Extending the Game

What you can safely add today, and what requires an approval or design decision first.

Safe to Add Today

• New block types — see Adding a Block Type.
• New hand-authored .vwr worlds — see Authoring a New .vwr World.
• Bug fixes to GalaxyEggbertSimple3D and faithful-remake gameplay parity work on it — explicitly allowed by the direction lock.

Requires a Design Decision First

• Billboard/object rendering — blocked on Easy3D::BillboardBatch getting a vertex builder + CNA renderer adapter (E3D-MIG-061/062), and on the open "billboard vs. textured cube" rendering-mode question for objects (see Gameplay and mobile-eggbert-reference/09-open-questions.md).
• Save format — whether to reuse mobile-eggbert's exact byte layout is an open question, not a default.
• Chunk-radius streaming — scheduled (E3D-MIG-057) but not yet implemented.

Requires Explicit User Approval

• Modifying ../mobile-eggbert, ../simple-3d, or ../easy-3d.
• Copying mobile-eggbert code or data (Tables.cpp arrays, Decor.cpp logic, GameData.cpp byte layout) into galaxy-eggbert, even as "just data."
• Adding new engine-layer investment to GalaxyEggbertSimple3D beyond bug fixes/parity work.
• Adding MeshCraft, Mesh World, Nova3D, further Simple3D features, or Lua to the active (CNA) path.

Never Do

• Invent gameplay mechanics that don't exist in mobile-eggbert (coins, time bonuses, coyote time, wall/double jump, combo multipliers, etc.) — see the Faithful-Remake rule in Gameplay.
• Add #ifdef engine guards to work around a backend gap — fix the backend instead.
• Mutate src/GalaxyEggbertSimple3D/ into the CNA implementation — new CNA code goes in src/GalaxyEggbertCNA/.