On a Mac, Godot 4 Web Exports only work on Safari

Both the macOS versions of Chrome and Firefox have a bug that stalls the loading of games exported from Godot 4.

The following is a technical explanation of what’s happening behind the scenes.

As of October 2023, with up-to-date software, the MacOS versions of both Firefox and Chrome can take an extra two minutes or more to load the web export version of a Godot4 project, or they may not load at all.

On all browsers Godot4 uses WebGL 2.0 to render the game graphics. WebGl 2.0 uses OpenGL. Apple has deprecated OpenGL on MacOS in favor of Metal, its proprietary graphics acceleration API.

The problem seems to lie in how those browsers execute the WebGL 2.0 calls on the Mac.

Firefox and Chrome utilize a translation layer called ANGLE to transform the OpenGL ES API calls into one of the hardware-supported APIs available for the platform on which they are running. The version of ANGLE used by Firefox and Chrome does not support Metal yet, so what is happening there is not optimal on Mac hardware.

New versions of the ANGLE library have implemented a Metal backend, and Chrome is working on updating the version they use.