Open Android Input Capture

An open-source Android library for Unity that enables pointer capture functionality on Android devices, allowing games to capture and control mouse/pointer input.

Overview

This project provides a way to implement pointer capture in Unity games running on Android. By default, Unity's behavior with mouse input is to stop once the mouse has reached the edge of the screen. This plugin allows you to continue moving with your mouse indefinitely, which is essential for first-person mouse gameplay. When enabled, it captures all mouse movements and button presses, preventing the system cursor from appearing and allowing your game to have full control over pointer input. This is especially useful for first-person games, 3D navigation, or any application requiring continuous mouse input without cursor interference.

Features

• Pointer Capture: Capture mouse/pointer movements on Android devices (API 26+)
• Unity Integration: Easy-to-use Unity package with simple API
• Automatic State Management: Ties capture state to Unity's Cursor.lockState
• Input Compatibility: Drop-in replacement for Unity's Input system methods
• Button Support: Handles up to 7 mouse buttons (left, right, middle, and 4 additional buttons)
• Scroll Wheel: Captures both vertical and horizontal scroll input
• Activity Lifecycle Aware: Automatically handles Android activity lifecycle events

Requirements

• Unity 2021.3 or later
• Android API 26 (Android 8.0 Oreo) or higher
• Android Studio (for building the AAR library)

Project Structure

├── AndroidInputCapture/          # Android library source
│   ├── app/                      # Main library module
│   │   └── src/main/java/com/example/androidinputcapture/
│   │       └── PointerCaptureHelper.java
│   └── unityLibrary/             # Unity library dependencies
│
└── AndroidInputCaptureUnityDemo/ # Unity demo project
    └── Assets/OpenPointerCapture/
        ├── Plugins/              # Contains android-input-capture.aar
        ├── Scripts/              # Unity C# scripts
        │   ├── PointerCaptureManager.cs
        │   ├── PointerCaptureNativeInterface.cs
        │   └── CapturedInput.cs
        └── Demo/                 # Demo scene and scripts

Installation

Option 1: Use Pre-built Unity Package

1. Copy the AndroidInputCaptureUnityDemo/Assets/OpenPointerCapture folder to your Unity project's Assets folder
2. The package includes a pre-built AAR file ready to use

Option 2: Build from Source

1. Open the AndroidInputCapture project in Android Studio
2. Build the project to generate the AAR file
3. Copy the generated AAR to your Unity project's Assets/Plugins/Android folder
4. Copy the Unity scripts from AndroidInputCaptureUnityDemo/Assets/OpenPointerCapture/Scripts to your project

Usage

Basic Setup

1. Add PointerCaptureManager component to a GameObject in your scene
2. The manager automatically captures pointer input when Cursor.lockState is set to CursorLockMode.Locked

Using Captured Input

Replace Unity's Input methods with CapturedInput equivalents:

using OpenPointerCapture;

// Instead of Input.GetMouseButtonDown(0)
if (CapturedInput.GetMouseButtonDown(0))
{
    // Handle left click
}

// Instead of Input.GetAxis("Mouse X")
float mouseX = CapturedInput.GetAxis("Mouse X");

// Instead of Input.mouseScrollDelta
Vector2 scrollDelta = CapturedInput.mouseScrollDelta;

// Instead of Input.mousePosition
Vector3 mousePos = CapturedInput.mousePosition;

Manual Control

If you need manual control over pointer capture:

// Begin capture
PointerCaptureNativeInterface.beginCapture();

// End capture
PointerCaptureNativeInterface.endCapture();

// Check capture state
bool isCaptured = PointerCaptureNativeInterface.isPointerCaptured();

Event-Based Input

Subscribe to pointer events directly:

void OnEnable()
{
    PointerCaptureManager.OnCapturedPointerMoved += HandlePointerMove;
    PointerCaptureManager.OnCapturedMouseButton += HandleMouseButton;
    PointerCaptureManager.OnCapturedScroll += HandleScroll;
}

void HandlePointerMove(Vector2 delta)
{
    // Handle mouse movement
}

void HandleMouseButton(int buttonIndex, bool isDown)
{
    // Handle button press/release
}

void HandleScroll(Vector2 scrollDelta)
{
    // Handle scroll wheel
}

Demo Scene

The project includes a comprehensive demo scene showcasing various features:

• Camera rotation with captured mouse movement
• Object interaction with mouse buttons
• UI elements that respond to captured input
• Visual feedback for button presses and scroll events

To run the demo:

1. Open AndroidInputCaptureUnityDemo in Unity
2. Load the scene Assets/OpenPointerCapture/Demo/OpenPointerCaptureDemo.unity
3. Build and run on an Android device

Implementation Details

Android Side

The PointerCaptureHelper class:

• Implements Android's OnCapturedPointerListener interface
• Manages activity lifecycle callbacks
• Stores input deltas and button states for Unity to poll
• Handles view attachment/detachment automatically

Unity Side

• PointerCaptureNativeInterface: JNI bridge to communicate with Android
• PointerCaptureManager: MonoBehaviour that polls for input and fires events
• CapturedInput: Static facade providing Input-compatible API

Limitations

• Requires Android API 26+ (Android 8.0 Oreo)
• Only works on Android devices with mouse/pointer support
• In Unity Editor, falls back to standard Input methods

Troubleshooting

Pointer capture not working

• Ensure your Android device is running API 26 or higher
• Check that the AndroidManifest.xml includes the library
• Verify that PointerCaptureManager is active in the scene

Input lag or missed events

• The system polls for input each frame, ensure stable frame rates
• For high-frequency input, consider increasing the polling rate

License

This project is open source and available under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.