Shader "Unlit/NewUnlitShader"
{
    Properties
    {
        _MainTex ("Texture", 2DArray) = "white" {}
        _TexNo ("TexNo", 2D) = "white" {}
        _MaskNo ("MaskNo", 2D) = "black" {}
        _MaskTex ("Mask", 2DArray) = "black" {}
        _BorderColor ("BorderColor", Color) = (1,1,1,1)
        _BorderWidth ("BorderWidth", Range(0,0.1)) = 0.05
    }
    SubShader
    {
        Tags
        {
            "RenderType"="Opaque"
        }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                float2 uv2: TEXCOORD2;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float2 uv2 : TEXCOORD2;

                // UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
            };

            UNITY_DECLARE_TEX2DARRAY(_MainTex);
            sampler2D _TexNo;
            sampler2D _MaskNo;
            UNITY_DECLARE_TEX2DARRAY(_MaskTex);

            float4 _MainTex_ST;
            float4 _TexNo_TexelSize;

            float4 _BorderColor;
            float _BorderWidth;

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

            float4 Blend(float4 color, float2 uv, float mask, int layer)
            {
                float4 col2 = UNITY_SAMPLE_TEX2DARRAY(_MainTex, float3(uv , layer));
                int idx = round(mask * 16);
                float4 maskTexCol = UNITY_SAMPLE_TEX2DARRAY(_MaskTex, float3(uv , idx));
                return lerp(color, col2, maskTexCol);
            }

            int GetTexNo(float f)
            {
                float idx = (f * 64);
                return round(idx);
            }

            fixed4 showGridLine(fixed4 col, float2 uv, float2 uv1)
            {
                if (uv.x < _BorderWidth || uv.y < _BorderWidth || uv.x > 1 - _BorderWidth || uv.y > 1 - _BorderWidth)
                {
                    col = _BorderColor;
                }

                return col;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                // 整个大uv往下偏移
                float2 uv = i.uv + float2(0, _TexNo_TexelSize.y);

                // 贴图编号
                float4 texNo = tex2D(_TexNo, uv);

                int layer1 = GetTexNo(texNo.r);
                int layer2 = GetTexNo(texNo.g);
                int layer3 = GetTexNo(texNo.b);
                int layer4 = GetTexNo(texNo.a);

                // 取出遮罩值
                float4 maskNo = tex2D(_MaskNo, uv);
                float4 col = UNITY_SAMPLE_TEX2DARRAY(_MainTex, float3(i.uv2 , layer1));
                if (layer2 > 0)
                {
                    col = Blend(col, i.uv2, maskNo.g, layer2);
                }

                if (layer3 > 0)
                {
                    col = Blend(col, i.uv2, maskNo.b, layer3);
                }

                if (layer4 > 0)
                {
                    col = Blend(col, i.uv2, maskNo.a, layer4);
                }

                // col = showGridLine(col, i.uv2, i.uv);

                return col;
            }
            ENDCG
        }
    }
}