Unity 2018 Shaders and Effects Cookbook

How it works...

The core that this shader uses is a grab pass to take what has already been rendered on the screen. The part where the distortion takes place is in the Fragment function. Here, a normal map is unpacked and used to offset the UV data of the grab texture:

half4 bump = tex2D(_BumpMap, i.texcoord);half2 distortion = UnpackNormal(bump).rg;i.uvgrab.xy += distortion * _Magnitude;

The _Magnitude slider is used to determine how strong the effect is: