The reflections were achieved using the Planar Reflections method.
A Reddit user known as Critsium-xy has recently posted an impressive demo showcasing how Godot Engine can be utilized to simulate digital water that closely mimics the appearance and behavior of real-life water.
In the engine, the developer set up a stunning interactive water surface, complete with refraction, ripples, and accurate reflections. According to the author, the realistic mirroring effect was achieved through the utilization of the Planar Reflections method, described in detail in our recent 80 Level Digest on how mirrors work in video games.
"I just make the capsule keep emitting particles of certain shapes and render only these particles using another camera, then pass this camera's image to shader to interrupt the normal map and vertex," commented the author. "The performance cost is quite cheap."
You can find the original Reddit post here. And if you want to learn more about setting up reflective surfaces in Godot, here are some great tutorials that you should definitely check out: