Shorthair is a portable C++ library uses the Longhair library to provide low-latency loss-recovery, which uses extra bandwidth to make almost any unreliable packet channel suitable for real-time communication.
Erasure codes in software are fast with low-overhead.
Advantages of using erasure codes in online games:
-
50% faster delivery over UDP than over TCP
-
50% less bandwidth used than naive redundancy
-
50% better recovery rate than parity redundancy
Improves the experience for multiplayer mobile apps.
Please take a look at my presentation on Erasure codes for more motivation: Erasure Codes in Software
The shorthair-mobile directory contains an easy-to-import set of C code that also builds properly for mobile devices and Windows-based computers.
This library is only available in C++ code, which you can wrap for your favorite language.
Your C++ code should have a class instance that derives from IShorthair and implements its interface:
// Called with the latest data packet from remote host
virtual void OnPacket(u8 *packet, int bytes);
// Called with the latest OOB packet from remote host
virtual void OnOOB(u8 *packet, int bytes);
// Send raw data to remote host over UDP socket
virtual void SendData(u8 *buffer, int bytes);
It is safe to call Send and SendOOB from any thread.
The same thread that calls Recv should also be calling Tick.
- Uses fastest, smallest Reed-Solomon codec available (Longhair).
- Full-duplex communication over a lossy channel.
- Adds a dial to control packet loss to any acceptable rate for applications over UDP.
- Calculates and generates precisely the amount of redundancy required to achieve the target loss rate.
- It supports variable-length data packets.
- Overhead is 5 bytes/packet.
- Does not require multiple threads.
- Library has a clean platform-independent interface with minimal configuration required.
This software was written entirely by myself ( Christopher A. Taylor [email protected] ). If you find it useful and would like to buy me a coffee, consider tipping.