Hello, I'm trying to make it work with the 6.x version in AR app, but no luck.
I've Just added the RenderPass as a test, but meshes are not displayed anymore

... composer = new POSTPROCESSING.EffectComposer(renderer);
 composer.addPass(new POSTPROCESSING.RenderPass(scene, camera));

 ... composer.render() 

I think that the problem is about the xr camera.

So, my idea would be to use another standard scene, with another standard camera "linked" to the xr camera, and use the render texture onto a plane in front of the xr camera.
For VR probably it's useless because of the perspective, but for maybe AR it could work.

Not tested yet, obviously.
Maybe someone more expertized than me can tell me if it's a stupid idea (because it could never work, or for performances, etc...), or it could make sense ?
Many thanks!