Halogen

A shader-powered macOS app launcher where applications are rendered as a GPU scene instead of a static grid UI.

---

Overview

Halogen is a customizable macOS launcher built around a real-time rendering engine. Instead of a traditional icon grid, apps are displayed as shader-driven objects inside a GPU-rendered interface.

Each application icon can have its own visual material, and the entire launcher can be styled using custom GLSL shaders and postprocessing effects.

---

Features

• GPU-rendered app grid (Three.js)
• Shader-based icon system (per-app overrides)
• Custom global icon shader fallback
• Configurable layout system
• Adjustable icon size, text, and positioning
• Window fade-in / fade-out transitions (Tauri events)
• External app indexing pipeline (Python)
• Icon extraction and conversion system
• TOML-based app manifest generation
• Demand-based rendering mode (performance optimized)

---

Architecture

Halogen is split into three layers:

1. Python (App Indexer)

• Scans macOS Applications folders
• Extracts app metadata
• Converts .icns icons to PNG
• Generates app manifest (applist.toml)

2. Tauri (System Bridge)

• Handles windowing
• Executes native commands
• Opens applications
• Acts as IPC layer between frontend and OS

3. React + Three.js (Render Engine)

• Renders app grid as a GPU scene
• Applies shader materials per icon
• Handles interaction and animation
• Controls visual state of the launcher

---

Rendering Model

Each app is rendered as:

• A plane mesh
• A texture (app icon)
• A fragment shader (custom or global fallback)

Shader uniforms can include:

• icon texture
• mouse interaction state
• position data

---