You said:
Reason I would like you to build me a basic Godot project with the following properties:
- A player character is seen from above, classic fallout 1+2 style.
- A humanoid model with basic animations (sourced elsewhere) is loaded from disk, as well as the model of a tree and a terrain map
- Also, a map file is loaded, holding the location of many of trees around the player.
- Pressing a or d rotates the camera around the player
- Moving the mouse and right-clicking moves the player relative to the cursor, i.e. holding the mouse to the right of the player and right clicking makes the player run to the right
- The player cannot run into trees
- If the cursor is far from the player as the right mouse button is held down they will run
- If the cursor is near to the player as the right mouse button is held down they will walk
- The player displays the requisite animations at all times, including an idle animation.
ChatGPT

Organizing the scene
Below is an example of how you might assemble a minimal Godot 4 project to achieve the features you requested:

1. Project Structure
A typical directory layout could look like this:

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YourProject/
├── project.godot
├── Assets/
│ ├── Character/ # Folder with your humanoid model + animations
│ │ ├── humanoid_mesh.tres
│ │ ├── idle.anim
│ │ ├── walk.anim
│ │ ├── run.anim
│ │ └── ...
│ ├── Tree/
│ │ ├── Tree.tscn # Scene for your tree
│ │ └── tree_mesh.tres
│ ├── Terrain/
│ │ ├── Terrain.tscn # Scene for your terrain (and collider)
│ │ └── terrain_mesh.tres
│ └── map_data.txt # File that lists tree positions
├── Main.tscn # Main scene that brings everything together
├── Player.tscn # The player’s main scene
└── Player.gd # Player script (attached to Player.tscn)
You can name the folders whatever you like, of course. The important point is having a clear place for each asset and scene.

2. Setting Up the Terrain
Create Terrain Scene
In Godot, create a new 3D scene (Node3D as the root) and name it Terrain.
Add a MeshInstance3D as a child. Load your terrain mesh into it.
Add a CollisionShape3D (or StaticBody3D + CollisionShape3D) so the player can’t walk through the ground.
Save it as Terrain.tscn.
Your terrain might look something like this:

scss
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Terrain.tscn (root is Node3D)
└── StaticBody3D
├── MeshInstance3D (terrain_mesh)
└── CollisionShape3D (matching the terrain shape)
3. Setting Up the Tree Scene
Create Tree Scene
Similarly, create a new 3D scene called Tree.tscn.
Make the root a StaticBody3D.
Add a MeshInstance3D with your tree mesh.
Add a CollisionShape3D that fits the trunk (so the player can’t run through).
Save as Tree.tscn.
Example:

scss
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Tree.tscn (root is StaticBody3D)
├── MeshInstance3D (tree_mesh)
└── CollisionShape3D (capsule or box shape around trunk)
4. Player Scene
Create Player Scene
Create a new 3D scene called Player.tscn.
Make the root a CharacterBody3D (so we can use move_and_slide() or Godot 4’s move_and_collide(), etc.).
Add a child AnimatedMeshInstance3D (or Skeleton3D + MeshInstance3D) that holds your humanoid mesh and skeleton.
Add an AnimationPlayer or AnimationTree (in Godot 4, an AnimationTree is often used with a State Machine node to handle idle/walk/run transitions).
Add a CollisionShape3D for the player’s body capsule (so they don’t pass through trees).
Example player scene structure:

scss
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Player.tscn (root is CharacterBody3D)
├── CollisionShape3D (capsule shape around the player)
├── Skeleton3D
│ └── MeshInstance3D (your humanoid mesh)
└── AnimationTree (with a StateMachine to handle Idle, Walk, Run)
Set Up Animations

In the AnimationTree, create a State Machine node with states Idle, Walk, and Run, each referencing your .anim or .blend animations.
Be sure to activate the AnimationTree by checking Active in the Inspector, then create a parameter of type AnimationNodeStateMachine to control it in code.
Attach a Script

Attach a script to Player.tscn (for example, Player.gd).
Below is an example in GDScript that handles:
Rotation with A/D.
Right-click to set a target position based on the mouse’s world ray.
Distinguishing walk vs run based on distance to the target.
Playing correct animations.
Player.gd
gdscript
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extends CharacterBody3D

# -- Adjustable speeds
@export var walk_speed := 3.0
@export var run_speed := 6.0

# -- Threshold distance for switching from walk to run:
@export var run_distance_threshold := 5.0

var target_position: Vector3 = Vector3.ZERO

# We'll hold the AnimationTree StateMachine playback for convenience
onready var anim_tree: AnimationTree = $AnimationTree
var anim_state: AnimationNodeStateMachinePlayback

func _ready():
# Grab the State Machine playback
anim_state = anim_tree.get_state_machine_playback()

# Optionally set the initial animation
anim_state.travel("Idle")


func _physics_process(delta: float) -> void:
# -----------------------------------------
# 1. Camera Orbit with A or D
# (Make sure you set Input Map "rotate_left" = A, "rotate_right" = D)
# -----------------------------------------
if Input.is_action_pressed("rotate_left"):
rotate_y(-1.5 * delta) # adjust speed as desired
if Input.is_action_pressed("rotate_right"):
rotate_y(1.5 * delta)

# -----------------------------------------
# 2. Move the Player toward target_position
# -----------------------------------------
var current_pos = global_transform.origin
var move_direction = target_position - current_pos
move_direction.y = 0 # ignore vertical difference for top-down movement
var distance_to_target = move_direction.length()

var velocity = Vector3.ZERO
if distance_to_target > 0.1:
# If not close to the target, move in that direction
move_direction = move_direction.normalized()

# Turn to face movement direction
look_at(current_pos + move_direction, Vector3.UP)

# Decide whether to walk or run
if distance_to_target > run_distance_threshold:
# Run
velocity = move_direction * run_speed
anim_state.travel("Run")
else:
# Walk
velocity = move_direction * walk_speed
anim_state.travel("Walk")
else:
# We are essentially at the target
anim_state.travel("Idle")

# -----------------------------------------
# 3. Apply movement using CharacterBody
# This automatically checks collisions with trees, terrain, etc.
# -----------------------------------------
velocity = move_and_slide(velocity, Vector3.UP)


func _input(event: InputEvent) -> void:
# -----------------------------------------
# Right-click sets a new target_position
# We'll do a raycast from the camera into the 3D world
# to figure out where the user clicked on the terrain.
# -----------------------------------------
if event is InputEventMouseButton:
if event.button_index == MouseButton.RIGHT and event.pressed:
var camera := get_viewport().get_camera_3d()
if camera:
var from = camera.project_ray_origin(event.position)
var dir = camera.project_ray_normal(event.position)
var space_state = get_world_3d().direct_space_state
var result = space_state.intersect_ray(
from,
from + dir * 1000.0,
[], # exclude array if you want to ignore certain colliders
collision_mask = 1 # adjust if needed
)

if result.size() > 0:
# For example, if you want to ensure the user only sets a target on the terrain:
# if result["collider"] is StaticBody3D: # or check name
target_position = result["position"]
Notes:

In _input, we do a raycast from the camera to find where on the terrain the player clicked, storing that in target_position.
In _physics_process, we compute movement direction, handle rotation to face the direction, then animate accordingly.
5. Main Scene
Finally, create a scene that brings everything together:

Create Main.tscn
Make the root a simple Node3D or Node (depending on your preference).
Add (or instance) a Camera3D as a child. Position it above the player’s starting area for a top-down or angled top-down look.
Instance the Terrain.tscn.
Instance the Player.tscn and place the player at some spawn point.
Load your map_data.txt file to determine where to place the trees.
Example map_data.txt
arduino
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# x, y, z for each tree
10, 0, 10
15, 0, 5
-5, 0, 20
Example script on Main (attached to Main.tscn’s root)
gdscript
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extends Node3D

func _ready():
# 1. Instance the terrain
var terrain_scene = preload("res://Assets/Terrain/Terrain.tscn")
var terrain = terrain_scene.instantiate()
add_child(terrain)

# 2. Instance the player
var player_scene = preload("res://Player.tscn")
var player = player_scene.instantiate()
# place the player at some starting point
player.global_transform.origin = Vector3(0, 0, 0)
add_child(player)

# 3. Load tree positions from map file
var tree_scene = preload("res://Assets/Tree/Tree.tscn")

var file_path = "res://Assets/map_data.txt"
var file = FileAccess.open(file_path, FileAccess.READ)
if file:
while file.get_position() < file.get_length():
var line = file.get_line().strip_edges()
if line == "" or line.begins_with("#"):
continue # skip empty lines or comments
var coords = line.split(",")
if coords.size() == 3:
var x = coords[0].to_float()
var y = coords[1].to_float()
var z = coords[2].to_float()

# Instance a tree and place it
var tree = tree_scene.instantiate()
tree.global_transform.origin = Vector3(x, y, z)
add_child(tree)
file.close()
Now you have:

A terrain loaded as StaticBody3D so the player can collide with it.
A player CharacterBody3D that’s controlled by keyboard for camera rotation (A/D) and by right-click to set movement targets.
A bunch of trees, each StaticBody3D with collision, placed according to your map file, preventing the player from running through them.
6. Input Map Settings
Open Project > Project Settings > Input Map and create these actions (if they don’t already exist):

rotate_left → Key: A
rotate_right → Key: D
(Optionally) set up any other controls you might need.
7. Tuning and Polishing
Camera
If you want a top-down camera that rotates around the player, you can add a Camera3D as a separate node, then script it to orbit the player in _physics_process(). Another approach is to simply rotate the player, and keep the camera stationary above, but that depends on your desired look.
Animations
Make sure your AnimationTree states ("Idle", "Walk", "Run") match exactly the states you call in code.
Ensure your run/walk speeds match your run/walk animations so it looks natural.
Collision
Make sure the collision layers and masks for the Player, Terrain, and Trees allow collision. Typically, Player is on “player” layer, Trees/Terrain on “environment” layer, with appropriate collision masks so they detect each other.
Distance Threshold
Adjust run_distance_threshold to any distance that feels right for switching from walking to running.
Walk vs. Run
The example logic is: if the distance to target is > run_distance_threshold, run; else walk. You can refine that (e.g., measure how far the mouse is from the player on the ground plane at the moment of the click).
8. Summary
With these steps, you’ll have:

Top-down 3D perspective with a humanoid model.
Camera rotation on A/D (by rotating the player or the camera).
Right-click movement: the player runs/walks toward the clicked point on the terrain, speed depending on how far the cursor is from the player.
Collision with trees: the player can’t pass through them.
Basic animations: idle, walk, run, automatically played depending on movement state.
This is a simple foundation; from here, you can add:

Better camera orbit (with smoothing, middle mouse drag, etc.).
More robust navigation (using a NavigationMesh or pathfinding).
More sophisticated animation blending or transitions in the AnimationTree.
Additional obstacles, environment objects, or user interface.
Good luck with your classic Fallout-style top-down project! If you run into quirks—particularly with collisions or animation transitions—double-check your nodes’ collision layers, AnimationTree parameter names, and that you’re using the correct Godot 4 methods (project_ray_origin, etc.).

You said:
Reason Alright, now I want you to take this to the next level. I want you to add the backbone implementation for what will become the Networking implementation for this game.

Add in a TCP-based packet library which uses a format based on the Ultima Online packet format, that is to say:
[packet header (two bytes)][packet length(eight bytes)][packet contents as determined by the packet data structure]

The library should handle the following basic functionality:
- Logging in to the game with a username and password
- Handling a rejected username and password
- Handling an accepted username and password by logging the player in to the game at their last location (given by the server as part of a status update packet)
- Updating the server on about the player's movements in the appropriate part of the game loop
- Accepting new information from the server about the state of other players/NPCs, their movements, or incoming speech packets.

Edit the UI as appropriate to complete this task.

The server implementation will be handled elsewhere, just assume it exists. Write a client library for the game to use, and then use that.
ChatGPT

Below is a conceptual example of how you might extend the project to include a TCP-based network client (in GDScript) that uses a packet format similar to Ultima Online’s:

css
[PacketHeader (2 bytes)] [PacketLength (8 bytes)] [PacketContents (variable)]

The client library handles:

  1. Logging in with username/password (sending credentials to server).
  2. Receiving acceptance or rejection of login.
  3. If accepted, placing the player in the game world at their “last location.”
  4. Periodically sending player movement updates to the server.
  5. Receiving world updates: other players, NPCs, speech, etc.

Disclaimer
This guide focuses on how to structure your client code. In a real project you’ll need to handle details like encryption, packet checksums, or advanced reliability. This example is simplified to show the “backbone” for networking.


Project Structure

A possible folder layout now (expanded from the prior version):

bash
YourProject/
├── project.godot
├── Assets/
│ ├── Character/
│ ├── Tree/
│ ├── Terrain/
│ └── map_data.txt
├── Main.tscn
├── Main.gd # Might handle receiving big world updates
├── Network/
│ ├── NetworkClient.gd # Our custom client library
│ └── Packet.gd # (Optional) Shared code to build/parse packets
├── Player.tscn
├── Player.gd
├── UI/
│ ├── LoginScreen.tscn
│ └── LoginScreen.gd
└── ...

Below, we’ll walk through the major pieces:

  1. A Login Screen (UI) that attempts to connect and log the user in.
  2. A NetworkClient singleton that handles all TCP communications and organizes incoming packets.
  3. Updated Player logic to send movement updates.
  4. Updated Main (or similar manager node) to handle major world updates from the server.

1. The Login Screen

Create a LoginScreen.tscn in UI/ with a simple UI:

  • LineEdit for username
  • LineEdit for password
  • Button for “Connect” / “Login”
  • A label or some feedback text

LoginScreen.tscn (Example)

mathematica
LoginScreen
└── CenterContainer
└── VBoxContainer
├── Label # "Username:"
├── LineEdit (username_field)
├── Label # "Password:"
├── LineEdit (password_field)
├── Button (login_button)
└── Label (message_label) # to show errors or status

LoginScreen.gd

Attach this script to the root of LoginScreen.tscn.

gdscript
extends Control

@onready var username_field = $CenterContainer/VBoxContainer/username_field
@onready var password_field = $CenterContainer/VBoxContainer/password_field
@onready var login_button = $CenterContainer/VBoxContainer/login_button
@onready var message_label = $CenterContainer/VBoxContainer/message_label

func _ready():
message_label.text = ""
password_field.secret = true # Hide password input

login_button.pressed.connect(_on_login_button_pressed)

func _on_login_button_pressed():
var username = username_field.text
var password = password_field.text

message_label.text = "Connecting..."

# Ask our NetworkClient to connect and login
var net_client = NetworkClient.get_singleton()
net_client.connect_to_server("127.0.0.1", 2593) # Example IP/port
net_client.request_login(username, password)

# We can wait for signals from the net client about success/failure

We’ll rely on the NetworkClient to:

  1. Perform the TCP connection.
  2. Attempt login (send credentials).
  3. Emit signals like login_accepted(location), login_rejected(), or login_failed_network().

So we’ll connect signals from the NetworkClient to this login screen.

gdscript
func _ready():
# ...
var net_client = NetworkClient.get_singleton()
net_client.login_accepted.connect(_on_login_accepted)
net_client.login_rejected.connect(_on_login_rejected)
net_client.login_failed_network.connect(_on_login_failed_network)

func _on_login_accepted(last_location: Vector3):
message_label.text = "Login successful!"
# Switch to Main.tscn (the game world)
var main_scene = preload("res://Main.tscn").instantiate()
get_tree().change_scene_to_packed(main_scene.packed_scene())

func _on_login_rejected():
message_label.text = "Login rejected. Check username/password."

func _on_login_failed_network():
message_label.text = "Network error. Cannot connect to server."

2. NetworkClient.gd

We’ll create a script as a singleton (autoload) so it’s accessible anywhere. Go to Project Settings > AutoLoad, add res://Network/NetworkClient.gd with a name NetworkClient.

Alternatively, you can dynamically instantiate this node in Main.tscn, but a singleton often simplifies usage.

Basic Flow

  • Connect to server with StreamPeerTCP.
  • Send a login packet.
  • Start reading in _process() or a dedicated thread to parse packets.
  • Emit signals (login accepted, login rejected, new NPC info, etc.) to let the rest of the game react.

Packet Format

We’ll follow the stated format:

csharp
[PacketHeader (2 bytes)]
[PacketLength (8 bytes)]
[PacketContents (... variable ...)]

Example:

  • The server might define a login packet with a header: 0x01 0x00 (2 bytes).
  • Then an 8-byte length: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 30 (which is decimal 30 bytes).
  • Then 30 bytes of content containing “username, password, etc.”

We can store the contents as a PackedByteArray or PoolByteArray in older Godot versions.

NetworkClient.gd Example

gdscript
extends Node

signal login_accepted(last_location)
signal login_rejected()
signal login_failed_network()

signal updated_players_state(data)
signal received_speech(data)
# ... Other signals as needed

var _tcp_client: StreamPeerTCP
var _connected: bool = false

# For partial reads, store incoming data buffer:
var _incoming_buffer = PackedByteArray()

# Singleton accessor (if using a manual approach)
static func get_singleton():
return get_node("/root/NetworkClient")

func _ready():
# Example: no-op. We might do stuff here or in `_process`.
pass

func connect_to_server(host: String, port: int) -> void:
_tcp_client = StreamPeerTCP.new()
var err = _tcp_client.connect_to_host(host, port)
if err != OK:
emit_signal("login_failed_network")
return
_connected = true

func request_login(username: String, password: String):
if not _connected:
emit_signal("login_failed_network")
return

# Build login packet
var header = _get_16bit(0x0100) # Suppose 0x0100 is "Login Request"
var contents = "username=%s;password=%s" % [username, password]
var contents_bytes = contents.to_utf8()

var length = contents_bytes.size()
var length_bytes = _get_64bit(length)

var packet = PackedByteArray()
packet.append_array(header)
packet.append_array(length_bytes)
packet.append_array(contents_bytes)

# Send it
_tcp_client.put_data(packet)

func _process(delta: float) -> void:
if not _connected:
return

# Check for incoming data
while _tcp_client.get_available_bytes() > 0:
var chunk = _tcp_client.get_data(_tcp_client.get_available_bytes())
_incoming_buffer.append_array(chunk)

# Attempt parsing as many complete packets as possible
_parse_incoming_packets()

func _parse_incoming_packets():
while true:
# Each packet: 2 bytes for header + 8 bytes for length + variable contents
if _incoming_buffer.size() < 10:
break # Not enough data to read even the header+length

# Read the first 2 bytes => packet header
var header = _incoming_buffer.subarray(0, 2)
var header_int = _parse_16bit(header)

# Next 8 bytes => length
var length_slice = _incoming_buffer.subarray(2, 8)
var content_length = _parse_64bit(length_slice)

var total_packet_size = 2 + 8 + content_length
if _incoming_buffer.size() < total_packet_size:
break # Not enough data yet to read the full contents

# We have a complete packet. Extract it
var content_start = 10
var content_end = 10 + content_length
var content_bytes = _incoming_buffer.subarray(content_start, content_length)

# Now remove these bytes from _incoming_buffer
_incoming_buffer = _incoming_buffer.subarray(total_packet_size)

# Parse the packet
_handle_packet(header_int, content_bytes)

func _handle_packet(header_int: int, content_bytes: PackedByteArray):
# Convert bytes to string for example
var content_str = content_bytes.get_string_from_utf8()

match header_int:
0x0101: # Suppose "Login Response"
# Maybe the response is either "ACCEPT: x,y,z" or "REJECT"
if content_str.begins_with("ACCEPT:"):
# parse location
# Example: "ACCEPT:0,0,0"
var coords_str = content_str.substr(7, content_str.length() - 7)
var coords_split = coords_str.split(",")
var x = coords_split[0].to_float()
var y = coords_split[1].to_float()
var z = coords_split[2].to_float()
emit_signal("login_accepted", Vector3(x, y, z))
else:
emit_signal("login_rejected")

0x0102: # Suppose "World/Player updates"
# Example: parse JSON or some structure
# "PLAYERS:[{id=...,pos=...,}, ...];NPCS:[...]"
emit_signal("updated_players_state", content_str)

0x0103: # Suppose "Speech"
emit_signal("received_speech", content_str)

# ... etc.

_:
print("Unknown header: ", header_int, " content: ", content_str)


# Helper functions to build/parse 16-bit and 64-bit
func _get_16bit(value: int) -> PackedByteArray:
var arr = PackedByteArray()
arr.push_back((value >> 8) & 0xFF)
arr.push_back(value & 0xFF)
return arr

func _parse_16bit(data: PackedByteArray) -> int:
return (data[0] << 8) | data[1]

func _get_64bit(value: int) -> PackedByteArray:
var arr = PackedByteArray()
for i in range(8):
# shift right by (8 * (7 - i)), store
arr.push_back((value >> (8 * (7 - i))) & 0xFF)
return arr

func _parse_64bit(data: PackedByteArray) -> int:
var result := 0
for i in range(8):
result = (result << 8) | data[i]
return result

Notes on This Networking Approach

  • This example is purely TCP with manual packet reading. You might want to run this code in a separate thread to avoid blocking the main game loop if the server sends large data. In Godot, you can do something similar in _process but be mindful of performance.
  • _parse_incoming_packets tries to read as many “complete” packets as possible from _incoming_buffer.
  • We only do very basic login logic. Real games would do encryption, hashing, handshake, etc.

3. Updating Player Movement

In your Player.gd, whenever the player moves, you can send an “update movement” packet to the server. For example, near the end of _physics_process when you compute new position:

gdscript
extends CharacterBody3D

@export var walk_speed := 3.0
@export var run_speed := 6.0
@export var run_distance_threshold := 5.0

var target_position: Vector3 = Vector3.ZERO

onready var anim_tree: AnimationTree = $AnimationTree
var anim_state: AnimationNodeStateMachinePlayback

func _ready():
anim_state = anim_tree.get_state_machine_playback()

func _physics_process(delta: float) -> void:
# [ ... your existing input + movement logic ... ]

var prev_pos = global_transform.origin
var new_vel = move_and_slide(velocity, Vector3.UP)
var new_pos = global_transform.origin

# If moved significantly, notify the server
if prev_pos.distance_to(new_pos) > 0.001:
_send_movement_update(new_pos)

func _send_movement_update(new_pos: Vector3):
var net = NetworkClient.get_singleton()
if net and net._connected:
# Build your movement packet
var header = net._get_16bit(0x0200) # Suppose "Movement Update" header
var contents = "POS:%f,%f,%f" % [new_pos.x, new_pos.y, new_pos.z]
var contents_bytes = contents.to_utf8()

var length_bytes = net._get_64bit(contents_bytes.size())

var packet = PackedByteArray()
packet.append_array(header)
packet.append_array(length_bytes)
packet.append_array(contents_bytes)

net._tcp_client.put_data(packet)

