Shader "Custom/Watercol"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _PaintTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            //#pragma multi_compile_fog

            #include "UnityCG.cginc"
            #include "UnityLightingCommon.cginc"

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float2 uvpaint : TEXCOORD1;
                fixed4 diff : COLOR0;
                float4 vertex : SV_POSITION;
                //UNITY_FOG_COORDS(1)
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            sampler2D _PaintTex;

            v2f vert (appdata_base v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                o.uvpaint = v.vertex.xy + v.vertex.zz;

                half3 worldNormal = UnityObjectToWorldNormal(-v.normal);
                half nl = max(0, dot(worldNormal, _WorldSpaceLightPos0.xyz));
                o.diff = nl * _LightColor0;
                o.diff.rgb += ShadeSH9(half4(worldNormal,1));

                //UNITY_TRANSFER_FOG(o,o.vertex);

                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
                fixed paint = tex2D(_PaintTex, i.uvpaint * 0.2 + col.xy * 0.35).r;

                float f = 2.5;
                i.diff *= f;
                i.diff = round(i.diff);
                i.diff /= f;
                i.diff = max(i.diff, 0.675);

                col *= i.diff;

                col.rgb += col.rgb * (paint - 0.5) * 0.8;

                //UNITY_APPLY_FOG(i.fogCoord, col);

                return col;
            }
            ENDCG
        }
    }
}