Dope Inventory

A high-performance Unity 2D grid inventory system with drag-and-drop support, item rotation, and stacking.

Features

• 2D Grid-Based Inventory: Efficient grid system using span-based bit arrays and unsafe pointers
• Drag & Drop: Intuitive item dragging between multiple inventories with visual feedback
• Item Rotation: Press R while dragging to rotate items (90°/180°/270°)
• Collision Detection: Real-time placement validation using shape overlap checks
• Object Pooling: Minimized GC allocations through pooling of shapes and UI elements
• uGUI Integration: Ready-to-use Unity UI components

Quick Start

Requirements

• Unity 2022.3 or later

Demo Scene

Open Assets/Scenes/Inventory(uGUI).unity to see a working example.

Architecture

Packages

This repository contains two Unity packages:

DopeGrid (com.fullmetalbagel.dope-grid)

Low-level grid shape library providing:

• IGridShape<T>: Interface for mutable grid shapes with typed cell values
• ImmutableGridShape: Memory-efficient readonly grid shapes using bit arrays
• IndexedGridBoard: Grid container managing multiple items with collision detection
• Grid transformations (rotation, flipping, trimming)

DopeInventory (com.fullmetalbagel.dope-inventory-ugui)

uGUI-based inventory system built on DopeGrid:

• IGameInventory/IUIInventory: Inventory model interfaces with GUID-based item tracking
• InventoryView: Main MonoBehaviour for inventory UI
• InventoryViewDragController: Drag-and-drop interaction handling
• InventoryItemViewPool: Object pooling for UI elements

Key Components

InventoryView (Packages/com.fullmetalbagel.dope-inventory-ugui/Runtime/UI/InventoryView.cs) Main component orchestrating inventory UI, handling user input, and synchronizing model-view state.

IGameInventory (Packages/com.fullmetalbagel.dope-inventory-ugui/Runtime/Model/IGameInventory.cs) Core inventory model interface managing item placement, movement, and removal with collision detection.

IndexedGridBoard (Packages/com.fullmetalbagel.dope-grid/Runtime/IndexedGridBoard.cs) Grid container storing item IDs per cell, providing efficient spatial queries and collision checking.

Development

Running Tests

Unity Tests:

# Open Test Runner in Unity Editor
# Window > General > Test Runner
# Click "Run All" for EditMode or PlayMode tests

.NET Tests (faster, no Unity dependency):

cd dotnet
dotnet test DopeGrid.sln

# With coverage
dotnet test --collect:"XPlat Code Coverage"

# Specific test
dotnet test --filter "FullyQualifiedName~TestName"

Code Style

• C# 10+ with nullable reference types enabled
• Unsafe code and pointers for performance-critical grid operations
• Pure functions marked with [Pure, MustUseReturnValue]
• Strict analyzer rules with TreatWarningsAsErrors

Project Structure

Packages/
├── com.fullmetalbagel.dope-grid/          # Low-level grid library
│   ├── Runtime/                            # Grid shapes, boards, transformations
│   └── Editor/                             # Editor utilities
├── com.fullmetalbagel.dope-inventory-ugui/ # Inventory UI system
│   ├── Runtime/
│   │   ├── Model/                          # Inventory model layer
│   │   ├── UI/                             # UI components
│   │   └── Input/                          # Input abstraction
Assets/
├── Scenes/                                 # Demo scenes
└── Tests/                                  # Unity test cases
dotnet/
└── DopeGrid/                               # Standalone .NET project (same source)

License

MIT License - see LICENSE for details.