Horizon Pack Example

This repository serves as a fully functional source template for a Horizon modpack. Horizon acts as the runtime environment, interpreting this directory structure, optionally compiling Java/C++ sources on the fly (only on 32bit for now).

Core Concepts

In the Horizon ecosystem, a "Pack" is a completely isolated game environment. Unlike traditional add-ons, a Horizon pack grants deep access to the game engine through multiple layers:

1. Native Layer (C/C++): Direct memory hooking, vtable manipulation, and JNI bridging into libminecraftpe.so.
2. Java Layer (Android/Dalvik): UI manipulation, activity injection (e.g., custom main menus, loading screens), and core API implementation.
3. Resource Patching (Assets): Directly allows to modify any existing assets from Java and reloading them from additional directories.
4. (Optional) Modding Layer (Inner Core): High-level modding API for defining blocks, items, and game logic without recompiling the core environment.

Horizon reads the manifest.json and automatically manages the LaunchSequence, compiling required sources via its execution directories before starting the application context.

Repository Structure

• manifest.json The strict descriptor file for the pack. Defines the pack's ID, version, target InnerCore engine version, and entry points.
• assets/ Contains all static visual and data resources.
  • images/: Texture atlases, UI sprites, entity skins, and environment maps.
  • materials/ & shaders/: Render controllers and GLSL shaders (.vertex / .fragment) for custom visual effects.
  • innercore/: Engine-specific visual assets (UI components, default mod icons, recipe panels).
  • res/: Android-level resources (layouts, localized strings, drawables) used by Horizon's UI injections.

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• java/ The Dalvik/Android source code and prebuilt .jar/.dex libraries.
  • src/com/zhekasmirnov/mcpe161/EnvironmentSetup.java: The primary Java entry point. Modifying this allows you to hook into the Horizon app lifecycle, abort launches, override resource paths, inject custom UI (buildCustomMenuLayout), and configure Ad domains.
  • src/io/nernar/instant/: Classes handling the fast-launch "Instant" mechanics and specific prepatching.

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• native/ C++ source code for native modification.
  • instant/module.cpp: Contains the JNI setup and symbol hooking (via HookManager). Modify this to intercept internal libminecraftpe.so calls (e.g., Level::addEntity, MinecraftClient::setScreen).
  • callbacks/: Native implementations for bridging C++ engine events back to the Java API (JavaCallbacks::invokeCallback).

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• so/ Contains pre-compiled native shared libraries for the target architecture (e.g., armeabi-v7a/libminecraftpe.so).

Development & Usage Workflow

1. Deployment: Place this repository folder directly into the Horizon packs/ directory on your device or development environment.
2. Java Modification: To alter the pre-game launch sequence, UI, or library injection, edit the Java sources in java/src/. Horizon's ExecutionDirectory will rebuild these sequences upon pack launch.
3. Native Modification: To add new engine hooks, create or modify .cpp files in native/. Ensure symbol names match the target ABI. Horizon handles the NDK compilation based on the manifest and native directory structure.
4. Resource Overrides: Place custom assets directly into assets/. The EnvironmentSetup.java handles ResourceManager configuration, routing atlases and materials appropriately.