• Programming Language: C# 10.0+
• Framework: .NET 9.0
• Graphics & I/O: OpenTK 4.x
• Testing Framework: xUnit 2.x
• Build System: .NET CLI / MSBuild

• Dependency Injection: Microsoft.Extensions.DependencyInjection
• Serialization: System.Text.Json
• Logging: Microsoft.Extensions.Logging
• Configuration: Microsoft.Extensions.Configuration

• Pattern: Model-View-ViewModel (MVVM) with Command pattern
• Structure: Modular, component-based design with clear separation of concerns
• Threading Model: Main thread for rendering, separate thread for simulation

• Simulation Core: Handles the logic and state of the redstone circuit
• Rendering Engine: Manages visualization using OpenTK
• Input Handler: Processes user input from keyboard/mouse
• UI Layer: Manages user interface elements and interactions
• Persistence Layer: Handles saving/loading circuits

• Class: GridSystem
• Responsibilities:
  • Maintain the 2D grid structure
  • Track component placement
  • Handle coordinate transformations
  • Support grid resizing operations
• Key Methods:
  • PlaceComponent(Component component, Vector2i position)
  • RemoveComponent(Vector2i position)
  • GetComponentAt(Vector2i position)
  • ResizeGrid(int width, int height)

• Base Class: RedstoneComponent (abstract)
• Derived Classes:
  • RedstoneWire
  • RedstoneButton
  • RedstoneSwitch
  • RedstoneTorch
  • RedstoneRepeater
  • RedstoneTransistor
• Interface: IPowerable
  • int PowerLevel { get; set; }
  • void UpdatePowerState()
  • bool CanReceivePowerFrom(Direction direction)
  • bool CanProvidePowerTo(Direction direction)

• Class: SignalPropagator
• Responsibilities:
  • Calculate signal paths
  • Manage signal strength decay
  • Handle update order
  • Process component interactions
• Key Methods:
  • PropagateSignals()
  • CalculateUpdateOrder()
  • UpdateComponentState(RedstoneComponent component)

• Class: SimulationController
• Responsibilities:
  • Manage simulation tick rate
  • Control simulation state (running, paused, step)
  • Handle timing and synchronization
• Key Methods:
  • Start()
  • Pause()
  • Step()
  • SetSpeed(float ticksPerSecond)

• Class: RedstoneRenderer
• Responsibilities:
  • Render grid and components
  • Handle camera transformations
  • Manage visual effects
• Key Methods:
  • Initialize()
  • Render(float deltaTime)
  • UpdateViewport(int width, int height)

• Class: AssetManager
• Responsibilities:
  • Load and manage textures
  • Handle component visual states
  • Provide sprite batching
• Key Methods:
  • LoadTextures()
  • GetComponentTexture(ComponentType type, PowerState state)
  • UnloadAssets()

• Class: CameraController
• Responsibilities:
  • Handle pan and zoom operations
  • Convert between screen and world coordinates
  • Manage view boundaries
• Key Methods:
  • Pan(Vector2 delta)
  • Zoom(float factor, Vector2 focusPoint)
  • ScreenToWorld(Vector2 screenPos)
  • WorldToScreen(Vector2 worldPos)

• Class: InputManager
• Responsibilities:
  • Process keyboard and mouse input
  • Map inputs to actions
  • Handle input modes (build, select, etc.)
• Key Methods:
  • ProcessInput()
  • RegisterAction(InputType input, Action action)
  • SetInputMode(InputMode mode)

• Class: ToolManager
• Responsibilities:
  • Manage available tools (place, select, delete)
  • Handle tool-specific input processing
  • Coordinate tool state changes
• Key Methods:
  • SelectTool(ToolType tool)
  • ProcessToolInput(InputEvent input)
  • CompleteToolAction()

• Class: UIManager
• Responsibilities:
  • Manage UI elements
  • Handle UI events
  • Coordinate UI updates
• Key Methods:
  • Initialize()
  • ProcessUIEvents()
  • UpdateUI()

• Class: ComponentPalette
• Responsibilities:
  • Display available components
  • Handle component selection
  • Provide component information
• Key Methods:
  • SelectComponent(ComponentType type)
  • GetSelectedComponent()
  • UpdatePaletteVisibility(bool visible)

• Class: AnalysisToolsPanel
• Responsibilities:
  • Display signal tracing
  • Show timing diagrams
  • Present power statistics
• Key Methods:
  • ShowSignalTrace(List<Vector2i> path)
  • UpdateTimingDiagram(Dictionary<Vector2i, List<PowerState>> states)
  • DisplayPowerStatistics(PowerStatistics stats)

• Class: CircuitPersistence
• Responsibilities:
  • Serialize/deserialize circuit state
  • Manage file operations
  • Handle version compatibility
• Key Methods:
  • SaveCircuit(string filename)
  • LoadCircuit(string filename)
  • ExportAsImage(string filename)

• Class: CircuitData
• Responsibilities:
  • Define serializable circuit structure
  • Track component metadata
  • Store grid configuration
• Properties:
  • Dictionary<Vector2i, ComponentData> Components
  • GridProperties GridConfig
  • SimulationProperties SimConfig

• Target Frame Rate: 60+ FPS on standard hardware
• Optimization Techniques:
  • Sprite batching
  • Frustum culling
  • Level-of-detail rendering
  • Hardware acceleration

• Target Update Rate: 20+ ticks per second with 1000+ components
• Optimization Techniques:
  • Spatial partitioning
  • Dirty region tracking
  • Lazy evaluation of inactive circuits
  • Parallelized signal calculation where possible

• Maximum Memory Usage: <1GB for standard circuits
• Techniques:
  • Object pooling for frequently created/destroyed components
  • Texture atlasing
  • Efficient grid representation

• Framework: xUnit 2.x
• Coverage Target: 80%+ for core simulation logic
• Key Test Areas:
  • Component behavior
  • Signal propagation
  • Grid operations
  • Serialization/deserialization

• Approach: Component interaction tests
• Key Test Areas:
  • Multi-component circuits
  • Signal timing across components
  • Save/load integrity

• Tools: Custom benchmarking harness
• Metrics:
  • FPS under various load conditions
  • Simulation ticks per second
  • Memory consumption
  • Load/save times

• Approach: Automated UI tests + manual verification
• Key Test Areas:
  • Component placement
  • Tool functionality
  • Camera controls

• Develop basic component classes
• Create signal propagation system
• Build simulation tick controller
• Implement unit tests for core simulation logic

• Set up OpenTK rendering pipeline
• Implement camera system
• Create component visualization
• Develop input handling system
• Build basic tool functionality
• Add grid navigation controls

• Implement all basic components (wire, torch, button, etc.)
• Add transistor component with configurable logic
• Create component interaction rules
• Implement power level visualization
• Add component-specific unit tests

• Build component palette interface
• Implement selection and editing tools
• Create circuit analysis views
• Add simulation control panel
• Develop debug visualization options

• Implement circuit serialization
• Create save/load functionality
• Add circuit export capabilities
• Implement circuit sharing features
• Build file format validation

• Performance optimization
• Bug fixing
• UI refinement
• Documentation
• Final testing

• Rendering Approach: 2D sprite-based rendering using OpenTK's GL API
• Shader Implementation:
  • Basic vertex/fragment shaders for grid and components
  • Special effects shaders for signal visualization
• Window Management:
  • GameWindow subclass for main application window
  • Event-driven rendering loop
  • Vsync support

• Mouse Input:
  • Use OpenTK's MouseMove, MouseDown, MouseUp events
  • Implement click, drag, and scroll handling
• Keyboard Input:
  • Use OpenTK's keyboard events for shortcuts and controls
  • Support for customizable key bindings

• Storage: Sparse dictionary-based grid (Dictionary<Vector2i, RedstoneComponent>)
• Spatial Partitioning: Quad-tree for efficient spatial queries
• Chunk System: Optional chunking system for large circuits

RedstoneComponent (abstract)
├── WireComponent
├── SourceComponent (abstract)
│   ├── ButtonComponent
│   ├── SwitchComponent
│   └── TorchComponent
├── LogicComponent (abstract)
│   ├── RepeaterComponent
│   └── TransistorComponent
└── SpecialComponent (abstract)
    └── ... (future components)

• Update Queue: Priority queue for component updates
• Dependency Graph: Directed graph for tracking signal dependencies
• Propagation Algorithm:
  1. Identify changed power sources
  2. Build update graph
  3. Topologically sort components
  4. Process updates in order

• Format: Custom JSON-based format
• Structure:

  {
    "version": "1.0",
    "metadata": {
      "name": "Example Circuit",
      "author": "User",
      "created": "2023-11-01T12:00:00Z"
    },
    "grid": {
      "width": 100,
      "height": 100
    },
    "components": [
      {
        "type": "wire",
        "position": { "x": 10, "y": 15 },
        "properties": { }
      },
      {
        "type": "repeater",
        "position": { "x": 11, "y": 15 },
        "rotation": 1,
        "properties": {
          "delay": 2,
          "locked": false
        }
      }
    ],
    "powerStates": {
      "10,15": 0,
      "11,15": 0
    }
  }

• Image Export: PNG with optional transparent background
• Circuit Sharing: Compressed binary format for efficient sharing

• UI rendering and updates
• Input processing
• OpenGL context operations

• Run simulation ticks at configured rate
• Process component updates
• Calculate signal propagation

• Thread-safe queue for cross-thread communication
• Double-buffered state for rendering
• Lock-free data structures where possible

• Custom exception types for simulation-specific errors
• Global exception handler for UI thread
• Graceful degradation for non-critical failures

• Structured logging using Microsoft.Extensions.Logging
• Log levels: Debug, Info, Warning, Error, Critical
• Log targets: Console, file, and in-application log viewer

• OpenTK (4.x): Graphics and input handling
• Microsoft.Extensions.DependencyInjection: DI container
• Microsoft.Extensions.Logging: Logging infrastructure
• Microsoft.Extensions.Configuration: Configuration management
• System.Text.Json: JSON serialization
• xUnit (2.x): Testing framework
• Moq: Mocking library for testing
• BenchmarkDotNet: Performance testing

• Visual Studio 2022 or later / Visual Studio Code with C# extensions
• .NET 9.0 SDK
• Git for version control
• GitHub Actions for CI/CD

• Primary: Windows 10/11 (x64)
• Secondary: macOS, Linux (via .NET cross-platform capabilities)
• Minimum Specifications:
  • CPU: Dual-core 2.0 GHz or better
  • RAM: 4 GB minimum, 8 GB recommended
  • GPU: OpenGL 3.3+ compatible
  • Storage: 100 MB for application, variable for circuit files

1. Simulation tick rate consistency
2. Rendering performance for large circuits
3. Memory usage for component-dense areas
4. Load/save times for large circuits

• Plugin architecture for future component types
• Event system for custom behaviors
• Scripting API for automation (future consideration)

• Follow Microsoft's C# coding conventions
• Use nullable reference types
• Implement proper XML documentation
• Follow SOLID principles

• Feature branching workflow
• Pull request reviews required
• Semantic versioning
• Automated CI/CD pipeline

• Unit tests required for all core simulation logic
• Integration tests for component interactions
• Performance tests for critical paths
• UI tests for main workflows

• API documentation generated from XML comments
• Architecture overview document
• User manual and tutorials
• Developer guidelines for contributions

This technical requirements document provides a comprehensive blueprint for implementing the 2D Redstone Circuit Simulator using C#, .NET 9.0, OpenTK, and xUnit. The modular architecture and clear separation of concerns will facilitate development across the implementation phases while ensuring the system meets all functional and performance requirements.