# 🏀 SportsBallEngine

A high-performance, cross-platform 3D game engine written in Swift 6, designed for professional sports games across multiple disciplines. Built with strict platform abstraction and protocol-oriented design.

## 🎯 Design Philosophy

### Clean Architecture

This engine follows industry-standard architectural principles:

1. **Strict Code Separation**
   - **Platform-Agnostic Core**: Pure Swift modules with NO platform-specific imports
   - **Platform Abstraction Layers (PAL)**: Thin, platform-specific modules that interact with OS APIs

2. **Protocol-Oriented Design**
   - All platform-dependent systems use Swift protocols
   - EngineCore depends only on protocols, never concrete implementations
   - Platform layers are dependency-injected at startup

3. **Explicit Rendering APIs**
   - Vulkan (primary cross-platform)
   - DirectX 12 (Windows optimization)
   - Metal (future macOS support)

## 🏗️ Architecture

```
┌─────────────────────────────────────────────────────────┐
│                      main.swift                         │
│           (Platform Detection & Injection)              │
└────────────┬────────────────────────────────────────────┘
             │
             ├──────────────┬──────────────┬──────────────┐
             │              │              │              │
             ▼              ▼              ▼              ▼
     ┌──────────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐
     │ EngineCore   │ │ Renderer │ │  Window  │ │  Input   │
     │ (Protocol-   │ │ Protocol │ │ Protocol │ │ Protocol │
     │  Agnostic)   │ └──────────┘ └──────────┘ └──────────┘
     └───┬──────────┘      │             │             │
         │                 │             │             │
         ├─────────┬───────┘             │             │
         │         │                     │             │
         ▼         ▼                     ▼             ▼
   ┌─────────┐ ┌─────────┐      ┌─────────────┐ ┌─────────────┐
   │ Physics │ │  Asset  │      │ Linux/Win32 │ │ Linux/Win32 │
   │ Engine  │ │ Loader  │      │   Window    │ │    Input    │
   └─────────┘ └─────────┘      └─────────────┘ └─────────────┘
                                          │
                                          ▼
                                 ┌─────────────────┐
                                 │ Vulkan / DX12   │
                                 │    Renderer     │
                                 └─────────────────┘
```

## 📦 Module Structure

### Platform-Agnostic Core Modules

#### **EngineCore**
- Main game loop (Carmack-style fixed timestep)
- Scene management
- System coordination
- **NO platform imports allowed**

#### **RendererAPI**
- Protocol definitions for rendering
- Camera, Scene, Entity types
- Vertex, Mesh, Material handles
- **NO platform imports allowed**

#### **PhysicsEngine**
- Sports-optimized physics simulation
- Ball/puck physics with spin and drag
- Player collision detection
- Impulse-based collision resolution
- **NO platform imports allowed**

#### **AssetLoader**
- 3D model loading (FBX, GLTF, OBJ)
- Texture loading (DDS, PNG, JPG)
- Skeletal animation data
- Animation blending system
- **NO platform imports allowed**

### Platform-Specific Modules

#### **PlatformLinux**
- GLFW/SDL windowing (X11/Wayland)
- Linux input handling
- ALSA/PulseAudio audio

#### **PlatformWin32**
- Win32 API windowing
- Raw Input / XInput
- WASAPI/XAudio2 audio

#### **VulkanRenderer**
- Vulkan 1.3 rendering backend
- Cross-platform (Linux + Windows)
- Explicit GPU resource management

#### **DX12Renderer**
- DirectX 12 rendering backend
- Windows-optimized path
- Low-level GPU control

## 🎮 Sports Game Optimizations

This engine is specifically designed for professional sports games across multiple disciplines:

### Character Rendering
- High-fidelity player models with PBR materials
- Skeletal animation with smooth blending
- State machine-driven movement (running, shooting, tackling)
- Facial animation support

### Physics
- Fast ball/puck simulation with spin
- Player-to-player collision detection
- Ball-to-player interaction physics
- Field boundaries and out-of-bounds detection

### Rendering
- Large stadium/arena rendering with LOD
- Crowd rendering and animation
- Dynamic lighting for different times of day
- Particle effects (grass, dust, sweat)

