How to Build a 3D Multiplayer Battleship Game: A Beginner - Friendly Guide to Vibecoding

What is Vibecoding?

Vibecoding is the art of building applications by describing what you want in natural language to an AI coding agent. Instead of writing code line-by-line, you communicate your vision, iterate on feedback, and guide the AI to create production-ready applications. Whether you're curious about what is vibe coding or already experimenting with it, the core idea stays the same: you talk, the AI builds, and you shape the result together.

The Journey: From Idea to Game

Step 1: The Initial Prompt

Here's what started it all:

Build me a 3d battleship multiplayer game - where each player can add
the ships positions on their screen and the other user can visually
drop bombs or strike the grid and see if its a hit or not. Use threeJS
and auth with invite codes to play 1 on 1

Key Elements of a Good Initial Prompt:

• Clear goal: "3D battleship multiplayer game"
• Specific features: "add ship positions", "drop bombs", "hit detection"
• Tech preferences: "threeJS", "invite codes"
• User flow: "1 on 1" gameplay

Beginner Tip: You don't need to be technical! Describe what you want as if explaining to a friend.

Step 2: Clarifying Questions

Before diving into code, the agent asked:

Question 1: Real-time Communication

• "Should the agent use WebSocket (Socket.io) for instant updates, or polling?"
• User's Choice: Websocket for real time

Question 2: Game Configuration

• "Standard 10x10 grid with 5 ships, or custom?"
• User's Choice: Standard 10x10 grid

Question 3: Game Flow

• "Player creates game → gets invite code → shares with opponent?"
• User's Choice: Yes that looks good

Question 4: Visual Design

• "Ocean-themed with water effects or clean minimalist grid?"
• User's Choice: Ocean themed

Why This Matters: These questions shape the entire application. The AI wants to build exactly what YOU envision, not guess.

The Build Process: Issues & Solutions

Issue 1: Socket Room Connection

User Report:

"Joining is not working. User who started game cannot place ships and 2nd player cannot join the same game."

What Was Wrong:

• Player 1 created a socket on HomePage, then navigated to GamePage and created a NEW socket
• The new socket never joined the game room
• Backend was emitting events to the room, but sockets weren't listening

The Fix:

// Added rejoin_game event
socket.emit('rejoin_game', {
 game_id: gameId,
 player_id: playerId
});

// Backend joins socket to room
await sio.enter_room(sid, game_id)

Lesson: When building real-time features, always ensure sockets join rooms on navigation.

Issue 2: Game State Transition

User Report:

"It says ship placed, waiting for opponent for both players."
"It does not transition to the battle screen."

What Was Wrong:

• Frontend socket listeners were set up AFTER the game_start event was emitted
• Players joined rooms, but events were missed

The Fix:

• Added game_state event that sends current state on rejoin
• Frontend checks if game is already "playing" and transitions immediately

Lesson: Always account for late-joining or reconnecting users.

Issue 3: Visual Improvements

User Request:

"Can we add numbering to the grid for better tracking. Fix initial camera view so the entire grid is visible. Once a ship is sunk, show the entire ship as red blocks."

What We Added:

1. Grid Labels: A-J columns, 1-10 rows using Three.js Text component
2. Camera Position: Adjusted to [4.5, 12, 14] with target [4.5, 0, 4.5]
3. Sunk Ship Logic:

const isSunk = hits && hits.every(hit => hit === true);
const showAsRed = isSunk || isHit;

Lesson: UI/UX improvements come from user feedback during testing.

Issue 4: Memory Leaks

User Report:

"Eventually the preview runs out of memory though."

What Was Wrong:

• Socket connections not cleaned up on navigation
• Three.js textures/geometries accumulating
• Old games stored indefinitely in backend

// Cleanup sockets
return () => {
 newSocket.removeAllListeners();
 newSocket.close();
};

// Disable reconnection
reconnection: false

Backend:

# Auto-cleanup old games
cutoff_time = datetime.now(timezone.utc) - timedelta(hours=2)
# Limit games to 100 max

Lesson: Always clean up resources in React's useEffect cleanup functions.

Issue 5: Performance Crash

User Report:

"The game crashes for 2nd user and does not reload upon refresh."

What Was Wrong:

• Heavy Three.js rendering (shadows, high-poly geometry, complex materials)
• Two players = double the GPU load

// Before: 32x32 subdivisions
<planeGeometry args={[12, 12, 32, 32]} />

// After: 4x4 subdivisions  
<planeGeometry args={[12, 12, 4, 4]} />

Changed Materials:

// Before: Expensive
<meshStandardMaterial />

// After: Fast
<meshBasicMaterial />

Other Optimizations:

• Disabled shadows
• Disabled antialiasing
• Set frameloop="demand" (only render when needed)
• Reduced sphere segments: 16x16 → 8x8
• Removed Environment component
• Fixed DPR at 1

Added Error Boundary:

// Catches crashes gracefully
<ErrorBoundary>
 <App />
</ErrorBoundary>

Lesson: 3D applications need aggressive performance optimization for web.

Issue 6: Landing Page Design

User Request:

"add the relevant buttons to this - keep this as landing page" (attached battleship image)

What We Did:

1. Downloaded image to /app/frontend/public/battleships-bg.png
2. Set as background with dark overlay for contrast
3. Updated buttons to military theme:
   • "Start New Battle" - Orange-red gradient
   • "Join Battle" - Blue-cyan gradient
4. Added "How to Play" section with 3 steps

Lesson: Visual assets dramatically improve user experience. Always optimize file sizes.

What You Built?

In this session, you created:

• Full-stack multiplayer game (Real-time WebSocket)
• 3D ocean battlefield (Three.js with optimizations)
• Invite code system (6-character codes)
• Turn-based combat (Hit/miss detection)
• Responsive UI (Tailwind + Shadcn)
• Memory optimizations (Error boundaries, cleanup)
• Professional landing page (Custom background, buttons)

Check out our finished product over at https://ocean-warfare-3d.emergent.host/ or build out your wildest ideas and share it with us on X or Discord