Caustics https://nemutas.github.io/caustics/ References https://threejs.org/examples/?q=spo#webgl_lights_spotlight https://qiita.com/kaneta1992/items/1f8d145e862391f37a99 https://madebyevan.com/webgl-water/ https://medium.com/@evanwallace/rendering-realtime-caustics-in-webgl-2a99a29a0b2c
