Crash when using CSG2 in a web worker context

Bugs
1

Hi everyone !

Unfortunately I cannot provide a playground to reproduce the issue.

Calling InitializeCSG2Async while in a worker thread leads to an error du to the use of importScripts() inside the method LoadScript of the class Tools.
It is pretty obvious from the method comment that it needs to access the DOM, which is not possible in a worker context.

This function is used internally by babylon components to load a script (identified by an url). When the url returns, the content of this file is added into a new script element, attached to the DOM (body element)

Then, because the script was not loaded, trying to instanciate a ManifoldMesh into the CSG.FromMesh method leads to a crash.

As CSG is now deprecated, any help to fix the issue would be greatly appreciated !

Thanks a lot for the amazing work !

2

You have analyzed it wonderfully - this is exactly the reason why it doesn’t work in webworkers.

We should be able to make _LoadScriptModuleAsync work if no document object is available. Want to create a github issue for that? You can reference this page when creating it.

3

I initialize it this way in my worker and it works fine:


async function initBabylon(canvas: OffscreenCanvas) {
  engine = new Engine(canvas, true);
  scene = new Scene(engine);

  try {
    const wasmUrl = "https://unpkg.com/manifold-3d@3.0.1/manifold.wasm";
    const response = await fetch(wasmUrl);
    const wasmBinary = await response.arrayBuffer();

    const wasm = await Module({
      wasmBinary,
      locateFile: (path) => `https://unpkg.com/manifold-3d@3.0.1/${path}`,
    });

    wasm.setup();
    Manifold = wasm.Manifold;
    ManifoldMesh = wasm.Mesh;

    await InitializeCSG2Async({
      manifoldInstance: Manifold,
      manifoldMeshInstance: ManifoldMesh,
    });

    console.log("CSG2 initialized successfully");
  } catch (error) {
    console.error("Failed to initialize CSG2:", error);
  }
}
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