uvshift

Shader "Unlit/uvshift"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _OffsetTex ("Texture", 2D) = "black" {}
        _Intensity ("Intensity", Range (0, 1)) = 0.5
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float2 uv2 : TEXCOORD1;
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            sampler2D _OffsetTex;
            float4 _OffsetTex_ST;
            float _Intensity;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                o.uv2 = TRANSFORM_TEX(v.uv, _OffsetTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                float2 uv_offset = tex2D(_OffsetTex, i.uv2).yz;
                uv_offset = float2(uv_offset.x - 0.5, uv_offset.y - 0.5) * _Intensity;
                fixed4 col = tex2D(_MainTex, i.uv + uv_offset);
                return col;
            }
            ENDCG
        }
    }
}