unity-migration

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Migrate a browser-based JavaScript/Canvas game to Unity (C#). Use for Shelter 2250 (or similar) when you need: (1) Unity project setup decisions (2D/URP/input/UI), (2) mapping existing JS classes/systems to Unity architecture, (3) porting core simulation loops (time/resources/rooms/dwellers/save), and (4) planning incremental milestones with parity checks.

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[Architecture Design]

When & Why to Use This Skill

This Claude skill streamlines the complex process of migrating browser-based JavaScript/Canvas games to the Unity (C#) engine. It provides a structured architectural framework for mapping legacy JS systems to Unity's component-based logic, ensuring a low-risk transition through phased milestones, simulation-first porting, and rigorous feature parity checks.

Use Cases

  • Case 1: Porting a web-based management simulation (like Shelter 2250) to Unity to support cross-platform releases on PC, Mobile, and WebGL.
  • Case 2: Re-architecting legacy JavaScript game logic into a modular Unity system using ScriptableObjects for data definitions and URP for modern 2D rendering.
  • Case 3: Implementing a synchronized game loop and save/load system in C# that maintains exact logic parity with an existing JavaScript codebase.
  • Case 4: Planning a multi-stage technical roadmap for game studios to transition legacy web titles to a professional game engine without breaking core mechanics.
nameunity-migration
descriptionMigrate a browser-based JavaScript/Canvas game to Unity (C#). Use for Shelter 2250 (or similar) when you need: (1) Unity project setup decisions (2D/URP/input/UI), (2) mapping existing JS classes/systems to Unity architecture, (3) porting core simulation loops (time/resources/rooms/dwellers/save), and (4) planning incremental milestones with parity checks.

Unity Migration (Shelter 2250)

0) Inputs to confirm (ask if missing)

  • Target Unity version (recommend latest LTS)
  • Render/UI approach: UGUI (Canvas) vs UI Toolkit (or hybrid)
  • 2D pipeline: built-in 2D vs URP 2D
  • Target platforms: WebGL/PC/Mobile
  • Parity target: “feature parity first” vs “re-architecture first”

1) Migration strategy (keep risk low)

  1. Create a new Unity project and commit it early.
  2. Port data + simulation first (no fancy visuals): resources, time, room placement rules, dwellers, save/load.
  3. Add a minimal debug UI (text HUD + simple buttons).
  4. Only then port visuals (room rendering, animations, VFX).
  5. Keep a running parity checklist (JS build vs Unity build).

2) Mapping guide (read only if needed)

  • For a concrete mapping of the current JS codebase to Unity scripts/components, read references/js-to-unity-map.md.
  • Scene: Boot (init, load/save), Game (world), UI (HUD/menus) or single Game scene + additive UI.
  • Game loop:
    • Render: per-frame (Update)
    • Simulation tick: fixed step (e.g., 1 sec real-time) using a GameTickService
    • “Game time” scale: multiplier (1/2/6x) applied consistently to tick + clock
  • Data:
    • Room types / costs: ScriptableObject (RoomTypeDefinition)
    • Traits: ScriptableObject (TraitDefinition)
    • Country bonuses: ScriptableObject (CountryDefinition)
  • State:
    • GameState plain C# object (serializable)
    • SaveService writes JSON to disk (PC) and PlayerPrefs/WebGL fallback

4) Incremental milestones (suggested)

  1. “Simulation only”: tick + resources + rooms + dwellers + save/load (no graphics)
  2. “Build mode”: placement preview + validation + costs + upgrade
  3. “UI parity”: resource bars + dwellers panel + room modal
  4. “Visual parity”: 2D cutaway rendering, lighting, animations
  5. “Content”: events, exploration, country-specific flavor

5) Parity checks (fast)

  • Room placement rule tests: given grid + rooms, validate allowed positions
  • Tick consistency: at 1x/2x/6x, 60 seconds real-time should advance:
    • 1x: 1 in-game hour
    • 2x: 2 in-game hours
    • 6x: 6 in-game hours
  • Save/load: load legacy saves (if required) and new saves