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Fixing sprites that restart unexpectedly in Scratch games

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GD

GameDebugger_2024

Posted on August 6, 2024 • Intermediate

🐛 Sprites restarting without being triggered - need debugging help!

I’m working on a betting game where players can bet on race winners. The flow should be: Race → Win Screen → Betting Stage → Start Button → Race. However, something weird is happening!

When the win screen ends, the race immediately starts again, completely skipping the betting stage. I’ve checked all my sprites and only the start button should broadcast the race start message, but somehow the race is triggering anyway.

I even tried disconnecting the custom block from the broadcast, but the sprites still move! Is this a Scratch bug, or am I missing something? Any debugging tips would be super helpful! 🤔

DS

DebugSpecialist_Pro

Replied 1 hour later • ⭐ Best Answer

Great question @GameDebugger_2024! This is a common issue in complex Scratch games. Let me help you debug this step by step! 🔍

🕵️ Step 1: Debug Hidden Broadcasts

First, let’s catch all broadcast messages to see what’s being triggered:

    // Add this to a temporary sprite for debugging
when I receive [any message v]
say (join [Received: ] (message)) for [2] seconds

// This will show you EVERY broadcast in your project

🎯 Step 2: Verify Your Start Button

Make sure your start button only sends one specific broadcast:

    // Correct start button code
when this sprite clicked
if <(game state) = [betting]> then
broadcast [start race v] and wait
else
say [Not ready to start!] for [1] seconds
end

🔧 Step 3: Add Debug Messages to Custom Blocks

Modify your race-starting block to show when it’s triggered:

    define Start Race
say [Race started by trigger!] for [1] seconds
set [debug info v] to (join [Started at: ] (timer))
// ... rest of your race code ...

// Also add this to see what calls it
define Start Race (caller)
say (join [Race started by: ] (caller)) for [2] seconds
// Then call it like: Start Race [start button] :: custom

🛑 Step 4: Proper Script Control

Add proper script stopping to your win screen:

    // In your win screen code
when I receive [show win v]
stop [other scripts in sprite v] // Stops racing scripts
broadcast [reset all v] and wait
show win screen
wait [3] seconds
broadcast [start betting v]

// In each racing sprite
when I receive [reset all v]
stop [other scripts in sprite v]
go to x: [starting x] y: [starting y]
point in direction [90]
set [speed v] to [0]
hide

🎮 Step 5: Implement State Management

Create a robust game state system:

    // Main game controller
when flag clicked
set [game state v] to [betting]
broadcast [show betting screen v]

when I receive [start race v]
if <(game state) = [betting]> then
set [game state v] to [racing]
broadcast [begin race v]
else
say [Cannot start race now!] for [1] seconds
end

when I receive [race finished v]
set [game state v] to [win screen]
broadcast [show win screen v]
wait [3] seconds
set [game state v] to [betting]
broadcast [show betting screen v]

🔍 Step 6: Advanced Debugging Techniques

Use these techniques to track down the issue:

    // Create a debug log
when flag clicked
delete [all v] of [debug log v]

// Add to any suspicious script
add (join (join [Time: ] (timer)) (join [ - Event: ] [your event name])) to [debug log v]

// Check for infinite loops
define check for loops
if <(length of [debug log v]) > [100]> then
say [Possible infinite loop detected!] for [3] seconds
stop [all v]
end

⚠️ Common Causes of Unexpected Restarts:

  • Hidden “when flag clicked” blocks: Check ALL sprites for green flag scripts
  • Broadcast loops: Script A broadcasts to Script B, which broadcasts back to A
  • Clone behavior: Clones might be triggering events unexpectedly
  • Timer-based triggers: Scripts using “when timer > X” might be firing
  • Key press events: Accidental key presses triggering movement
  • Touching conditions: Sprites touching each other causing events

🎯 Quick Fix Checklist:

  1. Add the broadcast debugger and run your game
  2. Check the debug messages to see what’s being triggered
  3. Look for any “when I receive” blocks that match those messages
  4. Add state checks to prevent actions in wrong game states
  5. Use “stop other scripts” blocks strategically

This systematic approach should help you identify exactly what’s causing the unexpected restarts! 🎮

GD

GameDebugger_2024

Replied 30 minutes later

@DebugSpecialist_Pro This is AMAZING! 🎉 The broadcast debugger immediately showed me the problem!

Turns out I had a hidden “when timer > 5” block in one of my racing sprites that was triggering the race start. I completely forgot about it! The state management system you provided is also much cleaner than what I had.

Thank you so much for the detailed debugging guide - this will help me avoid similar issues in the future! 🙏

BH

BugHunter_Expert

Replied 15 minutes later

Great debugging work everyone! 🔍 Here’s an additional tip for preventing these issues:

    // Create a master switch for debugging
when flag clicked
set [debug mode v] to [on] // Change to 'off' for final version

// Add to any critical script
if <(debug mode) = [on]> then
say (join [Script triggered: ] [script name]) for [1] seconds
end

This makes it easy to toggle debugging on/off without removing all your debug code!

VB

Vibelf_Community

Pinned Message • Moderator

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