4. Handling World Updates

In your Main.gd or wherever you prefer to manage the game state, you can connect to signals from the NetworkClient. For example, if the server sends info about other players/NPCs:

gdscript
extends Node3D

func _ready():
var net_client = NetworkClient.get_singleton()
net_client.updated_players_state.connect(_on_players_state)

func _on_players_state(json_str: String):
# parse the JSON or your custom data format
# update the positions of other players / NPCs in your scene
var data = parse_json(json_str)
if data.has("PLAYERS"):
for p in data["PLAYERS"]:
var id = p["id"]
var pos_arr = p["pos"]
var pos = Vector3(pos_arr[0], pos_arr[1], pos_arr[2])
# If you have a dictionary of remote player nodes, update them
# or instance new ones if needed

5. Putting It All Together

  1. Startup: The player first sees the LoginScreen.tscn.
  2. Login: They enter username/password, click “Login.”
    • NetworkClient connects and sends login credentials.
    • NetworkClient receives either “accept” or “reject” from the server, emits the respective signal.
  3. Game World: On accept, we load Main.tscn.
    • Place the local Player at the location given by the server.
    • Start receiving world updates.
    • The local Player script calls _send_movement_update() to let the server know about movement.
    • The server can inform other clients or respond with new game state.
  4. Other Data: The server might broadcast events (speech, NPC movement, etc.). The client _handle_packet() calls signals which Main.gd or other managers interpret to update the scene.

Final Thoughts

This outline provides the backbone for a custom TCP-based networking system in Godot 4:

  • Login flow with acceptance/rejection.
  • Packet reading with a custom header+length format.
  • Periodic player movement updates.
  • Incoming server updates to keep the game world synchronized.

For a more production-ready approach, you would add:

  • Threading or Godot’s low-level SceneTree networking loops to avoid blocking.
  • Error handling for partial or malformed packets.
  • Encryption / secure password handling.
  • Robust synchronization and possibly interpolation for entity movement.
  • Large chunk streaming (e.g., if you do partial world data streaming).

But as a foundation, this example should show you how to integrate a custom Ultima Online–style packet format and tie it into the game’s logic, UI, and scene updates.

You said:
Reason Now let's bring this prototype together. Add in the ability to type messages which appear above your head. Other players should be able to see these messages for a short period of time before they fade away. Subsequent messages push old ones up, but the 4th new messages erases the 1st early. Also, player names should be visible above the player's head at all times. Make whatever changes are necessary to make this into a 3D proof of concept top-down game in the style of Ultima Online, complete with multiplayer, movement and speech.
ChatGPT

Below is a high-level “proof of concept” demonstrating how you might stitch together multiplayer movement in a top-down 3D style (inspired by Ultima Online) with on-screen speech, including:

  1. Name labels above each player’s head.
  2. Short-lived chat messages (speech) that appear above the player, up to three lines, pushing old messages up and removing the oldest if a 4th is posted.
  3. Networked movement and chat using a simplified custom packet approach as described previously.

Important: The actual server implementation, player ID assignments, authentication, encryption, etc., would be done elsewhere. This example assumes you have a working server that broadcasts movement updates and chat messages in the Ultima Online–style packet format we discussed.


Outline

  1. Scene/Script Overview
  2. Player Scene
    • Label3D for the player’s name.
    • Label3D for chat lines (or a small multiline approach).
    • Methods to add/fade chat lines.
  3. Network Client
    • Receives movement and speech packets from the server.
    • Sends movement, sends new speech.
  4. UI for Chat Input
    • A simple input box for typing messages.
  5. Main Scene
    • Loads Player scenes on login.
    • Hooks up signals for server updates.
    • Maintains references to remote players.

Use this as a starting point—in a real project you’d refine UI, handle security, etc.


1. Scene/Script Overview

A possible folder structure:

bash
YourProject/
├── project.godot
├── Assets/...
├── UI/
│ ├── LoginScreen.tscn
│ ├── LoginScreen.gd
│ ├── ChatUI.tscn
│ └── ChatUI.gd
├── Main.tscn
├── Main.gd
├── Player.tscn
├── Player.gd
└── Network/
├── NetworkClient.gd # Singleton (autoload)
└── Packet.gd # (Optional) shared code for building/reading packets

Node relationships

  • Main.tscn might have:

    • A top-level Node3D or Node.
    • A Camera3D placed top-down or angled.
    • A DirectionalLight3D or similar.
    • A reference to Terrain.tscn, Player.tscn, etc.
    • Instanced remote players.
    • A child ChatUI 2D layer for text input.
  • Player.tscn (local or remote) includes:

    • CharacterBody3D root.
    • CollisionShape3D, AnimationTree, etc.
    • A child Label3D for name, a child Label3D for chat lines.
  • NetworkClient.gd (autoload):

    • Manages TCP connection, sends/receives packets.
    • Emits signals: login_accepted(), login_rejected(), speech_received(player_id, message), movement_update(player_id, pos), etc.

2. Player Scene

Player.tscn (Example Structure)

scss
Player (CharacterBody3D)
├── CollisionShape3D
├── Skeleton3D
│ └── MeshInstance3D (the humanoid model)
├── AnimationTree
├── NameLabel3D (for player's name)
└── SpeechLabel3D (for up to 3 lines of chat)
  • NameLabel3D: Always shows the player’s name.
  • SpeechLabel3D: Displays temporary chat messages.

Player.gd

Attach this to Player.tscn root:

gdscript
extends CharacterBody3D

@export var walk_speed := 3.0
@export var run_speed := 6.0
@export var run_distance_threshold := 5.0
@export var player_name := "Unnamed"

onready var anim_tree := $AnimationTree
onready var name_label_3d := $NameLabel3D
onready var speech_label_3d := $SpeechLabel3D

# We'll store up to 3 messages, each with [text, time_created].
var speech_lines := []
var max_lines := 3
var line_lifespan := 5.0 # Each line fades after 5 seconds

var anim_state: AnimationNodeStateMachinePlayback

func _ready():
anim_state = anim_tree.get_state_machine_playback()
# Initialize name label
name_label_3d.text = player_name

# Make them face the camera automatically
name_label_3d.billboard = BaseButton.BILLBOARD_ENABLED
speech_label_3d.billboard = BaseButton.BILLBOARD_ENABLED

func _physics_process(delta: float) -> void:
# Example local movement for the local player only.
# (Remote players won't do input logic.)
if is_network_master():
_handle_local_input(delta)
_update_speech_lines(delta)

func _handle_local_input(delta: float) -> void:
var velocity = Vector3.ZERO
# Example: rotate with A/D
if Input.is_action_pressed("rotate_left"):
rotate_y(-1.5 * delta)
if Input.is_action_pressed("rotate_right"):
rotate_y(1.5 * delta)

# Move with the target_position logic (like in previous examples).
# Or you might do WASD direct movement.
# [snip: your movement code from prior prototypes]

# move_and_slide, etc.
move_and_slide(velocity, Vector3.UP)

# Possibly send movement to server if changed significantly
_send_movement_to_server()

func _send_movement_to_server():
# Suppose we get the global position, send to server
var net = NetworkClient.get_singleton()
if net and net.is_connected_to_server():
net.send_movement_update(self.get_instance_id(), global_transform.origin)
# The server presumably identifies the correct "player_id",
# or we embed it in the packet.

# Called externally (or from ourselves) when a new chat line arrives
func add_speech_line(text: String) -> void:
# If we already have 3 lines, remove the oldest
if speech_lines.size() >= max_lines:
speech_lines.pop_front()
# Add the new line with a timestamp
speech_lines.append([text, OS.get_ticks_msec() / 1000.0])

# Update the actual label text
_rebuild_speech_label()

func _update_speech_lines(delta: float) -> void:
# Remove lines older than line_lifespan
var now = OS.get_ticks_msec() / 1000.0
var changed = false

for i in range(speech_lines.size()-1, -1, -1):
var creation_time = speech_lines[i][1]
if now - creation_time >= line_lifespan:
speech_lines.remove_at(i)
changed = true

if changed:
_rebuild_speech_label()

func _rebuild_speech_label() -> void:
# Build multiline text from the lines
var text_lines = []
for entry in speech_lines:
text_lines.append(entry[0])
speech_label_3d.text = "\n".join(text_lines)

Key points:

  • speech_label_3d is a single Label3D that displays multiple lines.
  • speech_lines is an array of [message_string, creation_time].
  • After 5 seconds, lines fade automatically. If the player sends a 4th line while 3 are still visible, the oldest is removed.
  • For remote players, the server will broadcast their position and speech; we call add_speech_line(...) on the correct Player node to show chat above their head.

