fish tank water distortion Shader for unity

Question

I am working on unity and trying to make a fish tank water distortion Shader effect with the following requirement:

1.its a 2D top down prospective.

2.every object under/in the fish tank has to be distorted, game objects might pass trough/under the fish tank (distortion) and game object might pass over the fish tank (no distortion) as well.

3.the fish tank does not follow the main camera.

I try to search online and most of the solution I get is to apply the shader to an object or to the main camera which will not meet requirement 3 or 2, can someone give me an ideal on what is the best way to deal with this ? I am working on a mobile game so the solution has to be light weighted on processing power. Many thanks !

Answer 1

I think I did something similar to what you are looking for few month ago.

I open-sourced the whole thing on GitHub and tried to keep it simple (script / prefab / shader).

How it works

1/ A shader for the water surface

It's a rather simple transparent bumped colored shader

• with a GrabPass, so it can display everything that has been drawn before
• with a bump mapping texture

• a Color to apply to the grabbed texture
• an additional sinusoïdal deformation with the magnitude parameter

So it’s basically just a simple transparent shader that applies a color and a bump texture.

Note: I'm not really skilled in writing shaders so this I cannot guaranteed it will be working on every platforms.

2/ A simple trick

The reflection is just a simple trick. For every object we want to reflect in the water, we create a new mirroded sprite!

Note: I'm not using the right sprite in this picture for the boat reflact but it's just a SpriteRenderer, it could be easily changed.

Note 2: the reflect creation can be automated with a script. That's what I did in my package.

Answer 2

Why don't you use two cameras?

One render the the fishtank and whatever will pass under and the other render everything else that shouldn't have distortion.