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How to implement double jumping mechanics in Scratch platformers

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JM

JumpMaster

Posted on August 5, 2024 • Intermediate

🦘 Need help with double jumping mechanics!

Hey everyone! I’m working on a platformer game and I’m trying to implement double jumping, but I’m having issues. I think my dashing mechanics might be interfering with the double jump script. 😤

I’ve been following some tutorials but I can’t seem to get it working properly. The character either doesn’t jump at all in mid-air, or jumps infinitely. Can someone help me understand how to properly implement this feature?

Note: I’m using some existing platformer code as a base, but I’m struggling with the jump counting logic.

PD

PlatformerDev_Pro

Replied 30 minutes later • ⭐ Best Answer

Great question @JumpMaster! Double jumping can be tricky to implement correctly. Here’s a comprehensive solution that should work perfectly:

🦘 Double Jump System Logic

Here’s how the double jump mechanics work:

flowchart TD A[🚩 Game Start] --> B[📊 Initialize Variables] B --> C[🎮 Player Input Loop] C --> D{🔍 Ground Check} D -->|On Ground| E[✅ Reset Jumps Available = 2] D -->|In Air| F[⏱️ Continue Current State] E --> G{⌨️ Jump Key Pressed?} F --> G G -->|No| H[⏱️ Wait Next Frame] G -->|Yes| I{🦘 Jumps Available > 0?} I -->|No| J[❌ Cannot Jump] I -->|Yes| K[🚀 Execute Jump] K --> L[📉 Decrease Jumps Available] L --> M[⬆️ Set Upward Velocity] M --> N{🎯 Jump Type?} N -->|First Jump| O[🎵 Ground Jump Sound] N -->|Second Jump| P[✨ Air Jump Sound + Effect] O --> Q[📍 Update Position] P --> Q J --> H Q --> H H --> C subgraph "Jump States" R["🌍 On Ground: 2 jumps available"] S["🌬️ First Jump: 1 jump available"] T["💫 Second Jump: 0 jumps available"] U["🚫 No Jumps: Must land to reset"] end subgraph "Ground Detection" V["📏 Check collision below player"] W["🎯 Use sensing blocks"] X["🔍 Color/sprite touching"] end style A fill:#e1f5fe style E fill:#c8e6c9 style K fill:#fff3e0 style L fill:#ffebee style J fill:#ffcdd2

🎯 Step 1: Set Up Variables

First, create these variables for your player sprite:

  • jumps_available - How many jumps the player can make
  • on_ground - Whether the player is touching the ground
  • gravity - Vertical velocity
  • jump_pressed - To prevent holding space for multiple jumps

🏃 Step 2: Ground Detection System

This is crucial for resetting your jump count:

    when flag clicked
forever
// Check if touching ground
if <touching color [#00FF00]?> then
set [on_ground v] to [true]
set [jumps_available v] to [2]  // Reset to 2 jumps (ground + air)
set [gravity v] to [0]
else
set [on_ground v] to [false]
end
end

🦘 Step 3: Jump Input Handling

Handle jump input with proper key press detection:

    when flag clicked
forever
// Detect jump key press (not held)
if <<key [space v] pressed?> and <(jump_pressed) = [false]>> then
set [jump_pressed v] to [true]

// Check if we can jump
if <(jumps_available) > [0]> then
set [gravity v] to [15]  // Jump strength
change [jumps_available v] by [-1]

// Play jump sound
play sound [jump v]
end
end

// Reset jump_pressed when key is released
if <not <key [space v] pressed?>> then
set [jump_pressed v] to [false]
end
end

📐 Step 4: Gravity and Movement

Apply gravity and handle vertical movement:

    when flag clicked
forever
// Apply gravity when not on ground
if <(on_ground) = [false]> then
change [gravity v] by [-1]  // Gravity strength

// Limit falling speed
if <(gravity) < [-15]> then
set [gravity v] to [-15]
end
end

// Move vertically
change y by (gravity)

// Check for ground collision after moving
if <<touching color [#00FF00]?> and <(gravity) < [0]>> then
repeat until <not <touching color [#00FF00]?>>
change y by [1]
end
set [gravity v] to [0]
end
end

🚀 Step 5: Advanced Double Jump with Visual Effects

Add some polish with particle effects:

    // When double jumping (in air)
if <<(jumps_available) = [1]> and <(on_ground) = [false]>> then
// Create double jump effect
repeat [5]
create clone of [particle v]
end

// Different jump strength for double jump
set [gravity v] to [12]  // Slightly weaker than first jump
change [jumps_available v] by [-1]
end

🛠️ Step 6: Troubleshooting Common Issues

Problem: Infinite jumping
Solution: Make sure you’re properly detecting ground contact and resetting jump count only when actually touching ground.

Problem: Can’t jump at all
Solution: Check that your jumps_available variable is being set to 2 when on ground.

Problem: Dashing interferes with jumping
Solution: Use separate variables for dash and jump states, and make sure they don’t conflict.

    // Separate dash handling
if <<key [x v] pressed?> and <(can_dash) = [true]>> then
set [dash_speed v] to [20]
set [can_dash v] to [false]
// Don't affect jump variables here
end

This should give you a solid double jump system! Let me know if you need help with any specific part! 😊

JM

JumpMaster

Replied 1 hour later

@PlatformerDev_Pro This is amazing! Thank you so much! 🎉

The ground detection was exactly what I was missing. Now my double jump works perfectly and doesn’t interfere with my dash mechanics!

GT

GameTutor_Alex

Replied 2 hours later

Great solution! Here are some additional tips for making your double jump even better:

  • Coyote Time: Allow jumping for a few frames after leaving the ground
  • Jump Buffering: Register jump input slightly before landing
  • Variable Jump Height: Shorter jumps when space is tapped vs held
  • Wall Jumping: Reset jumps when touching walls

These small details make platformers feel much more responsive! 🎮

VB

Vibelf_Community

Pinned Message • Moderator

🚀 Want to Master Advanced Platformer Mechanics?

Fantastic discussion everyone! For those looking to create even more sophisticated platformer systems, our community can help you implement:

  • 🏃 Advanced movement mechanics (wall jumping, sliding)
  • ⚡ Combo systems and special abilities
  • 🎯 Precise collision detection
  • 🌟 Smooth animation systems

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