DOOM 3, Quake 4 & Prey (2006)

The idTech4A++ Multi-Engine Architecture & Harmattan Runtime

idTech4A++ (Harmattan Edition) is an open-source native Android runtime maintained by glKarin. Originating from n0n3m4’s DIII4A project, it has grown into a versatile launcher for id Software’s id Tech 4 engine. Distributed via GitHub Releases and F-Droid (release harmattan73), it integrates modern enhancements from desktop source ports like dhewm3 and RBDOOM-3-BFG.

Unlike emulators, idTech4A++ compiles game logic into native C/C++ binaries for 64-bit (arm64-v8a) and 32-bit (armeabi-v7a) Android devices. The unified launcher hosts a roster of classic PC shooters:

• DOOM 3 & Resurrection of Evil: The 2004 horror FPS and its official expansion.
• DOOM 3: BFG Edition: Modernized rendering and flashlight mechanics via rbdoom3bfg.
• Quake 4: Raven Software’s 2005 Stroggos sequel featuring reconstructed game code.
• Prey (2006): Human Head Studios’ portal-and-gravity sci-fi shooter.
• Community Engines: Standalone support for The Dark Mod, RealRTCW, Wolfenstein: Enemy Territory (ET: Legacy), Serious Sam Classic, and Skin Deep.

Data Directory Setup for DOOM 3, Quake 4, and Prey Assets

Because idTech4A++ distributes only the compiled game engines, users must provide retail asset archives from their own PC copies on Steam or GOG:

1. Create a working folder on internal storage, such as /sdcard/diii4a/.
2. Copy the retail data folders containing *.pk4 archives from your PC into /sdcard/diii4a/:
   • Copy base/ for DOOM 3 (and d3xp/ for Resurrection of Evil).
   • Copy q4base/ for Quake 4.
   • Copy preybase/ for Prey (2006).
3. Install the idTech4A++ APK from GitHub Releases or F-Droid.
4. Launch the app, grant storage permissions, and set the working directory to /sdcard/diii4a/.
5. Choose your desired game engine from the top drop-down menu and start the game.

Vulkan and OpenGL ES Rendering Pipeline & Lighting Performance

id Tech 4 introduced real-time per-pixel lighting, normal mapping, and unified stencil shadow volumes. idTech4A++ renders these effects on mobile GPUs via modern Vulkan 1.1 and OpenGL ES 2.0/3.2 backends with multi-threaded execution.

The engine scales from vintage Android 4.4 devices to modern Android 15 flagships:

• Performance Targets: Snapdragon 845 hardware sustains 60 FPS in DOOM 3 and Prey at 1080p, while Snapdragon 8 Gen 1/2 chips reach 90 to 120 FPS with 4x MSAA.
• Engine Customization: Launcher menus provide granular toggles for shadow stencils, lighting passes, and resolution scaling to control device thermals.

Precision Gyroscope Aiming, Gamepad & Full Desktop Input Capture

Input versatility supports every handheld form factor:

• Motion Aiming: Smooth gyroscope aiming features adjustable sensitivity curves and dead-zone filters for pinpoint targeting.
• Touch Controls: A fully customizable HUD editor allows every button and virtual thumbstick to be moved, scaled, and assigned to console commands.
• Physical Gamepads: Bluetooth and USB-C gamepads map directly with analog trigger support and tactile rumble feedback.
• Mouse & Keyboard: Full USB and Bluetooth desktop mouse and keyboard capture provides raw cursor locking for authentic PC controls.