Spicy Launcher

A custom, lightweight Minecraft: Java Edition launcher built with JavaFX — featuring Microsoft authentication, automatic version installation, Fabric support, and a sleek dark/light UI.

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⚙️ How It Works

• Microsoft OAuth Authentication: Logs in via Microsoft's official OAuth flow and caches the token locally — no need to re-authenticate every launch.
• Offline Mode Support: No Microsoft account? No problem. Enter any username and play in offline mode instantly.
• Auto Version Installer: Automatically downloads and installs any selected Minecraft version if it's not already present, with real-time progress shown directly on the play button.
• Fabric Loader Support: Detects and correctly handles fabric-loader-* version strings, resolving asset indices automatically.
• Asset Index Auto-Detection: Reads version.json and recursively resolves inheritsFrom chains to find the correct asset index for any version.
• Dark / Light Theme: Toggle between dark and light mode — preference is saved and restored between sessions.
• Dev Log Window: Optionally attach a live log window to the running game process for debugging.
• Borderless Custom UI: Fully custom borderless window with drag-to-move support, minimize and close buttons handled manually via JavaFX.
• Settings Persistence: All user preferences (username, version, memory, window size, theme, etc.) are saved to a local JSON file.

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📁 Setup

1. Requirements

Requirement	Version
Java	17 or higher
JavaFX	17+ (bundled or on module path)
OS	Windows (stores data in %APPDATA%\.spicy)

2. Build

Clone the repository and build with your preferred build tool (Maven/Gradle). Make sure JavaFX is on the module path.

git clone https://github.com/yourusername/spicy-launcher.git
cd spicy-launcher
./gradlew run

Note: If you're packaging as a fat JAR, ensure JavaFX natives are included or run with --module-path pointing to your JavaFX SDK.

3. First Launch

On first launch, the launcher will:

1. Create the .spicy directory under %APPDATA%
2. Fetch available Minecraft versions from Mojang's API
3. Prompt you to log in with Microsoft (optional)

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🚀 Usage

Login Options

Microsoft Account (Premium)

• Click the MS Auth button
• Complete OAuth flow in the browser window that opens
• Your token is cached to ms_auth_cache.json — subsequent launches skip re-authentication

Offline Mode (Cracked)

• Leave Microsoft auth untouched
• Type any username into the username field
• A UUID is generated deterministically from your username (Spicy:<username>)

Playing

1. Select a Minecraft version from the dropdown
   • Versions already installed are highlighted in orange
   • Uninstalled versions are downloaded automatically on first launch
2. Hit Login / Play
3. Progress is shown live on the button itself (e.g. Downloading assets... %72)

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🎛️ Settings

Accessible via the ⚙️ settings button. Options include:

Setting	Description
Max Memory (MB)	JVM -Xmx heap allocation for Minecraft
Window Width / Height	Custom game resolution (0 = default)
Fullscreen	Launch Minecraft in fullscreen mode
Close Launcher on Launch	Hides the launcher window while the game is running; restores it on exit
Show Dev Log	Opens a live console window attached to the game process
Dark Theme	Toggle dark/light UI theme

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📁 File Structure

All launcher data is stored under:

%APPDATA%\.spicy\
├── launch_settings.json     # User preferences
├── ms_auth_cache.json       # Cached Microsoft token
├── assets\                  # Minecraft asset objects & indexes
├── versions\
│   └── 1.21.4\
│       ├── 1.21.4.json
│       └── 1.21.4.jar
└── libraries\               # Minecraft libraries

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🛠️ Technical Features

Feature	Description
JavaFX FXML UI	Declarative layout with MainViewController handling all logic
Async Everything	Version loading, auth, and game launch all run on background threads
Token Expiry Check	Cached MS tokens are validated on startup; expired tokens are silently cleared
Fabric Version Parsing	Strips fabric-loader- prefix and resolves base version for asset index lookup
Recursive Asset Resolution	Follows inheritsFrom in version JSONs to find the correct asset index
Button Progress Bar	A Region overlays the play button and grows proportionally to download progress
Themed Dialogs	Yes/No confirmation dialogs are custom-built to match the active theme
Multi-Instance Guard	Warns the user before launching a second game instance

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🏗️ Architecture Overview

spicy.launcher
├── ui/
│   ├── MainViewController.java    # Core UI logic, auth, launch flow
│   ├── SettingsDialog.java        # Settings popup
│   └── DevLogWindow.java          # Live game log viewer
├── core/
│   ├── MicrosoftAuthManager.java  # OAuth2 + Minecraft token flow
│   ├── GameLauncher.java          # Process builder, JVM args
│   └── VersionManager.java        # Version fetching, download, install
└── model/
    ├── DisplayVersion.java        # Version list item (id + installed flag)
    ├── LaunchContext.java         # All params passed to game process
    └── LaunchSettings.java        # JSON-serializable user preferences

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📦 Dependencies

Package	Purpose
javafx	UI framework (controls, FXML, scene graph)
gson	JSON serialization for settings and version manifests
aiohttp (if applicable)	Async HTTP for asset/version downloads

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⚠️ Disclaimer

This launcher is an independent, third-party project and is not affiliated with Mojang or Microsoft. Playing Minecraft via this launcher still requires a valid, purchased Minecraft: Java Edition license for online/authenticated play. The developer is not responsible for any account issues or misuse. Use responsibly.

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🌹 Special Thanks

@fantasywastaken for contributions and support