Crate ggrs

GGRS

GGRS (good game rollback system) is a reimagination of the GGPO network SDK written in 100% safe Rust 🦀. The callback-style API from the original library has been replaced with a much saner, simpler control flow. Instead of registering callback functions, GGRS returns a list of requests for the user to fulfill.

Structs

GameStateAccessor

A read-only accessor for the T that the user previously saved into a GameStateCell.

GameStateCell

An Arc<Mutex> that you can save()/load() a T to/from. These will be handed to the user as part of a GgrsRequest.

Message

A messages that NonBlockingSocket sends and receives. When implementing NonBlockingSocket, you should deserialize received messages into this Message type and pass them.

NetworkStats

The NetworkStats struct contains statistics about the current session.

P2PSession

A P2PSession provides all functionality to connect to remote clients in a peer-to-peer fashion, exchange inputs and handle the gamestate by saving, loading and advancing.

SessionBuilder

The SessionBuilder builds all GGRS Sessions. After setting all appropriate values, use SessionBuilder::start_yxz_session(...) to consume the builder and create a Session of desired type.

SpectatorSession

SpectatorSession provides all functionality to connect to a remote host in a peer-to-peer fashion. The host will broadcast all confirmed inputs to this session. This session can be used to spectate a session without contributing to the game input.

SyncTestSession

During a SyncTestSession, GGRS will simulate a rollback every frame and resimulate the last n states, where n is the given check distance. The resimulated checksums will be compared with the original checksums and report if there was a mismatch.

UdpNonBlockingSocket

A simple non-blocking UDP socket tu use with GGRS Sessions. Listens to 0.0.0.0 on a given port.

Enums

DesyncDetection

Desync detection by comparing checksums between peers.

GgrsError

This enum contains all error messages this library can return. Most API functions will generally return a Result<(), GgrsError>.

GgrsEvent

Notifications that you can receive from the session. Handling them is up to the user.

GgrsRequest

Requests that you can receive from the session. Handling them is mandatory.

InputStatus

InputStatus will always be given together with player inputs when requested to advance the frame.

PlayerType

Defines the three types of players that GGRS considers:

SessionState

A session is always in one of these states. You can query the current state of a session via current_state.

Constants

NULL_FRAME

Internally, -1 represents no frame / invalid frame.

Traits

Config

Compile time parameterization for sessions.

NonBlockingSocket

This NonBlockingSocket trait is used when you want to use GGRS with your own socket. However you wish to send and receive messages, it should be implemented through these two methods. Messages should be sent in an UDP-like fashion, unordered and unreliable. GGRS has an internal protocol on top of this to make sure all important information is sent and received.

Type Aliases

Frame

A frame is a single step of execution.

PlayerHandle

Each player is identified by a player handle.