Shader "UI/UIBlur"
{
    Properties
    {
        [PerRendererData] _MainTex ("Texture", 2D) = "white" {}
        // 模板测试属性 和 ColorMask 一般不控制，所以在属性面板上隐藏
        [HideInInspector]_StencilComp ("Stencil Comparison", Float) = 8
		[HideInInspector]_Stencil ("Stencil ID", Float) = 0
		[HideInInspector]_StencilOp ("Stencil Operation", Float) = 0
		[HideInInspector]_StencilWriteMask ("Stencil Write Mask", Float) = 255
		[HideInInspector]_StencilReadMask ("Stencil Read Mask", Float) = 255
    }
    SubShader
    {
		Tags
		{
			"Queue"="Transparent"
			"IgnoreProjector"="True"
			"RenderType"="Transparent"
			"PreviewType"="Plane"
			"CanUseSpriteAtlas"="True"
		}
		Stencil
		{
			Ref [_Stencil]
			Comp [_StencilComp]
			Pass [_StencilOp]
			ReadMask [_StencilReadMask]
			WriteMask [_StencilWriteMask]
		}
		Cull Off
		Lighting Off
		ZWrite Off
		ZTest [unity_GUIZTestMode]
		Blend SrcAlpha OneMinusSrcAlpha
		//ColorMask [_ColorMask]

        Pass
        {
                CGPROGRAM
                #pragma vertex vert
                #pragma fragment frag
                #pragma multi_compile _ UNITY_UI_ALPHACLIP
                #pragma multi_compile _ UNITY_SHADER_EDITOR
                #include "UnityUI.cginc"
                #include "UnityCG.cginc"

                fixed4 _TextureSampleAdd; // Unity管理：图片格式用Alpha8 
                float4 _ClipRect;// Unity管理：2D剪裁使用
                sampler2D _MainTex;
                sampler2D _BurTexture;
                struct a2v{
					float4 vertex       : POSITION;
					float4 color        : COLOR;
					float2 texcoord     : TEXCOORD0;
					UNITY_VERTEX_INPUT_INSTANCE_ID
            	};
				struct v2f{
                	float4 vertex       : SV_POSITION;
                	float4 color        : COLOR;
               		float2 texcoord     : TEXCOORD0;
                	UNITY_VERTEX_OUTPUT_STEREO
            	};
            	v2f vert(a2v IN){
                	v2f OUT;
                	UNITY_SETUP_INSTANCE_ID(IN);
					UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);// 实例化处理
                	OUT.vertex = UnityObjectToClipPos(IN.vertex);// 模型空间到裁剪空间
                	OUT.color = IN.color;
                	OUT.texcoord = IN.texcoord;
                	return OUT;
            	}
            	fixed4 frag(v2f IN):SV_Target{
                        // 直接读取纹理颜色 并且乘上 ImageColor
                	//half4 color = tex2D(_MainTex,IN.texcoord) ;//* IN.color;
            		float2 uv=IN.vertex.xy/_ScreenParams.xy;
            		
            		//#ifndef  UNITY_SHADER_EDITOR
            		//uv=float2(uv.x,1-uv.y);
            		//#endif
            		
            		half4 brackground = tex2D(_BurTexture,uv);//* IN.color;
            		//float alpha= color.a*IN.color.a;
            		//color.rgb=color.rgb*alpha+brackground.rgb*(1-alpha);
            		//alpha=smoothstep(0,0.2,color.a);
                	return float4(brackground.rgb,1);
				}
                 ENDCG
        }
    }
}