Parallax occlusion mapping is quite heavy itself, though. Transparent layers stacked on top of each other are also quite expensive due to overdraw. Probably th

Parallax occlusion mapping is quite heavy itself, though. Transparent layers stacked on top of each other are also quite expensive due to overdraw. Probably the cheapest way to add a little bit of 3D-ness would be to write the fluid sim to a texture, use it as a height map, and sample the texture a second time while offsetting the uvs slightly based on height map and camera position. Still not a great solution, and would probably only work if it was a wall of fluid in front of you.