Chat System

💬 Simple AES Chat (Focus + Whisper Walkthrough)

Work in Progress

This tutorial is still evolving. Some steps or naming may shift as AES matures. If something looks off, please let us know via Discord.

This example shows a minimal multiplayer chat using a single AES Event (AES_ChatMessage) plus 5 supporting Blueprints. Core ideas:

• A Whisper hop PlayerController → GameState (server) followed by a multicast.
• A local Focus path so the Player Controller hears HUD‑originated messages before relaying them.
• Re‑generation on each client (fan‑out) so UI stays decoupled from RPC details.

🛍️ Required Assets

Instead of a squished table, here’s a card grid:

1. AES_ChatMessage Event

Single AES Event carrying User + Message.

• Mark both fields Instance Editable & Expose on Spawn.
• Gives pins on Generate Event.

2. GM_ChatDemo GameMode

Glue class that designates GS_ChatDemo + PC_Chatter. No extra logic.

3. GS_ChatDemo GameState

Owns stable Identity (Object ID = GameState), listens for Whisper chat, multicast → re‑generate locally.

• Registers Whisper for AES_ChatMessage.
• Multicast MC_ChatMessage fan‑out.

4. PC_Chatter PlayerController

Local input + bridge to server. Focus‑listens for HUD messages (broadcaster ChatHud).

• RPC SR_SendMessage → server Whisper to GameState.
• Spawns HUD if locally controlled.

5. W_ChatHUD Widget

Text entry + scroll list. Generates local (no target) events; also Focus‑listens to GameState re‑broadcast.

• Identity with Object ID = ChatHud.
• Creates & focuses input; sends on Enter / button.

6. W_ChatMessage Widget

Visual row; fade in → delay → fade out, then remove.

• Sets User: prefix & message text.

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1. 💌 Create the Event: AES_ChatMessage

1. Right‑click → AES → Event → name it AES_ChatMessage.
2. Add 2 properties:

• User (Name or String) – set Instance Editable + Expose on Spawn.
• Message (String / Text) – also Instance Editable + Expose on Spawn.

Because the properties are exposed, the Generate Event node will give you pins for User + Message when you pick this Event Class.

Tip

Need a refresher on generation vs targeting? See Generate Event and Register.

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2. 🎮 Game Mode: GM_ChatDemo

Very simple: in the world settings, set Default Game State Class to GS_ChatDemo and Player Controller Class to PC_Chatter. (Any default pawn is fine / irrelevant.)

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3. 🧠 Game State: GS_ChatDemo

Responsibilities:

1. On Begin Play call Generate Identity with:

• Object = Self
• Object ID = GameState (hard-coded label so clients & server agree; there is only one Game State instance).

2. Register for Whisper of AES_ChatMessage (using the Identity you just generated) – this lets the server receive direct chat events targeted at the Game State.
3. Implement a custom event MC_ChatMessage marked Multicast (reliable optional) with params: User (Name) & Message (String/Text).
4. When AES_ChatMessage Whisper arrives on server:

• Extract its payload (User, Message).
• Call MC_ChatMessage(User, Message) so every client (including sender) hears it.

5. Inside MC_ChatMessage on each client:

• Call Generate Event (no Target Id) with Event = AES_ChatMessage, filling the same User + Message. This turns the network replication into a local broadcast path so UI elements (e.g. Focus registrations) can respond uniformly.

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4. 🕹️ Player Controller: PC_Chatter

Responsibilities:

1. On Begin Play → Generate Identity (no Object ID needed, let it be unique per player).
2. If Is Local Controller:

• Create and add a W_ChatHUD to viewport.

3. Register for Focus for AES_ChatMessage where Broadcaster ID = ChatHud. (You will generate an Identity in the HUD with that Object ID, making it the broadcaster for local typed messages.)
4. Custom Event SR_SendMessage (RunOnServer) with params User + Message.

• On server: Call Generate Event for AES_ChatMessage with Target Id = GameState (the Game State’s Identity ID) so it arrives as a Whisper and triggers the server’s registration.

5. Local handling of HUD-origin messages: when the Focus registration fires (HUD generated an event without target), call SR_SendMessage to hop to server.

Flow so far (local player typing): W_ChatHUD (Generate Event no target) → Focus hit in PC_Chatter → SR_SendMessage → Server → Generate Event (Target Id = GameState) → GS_ChatDemo Whisper → MC_ChatMessage → All clients → each client re‑generates (no target) → their UIs respond.

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5. 🗨️ HUD Widget: W_ChatHUD

UI Elements (suggested):

• ScrollBox (messages container)
• EditableTextBox (TXT_Message)
• Button (BTN_Send)

Setup on Construct / Begin Play:

1. Generate Identity with Object ID = ChatHud (important – matches the Focus listener in the Player Controller).
2. Register for Focus of AES_ChatMessage with Broadcaster ID = GameState so it hears messages fanned out after the multicast re‑generation.
3. Show mouse cursor (via owning Player Controller) & set keyboard focus to the text box.

Sending a message (two entry points):

• On Text Box OnTextCommitted (OnEnter) – if not empty
• On BTN_Send clicked – if not empty

Then:

1. Grab Player State name (or fallback like “You”).
2. Call Generate Event (Event = AES_ChatMessage) without Target Id and fill User + Message.

• Player Controller hears it (Focus: broadcaster = ChatHud) and triggers the server path.

3. Clear the text box & refocus it.

Receiving messages from Game State:

• Focus registration (broadcaster = GameState) fires when Game State re‑generates after multicast.
• Create a W_ChatMessage widget, set its User & Message, add to ScrollBox, then scroll to end.

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6. 🧾 Message Row: W_ChatMessage

On Construct:

1. Set TXT_User to User + ":" (or style as you like) and TXT_Message to message text.
2. Play a FadeIn animation.
3. Delay (e.g. 10s) then play FadeOut; on animation finished remove self.

Challenge Yourself

Optional polish: color the local player differently!

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📎 Event & Identity Cheat Sheet

Action	Generate Event Call	Target Id	Who Listens
User types locally	AES_ChatMessage	(none)	Player Controller (Focus: ChatHud)
PC → Server	(RPC only)	—	—
Server relays to GS	AES_ChatMessage	GameState	Game State (Whisper)
Server → clients	(Multicast RPC)	—	All clients run handler
Clients re-fan-out	AES_ChatMessage	(none)	Local HUD Focus (GameState) + any other listeners

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🛠️ Troubleshooting

Symptom	Likely Cause	Fix
No messages appear anywhere	Game State Identity not generated or wrong Target Id used	Ensure GS sets Object ID = GameState & server PC uses that Identity ID as Target
HUD never triggers server	PC not Focus-registered for broadcaster ChatHud	Verify Focus registration broadcaster ID = ChatHud
Messages only local, no replication	Forgot SR_SendMessage RPC or Whisper generation step	Ensure PC server RPC runs & generates with Target Id
Messages duplicated	Multiple Focus registrations or re‑generation done twice	Check you only re‑generate inside multicast once

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✅ Recap

You built a pipeline that:

1. Generates per‑object Identities (HUD, PC, Game State) with intentional Object IDs where needed (ChatHud, GameState).
2. Uses Focus (no Target Id generation) for local HUD → Player Controller message origination.
3. Uses Whisper (Target Id = GameState) for authoritative server ingestion.
4. Multicasts & re‑generates (no target) to create a uniform UI consumption path.

Challenge Yourself

Add timestamps, slash commands, or color‑coding by user. Split it into global, party chat and whispers - go crazy!

That’s the full loop—concise, network aware, and a clean example of Focus + Whisper interop.