Bluetooth Custom Transport for Unity Netcode for GameObjects

This repository provides a custom communication layer for Netcode for GameObjects (NGO) using Bluetooth as its underlying transport mechanism. The package is designed for Android and requires a minimum target API level of 33.

The transport supports a stable two-device connection using predefined roles (Server and Client). If the client crashes and restarts the application, it can seamlessly reconnect to the server without requiring the host to reconfigure its state.

---

📦 Project Structure

Below are the key folders and files included in this package:

• Plugin: Contains the custom Bluetooth Android plugin and configuration templates
  • BlueT-release.aar: Precompiled Android plugin
  • Manifest_and_gradle_configs.txt: Required lines for Android manifest and Gradle templates
  • SourceCode_plugin.java: Source code for rebuilding the .aar plugin
  • build.gradle.kts: Reference Gradle configuration for plugin reconstruction
• Scripts: C# scripts for integrating the Bluetooth transport into your Unity project with Netcode integration, including an example of partial implementation BTforNetcodeExample.cs

---

1. Unity Project Setup

To correctly integrate the Bluetooth transport plugin into your Unity project, follow the steps below.

1.1 Enable Custom Android Build Templates

In Unity, navigate to:

Project Settings → Player → Publishing Settings

Enable the following options:

• Custom Main Manifest
• Custom Main Gradle Template
• Custom Gradle Properties Template

These will allow modification of Unity's default Android build configuration.

1.2 Install the Bluetooth Plugin

1. Copy the file BlueT-release.aar into your Unity project directory:

   Assets/Plugins/Android
   

2. Select the .aar file inside Unity. In the Inspector, enable:

   • Load on Startup → true

   Then click Apply.

1.3 Update Manifest and Gradle Templates

In the folder:

Assets/Plugins/Android

modify the following files:

• AndroidManifest.xml
• mainTemplate.gradle
• gradleTemplate.properties

Add all required lines found in:

• Manifest_and_gradle_configs.txt

These entries are required for Bluetooth permissions, features, and Gradle compatibility with the plugin.

1.4 Set API Levels

In Unity:

Project Settings → Player → Other Settings

Ensure:

• Target API Level: 33 (mandatory, you can try to rebuild the .aar the only constrain was the trivial use of the library: androidx.annotation.RequiresPermission)
• (the original project used a Minimum API Level = 29)

1.5 Import C# Scripts

Import all scripts inside:

• Scripts

Place them in any folder inside Assets, except Plugins or Editor.

---

2. Rebuilding the Android Plugin (Optional)

If you need to modify or extend the Bluetooth Android plugin, follow the official reconstruction procedure below.

2.1 Create a New Android Studio Project

1. Open Android Studio and create a new project.
2. Choose Gradle Kotlin DSL (gradle.kts) as your configuration (recommended).
3. Create a new module, then delete all unnecessary files so that the module is recognized as an Android Library.

In settings.gradle, ensure:

include(":<YourModuleName>")

Remove:

include(":app")

2.2 Add the Plugin Source Code

1. Rename:

   SourceCode_plugin.java → BluetoothPlugin.java

2. Place the file inside your module’s Java source path:

<ModuleDirectory>/src/main/java/com/<YourProjectName>

2.3 Configure Gradle

Inside the module directory, locate:

<ModuleDirectory>/build.gradle.kts

Overwrite its contents with the provided reference configuration:

• build.gradle.kts

Sync the project to follow the new gradle rules.

2.4 Build the Plugin

Open the Gradle console and run:

./gradlew :<YourModuleName>:assembleRelease

After the build completes, the generated .aar file will be located in:

<ModuleDirectory>/build/outputs/aar

Use this file to replace BlueT-release.aar in your Unity project.

---