Demo 10 - Water distortion

Shader "Custom/WaterDistortion" {
    Properties {
        _MainTex ("Main texture", 2D) = "white" {}
        _NoiseTex ("Noise texture", 2D) = "grey" {}

        _Mitigation ("Distortion mitigation", Range(1, 30)) = 1
        _SpeedX("Speed along X", Range(0, 5)) = 1
        _SpeedY("Speed along Y", Range(0, 5)) = 1
    }

    SubShader {
        Tags { "RenderType"="opaque" }

        Pass {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            sampler2D _MainTex;
            sampler2D _NoiseTex;
            float _SpeedX;
            float _SpeedY;
            float _Mitigation;

            struct v2f {
                half4 pos : SV_POSITION;
                half2 uv : TEXCOORD0;
            };

            fixed4 _MainTex_ST;

            v2f vert(appdata_base v) {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                return o;
            }

            half4 frag(v2f i) : COLOR {
                half2 uv = i.uv;
                half noiseVal = tex2D(_NoiseTex, uv).r;
                uv.x = uv.x + noiseVal * sin(_Time.y * _SpeedX) / _Mitigation;
                uv.y = uv.y + noiseVal * sin(_Time.y * _SpeedY) / _Mitigation;
                return tex2D(_MainTex, uv);
            }

            ENDCG
        }
    }
    FallBack "Diffuse"
}