This was pretty cool, but I couldn't help being struck by how utterly poorly it performs, especially as soon as you add just a handful of objects and two light

This was pretty cool, but I couldn't help being struck by how utterly poorly it performs, especially as soon as you add just a handful of objects and two light sources. Sure, it's written in JS, but JS has come a long way in terms of performance, and so have our computers. This demonstration instantly makes me think of Blizzard's Diablo II from 2000, which features an identical effect during gameplay, with a seemingly infinite number of shadow-generating obstacles and as many light sources casting shadows as there are players on the screen, and it runs perfectly smooth even on a 500mhz P3.