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Fixing mouse detection issues with list management

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LM

ListManager_Expert

Posted on January 25, 2024 • Intermediate

🖱️ Mouse detection suddenly stopped working

Hi everyone! I’m having a strange issue with my project that has PEN sliders:

  • The sliders work perfectly in TurboWarp
  • They worked in Scratch initially, but suddenly stopped
  • Mouse detection seems to be completely broken now
  • No error messages, just silent failure

The project uses lists to track button interactions. Could this be related to the mouse detection issue? Any ideas what might be causing this? 🤔

DB

DebugMaster_Pro

Replied 3 hours later • ⭐ Best Answer

Excellent detective work @ListManager_Expert! This is a classic list overflow issue. Here’s exactly what’s happening and how to fix it:

🔍 The Root Cause: List Overflow

Here’s what’s happening in your project:

flowchart TD A[🚀 Project Starts] --> B[Mouse Interactions Begin] B --> C[Add Items to List] C --> D{List Size Check} D -->|< 200,000 items| E[✅ Normal Operation] D -->|≥ 200,000 items| F[❌ List Limit Reached] E --> G[Mouse Detection Works] F --> H[🚫 Mouse Detection Fails] G --> I[Continue Adding Items] H --> J[Silent Failure Mode] I --> C J --> K[Project Appears Broken] style A fill:#e1f5fe style F fill:#ffebee style H fill:#ffebee style K fill:#ffebee style E fill:#e8f5e8

🛠️ The Problem: Missing List Cleanup

Your “buttons” list keeps growing without ever being cleared. Here’s what’s missing:

    // The missing cleanup block
delete all of [buttons v]

✅ Complete Fix Implementation

Here’s how to properly manage your button list:

    // Proper list management for sliders
when flag clicked
forever
// Clear the list at the start of each frame
delete all of [buttons v]

// Rebuild button list for current frame
set [button count v] to [0]

// Add each active button
repeat (number of sliders)
change [button count v] by (1)
add (join [slider_] (button count)) to [buttons v]
end

// Process mouse interactions
if <mouse down?> then
broadcast [check button clicks v]
end

wait (0.01) secs // Small delay for performance
end

🎯 Advanced List Management Techniques

Technique 1: Circular Buffer

    // Circular buffer for limited list size
define add to circular buffer (item) max size (max)
if <(length of [buffer v]) ≥ (max)> then
delete (1) of [buffer v]
end
add (item) to [buffer v]

Technique 2: Batch Cleanup

    // Periodic cleanup system
when flag clicked
set [cleanup timer v] to [0]
forever
change [cleanup timer v] by (1)

// Clean up every 300 frames (5 seconds at 60fps)
if <(cleanup timer) > [300]> then
delete all of [buttons v]
delete all of [temp data v]
set [cleanup timer v] to [0]
broadcast [lists cleaned v]
end

wait (0.016) secs // 60 FPS timing
end

Technique 3: Smart List Management

    // Smart list with size monitoring
define add item safely (item) to list (list name)
if <(length of (list name)) > [150000]> then
// Emergency cleanup when approaching limit
repeat (50000)
delete (1) of (list name)
end
broadcast [list overflow prevented v]
end
add (item) to (list name)

🚀 Optimized Slider System

Here’s a complete, optimized slider implementation:

    // Optimized slider system
when flag clicked
set [slider update needed v] to [true]

forever
if <(slider update needed) = [true]> then
// Clear and rebuild slider data
delete all of [slider positions v]
delete all of [slider values v]

// Initialize sliders
repeat (number of sliders)
add [0] to [slider positions v] // Default position
add [50] to [slider values v]   // Default value
end

set [slider update needed v] to [false]
end

// Handle mouse interactions efficiently
if <mouse down?> then
broadcast [update sliders v]
end

wait (0.02) secs
end

// Slider interaction handler
when I receive [update sliders v]
set [slider id v] to [1]
repeat (length of [slider positions v])
// Check if mouse is over this slider
if <<(mouse x) > ((item (slider id) of [slider x positions v]) - [50])> and <(mouse x) < ((item (slider id) of [slider x positions v]) + [50])>> then
if <<(mouse y) > ((item (slider id) of [slider y positions v]) - [10])> and <(mouse y) < ((item (slider id) of [slider y positions v]) + [10])>> then
// Update slider value
replace item (slider id) of [slider values v] with (mouse x)
broadcast [slider changed v]
end
end
change [slider id v] by (1)
end

🔧 Debugging List Issues

Here’s how to monitor and debug list problems:

    // List monitoring system
when flag clicked
forever
// Monitor list sizes
set [buttons list size v] to (length of [buttons v])
set [data list size v] to (length of [temp data v])

// Warning system
if <(buttons list size) > [100000]> then
say (join [WARNING: List size ] (buttons list size)) for (2) secs
end

// Emergency cleanup
if <(buttons list size) > [180000]> then
delete all of [buttons v]
say [EMERGENCY: List cleared!] for (3) secs
end

wait (1) secs
end

💡 Prevention Tips

  • Regular cleanup: Always clear lists when they’re no longer needed
  • Size monitoring: Keep track of list sizes in complex projects
  • Efficient algorithms: Use algorithms that don’t require growing lists
  • Testing: Test your project for extended periods to catch overflow issues

Remember: TurboWarp doesn’t have the 200,000 item limit, which is why it worked there! 🎯

LM

ListManager_Expert

Replied 1 hour later

@DebugMaster_Pro This is incredible! 🎉 Adding the “delete all” block fixed it immediately!

I had no idea about the 200,000 item limit. This explains why it worked in TurboWarp but not in Scratch. Thank you for the detailed explanation and monitoring system!

PM

PerformanceMonitor_Sam

Replied 2 hours later

Great solution! Here’s a quick performance tip for anyone dealing with large lists:

    // Performance-optimized list operations
define clear list efficiently (list name)
// Instead of deleting items one by one
// Use 'delete all' which is much faster
delete all of (list name)

// For partial cleanup, delete in chunks
define remove old items from (list name) keep last (keep count)
set [items to remove v] to ((length of (list name)) - (keep count))
if <(items to remove) > [0]> then
repeat (items to remove)
delete (1) of (list name)
end
end

This prevents performance issues when dealing with large datasets! ⚡

VB

Vibelf_Community

Pinned Message • Moderator

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