A multiplayer twin-stick shooter tech demo implementing Server-Authoritative logic with Client-Side Prediction and Reconciliation (Rollback) using Unity Netcode for Game Objects (NGO).
Above: Client performing instant movement inputs despite 200ms simulated network latency.
Above: Client snapping back to server expected position.
This project demonstrates the implementation of networking concepts to ensure responsive gameplay in a high-latency environment.
- Input Packing: Inputs (Movement, Mouse Pos, Bitmasked Buttons) are packed into structs and sent to the server every tick.
- Circular Buffers: The client maintains an Input Buffer and State Buffer.
- Prediction: The client simulates physics locally immediately upon input.
- Reconciliation: When the server sends a position/velocity/state payload the client compares it to the history buffer. If the error exceeds the client resets to the server state and re-simulates all subsequent inputs to the present frame.
Abilities are modular ScriptableObjects (AbilityBase), decoupled from the network transport layer.
- State Management: The system handles complex state transitions (Normal -> Casting -> Dashing -> Blocking) using a finite state machine logic within
PlayerAbilitySystem. - Rollback Compatibility: Visuals (
TransientVisual) and cooldowns support rollback. If a client mispredicts an ability cast, the visual and state are corrected during reconciliation.
Engine: Unity 6 Networking: Unity Netcode for Game Objects (NGO) Physics: Unity 2D Physics Language: C#