Razor synchronizes the state of multiple game clients with a server over the internet.

Features include:

• A light-weight, low latency, immediate-mode API for clients and servers
• Compiles on Windows, Linux, and OSX
• Compatible with any type of data state from FPS games, to strategy, to realtime business applications
• Engine-agnostic design that can be integrated into small and large projects
• Syncable datatypes including Vector3, Matrix44, Quaternion, and Arrays
• Syncable datastructs that encapsulate groups of data
• Clock synchronization and latency estimation
• Automatic multipart packet assembly and disassembly
• An easy to use raw UDP Connection class with a few nice features

The main problem that is difficult to solve in network state synchronization is how to account for the race conditions induced by the latency inherent in sending packets over the internet.

The second and related problem is after you have received new information from a remote source that affects your local state, how to gracefully update your state to account for the new information.

Razor's objective is to automate the process of keeping remote states synchronized and helping to gracefully update the local state when new information arrives.

Additionally, Razor aims to make all this simple and free of byte manipulation for applications using the library.

Most netcode is integrated deep into a game engine because it is difficult to separate the intricate inner workings of netcode's state manipulation from the actual data state.

Razor applies the principle of "bring your own state manipulation" so Razor's netcode may be shared with many types of engines.

Razor assumes your application is capable of the following:

• Serializing a data state (helper data types are included in Razor)
• Deserializing a foreign data state and actualizing it into the current state (helpers included)
• Serialization and deserialization of commands

Additionally, you can increase the effectiveness of your application's synchronization with the following additional features:

• Ability to rewind and fast-forward through time
• Ability to record and authorize commands

Razor uses three separate channels of communication to orchestrate synchronization:

• Data States
• Commands
• Events

Data States are raw serializations of the server's state that are periodically shared with clients. Data States allow clients to absolutely synchronize with the server, except for the latency the state took to get to the client. Because Data States are relatively large and processor intensive, they are only shared occassionally and other more optimal approaches are used to make up the difference. Razor will request your data state, send it over the internet, and then request that your client load it, but it will be your responsibility to have a strategy for latency.

Commands are your application's notation for things that users do. Razor provides an automatic method of broadcasting them among the clients. Razor provides no guarantees on delivery of user commands, or whether the same command is received multiple times. It will be your responsibility to play them correctly in your application's logic, to ensure if there are lost packets that the commands are rebroadcast, and to ensure if a duplicate command is received it is caught.

Events are authoritative chronologically-recorded conclusions to application logic. Events have a distinct difference from commands, because they are only generated by the server. Razor guarantees delivery and exact synchronicity of events. It is your responsibility to create and respond to them. Events are useful if you would like to ensure your chronographically-fluid application has certain things not be replayed multiple times. A good example is a death animation.

Dependencies:

• C++20 compiler (g++-12 or higher)
• make
• pthread
• SDL2
• SDL2_net
• curl

Build the static library (librazor.a):

make

Build the test executable:

make test

Run the test executable:

./razortest

Razor is designed to be used as a static library. To link against it, add librazor.a into your project directory and add ./librazor.a to your linking step next to your object files. Ensure Razor's includes are in your project's includes directory.

API Documentation for razor is pending.