Last Salvation

The core architectural challenge in Last Salvation was making blockchain interactions feel native to the game loop. Cryptographic signing and network round-trips to the Aptos consensus layer are inherently blocking operations. Running them on the Unreal Engine game thread would cause visible frame hitches every time a player activates an NFT ability or triggers a loot transaction.

The solution was the MP_Aptos plugin, which wraps all Aptos SDK calls inside UE5 async task graph workers. When a game event triggers a blockchain action (e.g., ability activation, loot drop, marketplace transaction), the game thread posts the request to a background worker and immediately continues the simulation. The worker handles the signing, REST call, and JSON parsing. Results are marshaled back to the game thread via multicast delegates, triggering the corresponding gameplay response (ability activation, item grant, etc.) on the next tick after consensus.

The GAS (Gameplay Ability System) layer owns all combat mechanics. Core abilities (attacks, dodges, skill trees) are purely local and never touch the blockchain. On-chain actions are a separate layer applied on top of GAS: they modify ability parameters or grant cosmetic effects after consensus confirms. This ensures competitive integrity, since the baseline game works identically whether a player is connected to the blockchain or not.

The project was built on the Lyra Framework rather than a custom GAS setup, which provided a production-grade multiplayer foundation (EOS integration, replication graphs, server-authoritative game state) without rebuilding it from scratch.