How to make sprites follow a path in tower defense games
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PathMaster_Dev
Posted on January 22, 2024 • Intermediate
🎮 Tower Defense Path Following Problem
Hey everyone! I’m working on a tower defense game in Scratch and I’m having trouble making enemies follow the designated path. Currently, my enemies just move toward the center of the path sprite instead of following the actual route. Here’s what I’m trying to achieve:
- Enemies spawn and follow a predefined path
- They navigate through turns and curves smoothly
- Multiple enemies can follow the same path without colliding
My current code just makes them point toward the path sprite and move forward, but they don’t follow the actual path layout. Any help would be greatly appreciated! 🙏
TowerDefense_Expert
Replied 3 hours later • ⭐ Best Answer
Great question @PathMaster_Dev! Path following in tower defense games is a classic challenge. Here are several effective approaches to solve this problem:
🗺️ Path Following System Overview
Here’s how a robust path-following system works:
🔧 Method 1: Waypoint System (Recommended)
Create a list of coordinates that define your path:
when flag clicked // Create waypoint lists delete all of [Path X v] delete all of [Path Y v] // Add waypoints for your path add [100] to [Path X v] add [150] to [Path Y v] add [200] to [150] to [Path X v] add [150] to [Path Y v] add [200] to [Path X v] add [50] to [Path Y v] add [300] to [Path X v] add [50] to [Path Y v] // Initialize enemy set [Current Waypoint v] to [1] set [Speed v] to [3]
// Enemy movement script when I receive [spawn enemy v] forever if <(Current Waypoint) <= (length of [Path X v])> then // Get target position set [Target X v] to (item (Current Waypoint) of [Path X v]) set [Target Y v] to (item (Current Waypoint) of [Path Y v]) // Calculate distance to target set [Distance v] to (sqrt of (((Target X) - (x position)) * ((Target X) - (x position))) + (((Target Y) - (y position)) * ((Target Y) - (y position)))) if <(Distance) < [10]> then // Reached waypoint, move to next change [Current Waypoint v] by [1] else // Move toward current waypoint point towards x: (Target X) y: (Target Y) move (Speed) steps end else // Reached end of path broadcast [enemy reached end v] delete this clone end end
🎨 Method 2: Color-Based Path Following
Use different colors on your path sprite to control movement direction:
when flag clicked forever // Check color beneath enemy if <touching color [#ff0000]?> then point in direction [90] // Right end if <touching color [#00ff00]?> then point in direction [0] // Up end if <touching color [#0000ff]?> then point in direction [-90] // Left end if <touching color [#ffff00]?> then point in direction [180] // Down end move (3) steps // If off path, find nearest path color if <not <touching color [#ff0000]?>> and <not <touching color [#00ff00]?>> and <not <touching color [#0000ff]?>> and <not <touching color [#ffff00]?>> then // Return to path logic here end end
🚀 Method 3: Advanced Smooth Following
For smoother movement with curves:
// Smooth path following with interpolation define move to waypoint (target x) (target y) set [dx v] to ((target x) - (x position)) set [dy v] to ((target y) - (y position)) set [distance v] to (sqrt of ((dx) * (dx)) + ((dy) * (dy))) if <(distance) > [5]> then // Normalize direction and apply speed set [move x v] to (((dx) / (distance)) * (Speed)) set [move y v] to (((dy) / (distance)) * (Speed)) change x by (move x) change y by (move y) // Smooth rotation set [target direction v] to ((atan of ((dy) / (dx))) + (90)) if <(dx) < [0]> then change [target direction v] by [180] end // Gradually turn toward target direction set [angle diff v] to ((target direction) - (direction)) if <(angle diff) > [180]> then change [angle diff v] by [-360] end if <(angle diff) < [-180]> then change [angle diff v] by [360] end turn right ((angle diff) / [5]) degrees end
💡 Pro Tips for Better Path Following
- Waypoint Spacing: Place waypoints closer together for smoother curves
- Speed Control: Slow down near waypoints to prevent overshooting
- Multiple Paths: Use different lists for different difficulty levels
- Enemy Spacing: Add delays between spawns to prevent clustering
// Enemy spawning with proper spacing when flag clicked repeat [10] broadcast [spawn enemy v] wait [1.5] seconds // Spacing between enemies end
The waypoint method is most reliable and gives you complete control over the path. Start with that approach and you’ll have enemies following your path perfectly! 😊
PathMaster_Dev
Replied 45 minutes later
@TowerDefense_Expert This is absolutely perfect! 🎉
The waypoint system worked like a charm! My enemies are now following the path exactly as intended. The smooth interpolation method is especially nice for making the movement look more natural.
Quick question - how would I handle multiple enemy types with different speeds on the same path?
GameDev_Sarah
Replied 2 hours later
@PathMaster_Dev For different enemy types, just use a variable for each enemy’s speed! Here’s how:
// When creating enemy clone when I start as a clone if <(Enemy Type) = [fast]> then set [Speed v] to [5] else if <(Enemy Type) = [slow]> then set [Speed v] to [2] else set [Speed v] to [3] // normal speed end end
This way each enemy maintains its own speed while following the same path! 🚀
Vibelf_Community
Pinned Message • Moderator
🚀 Ready to Build Advanced Tower Defense Games?
Excellent discussion on path following mechanics! For those looking to create even more sophisticated tower defense systems, our community can help you implement:
- 🎯 Advanced AI pathfinding algorithms
- 🏰 Dynamic tower placement systems
- ⚡ Special abilities and power-ups
- 🌊 Wave management and difficulty scaling
📚 Related Discussions
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