How to detect sprite movement direction and state in Scratch
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CodeExplorer_Sam
Posted on July 26, 2025 • Intermediate
🎯 Need help detecting sprite movement states
Hey everyone! I’m working on a project with fly sprites that have different movement behaviors. Here’s my situation:
- My Fly sprite moves randomly most of the time
- When a specific event happens, it should move to coordinates X: 0 Y: -150
- I need to detect when it’s moving to those specific coordinates vs. moving randomly
- I also need to detect when the sprite isn’t moving at all
The tricky part is that I’m using clones, and each clone might have different movement states. How can I track this properly? 🤔
SpriteManager_Pro
Replied 1 hour later • ⭐ Best Answer
Great question @CodeExplorer_Sam! This is a common challenge when working with clones and movement states. Here’s a comprehensive solution:
🎯 Movement Detection System
Here’s how to track different movement states for each clone:
🔧 Step 1: Create Movement State Variables
First, create these variables for tracking movement states:
when flag clicked // Create 'for this sprite only' variables set [Movement State v] to [random] set [Target X v] to [0] set [Target Y v] to [0] set [Previous X v] to (x position) set [Previous Y v] to (y position)
🎲 Step 2: Random Movement Detection
Here’s how to implement and detect random movement:
// Random movement script when flag clicked forever if <(Movement State) = [random]> then // Store previous position set [Previous X v] to (x position) set [Previous Y v] to (y position) // Random movement change x by (pick random (-5) to (5)) change y by (pick random (-5) to (5)) // Keep sprite on screen if <(x position) > [240]> then set x to [240] end if <(x position) < [-240]> then set x to [-240] end if <(y position) > [180]> then set y to [180] end if <(y position) < [-180]> then set y to [-180] end wait (0.1) seconds end end
🎯 Step 3: Target Movement System
For moving to specific coordinates:
// Target movement script when flag clicked forever if <(Movement State) = [target]> then // Store previous position set [Previous X v] to (x position) set [Previous Y v] to (y position) // Move toward target if <(distance to x: (Target X) y: (Target Y)) > [5]> then point towards x: (Target X) y: (Target Y) move (3) steps else // Reached target set [Movement State v] to [idle] go to x: (Target X) y: (Target Y) end wait (0.05) seconds end end
🛑 Step 4: Movement Detection Functions
Create custom blocks to detect movement states:
// Custom block: Is Moving? define Is Moving? if <<not <(x position) = (Previous X)>> or <not <(y position) = (Previous Y)>>> then set [Is Moving v] to [true] else set [Is Moving v] to [false] end // Custom block: Is Moving to Target? define Is Moving to Target? if <<(Movement State) = [target]> and <(Is Moving) = [true]>> then set [Moving to Target v] to [true] else set [Moving to Target v] to [false] end // Custom block: Is Moving Randomly? define Is Moving Randomly? if <<(Movement State) = [random]> and <(Is Moving) = [true]>> then set [Moving Randomly v] to [true] else set [Moving Randomly v] to [false] end
⚡ Step 5: State Change System
Handle state changes with events:
// Event handler for changing to target movement when I receive [move to target v] set [Movement State v] to [target] set [Target X v] to [0] set [Target Y v] to [-150] // Event handler for random movement when I receive [start random movement v] set [Movement State v] to [random] // Event handler for stopping when I receive [stop movement v] set [Movement State v] to [idle]
📊 Step 6: Movement Status Display
Optional: Display current movement status:
when flag clicked forever // Update detection Is Moving? Is Moving to Target? Is Moving Randomly? // Display status (optional) if <(Movement State) = [random]> then say [Moving randomly] for (0.1) seconds else if <(Movement State) = [target]> then say (join [Moving to: ] (join (Target X) (join [, ] (Target Y)))) for (0.1) seconds else if <(Movement State) = [idle]> then say [Not moving] for (0.1) seconds end end end end
This system gives you complete control over movement detection! Each clone can have its own movement state, and you can easily check what type of movement is happening. 🎮
CloneVars_Expert
Replied 45 minutes later
@CodeExplorer_Sam Just to clarify the clone variable concept that was mentioned earlier:
When you create a variable “for this sprite only”, each clone gets its own copy of that variable. This is perfect for your use case! 🎯
// Each clone can have different values when I start as a clone set [Movement State v] to [random] // This clone starts with random movement set [Clone ID v] to (length of [Clone List v]) // Unique identifier add (Clone ID) to [Clone List v]
This way, Clone #1 might be moving randomly while Clone #2 is moving to target coordinates, and Clone #3 is idle - all independently! 🚀
CodeExplorer_Sam
Replied 20 minutes later
@SpriteManager_Pro @CloneVars_Expert This is exactly what I needed! 🎉
The “for this sprite only” variables make perfect sense now. I implemented the movement state system and it works beautifully! Each clone can now track its own movement independently.
Thanks for the detailed explanation and code examples! 🙏
Vibelf_Community
Pinned Message • Moderator
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Excellent discussion on movement detection! For those wanting to explore more advanced sprite control concepts:
- 🎯 Advanced pathfinding algorithms
- 🤖 AI-driven sprite behaviors
- 🎮 Complex clone management systems
- 📊 Performance optimization for many sprites
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