コンテンツにスキップ

Making Sprites Appear on Collision Detection

このコンテンツはまだ日本語訳がありません。

💡 Having trouble with Scratch block assembly? Don’t know how to implement code logic? 🚀 Get Help Now

PG

PongGameDev

Posted on January 23, 2024 • Beginner

🏓 Need help with collision detection in Pong game

Hello everyone! I’m creating a Pong game and I’m stuck on a specific mechanic. Here’s my setup:

  • Ball sprite - moves around the screen
  • Paddle sprite - player controls this
  • Red line sprite - acts as the game boundary
  • ”Game Over” sprite - should appear when player loses

I want the “Game Over” sprite to appear when the ball touches the red line (meaning the player missed the ball). I’ve tried using color collision detection, but I can’t figure out how to make the fourth sprite appear when this collision happens.

Any help would be greatly appreciated! 🙏

CD

CollisionDetector_Pro

Replied 2 hours later • ⭐ Best Answer

Perfect question @PongGameDev! Collision detection with sprite visibility control is a fundamental game mechanic. Here’s a complete solution for your Pong game:

🎯 Collision Detection Flow

Here’s how the collision system works:

flowchart TD A[🚀 Game Start] --> B[Initialize All Sprites] B --> C[Ball Starts Moving] C --> D[🏓 Game Loop] D --> E{Ball Collision Check} E -->|Touches Paddle| F[🏓 Bounce Ball] E -->|Touches Wall| G[🔄 Bounce Ball] E -->|Touches Red Line| H[💥 Game Over Trigger] E -->|No Collision| D F --> I[Play Bounce Sound] G --> I H --> J[Broadcast 'Game Over'] I --> D J --> K[Show Game Over Sprite] K --> L[Stop Ball Movement] L --> M[Display Final Score] M --> N{Play Again?} N -->|Yes| O[Reset Game] N -->|No| P[🏁 End Game] O --> B style A fill:#e1f5fe style H fill:#ffebee style J fill:#fff3e0 style K fill:#f3e5f5 style P fill:#e8f5e8

🏓 Step 1: Ball Sprite Collision Detection

Add this code to your Ball sprite:

    when flag clicked
forever
move [5] steps

// Check collision with red line (game over condition)
if <touching [Red Line v]?> then
broadcast [game over v]
stop [this script v]
end

// Check collision with paddle (bounce)
if <touching [Paddle v]?> then
point in direction ((180) - (direction))
play sound [bounce v]
end

// Check collision with walls (bounce)
if <touching color [#000000]?> then
point in direction ((180) - (direction))
end
end

🎮 Step 2: Game Over Sprite Setup

Add this code to your Game Over sprite:

    when flag clicked
hide
go to x: [0] y: [0]
set size to [100] %

when I receive [game over v]
show
play sound [game over v]
repeat [10]
change [brightness v] effect by [10]
wait [0.1] seconds
change [brightness v] effect by [-10]
wait [0.1] seconds
end

🔴 Step 3: Red Line Sprite (Alternative Method)

You can also put the collision detection in the Red Line sprite:

    when flag clicked
forever
if <touching [Ball v]?> then
broadcast [game over v]
stop [this script v]
end
end

🎯 Step 4: Advanced Collision Detection

For more precise collision detection, use this enhanced version:

    // In Ball sprite - more precise collision
when flag clicked
set [game active v] to [true]

forever
if <(game active) = [true]> then
move [5] steps

// Store current position
set [ball x v] to (x position)
set [ball y v] to (y position)

// Check multiple collision types
if <touching [Red Line v]?> then
set [game active v] to [false]
broadcast [ball hit red line v]
stop [this script v]
end

// Paddle collision with angle calculation
if <touching [Paddle v]?> then
set [hit angle v] to ((x position) - ([x position v] of [Paddle v]))
point in direction ((hit angle) + [90])
play sound [paddle hit v]
end
end
end

📊 Step 5: Game State Management

Create a comprehensive game management system:

    // Game Manager (can be in Stage or any sprite)
when flag clicked
set [score v] to [0]
set [lives v] to [3]
set [game state v] to [playing]
broadcast [game start v]

when I receive [ball hit red line v]
change [lives v] by [-1]
if <(lives) > [0]> then
broadcast [life lost v]
wait [2] seconds
broadcast [respawn ball v]
else
set [game state v] to [game over]
broadcast [final game over v]
end

✨ Step 6: Enhanced Game Over Display

Make your game over screen more engaging:

    // Enhanced Game Over Sprite
when I receive [final game over v]
show
go to x: [0] y: [50]
set size to [0] %

// Smooth appearance animation
repeat [20]
change size by [5]
wait [0.05] seconds
end

// Pulsing effect
forever
repeat [10]
change size by [2]
wait [0.1] seconds
end
repeat [10]
change size by [-2]
wait [0.1] seconds
end
end

🔧 Step 7: Reset Functionality

Add a reset system for replay:

    // Reset system (Space key to restart)
when [space v] key pressed
if <(game state) = [game over]> then
broadcast [reset game v]
end

when I receive [reset game v]
// Reset all sprites to starting positions
set [score v] to [0]
set [lives v] to [3]
set [game state v] to [playing]
hide // Hide game over sprite
broadcast [game start v]

Pro Tips:

  • 🎯 Use broadcasting for clean communication between sprites
  • 🔄 Always hide sprites that shouldn’t be visible at game start
  • 📍 Set sprite positions explicitly to avoid placement issues
  • 🎵 Add sound effects to make collisions feel more impactful
  • ⚡ Use variables to control game state and prevent unwanted interactions

This system gives you complete control over sprite visibility and collision responses! 🎉

PG

PongGameDev

Replied 30 minutes later

@CollisionDetector_Pro This is absolutely perfect! 🎉 The broadcasting method works like a charm!

I got the basic collision working, and the game over sprite appears exactly when it should. Quick question - how can I make the ball reset to the center when the game restarts?

GR

GameResetExpert

Replied 45 minutes later

@PongGameDev Great question! Here’s how to reset the ball position:

    // In Ball sprite
when I receive [game start v]
go to x: [0] y: [0]
point in direction [90]
set [game active v] to [true]
wait [1] seconds
// Start moving again

This ensures the ball always starts from the center with a consistent direction! 🏓

VB

Vibelf_Community

Pinned Message • Moderator

🎮 Master Advanced Game Mechanics

Excellent discussion on collision detection and sprite management! For those ready to build more sophisticated games, explore:

  • 🎯 Multi-sprite collision systems
  • 🔄 Advanced physics simulations
  • 🎨 Dynamic sprite generation
  • 🏆 Complex game state management

📚 Related Topics

Ready to create professional-quality games? Get personalized guidance from our expert game development tutors!