Godot 4 Player Movement State Machine

A robust, scalable Finite State Machine (FSM) implementation for 2D character movement in Godot 4.4.

This project demonstrates how to decouple complex character logic into isolated, manageable state scripts using the Blackboard Pattern and Hierarchical States, preventing the dreaded "spaghetti code" that usually comes with platformer or top-down controllers.

🌐 Live Demo

Play the web export right in your browser here: Vercel deploy

✨ Features

• Decoupled Logic: The Player acts as the blackboard (storing velocity, inputs, and physical memory), while independent State nodes handle the actual behavior.
• Hierarchical State Machine: States inherit from parent categories (e.g., StateJump and StateFall inherit from StateOffGround to share gravity math).
• State Stack / Memory: Allows the state machine to remember previous states and cleanly revert (perfect for hit-stun or pausing).
• Smooth Animations: Handles animation switching dynamically based on state entry and input direction without interrupting the game loop.
• Web-Ready: Configured for cross-origin isolation (SharedArrayBuffer) for easy deployment to Vercel or itch.io.

🏗️ Architecture / File Structure

The state machine is built on a clear inheritance tree to prevent code duplication:

• state_machine.gd - The manager that handles the active state and transitions.
• base_state.gd - The virtual base class all states inherit from.
  • Ground States:
    • state_idle.gd - Handles coming to a stop and resting.
    • move_state.gd - Parent class for horizontal movement.
      • state_walk.gd - Standard movement.
      • state_run.gd - Faster movement.
    • state_crouch.gd - Handles slowing down and shrinking the hitbox.
  • Airborne States (state_off_ground.gd): Handles gravity and air-strafing.
    • state_jump.gd - Upward momentum and variable jump heights.
    • state_fall.gd - Downward momentum and landing logic.

🎮 Controls (Default)

• Move: W/A/S/D
• Jump: Spacebar
• Crouch: Ctrl
• Run: Shift