How to fix plane moving backwards in Scratch
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FlightSimDev
Posted on January 22, 2024 • Intermediate
✈️ Aircraft movement issues in my flight game
I’m developing a flight simulator in Scratch where players control an aircraft with the mouse pointer. I’m facing two major problems:
- The plane can move backwards, which looks unrealistic for aircraft movement
- Enemy aircraft also move backwards and behave strangely near screen edges
- Enemy planes slow down and make weird turns when approaching boundaries
I want to create realistic flight physics where planes always move forward. Any suggestions for fixing these movement issues? 🛩️
AeronauticsProf
Replied 1 hour later • ⭐ Best Answer
Great question @FlightSimDev! The issue you’re experiencing is very common in flight games. Here’s a comprehensive solution:
🔧 Step 1: Fix Sprite Orientation
The main problem is that Scratch sprites are designed to face right (90 degrees) by default, but aircraft sprites often face up (0 degrees). Here’s how to fix it:
when flag clicked set rotation style [all around v] point in direction [90] // Right-facing // If your plane sprite faces up, rotate the costume 90 degrees clockwise in the editor
✈️ Step 2: Implement Forward-Only Movement
Create a movement system that always moves the plane forward in its current direction:
when flag clicked forever // Calculate angle to mouse set [target angle v] to ([atan v] of ((mouse y) - (y position)) / ((mouse x) - (x position))) // Smooth rotation towards target if <(target angle) > (direction)> then turn right [3] degrees else turn left [3] degrees end // Always move forward move [5] steps end
🎯 Step 3: Advanced Mouse Following
For more realistic aircraft behavior that prevents backward movement:
when flag clicked set [speed v] to [3] set [turn rate v] to [2] forever // Calculate desired direction set [dx v] to ((mouse x) - (x position)) set [dy v] to ((mouse y) - (y position)) set [target direction v] to ([atan2 v] of (dy) (dx)) // Smooth turning with limited turn rate set [angle diff v] to ((target direction) - (direction)) // Normalize angle difference to -180 to 180 if <(angle diff) > [180]> then change [angle diff v] by [-360] end if <(angle diff) < [-180]> then change [angle diff v] by [360] end // Apply limited turning if <(abs of (angle diff)) > (turn rate)> then if <(angle diff) > [0]> then turn right (turn rate) degrees else turn left (turn rate) degrees end else point in direction (target direction) end // Move forward at constant speed move (speed) steps end
🤖 Step 4: Fix Enemy AI Movement
For enemy aircraft that behave realistically:
// Enemy AI script when flag clicked set [enemy speed v] to [2] set [enemy turn rate v] to [1.5] forever // Find player position set [target x v] to ([x position v] of [Player v]) set [target y v] to ([y position v] of [Player v]) // Calculate direction to player set [dx v] to ((target x) - (x position)) set [dy v] to ((target y) - (y position)) set [target dir v] to ([atan2 v] of (dy) (dx)) // Smooth turning set [turn amount v] to ((target dir) - (direction)) // Normalize turn amount if <(turn amount) > [180]> then change [turn amount v] by [-360] end if <(turn amount) < [-180]> then change [turn amount v] by [360] end // Apply limited turning if <(abs of (turn amount)) > (enemy turn rate)> then if <(turn amount) > [0]> then turn right (enemy turn rate) degrees else turn left (enemy turn rate) degrees end end // Always move forward move (enemy speed) steps // Boundary checking - turn away from edges if <(x position) > [220]> then turn left [10] degrees end if <(x position) < [-220]> then turn right [10] degrees end if <(y position) > [160]> then turn left [10] degrees end if <(y position) < [-160]> then turn right [10] degrees end end
🚀 Step 5: Additional Realism Features
To make your flight game even more realistic:
Banking Effect:
// Add banking animation when flag clicked forever if <key [left arrow v] pressed?> then set [rotation style v] to [left-right] turn left [2] degrees else if <key [right arrow v] pressed?> then set [rotation style v] to [left-right] turn right [2] degrees else set [rotation style v] to [all around] end end end
Speed Control:
// Variable speed based on angle to target set [distance to target v] to (sqrt of (((dx) * (dx)) + ((dy) * (dy)))) if <(distance to target) > [100]> then set [speed v] to [4] // Faster when far else set [speed v] to [2] // Slower when close end
This solution will give you realistic aircraft movement where planes always move forward and turn smoothly toward their targets! ✈️
FlightSimDev
Replied 45 minutes later
@AeronauticsProf This is absolutely perfect! 🎉
The atan2 function and smooth turning completely solved my backward movement issue. The enemy AI now behaves much more realistically too. Thank you for the detailed explanation!
One quick follow-up: How can I add a minimum turning radius to make the planes feel heavier?
PhysicsExpert_Sam
Replied 2 hours later
@FlightSimDev Great question about turning radius! Here’s how to add realistic physics:
// Add minimum turning radius based on speed set [current speed v] to [3] set [max turn rate v] to ([10] / (current speed)) // Slower turning at higher speeds // In your movement loop: if <(abs of (angle diff)) > (max turn rate)> then if <(angle diff) > [0]> then turn right (max turn rate) degrees else turn left (max turn rate) degrees end end
This makes faster planes turn more slowly, creating realistic flight physics! ✈️
Vibelf_Community
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