Engine-agnostic

Movement Systems

Movement is a core mechanic in most games. This guide explains how to implement movement in martini-kit, covering both framework-agnostic logic and framework-specific rendering.

Movement Types

Top-Down Movement

8-directional or analog movement from a bird’s-eye view.

Top-Down Movement → - Complete guide

Best for: RPGs, twin-stick shooters, strategy games

Platformer Movement

Side-scrolling movement with jumping and gravity.

Platformer Movement → - Complete guide

Best for: Platformers, side-scrollers, Metroidvanias

Advanced Movement

Advanced movement techniques and patterns.

Advanced Movement → - Complete guide

Best for: Complex movement systems, special mechanics

Key Concepts

Input Storage Pattern

Store player input in state, process in tick action:

interface GameState {
  players: Record<string, Player>;
  inputs: Record<string, PlayerInput>; // Separate input state
}

actions: {
  // Store input
  move: createInputAction('inputs'),
  
  // Process input every frame (host only)
  tick: createTickAction((state, delta) => {
    Object.entries(state.inputs).forEach(([playerId, input]) => {
      const player = state.players[playerId];
      // Apply movement based on input
    });
  })
}

Host-Authoritative Movement

Host: Processes input, updates positions, runs physics
Clients: Send input, receive position updates, interpolate

This prevents cheating and ensures consistency.

Interpolation

Clients should interpolate between received positions for smooth movement:

// Phaser example
update() {
  if (!this.adapter.isHost()) {
    this.adapter.updateInterpolation(); // Smooth movement
  }
}

Choosing a Movement System

Type	Complexity	Best For
Top-Down	Low	Action games, shooters
Platformer	Medium	Jump-based games
Grid-Based	Medium	Turn-based, puzzle games

Next Steps

Choose your movement type and follow both the core logic and framework-specific guides:

Read the Core Logic guide for your movement type
Read the Phaser Implementation guide (or implement in your engine)
Combine both for a complete movement system