Add your Unity WebGL apps to next.js projects

System Requirements:

• Node.js 16.8 or later.
• macOS, Windows (including WSL), and Linux are supported.

Getting Started

In your terminal/git-bash run the following commands

1. In a new directory create a new nextJS project

npx create-next-app@latest

Accept all the default options and open your next.js project in a code editor

2. Install webgl-nextjs package to your project

change directory to the root of your new next.js project and run the following command:

npm i webgl-nextjs

3. Create a new pages directory in your next project -if it wasn't generated-, in the pages directory create a new file test.js and copy and paste the following code.

//filename: /pages/test.js
import { WebGL } from 'webgl-nextjs'
import React, { useRef } from 'react';

export default function TestMePage() {
  const webGLRef = useRef(null);
  
  var buildUrl = "https://storage.googleapis.com/multisync/multisync/app-builds"; //replace with your CDN
  let config = {
    dataUrl: buildUrl + "/webgl-test-js.data",//replace with your build file name
    frameworkUrl: buildUrl + "/webgl-test-js.framework.js",//replace with your build file name
    codeUrl: buildUrl + "/webgl-test-js.wasm",//replace with your build file name
    loaderUrl: buildUrl + "/webgl-test-js.loader.js",//replace with your build file name
  };

  return (
      <WebGL
        ref={webGLRef}
        config={config}
        onLoaded={()=>console.log('webgl loaded')}
        onMessage={()=>console.log('msg received')}
        style={{ width: '100%', height: '100%', position: 'relative' }}
      />
  )
}

4. In your terminal run

 npm run dev 

You should see this in your browser under http://localhost:3000/test

🥳 You just added WebGL game/app to the next project 🥳

Usage

  <WebGL
    ref={webGLRef} //reference used to send messages to Unity WebGL app
    config={config} //config unity loader config
    onLoaded={onLoaded}//onLoaded callback function to be called when unity application is loaded
    onMessage={onMessage}//onMessage callback function to be called when unity application sends a message to JS layer
    style={{ width: '100%', height: '100%', position: 'relative' }}//add your style
    />

Rendering

• In UnityEditor, In your Build Settings Set your target platform to WebGL.

• Once the project is built locate the following directory Build, your should have 4 files

  • ~.wasm.
  • ~.data.
  • ~.framework.
  • ~.loader.

• Host these 4 files remotely or locally and save their absolute addresses to be used in the config.

  let config = {
    dataUrl: "",//replace with your build file name
    frameworkUrl: "",//replace with your build file name
    codeUrl: "",//replace with your build file name
    streamingAssetsUrl: "StreamingAssets",//replace with StreamingAssets path
    loaderUrl: "",//replace with your build file name
  };

Loading

• To run any code after the unity webgl app is loaded, utilize the onLoaded callback, it gets triggered once the application is loaded.

   const onLoaded = () => {
    console.log(`Loaded`);
  };

Messaging between JS and Unity

• In your Unity project, create Plugins folders (Assets/Plugins) and add protocol.jslib.

Assets/Plugins/protocol.jslib

mergeInto(LibraryManager.library, {
    SendMessageToJS: function(messageType, messageContent) {
        // This method can be called from Unity to send messages to JS.

        // Convert pointer to string.
        var messageTypeStr = UTF8ToString(messageType);
        var messageContentStr = UTF8ToString(messageContent);

        // Forward the message to your nextjs app or handle it here.
        console.log(`Received message of type ${messageTypeStr}: ${messageContentStr}`);
    },
    SendMessageToUnity: function(messageType, messageContent) {
        // This method can be called from JS to send messages to Unity.
        // You'll need to implement a corresponding method in your Unity C# script.
        SendMessage('HandleJSMessages', 'ReceiveMessage', `${messageType}\n${messageContent}`);
    }
});

Receiving and Sending messages from Unity to NextJS

• In your Unity Project, create a game object called HandleJSMessages and the following script to HandleJSMessages gameobject.

using System.Runtime.InteropServices;
using UnityEngine;

public class HandleJSMessages : MonoBehaviour
{
    [System.Obsolete]
    private void Awake()
    {
        if (Application.platform == RuntimePlatform.WebGLPlayer)
        {
            Debug.Log("HandleJSMessages Activated");//look for this message in the browser to ensure its working, delete before production
            DontDestroyOnLoad(this);
        }
    }

    [DllImport("__Internal")]
    private static extern void SendMessageToJS(string messageType, string messageContent);

    /// <summary>
    /// Sends a message from Unity WebGL build to the nextjs app that has webgl-nextjs package
    /// </summary>
    /// <param name="type">any type you want</param>
    /// <param name="content">the content for the message</param>
    [System.Obsolete]
    public void SendToJS(string type, string content)
    {
        string message = type + ":" + content;
        Application.ExternalCall("SendMessageToJS", message);
    }

    /// <summary>
    /// Receive message from the nextjs app that has webgl-nextjs package
    /// </summary>
    /// <param name="message"></param>
    [System.Obsolete]
    public void ReceiveMessage(string message)
    {
        var parts = message.Split('\n');//type\ncontent
        var type = parts[0];
        var content = parts[1];
        // Handle the message here. This will be called from JS.
        Debug.Log($"Received message of type {type}: {content}");//look for this message in the browser to ensure its working, delete before production

        //Some Logic ...
        switch(type)
        {
            case "nextjs-request":
                SendToJS("unity-response", "Ahmed");//send message to nextjs
                break;
            default:
                Debug.Log($"received unknown type message {type}");
                break;
        }
    }
}

Receiving and Sending messages from NextJS to Unity

• To Send a message from NextJS to Unity, utilize the reference to the WebGL component. webGLRef.current.sendMessage('MyMessageType', 'Hello, Unity!');// customize the type and the content of the message
• Upon receiving a message from Unity Webgl, you can utilize the onMessage listener

  const onMessage = (type, content) => {
    console.log(`Received message of type ${type}: ${content}`);// you should see in chrome console
    switch(type)
      {
          //logic based on the type
      }
  };

Full Example

//This file is created in a nextjs projet under /pages/testme.js
//Used for testing it should render your unity webgl app

import { WebGL } from 'webgl-nextjs'
import React, { useRef } from 'react';

export default function TestMePage() {
  const webGLRef = useRef(null);

  var buildUrl = "./Build"; //replace with your CDN
  let config = {
    id: "unity-container",
    dataUrl: buildUrl + "/test-webgl.data",//replace with your build file name
    frameworkUrl: buildUrl + "/test-webgl.framework.js",//replace with your build file name
    codeUrl: buildUrl + "/test-webgl.wasm",//replace with your build file name
    loaderUrl: buildUrl + "/test-webgl.loader.js",//replace with your build file name
  };

  const onLoaded = () => {
    console.log(`UnityWebGL Loaded`);
    webGLRef.current.sendMessage('nextjs-request', 'send me your name');
  };

  const onMessage = (message) => {
    console.log('Received message from Unity,  message: ' + message);
    const type = message.split(':')[0];
    const content = message.split(':')[1];
    console.log('type: ' + type + ' content: ' + content);
    switch (type) {
      case "unity-response":
        console.log(`name received:${content}`);
        break;
    }
  }

  return (
    <WebGL
      config={config}
      onLoaded={onLoaded}
      onMessage={onMessage}
      style={{ width: '100%', height: '100%', position: 'relative' }}
      ref={webGLRef}
    />
  )
}

Support:

• Email: contact@multisync.io
• Discord: https://discord.gg/YHmsekzMV5