Shader "Nature/Terrain/Diffuse"
{
    Properties
    {
        [HideInInspector] _Control ("Control (RGBA)", 2D) = "red" {}
        [HideInInspector] _Splat3 ("Layer 3 (A)", 2D) = "white" {}
        [HideInInspector] _Splat2 ("Layer 2 (B)", 2D) = "white" {}
        [HideInInspector] _Splat1 ("Layer 1 (G)", 2D) = "white" {}
        [HideInInspector] _Splat0 ("Layer 0 (R)", 2D) = "white" {}
        //Used in fallback on old cards & base map
        [HideInInspector] _MainTex ("BaseMap (RGB)", 2D) = "white" {}
        [HideInInspector] _Color ("Main Color", Color) = (1,1,1,1)
    }

    SubShader
    {
        Tags
        {
            "SplatCount" = "4"
            "Queue" = "Geometry-100"
            "RenderType" = "Opaque"
        }
        Blend SrcAlpha OneMinusSrcAlpha
        CGPROGRAM
        #pragma surface surf Lambert nolightmap
		#pragma target 3.0
        struct Input
        {
            float2 uv_Control : TEXCOORD0;
            float2 uv_Splat0 : TEXCOORD1;
            float2 uv_Splat1 : TEXCOORD2;
            float2 uv_Splat2 : TEXCOORD3;
            float2 uv_Splat3 : TEXCOORD4;
        };

        sampler2D _Control;
        sampler2D _Splat0,_Splat1,_Splat2,_Splat3;

        void surf (Input IN, inout SurfaceOutput o)
        {
            fixed4 splat_control = tex2D (_Control, IN.uv_Control);
            fixed4 firstSplat = tex2D (_Splat0, IN.uv_Splat0);
            fixed3 col;
            col = splat_control.r * tex2D (_Splat0, IN.uv_Splat0).rgb;
            col += splat_control.g * tex2D (_Splat1, IN.uv_Splat1).rgb;
            col += splat_control.b * tex2D (_Splat2, IN.uv_Splat2).rgb;
            col += splat_control.a * tex2D (_Splat3, IN.uv_Splat3).rgb;
            o.Albedo = col;
            o.Alpha = 1;
            if(tex2D(_Splat0, IN.uv_Splat0).a == 0)
                o.Alpha = 1 - splat_control.r;
            else if(tex2D(_Splat1, IN.uv_Splat1).a == 0)
                o.Alpha = 1 - splat_control.g;
            else if(tex2D(_Splat2, IN.uv_Splat2).a == 0)
                o.Alpha = 1 - splat_control.b;
            else if(tex2D(_Splat3, IN.uv_Splat3).a == 0)
                o.Alpha = 1 - splat_control.a;
        }
        ENDCG
    }

    Dependency "AddPassShader" = "Hidden/TerrainEngine/Splatmap/Lightmap-AddPass"
    Dependency "BaseMapShader" = "Diffuse"

    //Fallback to Diffuse
    Fallback "Diffuse"
}