[Design Pattern] Facade Pattern

One-line pattern summary

A pattern that wraps a complex subsystem with a simple top-level API to improve usability.

Typical Unity use cases

• When hiding a game boot sequence behind one method.
• When internal module details should be hidden from the outside.

Parts (roles)

• Facade
• Subsystem
• Client

Unity example (C#)

The code below is a simplified Unity example based on the scenario described above.

public sealed class GameStartupFacade
{
    private readonly SaveSystem saveSystem = new();
    private readonly AudioSystem audioSystem = new();
    private readonly UiSystem uiSystem = new();

    public void StartGame()
    {
        saveSystem.Load();
        audioSystem.Initialize();
        uiSystem.OpenLobby();
    }
}

Advantages

• It clarifies module boundaries and reduces coupling.
• Features can be extended or integrated without modifying existing code.

Things to watch out for

• If wrapper layers become too deep, debugging gets harder.
• Interfaces should stay small so responsibility boundaries do not blur.

Interaction diagram

This shows the flow where complex subsystem calls are simplified into a single entry point.

flowchart LR

  client["Game Bootstrap"]
  facade["StartGameFacade"]
  assets["AssetLoader"]
  save["SaveSystem"]
  network["NetworkClient"]
  result["Ready To Play"]

  client -- "StartGame()" --> facade
  facade -->|load| assets
  facade -->|restore| save
  facade -->|connect| network
  assets --> result
  save --> result
  network --> result