Snapshot System

The snapshot system is a core component of the Rummage game engine that provides serialization and deserialization of game state. This system is essential for networking, replay functionality, and save/load capabilities.

Overview

The snapshot system enables:

• Networked Multiplayer: Synchronizing game state between players
• Replay System: Recording and replaying games
• Undo Functionality: Allowing players to revert to previous game states
• Save/Load: Persisting game state between sessions
• Crash Recovery: Automatically recovering from application crashes

Documentation Sections

This documentation covers the following aspects of the snapshot system:

• Overview: Detailed introduction to the snapshot concept and architecture
• Implementation: Technical details of the snapshot implementation
• Integration with Networking: How snapshots are used in the multiplayer system
• Persistent Storage: Using bevy_persistent for robust state persistence
• Testing: Approaches to testing snapshot functionality
• API Reference: Complete reference of snapshot-related types and functions

Technical Architecture

The snapshot system uses a component-based approach to serialize and deserialize entities in the game world. It captures the state of all relevant entities and components at a specific point in time, allowing the game state to be reconstructed later.

Key Features

• Selective Serialization: Only relevant components are included in snapshots
• Efficient Storage: Compact binary representation of game state
• Event-Based Triggering: Snapshots can be triggered by game events
• Queue Management: Processing of snapshots is managed to avoid performance impact
• Integration Points: Well-defined interfaces for networking and replay systems
• Persistent Storage: Robust save/load functionality with automatic recovery

Usage in Rummage

The snapshot system is used throughout Rummage:

1. Networking: Synchronizing game state between clients
2. Game History: Recording turn-by-turn snapshots for replay and analysis
3. Testing: Verifying game state correctness in unit and integration tests
4. Save/Load: Allowing games to be saved and resumed later
5. Crash Recovery: Automatically restoring state after unexpected crashes
6. Rollback: Supporting undo functionality for players

bevy_persistent Integration

The snapshot system leverages the bevy_persistent crate to provide robust save/load functionality:

• Automatic Persistence: Game state is automatically saved at key moments
• Error Recovery: Comprehensive error handling for corrupted saves
• Efficient Format: Optimized binary serialization for large game states
• Incremental Saves: Only changed data is saved to improve performance
• Cross-Platform: Works consistently across all supported platforms

See the detailed documentation sections for more information on each aspect of the snapshot system.