BestoNet is a custom rollback networking solution developed for the fighting game Idol Showdown. Built in C# for Unity, it integrates with Facepunch Steamworks to provide a robust and efficient rollback implementation.

This is a work in progress as a library, and won't work right out the box

📚 Documentation

• Contributing Guide
• Code of Conduct
• Development Roadmap

Background

Originally we used Unity GGPO but there were some issues.

• Unplayable connections at long distances (experiencing ~7 frames of rollback)
• Maintenance difficulties due to GGPO's C++ codebase
• System instability during poor network conditions
• Using GGPO required a relay system that added extra latency to online matches

Core Features

Rollback Management

• Speculative Frame Saving: Saves CPU time and preventing 7 frame rollbacks
  • Currently saves the midpoint frame, confirm frame, and end frame
• Input Prediction: Will predict the next input using the previously received input
• Rift Management: Many different options to deal with one sided rollback and game syncing
• Reliable Input Messaging: Maintains a 7-frame input buffer to handle packet loss and out-of-order delivery

Implementation Requirements

1. Frame Timing: Idol Showdown currently uses a separate thread as a timer.
2. Spectator: The current implementation contains a call to send confirmed frame inputs to a spectator buffer
3. State management system: Deterministic game logic is required. For efficiency reasons, we recommend avoiding using byte[] with BinaryWriter/Reader

Configuration

Current Unity Configuration Settings

Note: The MaxRollbackFrames setting currently shows 4 frames but effectively provides ~8 frames of rollback in Idol Showdown. This discrepancy is known but functional.

Credits

This implementation draws inspiration from:

• MK/Injustice GDC presentation
• Zinac's rollback implementation guide
• GekkoNet's Rollback System

Special thanks to Rin Iota for developing the original networking foundation that enabled ISD Rollback's creation.

Contributing

This is an open-source project accepting community contributions. Please read our Contributing Guide and Code of Conduct before submitting pull requests.

License

This project is licensed under the MIT License - see the LICENSE file for details.