### Performance
- Fixed timestep physics (60 Hz)
- Multithreaded asset streaming
- GPU-driven rendering
- Spatial culling and occlusion

## 🚀 Building & Running

### Prerequisites

- **Swift 6.0+**
- **Platform-specific dependencies:**
  - Linux: Vulkan SDK, GLFW/SDL
  - Windows: DirectX 12 SDK, GLFW/SDL or Win32 API

### Build Commands

```bash
# Build the engine
swift build

# Build release version
swift build -c release

# Run the engine
swift run

# Run with options
swift run SportsBallEngine -- --renderer vulkan --width 2560 --height 1440
```

### Command-Line Options

```
Usage: SportsBallEngine [OPTIONS]

Options:
  --renderer, -r <api>     Renderer API (vulkan, dx12) [Windows only]
  --title, -t <title>      Window title
  --width, -w <pixels>     Window width (default: 1920)
  --height, -h <pixels>    Window height (default: 1080)
  --help                   Show this help message

Examples:
  SportsBallEngine --renderer vulkan --width 2560 --height 1440
  SportsBallEngine --title "My Sports Game"
```

## 🔧 Development

### Adding New Platform Support

1. Create new module: `Sources/Platform{Name}/`
2. Implement protocols: `WindowManager`, `InputHandler`, `AudioEngine`
3. Add to `PlatformFactory` in `main.swift`
4. Update `Package.swift` dependencies

### Adding New Renderer

1. Create new module: `Sources/{API}Renderer/`
2. Implement `Renderer` protocol from `RendererAPI`
3. Add to `PlatformFactory.createRenderer()`
4. Update `Package.swift` dependencies

### Project Structure

```
SportsBallEngine_1/
├── Package.swift              # Swift Package Manager manifest
├── README.md                  # This file
├── Sources/
│   ├── SportsBallEngine/     # Main entry point
│   │   └── main.swift
│   ├── EngineCore/           # Platform-agnostic core
│   │   └── Engine.swift
│   ├── RendererAPI/          # Protocol definitions
│   │   ├── RendererProtocol.swift
│   │   ├── InputProtocol.swift
│   │   ├── WindowProtocol.swift
│   │   └── AudioProtocol.swift
│   ├── PhysicsEngine/        # Physics simulation
│   │   └── PhysicsWorld.swift
│   ├── AssetLoader/          # Asset management
│   │   └── AssetManager.swift
│   ├── VulkanRenderer/       # Vulkan backend
│   │   └── VulkanRenderer.swift
│   ├── DX12Renderer/         # DirectX 12 backend
│   │   └── DX12Renderer.swift
│   ├── PlatformLinux/        # Linux platform layer
│   │   └── LinuxPlatform.swift
│   └── PlatformWin32/        # Windows platform layer
│       └── Win32Platform.swift
└── Tests/
    └── EngineCoreTests/
```

## 🎯 Sports Game Features (Roadmap)

### Phase 1: Core Engine ✅
- [x] Platform abstraction layer
- [x] Renderer protocols (Vulkan, DX12)
- [x] Physics engine
- [x] Asset loading system
- [x] Main game loop

### Phase 2: Sports-Specific Features
- [ ] Skeletal animation system
- [ ] Animation blending
- [ ] State machines for player AI
- [ ] Ball physics with spin
- [ ] Stadium rendering
- [ ] Crowd simulation

### Phase 3: Advanced Features
- [ ] Networking (multiplayer)
- [ ] Replay system
- [ ] Statistics tracking
- [ ] Dynamic weather
- [ ] Commentary system

## 📝 License

Copyright (c) 2025. All rights reserved.

## 🙏 Acknowledgments

- **Swift Community** - For excellent cross-platform support
- **Open Source Contributors** - For graphics API bindings and tooling

---

**Note**: This is a foundational structure. Renderer implementations are currently stubs that demonstrate the architecture. Production use would require:
- Actual Vulkan/DirectX 12 C bindings
- Complete shader pipeline
- Full asset format parsers
- Advanced physics optimizations
- Networking layer

The architecture is production-ready; the implementations are educational scaffolding.