Game Engine

This section covers the core game engine that powers Rummage, the Magic: The Gathering Commander format implementation built with Bevy 0.15.x.

Architecture Overview

The Rummage game engine is built on Bevy's Entity Component System (ECS) architecture, providing a robust foundation for implementing the complex rules and interactions of Magic: The Gathering. The engine is designed with the following principles:

• Separation of Concerns: Game logic is separated from rendering and input handling
• Data-Oriented Design: Game state is represented as components on entities
• Event-Driven Architecture: Systems communicate through events
• Deterministic Execution: Game logic runs deterministically for network play
• Extensible Systems: New cards and mechanics can be added without modifying core systems

Core Components

The game engine consists of several interconnected systems:

• State Management: How game state is tracked and updated
  • Entity and component management
  • Game state progression
  • Player state handling
• Event System: How game events are processed and handled
  • Event dispatching
  • Event handling
  • Custom event types
• Snapshot System: How game state is serialized for networking and replays
  • State serialization
  • Deterministic snapshots
  • Replay functionality

Integration Points

The game engine integrates with several other systems:

• Card Systems: Card representation and effects
• MTG Rules: Implementation of game rules
• UI Systems: Visual representation and interaction
• Networking: Multiplayer functionality

Plugin Structure

The game engine is organized as a set of Bevy plugins that can be added to your Bevy application:

#![allow(unused)]
fn main() {
// Initialize the game engine
App::new()
    .add_plugins(DefaultPlugins)
    .add_plugins(RummageGameEnginePlugin)
    .run();
}

Implementation Status

The game engine currently implements:

• ✅ Core turn structure
• ✅ Basic card mechanics
• ✅ Zone management
• 🔄 Stack implementation
• 🔄 Combat system
• ⚠️ Comprehensive rules coverage
• ⚠️ Advanced card interactions

Extending the Engine

For information on extending the game engine with new cards or mechanics, see the Development Guide.