Deterministic Rollback Netcode & Frame Resimulation Engine

Production-Ready Deterministic GGPO-Style Rollback Netcode Engine written entirely in native Python 3.10+ standard library with zero external dependencies. Engineered for real-time multiplayer games, fighting games, arcade battlers, deterministic RTS, and physics-driven simulations requiring instant responsiveness and zero perceived latency.

Key Architectural Modules

• Circular State & Input Ring Buffer: High-performance ring buffer storing continuous frame game states, quantised player inputs, and authoritative server confirmations.
• Frame Resimulation & Rollback: When an authoritative late packet arrives, rewinds the simulation state back N frames, injects confirmed inputs, and fast-forward resimulates back to current render frame in sub-millisecond execution.
• Input Prediction Matrix: Multiple prediction models including Repeat-Last-Input, Neutral/Zero-Input, and Markov Transition Probability predictors for seamless input smoothing under high jitter.
• Canonical Checksumming & Desync Verification: Instant CRC32 and cryptographic SHA-256 state hashing on every frame step with automated desync trigger detection and snapshot dumping.
• Synthetic Network Condition Simulator: Built-in headless network simulator injecting realistic ping latency (e.g. 150ms), packet jitter (+/- 25ms), packet drop/loss rates, and out-of-order packet delivery for bulletproof CI/CD stress testing.
• Comprehensive CLI Toolsuite: Headless match runner, 50,000+ frame steps/sec benchmark suite, telemetry inspection, and full JSON match replay export.

Technical Specifications & Quality Metrics

• 351 Automated Tests: 100% passing pytest test suite verifying buffers, predictor models, checksums, network chaos simulation, and multi-frame rollbacks.
• Extreme Performance: Over 50,000 headless frame steps per second in pure Python; easily ported or bound to C/C++/C# via C-interop.
• Multiplayer Session Manager: Peer management, client discovery, input distribution, and synchronized local simulation.
• Zero Runtime Dependencies: Uses only Python 3.10+ standard library modules.
• 100% Royalty-Free Commercial License: Free for use in commercial and indie game productions.