五彩斑斓的黑+高斯模糊

Shader "xShader/UGUIImage"
{
 Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)

        _StencilComp ("Stencil Comparison", Float) = 8
        _Stencil ("Stencil ID", Float) = 0
        _StencilOp ("Stencil Operation", Float) = 0
        _StencilWriteMask ("Stencil Write Mask", Float) = 255
        _StencilReadMask ("Stencil Read Mask", Float) = 255

        _ColorMask ("Color Mask", Float) = 15

        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0

        // Gaussian Blur
        _TextureSize ("_TextureSize",Float) = 256
        _BlurRadius ("_BlurRadius",Range(0,4) ) = 3
        // Gray
        _Gray ("_Gray",Range(0,1) ) = 0.2
    }

    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
        {
            Name "Default"
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0

            #include "UnityCG.cginc"
            #include "UnityUI.cginc"

            #pragma multi_compile __ UNITY_UI_CLIP_RECT
            #pragma multi_compile __ UNITY_UI_ALPHACLIP

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                float2 texcoord  : TEXCOORD0;
                float4 worldPosition : TEXCOORD1;
                UNITY_VERTEX_OUTPUT_STEREO
            };

            sampler2D _MainTex;
            fixed4 _Color;
            fixed4 _TextureSampleAdd;
            float4 _ClipRect;
            float4 _MainTex_ST;

            float4 _MainTex_TexelSize;

            // Gaussian Blur
            float _TextureSize;
            float _BlurRadius;

            //Gray
            float _Gray;

            float4 GetBlurColor( float2 uv,fixed4 inColor)
            {
                float space = 1.0/_TextureSize; //算出一个像素的空间
                int count = _BlurRadius * 2  + 1; //取值范围
                count *= count;
                //将以自己为中心，周围半径的所有颜色相加，然后除以总数，求得平均值
                float4 colorTmp = float4(0,0,0,0);
                for( int x = -_BlurRadius ; x <= _BlurRadius ; x++ )
                {
                    for( int y = -_BlurRadius ; y <= _BlurRadius ; y++ )
                    {
                        // float4 color = tex2D(_MainTex,uv + float2(x * space,y * space));
                        half4 color = (tex2D(_MainTex,uv + float2(x * space,y * space))) * inColor;
                        colorTmp += color;
                    }  
                }
                return colorTmp/count;
            }


            v2f vert(appdata_t v)
            {
                v2f OUT;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
                OUT.worldPosition = v.vertex;
                OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);

                OUT.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);

                OUT.color = v.color * _Color;
                return OUT;
            }


            fixed4 frag(v2f IN) : SV_Target
            {

                half4 color;

                if(_BlurRadius == 0) {
                    color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
                }else {
                    // Gaussian Blur
                    color = GetBlurColor(IN.texcoord,IN.color);
                }

                // 五彩斑斓的灰
                if(_Gray>0) {
                    float baseGray = (color.r * 0.299f + color.g * 0.578f + color.b * 0.114f);
                    color.r = baseGray * (1.0f -_Gray) + color.r * _Gray ;
                    color.g = baseGray * (1.0f - _Gray) + color.g * _Gray ;
                    color.b = baseGray * (1.0f - _Gray)  + color.b * _Gray ;
                }

                #ifdef UNITY_UI_CLIP_RECT
                color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
                #endif

                #ifdef UNITY_UI_ALPHACLIP
                clip (color.a - 0.001);
                #endif

                return color;
            }
        ENDCG
        }
    }
}