3. Network Client Updates

Below is an excerpt of how you might expand the previously discussed NetworkClient.gd to handle speech. We assume:

  • The server sends a “speech” packet with a header (e.g., 0x0103) plus data:
    • player_id or some unique identifier
    • message string
  • The client calls a signal or function that updates the corresponding player’s chat lines.
gdscript
extends Node

signal speech_received(player_id, message)
signal movement_received(player_id, position_vector3)
signal login_accepted(last_location)
signal login_rejected()
signal login_failed_network()

var _tcp_client: StreamPeerTCP
var _connected = false
var _incoming_buffer = PackedByteArray()

static func get_singleton() -> NetworkClient:
return get_node("/root/NetworkClient")

func is_connected_to_server() -> bool:
return _connected

func connect_to_server(host: String, port: int):
_tcp_client = StreamPeerTCP.new()
var err = _tcp_client.connect_to_host(host, port)
if err != OK:
emit_signal("login_failed_network")
return
_connected = true

func _process(delta: float) -> void:
if not _connected:
return
while _tcp_client.get_available_bytes() > 0:
var chunk = _tcp_client.get_data(_tcp_client.get_available_bytes())
_incoming_buffer.append_array(chunk)
_parse_incoming_packets()

func _parse_incoming_packets() -> void:
# (Same approach as before: read [2 bytes header][8 bytes length][content])
while true:
if _incoming_buffer.size() < 10:
break
var header_int = _parse_16bit(_incoming_buffer.subarray(0,2))
var content_length = _parse_64bit(_incoming_buffer.subarray(2,8))
var total_size = 2 + 8 + content_length
if _incoming_buffer.size() < total_size:
break
var content_start = 10
var content_end = 10 + content_length
var content = _incoming_buffer.subarray(content_start, content_length)
_incoming_buffer = _incoming_buffer.subarray(total_size)
_handle_packet(header_int, content)

func _handle_packet(header_int: int, content_bytes: PackedByteArray):
var content_str = content_bytes.get_string_from_utf8()
match header_int:
0x0101: # login response
if content_str.begins_with("ACCEPT:"):
# parse location from content
# e.g. "ACCEPT:0,0,0"
var coords = content_str.substr(7, content_str.length() - 7).split(",")
emit_signal("login_accepted", Vector3(coords[0].to_float(), coords[1].to_float(), coords[2].to_float()))
else:
emit_signal("login_rejected")

0x0102: # Movement update from other players
# Suppose content = "PLAYER_ID=123;POS=1.0,0,2.5"
# This is just an example format
var dict_data = parse_server_data(content_str)
var player_id = dict_data["PLAYER_ID"]
var pos_arr = dict_data["POS"].split(",")
var pos_vec = Vector3(pos_arr[0].to_float(), pos_arr[1].to_float(), pos_arr[2].to_float())
emit_signal("movement_received", player_id, pos_vec)

0x0103: # Speech
# Suppose content = "PLAYER_ID=123;MSG=Hello everyone!"
var dict_data = parse_server_data(content_str)
emit_signal("speech_received", dict_data["PLAYER_ID"], dict_data["MSG"])

_:
print("Unknown header: %s content: %s" % [header_int, content_str])

# Example function to parse "KEY=VALUE;KEY2=VALUE2"
func parse_server_data(text: String) -> Dictionary:
var result = {}
var parts = text.split(";")
for part in parts:
if part.find("=") != -1:
var kv = part.split("=")
result[kv[0]] = kv[1]
return result

# SENDING MESSAGES TO SERVER
func send_movement_update(player_id: int, pos: Vector3):
# Example packet: header=0x0200, content="PLAYER_ID=XYZ;POS=x,y,z"
if not _connected:
return
var header = _get_16bit(0x0200)
var content_str = "PLAYER_ID=%d;POS=%f,%f,%f" % [player_id, pos.x, pos.y, pos.z]
var content_bytes = content_str.to_utf8()
var length_bytes = _get_64bit(content_bytes.size())
var packet = PackedByteArray()
packet.append_array(header)
packet.append_array(length_bytes)
packet.append_array(content_bytes)
_tcp_client.put_data(packet)

func send_speech(player_id: int, message: String):
if not _connected:
return
var header = _get_16bit(0x0103) # same header we expect for speech
var content_str = "PLAYER_ID=%d;MSG=%s" % [player_id, message]
var content_bytes = content_str.to_utf8()
var length_bytes = _get_64bit(content_bytes.size())
var packet = PackedByteArray()
packet.append_array(header)
packet.append_array(length_bytes)
packet.append_array(content_bytes)
_tcp_client.put_data(packet)

# Helper 16/64-bit read/writes:
func _get_16bit(value: int) -> PackedByteArray:
var arr = PackedByteArray()
arr.push_back((value >> 8) & 0xFF)
arr.push_back(value & 0xFF)
return arr

func _parse_16bit(data: PackedByteArray) -> int:
return (data[0] << 8) | data[1]

func _get_64bit(value: int) -> PackedByteArray:
var arr = PackedByteArray()
for i in range(8):
arr.push_back((value >> (8*(7-i))) & 0xFF)
return arr

func _parse_64bit(data: PackedByteArray) -> int:
var result = 0
for i in range(8):
result = (result << 8) | data[i]
return result

Key new additions:

  • send_speech(player_id, message) sends chat text to the server.
  • speech_received signal fires on arrival of a speech packet.
  • movement_received signal for remote movements.
  • We parse the server data into something we can handle easily.
  • Real servers would do more robust data validation.

4. UI for Chat Input

We can create a small UI that appears on top of the screen to let the user type messages, e.g., ChatUI.tscn:

scss
ChatUI (CanvasLayer)
└── MarginContainer
└── HBoxContainer
├── LineEdit (chat_input)
└── Button (send_button)

ChatUI.gd

gdscript
extends CanvasLayer

signal chat_submitted(message)

@onready var chat_input = $MarginContainer/HBoxContainer/chat_input
@onready var send_button = $MarginContainer/HBoxContainer/send_button

func _ready():
send_button.pressed.connect(_on_send_pressed)
# Alternatively, let user press Enter in the LineEdit
chat_input.gui_input.connect(_on_input)

func _on_send_pressed():
if chat_input.text.strip_edges() != "":
emit_signal("chat_submitted", chat_input.text.strip_edges())
chat_input.text = ""

func _on_input(event: InputEvent) -> void:
if event is InputEventKey and event.pressed:
if event.keycode == Key.ENTER:
_on_send_pressed()

Flow:

  1. The user types a message in chat_input.
  2. Pressing the button or Enter emits chat_submitted(message).
  3. We connect that signal in Main.gd to call NetworkClient.send_speech(local_player_id, message).

5. Main Scene

Main.tscn

Might contain:

  • Root Node3D or Node.
  • A Camera3D for top-down view.
  • Instanced Terrain.tscn.
  • Instanced local Player for our user.
  • A dictionary of “remote player nodes” for other players.
  • A ChatUI (CanvasLayer) for text input.

