Using custom extensions with THREE.js

[remote elk]

if you look at the code for their demo, they actually don't, it's just in the docs:

https://github.com/gkjohnson/threejs-sandbox/blob/8d110e749be46477a094354a6e4a47a45f9eb80a/motionBlurPass/webgl_postprocessing_perobjectmotionblur.html#L198

you can extend THREE.* this if your extension isn't using ES Modules.