Shader "Custom/Fog" 
{
    Properties
    {
        _MainTex ("Main", 2D) = "white" {}
        _SubTex ("Sub", 2D) = "white" {}
        _Sub2Tex ("Sub", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque"}
        ZWrite Off
        Cull Off

        Pass
        {
            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

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

            struct v2f
            {
                float4 vertex : SV_POSITION;
                float2 main_uv : TEXCOORD0;
                float2 sub_uv : TEXCOORD1;
                float2 sub2_uv : TEXCOORD2;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            sampler2D _SubTex;
            float4 _SubTex_ST;

            sampler2D _Sub2Tex;
            float4 _Sub2Tex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.main_uv = TRANSFORM_TEX(v.uv, _MainTex);
                o.sub_uv = TRANSFORM_TEX(v.uv, _SubTex);
                o.sub2_uv = TRANSFORM_TEX(v.uv, _Sub2Tex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 main = tex2D(_MainTex, i.main_uv);

                fixed2 uv = i.sub_uv;
                uv.x += 0.05*_Time.y;
                fixed4 sub = tex2D(_SubTex, uv);

                fixed2 uv2 = i.sub_uv;
                uv2.x += 0.01*_Time.y;
                fixed4 sub2 = tex2D(_Sub2Tex, uv2);
                fixed3 color = fixed3(0.8,0.5,1);
                fixed4 col = fixed4(sub.rgb*sub2.rgb*color,(1-main.r)*sub.r);
                
                return col;
            }
            ENDCG
        }
    }
}