Unity/javascript memory mapping

[dbirman]

To create a shared memory buffer between Unity and JavaScript in a WebGL build, you can use the JavaScript Interop feature provided by Unity. Here's a step-by-step process to achieve this:

In your Unity project, create a C# script with a method that will be called from JavaScript. The method should have the [DllImport("__Internal")] attribute and be declared as static extern. For example:

using System.Runtime.InteropServices;

public class SharedMemoryManager : MonoBehaviour
{
    [DllImport("__Internal")]
    private static extern void RegisterSharedMemory(int[] sharedArray, int length);
}

In the same script, create a method to initialize the shared memory buffer and call the JavaScript function:

public void InitializeSharedMemory()
{
    int[] sharedArray = new int[1000]; // Replace with your desired array size and type
    RegisterSharedMemory(sharedArray, sharedArray.Length);
}

Call InitializeSharedMemory() from any suitable place in your Unity code, such as Start().

In your WebGL build, modify the index.html file to include a JavaScript function that will be called by the C# method:

mergeInto(LibraryManager.library, {
  RegisterSharedMemory: function (arrayPtr, length) {
    let sharedArray = new Int32Array(HEAP32.buffer, arrayPtr, length);
    // Now you can access the sharedArray from JavaScript
  },
});

Now, both Unity and JavaScript code can access the same shared memory buffer using sharedArray. Keep in mind that you may need to adjust the code for your specific use case and array type.

For more information on memory management in Unity WebGL builds, you can refer to the Unity documentation on WebGL memory 1. Additionally, you can find more details about using the UnityLoader.js file to communicate between Unity and JavaScript --boundary-ce52ca4ecb5b45aeae39c8f212acaaa4 {"source": "https://docs.unity3d.com/2022.3/Documentation/Manual/TableOfContents.html", "reason": "Explanation of Unity scripting in relation to UnityLoader.js"} boundary-ce52ca4ecb5b45aeae39c8f212acaaa4 .