Main.gd

gdscript
extends Node3D

var local_player_id: int = -1
var players := {} # Dictionary of player_id -> Player node

func _ready():
# Suppose we got the local player's spawn location from login
# For demonstration, let's just set it manually or get it from a passed variable

# 1. Instance the local player
var local_player_scene = preload("res://Player.tscn").instantiate()
local_player_scene.player_name = "LocalHero" # or from server data
local_player_id = local_player_scene.get_instance_id() # or the real server ID
add_child(local_player_scene)
local_player_scene.global_transform.origin = Vector3(0,0,0)

# Add it to our dictionary
players[local_player_id] = local_player_scene

# 2. Add ChatUI for local user input
var chat_ui_scene = preload("res://UI/ChatUI.tscn").instantiate()
add_child(chat_ui_scene) # because it's a CanvasLayer

# Connect chat signal
chat_ui_scene.chat_submitted.connect(_on_chat_submitted)

# 3. Connect to NetClient signals
var net_client = NetworkClient.get_singleton()
net_client.movement_received.connect(_on_movement_received)
net_client.speech_received.connect(_on_speech_received)

func _on_chat_submitted(message: String):
# Called when the local user typed a chat line
# Send it to the server
var net_client = NetworkClient.get_singleton()
net_client.send_speech(local_player_id, message)

# Also show it above the local player's head immediately
# (We assume the server eventually echoes it back for remote players.)
if players.has(local_player_id):
players[local_player_id].add_speech_line(message)

func _on_movement_received(player_id, pos_vec: Vector3):
# If we don't have a node for that player yet, instance one
if not players.has(player_id):
var new_player = preload("res://Player.tscn").instantiate()
new_player.player_name = "Player_%d" % player_id
add_child(new_player)
players[player_id] = new_player

# Update that player's position
players[player_id].global_transform.origin = pos_vec

func _on_speech_received(player_id, message):
# If we don't have that player, create them (just like in movement)
if not players.has(player_id):
var new_player = preload("res://Player.tscn").instantiate()
new_player.player_name = "Player_%d" % player_id
add_child(new_player)
players[player_id] = new_player

players[player_id].add_speech_line(message)

Explanation:

  • When the server notifies us (movement_received), we ensure there is a Player node. If it doesn’t exist, we create one. Then we set its position.
  • When the server sends speech_received, we do the same check for that player’s node, then call add_speech_line(message).

In a real game, each player would have a persistent server ID. For the local player, the server might say: “You are player_id = 42,” and you store that in local_player_id.


Putting It All Together

User experience:

  1. Launch the game, see a LoginScreen.
  2. After connecting (and if accepted), you load Main.tscn.
  3. Your local player appears in the top-down world.
  4. You can move around locally (the client updates the server). The server broadcasts your new position to others.
  5. Other players appear in your scene as soon as the server tells you about them.
  6. You type chat in the ChatUI, press Enter—your local player’s speech shows above your head, and the server broadcasts that speech to other players.
  7. When other players chat, you receive a speech_received packet, find the correct player node, and show the chat.
  8. Each chat line is limited to 3 lines at a time per player, and each line fades after 5 seconds.

Final Notes

  • This is a prototype. In a real production environment, you’ll handle:
    • Synchronization: Who “owns” which player? Interpolation for smooth remote movement.
    • Security: Credentials encryption, data validation, server authority.
    • Robust UI: Scrolling chat logs, toggles for chat windows, more sophisticated text entry.
    • Name display: A real MMO typically keeps names consistent from the server or a character database.
  • You can refine the Label3D or use Godot 4’s new Control3D system to ensure consistent appearance in 3D.
  • For genuine top-down camera, place the camera above the scene, angled slightly, or do an orthographic projection.
  • The logic here illustrates the backbone for custom networking, movement, and ephemeral “speech bubble” messages in the style of Ultima Online.

Use this foundation to continue building your 3D top-down, multiplayer environment where players can see each other move and chat above their heads!

You said:
Now, please write me a full protocol description which documents every single packet required to create the behaviour outlined above, documenting the packet's header, length (if static), fields and their data types, and whether the packet is sent from client to server, server to client, or both.
ChatGPT

Below is an example protocol documentation consistent with the “Ultima Online–style” packets described in the previous prototypes. This protocol is not an official Ultima Online protocol but rather inspired by its structure. We assume a TCP stream where the client and server exchange variable-length packets with the following overall layout:

css
[ 2-byte PacketHeader ] [ 8-byte PacketLength ] [ PacketData (variable) ]
  • PacketHeader: 2 bytes (unsigned integer, big-endian). Identifies the packet type.
  • PacketLength: 8 bytes (unsigned integer, big-endian). Tells how many bytes of PacketData follow.
  • PacketData: Varies by packet type.

All numeric fields (e.g., headers, player IDs, floats) are assumed big-endian unless otherwise noted.
Strings (e.g. user names, messages) are typically UTF-8 encoded and embedded in a simple “KEY=VALUE;KEY=VALUE;...” format for this prototype.


Packet Overview

We define 5 primary packet types for the functionality outlined:

  1. 0x0100 – Login Request (Client → Server)
  2. 0x0101 – Login Response (Server → Client)
  3. 0x0200 – Movement Update (Client → Server)
  4. 0x0102 – Movement Update (Server → Client)
  5. 0x0103 – Speech (Both Directions)

These cover:

  • Logging in (Login Request / Response)
  • Player movement (both client informing the server, and server informing other clients)
  • Chat messages (“speech”) that appear above players’ heads.

Below is a detailed breakdown of each packet’s structure.


1. Packet Layout

Every packet begins with:

FieldSize (bytes)Description
Header2Big-endian unsigned integer (0x0100, 0x0101, 0x0102, 0x0103, 0x0200, etc.)
Length8Big-endian unsigned integer, the length of the Data section in bytes.
Data (Body)variableVaries per packet. Typically an ASCII/UTF-8 string in the format KEY=VALUE;....

Example Transmission

When sending a packet with header = 0x0100 (Login Request) and a data payload of 30 bytes, the format is:

  1. 2 bytes for 0x0100
  2. 8 bytes (big-endian) for 30
  3. 30 bytes of data

2. Login Packets

2.1. Login Request (0x0100)

  • Direction: Client → Server
  • Purpose: Client attempts to log in with a username and password.

Header: 0x0100
Length: Computed from the size of the data that follows.
Data: A text payload containing username and password, typically in the format:

php
username=<USERNAME>;password=<PASSWORD>
  • <USERNAME>: UTF-8 string
  • <PASSWORD>: UTF-8 string

Example:

css
[0x01 0x00] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x1C] username=Bob;password=MySecret

(Where 0x1C = 28 decimal bytes of data.)

2.2. Login Response (0x0101)

  • Direction: Server → Client
  • Purpose: Server indicates whether the login was accepted or rejected. If accepted, it may include the player’s initial position (x,y,z).

Header: 0x0101
Length: Computed from the size of the text payload.
Data: One of two possible forms:

  1. Rejected
    REJECT
    or
  2. Accepted with a starting location, e.g.
    makefile
    ACCEPT:0,0,0
    The format can vary, but an example is ACCEPT:x,y,z to indicate spawn coordinates or last-known location.

Examples:

  • Rejected (no coordinates):

    css
    [0x01 0x01] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x06] REJECT

    (Data length = 6 bytes)

  • Accepted:

    css
    [0x01 0x01] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x0D] ACCEPT:0,0,0

    (Data length = 13 bytes)


3. Movement Packets

There are two movement-related packets:

  • Client → Server: 0x0200
  • Server → Client: 0x0102

3.1. Client → Server Movement Update (0x0200)

  • Direction: Client → Server
  • Purpose: The client informs the server of the player’s new position (e.g., after input changes).
  • Header: 0x0200

Data: Typically a format such as:

php
PLAYER_ID=<ID>;POS=<X>,<Y>,<Z>
  • PLAYER_ID: An integer or the ID assigned by the server. In some prototypes, this might be the local Godot instance ID, or a unique server ID for the character.
  • POS: Comma-separated floats for the new position.

