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Creating an Online 2D Multiplayer Game in Scratch

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💡 Struggling with multiplayer game development? Need help with cloud variables and networking? 🚀 Get Expert Help

GE

GameDev_Explorer

Posted on January 22, 2024 • Advanced

🌐 Need help creating an online 2D multiplayer game

Hey everyone! I’m working on an ambitious 2D game project that I want to make multiplayer. I have some experience with cloud variables but I’m struggling with the more complex aspects of online game development.

Specifically, I need help with:

  • Setting up proper player synchronization
  • Managing shared game state across multiple players
  • Handling player connections and disconnections
  • Creating efficient data structures for multiplayer

I’ve seen some multiplayer games on Scratch but I’m not sure how to implement the networking logic properly. Any guidance would be amazing! 🙏

MP

MultiplayerMaster

Replied 3 hours later • ⭐ Best Answer

Great question @GameDev_Explorer! Creating multiplayer games in Scratch is definitely challenging but totally doable. Here’s a comprehensive guide to get you started:

🏗️ Multiplayer Game Architecture

Here’s how a typical multiplayer game flow works:

flowchart TD A[🎮 Player Joins] --> B[Get Unique Player ID] B --> C[Initialize Player Data] C --> D[📡 Connect to Cloud Variables] D --> E[🔄 Game Loop] E --> F{Player Input?} F -->|Movement| G[Update Local Position] F -->|Action| H[Update Local State] F -->|No Input| I[Read Other Players] G --> J[📤 Send to Cloud] H --> J J --> K[📥 Receive from Cloud] I --> K K --> L[🎨 Update Display] L --> M{Game Active?} M -->|Yes| E M -->|No| N[🏁 Cleanup & Exit] style A fill:#e1f5fe style D fill:#f3e5f5 style J fill:#e8f5e8 style K fill:#fff3e0 style N fill:#fce4ec

🔧 Step 1: Player ID System

First, create a system to assign unique IDs to each player:

    when flag clicked
set [My Player ID v] to [0]
repeat until <not <(My Player ID) = [0]>>
change [My Player ID v] by [1]
if <([player (My Player ID) active v] of [☁ cloud data v]) = []> then
set [☁ player (My Player ID) active v] to [1]
set [☁ player (My Player ID) x v] to [0]
set [☁ player (My Player ID) y v] to [0]
else
if <(My Player ID) > [10]> then
say [Server Full!] for [3] seconds
stop [all v]
end
end
end

🎯 Step 2: Position Synchronization

Keep all players synchronized across the network:

    // Main player movement and sync
when flag clicked
forever
// Handle local player movement
if <key [right arrow v] pressed?> then
change x by [5]
set [☁ player (My Player ID) x v] to (x position)
end
if <key [left arrow v] pressed?> then
change x by [-5]
set [☁ player (My Player ID) x v] to (x position)
end
if <key [up arrow v] pressed?> then
change y by [5]
set [☁ player (My Player ID) y v] to (y position)
end
if <key [down arrow v] pressed?> then
change y by [-5]
set [☁ player (My Player ID) y v] to (y position)
end

// Update timestamp for activity
set [☁ player (My Player ID) timestamp v] to (timer)
end

👥 Step 3: Other Players Display

Create clones to represent other players:

    // For other player sprites (clones)
when flag clicked
set [Other Player ID v] to [1]
repeat [10]
if <not <(Other Player ID) = (My Player ID)>> then
if <([player (Other Player ID) active v] of [☁ cloud data v]) = [1]> then
create clone of [myself v]
end
end
change [Other Player ID v] by [1]
end

when I start as a clone
set [My Clone ID v] to (Other Player ID)
forever
if <([player (My Clone ID) active v] of [☁ cloud data v]) = [1]> then
go to x: ([player (My Clone ID) x v] of [☁ cloud data v]) y: ([player (My Clone ID) y v] of [☁ cloud data v])
show
// Check if player is still active (within last 10 seconds)
if <((timer) - ([player (My Clone ID) timestamp v] of [☁ cloud data v])) > [10]> then
set [☁ player (My Clone ID) active v] to []
delete this clone
end
else
delete this clone
end
end

💬 Step 4: Chat System (Optional)

Add a simple chat system for player communication:

    // Chat system
when [space v] key pressed
ask [Enter message:] and wait
if <not <(answer) = []>> then
set [☁ chat message v] to (join (join [Player ] (My Player ID)) (join [: ] (answer)))
set [☁ chat timestamp v] to (timer)
end

// Display chat messages
when flag clicked
set [last chat time v] to [0]
forever
if <([☁ chat timestamp v]) > (last chat time)> then
say ([☁ chat message v]) for [5] seconds
set [last chat time v] to ([☁ chat timestamp v])
end
end

🎮 Step 5: Game State Management

For more complex games, manage shared game state:

    // Game state management
when flag clicked
if <(My Player ID) = [1]> then
// Player 1 is the host/server
set [☁ game state v] to [waiting]
set [☁ game timer v] to [0]
forever
if <([☁ game state v]) = [waiting]> then
// Count active players
set [active players v] to [0]
repeat [10]
if <not <([player (counter) active v] of [☁ cloud data v]) = []>> then
change [active players v] by [1]
end
change [counter v] by [1]
end

if <(active players) ≥ [2]> then
set [☁ game state v] to [starting]
set [☁ game timer v] to [5]
end
end

if <([☁ game state v]) = [starting]> then
change [☁ game timer v] by [-0.1]
if <([☁ game timer v]) ≤ [0]> then
set [☁ game state v] to [playing]
set [☁ game timer v] to [60]
end
end

wait [0.1] seconds
end
end

⚡ Step 6: Optimization Tips

Important optimizations for smooth multiplayer:

  • Rate Limiting: Don’t update cloud variables every frame
  • Data Compression: Use shorter variable names and compact data
  • Prediction: Show local changes immediately, sync later
  • Cleanup: Remove inactive players automatically
    // Optimized update system
when flag clicked
set [update timer v] to [0]
forever
change [update timer v] by [1]
if <(update timer) > [3]> then // Update every 3 frames
set [☁ player (My Player ID) x v] to (x position)
set [☁ player (My Player ID) y v] to (y position)
set [update timer v] to [0]
end
end

This should give you a solid foundation for your multiplayer game! Remember to test with friends and iterate on the design. Good luck! 🚀

GE

GameDev_Explorer

Replied 1 hour later

@MultiplayerMaster This is incredible! Thank you so much! 🎉

I got the basic player synchronization working. One question - how do I handle lag and make the movement feel smoother for players with slower connections?

NE

NetworkExpert_Sam

Replied 2 hours later

@GameDev_Explorer Great question about lag compensation! Here are some techniques:

    // Lag compensation with interpolation
when flag clicked
forever
// Store previous position
set [prev x v] to (x position)
set [prev y v] to (y position)

// Get target position from cloud
set [target x v] to ([player (Other Player ID) x v] of [☁ cloud data v])
set [target y v] to ([player (Other Player ID) y v] of [☁ cloud data v])

// Smooth interpolation
change x by (((target x) - (x position)) / [5])
change y by (((target y) - (y position)) / [5])
end

This creates smooth movement even with network delays! Also consider client-side prediction for the local player. 🎯

VB

Vibelf_Community

Pinned Message • Moderator

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