Ripple Shader

Thank to Adrian Boeing I was inspired this morning to hack together a ripple shader for Unity3D. Thanks for the math Adrian. You can see the animated effect here.

Shader "DM/Ripple Shader" {
    Properties {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Texture", 2D) = "white" {}
        _Scale ("Scale", Range(0.5,500.0)) = 3.0
        _Speed ("Speed", Range(-50,50.0)) = 1.0
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200
        Cull Off
        CGPROGRAM
        #pragma surface surf Lambert
        #include "UnityCG.cginc"
        
        half4 _Color;
        half _Scale;
        half _Speed;
        sampler2D _MainTex;
        
        struct Input {
            float2 uv_MainTex;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            half2 uv = (IN.uv_MainTex - 0.5) * _Scale;
            half r = sqrt (uv.x*uv.x + uv.y*uv.y);
            half z = sin (r+_Time[1]*_Speed) / r;
            o.Albedo = _Color.rgb * tex2D (_MainTex, IN.uv_MainTex+z).rgb;
            o.Alpha = _Color.a;
            o.Normal = (z, z, z);
        }
        ENDCG
    } 
    FallBack "Diffuse"
}