Example:

css
[0x02 0x00] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x1C]
PLAYER_ID=42;POS=100.0,0.0,200.5

Where 0x1C (28 bytes) is the length of the text PLAYER_ID=42;POS=100.0,0.0,200.5.

3.2. Server → Client Movement Update (0x0102)

  • Direction: Server → Client
  • Purpose: The server broadcasts or sends to each client the updated position of a player (or NPC).

Header: 0x0102
Data: In the same key/value style:

php
PLAYER_ID=<ID>;POS=<X>,<Y>,<Z>

Example:

css
[0x01 0x02] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x20]
PLAYER_ID=99;POS=-5.2,0.0,45.0

Where 0x20 (32 decimal) is the payload length.

Note: The server presumably manages the canonical positions of all players. When any client moves, the server receives that update, updates the game state, and then sends out 0x0102 packets to all other clients so they see the new position of that player.


4. Speech Packets

We use a single header 0x0103 for chat/speech messages. This packet is used both from client to server (to say something) and from server to client (to inform others of what someone said).

4.1. Client → Server Speech (0x0103)

  • Direction: Client → Server
  • Purpose: The local player types or triggers a “speech” event, sending the text to the server. The server will then broadcast it.

Header: 0x0103
Data: Usually includes:

php
PLAYER_ID=<ID>;MSG=<STRING>
  • PLAYER_ID: The ID the server uses to identify this player.
  • MSG: The text the player typed, UTF-8 encoded.

Example:

css
[0x01 0x03] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x1D]
PLAYER_ID=42;MSG=Hello Everyone

Data length = 29 bytes.

4.2. Server → Client Speech (0x0103)

  • Direction: Server → Client
  • Purpose: The server tells each client that PLAYER_ID has spoken.

Header: 0x0103 (same as above)
Data: Identical format to the client version:

php
PLAYER_ID=<ID>;MSG=<STRING>

Example:

css
[0x01 0x03] [0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x22]
PLAYER_ID=99;MSG=Hi from across the map!

Clients use this data to display the speech text (e.g., above the player’s head) and fade it out after some time.


5. Summary Table of Packet Types

Packet NameHeaderDirectionData FormatDescription
Login Request0x0100Client → Serverusername=<string>;password=<string>Client attempts to log in.
Login Response0x0101Server → ClientEither REJECT or ACCEPT:x,y,zServer responds to login request with acceptance or rejection. If accepted, includes spawn coords.
Movement Update (C→S)0x0200Client → ServerPLAYER_ID=<int>;POS=<float>,<float>,<float>Client informs server of its new position.
Movement Update (S→C)0x0102Server → ClientPLAYER_ID=<int>;POS=<float>,<float>,<float>Server informs clients of a player’s (or NPC’s) updated position.
Speech0x0103Both waysPLAYER_ID=<int>;MSG=<string>Client → Server: user typed a message. Server → Client: broadcast the message from a given player.

6. Additional Implementation Details

  1. Data Encoding:

    • Headers are 2-byte (big-endian).
    • Length is 8-byte (big-endian).
    • The payload is typically UTF-8 text with semicolon-delimited key-value pairs.
    • In a more advanced system, you might use a binary structure or an actual JSON format. The above is just the minimal example.
  2. Flow:

    • Login: Client sends 0x0100 → Server. Server replies 0x0101. If accepted, the client spawns in the game.
    • Movement: The client sends 0x0200 whenever the position changes significantly. The server updates the internal state, then sends 0x0102 to all relevant clients to keep them in sync.
    • Speech: The client sends 0x0103 to say something. The server then broadcasts 0x0103 back to other clients so they can display that speech.
  3. Security / Reliability:

    • Because this is a TCP-based example, reliability is handled at the transport layer.
    • Authentication, encryption, or checksums are not covered here but would be critical in a real production environment.
    • The server must validate fields (e.g., do not trust PLAYER_ID from the client).
  4. Big-Endian vs. Little-Endian:

    • The original Ultima Online protocols are known for big-endian (network byte order). This example follows that.
    • If you need little-endian, you must adapt both client and server code consistently.
  5. Example Packet Lifecycle:

    • Client logs in with 0x0100.
    • Server returns 0x0101 with ACCEPT:50,0,50.
    • Client spawns the player at (50,0,50).
    • Client moves, sends 0x0200 with PLAYER_ID=42;POS=55,0,52.
    • Server updates position and sends 0x0102 with the same data to all other clients.
    • Client types a chat line “Hello.” 0x0103: PLAYER_ID=42;MSG=Hello!
    • Server echoes 0x0103: PLAYER_ID=42;MSG=Hello! to everyone else.

With these five core packets, you can implement the 3D top-down prototype with:

  • Multiplayer movement
  • Login
  • On-screen speech (limited lines, fade-out, etc.).

This specification may expand to additional packets for inventory, combat, or more advanced MMO features, but it covers all required behavior from the prior prototype.

You said:
Reason Now, please write me a prototype server in Ruby which will handle all of the above behaviour. Use any third party gems that are required, as many as you like, including the Bindata gem for packet data management, but it must be a full prototype server implementation which will allow interactions between two instances of the client described above.

Your output should be the full code listing for the Ruby server prototype, with an appendix of any changes that need making to the client code (if any)
ChatGPT

Below is a proof-of-concept Ruby server implementation that handles the Login, Movement, and Speech packet types as described in our protocol. It uses Bindata to parse and construct packets, listens for multiple clients (threads), and broadcasts updates to all connected clients. This example is deliberately simple and not production-ready; it lacks encryption, robust error handling, etc. but demonstrates the core logic needed to coordinate two or more of the Godot clients we specified.


Server Code

Save the following as server.rb (or similar). Then run it with ruby server.rb. By default, it listens on port 2593.

ruby
#!/usr/bin/env ruby
# frozen_string_literal: true

##
# A prototype Ruby server for the Ultima Online–style protocol described.
# Requires:
# gem install bindata
# (and optionally "gem install concurrent-ruby" or other concurrency libs if you expand)

require 'socket'
require 'bindata'

##
# BinData Definitions
# We define a "BasePacket" structure that reads:
# 2 bytes :header (uint16 big-endian)
# 8 bytes :length (uint64 big-endian)
# N bytes :payload (string, length = :length)
#
class BasePacket < BinData::Record
endian :big

uint16 :header
uint64 :length
string :payload, read_length: :length
end

##
# Helper to build packets for sending.
#
def build_packet(header, payload_string)
# Build a BinData object, which can then be #to_binary_s for sending
packet = BasePacket.new(
header: header,
length: payload_string.bytesize,
payload: payload_string
)
packet.to_binary_s
end

##
# Our simple in-memory store of connected players:
# :socket => the TCPSocket to write back to
# :player_id => integer ID assigned by server
# :username => string
# :x, :y, :z => floats for the player's position
# :logged_in => bool
# We store them by an integer ID assigned by the server.
#
$NEXT_PLAYER_ID = 1
$CLIENTS = {} # player_id => { data... }

##
# A simple “keyword=stuff;keyword=stuff” parser
# returns a Hash like { "PLAYER_ID"=>"42", "POS"=>"1,0,2" }
#
def parse_kv_semicolon(str)
result = {}
parts = str.split(';')
parts.each do |part|
if part.include?('=')
key, value = part.split('=', 2)
result[key] = value
end
end
result
end

##
# Start the server on port 2593 (typical UO).
#
PORT = 2593

server = TCPServer.new(PORT)
puts "Server listening on port #{PORT}..."

##
# MAIN SERVER LOOP:
# Accept new connections, spawn a thread per client.
#
loop do
client_socket = server.accept
Thread.new do
begin
# Assign a server-side unique player_id
player_id = $NEXT_PLAYER_ID
$NEXT_PLAYER_ID += 1

# Initialize the record in $CLIENTS
$CLIENTS[player_id] = {
socket: client_socket,
player_id: player_id,
username: nil,
x: 0.0,
y: 0.0,
z: 0.0,
logged_in: false
}

puts "Client connected with temp player_id=#{player_id}"

buffer = ''.b # We'll accumulate bytes from the socket here

loop do
data = client_socket.recv(4096)
if data.nil? || data.bytesize == 0
# Connection closed
puts "Client (player_id=#{player_id}) disconnected."
break
end

buffer << data

# Attempt to parse as many complete packets as possible from 'buffer'
while buffer.bytesize >= 10
# We need at least 10 bytes to read header(2) + length(8)
header = buffer[0, 2].unpack1('n') # :uint16 big-endian
length = buffer[2, 8].unpack1('Q>') # :uint64 big-endian
total_needed = 10 + length

break if buffer.bytesize < total_needed

# We can read a complete packet
packet_data = buffer[0, total_needed]
buffer.slice!(0, total_needed) # remove from buffer

# Parse with BinData
packet = BasePacket.read(packet_data)

# Process the packet
process_packet(player_id, packet.header, packet.payload)
end
end

rescue => e
puts "Error in client thread (player_id=#{player_id}): #{e}"
ensure
# On thread exit, remove from $CLIENTS
$CLIENTS.delete(player_id)
client_socket.close rescue nil
puts "Cleaned up player_id=#{player_id}."
end
end
end

##
# process_packet - handle each packet type
#
def process_packet(player_id, header, payload_str)
client = $CLIENTS[player_id]
return unless client

case header
when 0x0100
# LOGIN REQUEST
# Payload: "username=Bob;password=Secret"
kv = parse_kv_semicolon(payload_str)
username = kv['username'] || ''
password = kv['password'] || ''

# For prototype: accept all logins if not blank. Otherwise reject.
if username.strip.empty? || password.strip.empty?
# Reject
send_login_reject(client)
else
# Accept, store username, set default position
client[:username] = username
client[:logged_in] = true
client[:x] = 50.0 # Just an example spawn
client[:z] = 50.0
puts "Player #{player_id} (#{username}) logged in."
send_login_accept(client, client[:x], client[:y], client[:z])
end

when 0x0200
# MOVEMENT UPDATE (Client -> Server)
# e.g. "PLAYER_ID=42;POS=100.0,0.0,200.5"
kv = parse_kv_semicolon(payload_str)
if kv['POS']
coords = kv['POS'].split(',')
client[:x] = coords[0].to_f
client[:y] = coords[1].to_f
client[:z] = coords[2].to_f
# Broadcast to all clients that this player moved
broadcast_movement(client)
end

when 0x0103
# SPEECH (client -> server or server -> client)
# We interpret client->server, then broadcast to all
# "PLAYER_ID=42;MSG=Hello"
kv = parse_kv_semicolon(payload_str)
message = kv['MSG'] || ''
broadcast_speech(player_id, message)

else
# Unknown or unhandled
puts "Unknown header=#{header.to_s(16)}, payload=#{payload_str}"
end
end

##
# send_login_accept - build and send 0x0101 ACCEPT
#
def send_login_accept(client, x, y, z)
msg = "ACCEPT:#{x},#{y},#{z}"
packet_bin = build_packet(0x0101, msg)
client[:socket].write(packet_bin)
end

##
# send_login_reject - build and send 0x0101 REJECT
#
def send_login_reject(client)
packet_bin = build_packet(0x0101, 'REJECT')
client[:socket].write(packet_bin)
end

##
# broadcast_movement - build a 0x0102 (Movement Update, S->C) for everyone
# "PLAYER_ID=<id>;POS=<x>,<y>,<z>"
#
def broadcast_movement(client)
msg = "PLAYER_ID=#{client[:player_id]};POS=#{client[:x]},#{client[:y]},#{client[:z]}"
packet_bin = build_packet(0x0102, msg)
# Send to all
$CLIENTS.each_value do |c|
begin
c[:socket].write(packet_bin) if c[:logged_in]
rescue
# ignore broken pipe, etc.
end
end
end

##
# broadcast_speech - build a 0x0103 (Speech), send to all
# "PLAYER_ID=<id>;MSG=<string>"
#
def broadcast_speech(player_id, message)
msg = "PLAYER_ID=#{player_id};MSG=#{message}"
packet_bin = build_packet(0x0103, msg)
$CLIENTS.each_value do |c|
begin
c[:socket].write(packet_bin) if c[:logged_in]
rescue
# ignore errors
end
end
end

How to Run

  1. Install Ruby (2.7+ recommended).
  2. gem install bindata
  3. Save the above as server.rb.
  4. Run ruby server.rb. It will listen on port 2593.
  5. Launch two or more instances of the Godot client (the one we described earlier) connecting to 127.0.0.1:2593, log in, and you can see movement updates / chat broadcast to each client.

Appendix: Potential Client Code Changes

Below are minor clarifications or changes you might need in the Godot GDScript client to match this Ruby server’s expectations:

  1. Login Request:

    • The client currently sends 0x0100 with username=...;password=.... This is exactly what the server code expects. No change needed unless you want to do more advanced checks (like empty password → reject).
  2. Player IDs:

    • In our prototypes, we used the local “instance_id” as the PLAYER_ID in Movement Update and Speech.
    • But the Ruby server automatically assigns a server-side ID to each new connection.
    • That means the client can’t reliably guess PLAYER_ID until the server sends it.

    Simplest approach:

    • Once the client is “logged in,” the server can send an additional packet or the ACCEPT string that includes the assigned PLAYER_ID, e.g. ACCEPT:42,50,0,50 (ID + position).
    • Then the client sets local_player_id = 42 (or whatever).
    • The client uses local_player_id in subsequent movement/speech packets.

    So you could:

    • Add an extra field to the server’s ACCEPT: string. For example:
      makefile
      ACCEPT:42,50.0,0.0,50.0
      Then in the client, parse the first number as the player ID, and the next three as x,y,z.

    Change in server (optional):

    ruby
    def send_login_accept(client, x, y, z)
    pid = client[:player_id]
    msg = "ACCEPT:#{pid},#{x},#{y},#{z}"
    packet_bin = build_packet(0x0101, msg)
    client[:socket].write(packet_bin)
    end

    Then the client can do:

    gdscript
    # On receiving 0x0101 with "ACCEPT:pid,x,y,z"
    var tokens = content_str.substr(7, content_str.length() - 7).split(",") # after 'ACCEPT:'
    var assigned_id = tokens[0].to_int()
    var x = tokens[1].to_float()
    var y = tokens[2].to_float()
    var z = tokens[3].to_float()
    local_player_id = assigned_id
    # place local player at (x,y,z)

    That way, all subsequent client → server packets can use the correct, server-approved PLAYER_ID.

  3. Collision:

    • No direct changes needed, but remember that the server currently trusts the client’s position. For a real MMO, you’d do more checks.
  4. Speech:

    • No changes are strictly necessary. The client logic is: “Send 0x0103 with PLAYER_ID=...,MSG=...,” then expect to receive 0x0103 from the server for everyone’s chat.

In short, the main recommended code change is to let the server tell the client which PLAYER_ID to use, instead of the client guessing. This is easily done by editing the ACCEPT: string in the send_login_accept method and the corresponding parse logic in the client’s login_accepted handler.


Final Notes

  • This is a barebones example.
  • It supports multiple simultaneous clients, broadcast chat, and movement.
  • All data (username, password, positions) is in clear text.
  • There is no data persistence—restarting the server loses data.
  • It demonstrates how to parse our custom [2-byte header][8-byte length][payload] protocol using Bindata.

This should suffice as a working prototype to test the Godot 3D top-down clients we built earlier.