Delta - Game State Synchronization

Efficient delta compression for multiplayer games in Go. Only transmit what changed, not the entire state.

Installation

go get github.com/cbodonnell/delta
go install github.com/cbodonnell/delta/cmd/deltagen@latest

Quick Start

1. Define Your Game State

// delta:entity
type GameState struct {
    ID         int64   // Required
    PlayerX    float64
    PlayerY    float64
    Score      int32
    PlayerName string
    Inventory  []string
}

2. Generate Delta Code

deltagen -input .

3. Use Deltas

// Create states
state1 := &GameState{ID: 1, PlayerX: 10, Score: 100}
state2 := state1.Clone().(*GameState)
state2.PlayerX = 15  // Player moved
state2.Score = 120   // Score changed

// Create and serialize delta
delta := state1.Delta(state2)
var buf bytes.Buffer
delta.Serialize(&buf)

// Apply delta elsewhere
newDelta := &GameStateDelta{}
newDelta.Deserialize(&buf)
state1.ApplyDelta(newDelta)  // state1 now equals state2

Supported Types

• Primitives: bool, int8-int64, uint8-uint64, float32, float64, and string
• Collections: []T, map[K]V, and []byte, where K and V are supported primitive types

Network Usage

// Server: send only changes
delta := client.lastState.Delta(newState)
sendToClient(delta)
client.lastState = newState.Clone()

// Client: apply changes
delta := receiveDelta()
gameState.ApplyDelta(delta)

Requirements

• Structs must have // delta:entity comment
• Must include ID int64 field
• Only exported fields are processed