSynchronizer" type="MultiplayerSynchronizer" parent="."]
+replication_config = SubResource("SceneReplicationConfig_fb1vy")
+
+[node name="PlayerInput" type="MultiplayerSynchronizer" parent="."]
+root_path = NodePath(".")
+replication_config = SubResource("SceneReplicationConfig_hoavk")
+script = ExtResource("2_ju3m6")
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="."]
+shape = SubResource("CapsuleShape3D_37qaq")
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="."]
+mesh = SubResource("CapsuleMesh_jab13")
+
+[node name="Camera3D" type="Camera3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1.40432, 2.04444)

netnet/player_input.gd

@@ -0,0 +1,23 @@
+extends MultiplayerSynchronizer
+
+# Set via RPC to simulate is_action_just_pressed.
+@export var jumping := false
+
+# Synchronized property.
+@export var direction := Vector2()
+
+func _ready():
+	# Only process for the local player
+	set_process(get_multiplayer_authority() == multiplayer.get_unique_id())
+
+
+@rpc("call_local")
+func jump():
+	jumping = true
+
+func _process(delta):
+	# Get the input direction and handle the movement/deceleration.
+	# As good practice, you should replace UI actions with custom gameplay actions.
+	direction = Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")
+	if Input.is_action_just_pressed("ui_accept"):
+		jump.rpc()

netnet/project.godot

@@ -0,0 +1,16 @@
+; Engine configuration file.
+; It's best edited using the editor UI and not directly,
+; since the parameters that go here are not all obvious.
+;
+; Format:
+;   [section] ; section goes between []
+;   param=value ; assign values to parameters
+
+config_version=5
+
+[application]
+
+config/name="Network Example Gd4"
+config/description="Scene replication example in 3D with Godot 4"
+run/main_scene="res://multiplayer.tscn"
+config/features=PackedStringArray("4.0")

netnet/sphere.tscn

@@ -0,0 +1,37 @@
+[gd_scene load_steps=5 format=3 uid="uid://c6br8h3si2ypg"]
+
+[sub_resource type="PhysicsMaterial" id="PhysicsMaterial_mp5c4"]
+friction = 0.0
+bounce = 1.0
+
+[sub_resource type="SphereMesh" id="SphereMesh_deuj3"]
+
+[sub_resource type="SphereShape3D" id="SphereShape3D_h6jr2"]
+
+[sub_resource type="SceneReplicationConfig" id="SceneReplicationConfig_q1o6k"]
+properties/0/path = NodePath(".:linear_velocity")
+properties/0/spawn = true
+properties/0/sync = true
+properties/1/path = NodePath(".:angular_velocity")
+properties/1/spawn = true
+properties/1/sync = true
+properties/2/path = NodePath(".:position")
+properties/2/spawn = true
+properties/2/sync = true
+properties/3/path = NodePath(".:rotation")
+properties/3/spawn = true
+properties/3/sync = true
+
+[node name="Sphere" type="RigidBody3D"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 2.42886, 0)
+physics_material_override = SubResource("PhysicsMaterial_mp5c4")
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="."]
+mesh = SubResource("SphereMesh_deuj3")
+skeleton = NodePath("../CollisionShape3D")
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="."]
+shape = SubResource("SphereShape3D_h6jr2")
+
+[node name="MultiplayerSynchronizer" type="MultiplayerSynchronizer" parent="."]
+replication_config = SubResource("SceneReplicationConfig_q1o6k")