Shader "URP/GridShader"
{
	Properties
	{
		_Size("Size",vector) = (1,1,0,0)
		_Alpha("Alpha",Range(0, 1)) = 1
		_UserInput("UserInput",Range(0, 1)) = 0
    }
    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue" = "Transparent"}

		blend srcalpha oneminussrcalpha
		zwrite off
		ztest off
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

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

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
				float3 worldPos : TEXCOORD1;
            };

			struct RenderData {
				int barrier;
				float isSelected;
				float r;
				float g;
				float b;
			};

			StructuredBuffer<RenderData> _InputData;
			uniform float4 _Size;
			uniform float _Alpha;
			uniform float _UserInput;
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
				o.worldPos = mul(unity_ObjectToWorld, v.vertex);
				o.uv = v.uv;
                return o;
            }

#define width _Size.x
#define height _Size.y
            fixed4 frag (v2f i) : SV_Target
            {
				//细的分割线
				float x0 = i.uv.x * width;
				float y0 = i.uv.y * height;

				fixed xLine0 = abs((x0 - floor(x0)) - 0.5) * 2.0;
				fixed yLine0 = abs((y0 - floor(y0)) - 0.5) * 2.0;
				fixed edgeLine0 = max(xLine0, yLine0);

				float w0 = fwidth(edgeLine0 * 0.5) * 2.0;
				edgeLine0 = smoothstep(-w0, w0, edgeLine0 - 0.925);
				//细的分割线结束

				//粗的分割线
				float x1 = i.uv.x * width * 0.05;
				float y1 = i.uv.y * height * 0.05;

				fixed xLine1 = abs((x1 - floor(x1)) - 0.5) * 2.0;
				fixed yLine1 = abs((y1 - floor(y1)) - 0.5) * 2.0;
				fixed edgeLine1 = max(xLine1, yLine1);

				float w1 = fwidth(edgeLine1 * 0.5) * 2.0;
				edgeLine1 = smoothstep(-w1, w1, edgeLine1 - 0.925);
				//粗的分割线结束

				float cameraDis = distance(_WorldSpaceCameraPos.xyz, i.worldPos);
				float cameraFade = smoothstep(70, 100, cameraDis);
				fixed3 col = fixed3(0, 0, 0);
				
				if(_UserInput < 0.5)
				{
					col = fixed3(1,1,1);			
					cameraFade = 1; //只显示粗线
            		float lineAlpha = max(edgeLine0 * (1 - cameraFade), edgeLine1 * cameraFade);
					return fixed4(col, _Alpha * lineAlpha * 0.5);
				}
				
				int index = floor(x0) + floor(y0) * width;	
				col = fixed3(_InputData[index].r, _InputData[index].g, _InputData[index].b);
				col = lerp(col, fixed3(1, 1, 1), edgeLine0 * (1 - cameraFade));
				col = lerp(col, fixed3(0, 0, 0), edgeLine1 * cameraFade);
				col = lerp(col, fixed3(1, 1, 0), _InputData[index].isSelected);
				return fixed4(col, _Alpha);
				
            }
            ENDCG
        }
    }
}