https://www.youtube.com/watch?v=9XWxsJKpYYI

When Half-Life: Alyx patched in these shaders to make bottles look like they had liquid in them, people rightfully lost their minds. Because they look really, really good — like there's a real physics simulation involved. But there's not! So, let's figure out how developer Matt Wilde made these stellar liquid shaders.

0:00 The liquid in Half-Life: Alyx is ridiculously good
0:37 A brief history of LIQUIDS
1:34 Shaders are magic
3:02 How Matt started on Alyx
3:45 How the shader is made
6:08 Breaking bottles
6:17 Reflection and refraction
8:43 So-called "realism"
9:39 This shader is art!