Unity3D UGUI特效之Image高斯模糊效果

2020-01-24 00:09:07

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这几天研究了下模糊特效，看了很多文章，其原理就是拿取图片或屏幕数据，然后将周围的元素和目标位置的颜色值进行一个融合计算，然后自己写了一个小小的测试程序。

这个模糊也可以分成两种，一个是自身模糊，一个是从屏幕上取值进行模糊。第一个用于一些小的列表展示，比如未解锁时，是模糊的。第二个是凸显弹框效果的，将背景都模糊掉，自己将这个稍微加强了些可以指定模糊一个位置。

针对移动平台，使用高斯模糊，其实效率不是很高，如果要很好的效果，那么速度卡；如果要速度快，那么效果达不到要求。但是还是在这里记录下，兴许以后能用上。

先说第一个，挂在Image下的模糊特效。

Shader "Custom/FrontBlur" { Properties { [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {} _Color ("Tint", Color) = (1,1,1,1)  [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 [HideInInspector]_ColorMask ("Color Mask", Float) = 15 [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0  _Size ("Size", Range(0, 50)) = 5 } 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 "FrontBlurHor" CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma target 2.0 #include "UnityCG.cginc" #include "UnityUI.cginc" #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 };  fixed4 _Color; fixed4 _TextureSampleAdd; float4 _ClipRect; v2f vert(appdata_t IN) { v2f OUT; UNITY_SETUP_INSTANCE_ID(IN); UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT); OUT.worldPosition = IN.vertex; OUT.vertex = UnityObjectToClipPos(OUT.worldPosition); OUT.texcoord = IN.texcoord;  OUT.color = IN.color * _Color; return OUT; } sampler2D _MainTex; float4 _MainTex_TexelSize; float _Size; half4 GrabPixel(v2f i, float weight, float kernelx){ if (_Size <= 1 || weight == 0){  return tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size, i.texcoord.y)) * weight; }else{  half4 sum = half4(0,0,0,0);  sum += tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size*0.2, i.texcoord.y))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size*0.4, i.texcoord.y))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size*0.6, i.texcoord.y))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size*0.8, i.texcoord.y))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x + _MainTex_TexelSize.x*kernelx*_Size*1.0, i.texcoord.y))*0.2;  return (sum + _TextureSampleAdd) * weight; } } half4 GrabPixely(v2f i, float weight, float kernely){ if (_Size <= 1 || weight == 0){  return tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size)) * weight; }else{  half4 sum = half4(0,0,0,0);  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.2))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.4))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.6))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.8))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*1.0))*0.2;  return (sum + _TextureSampleAdd) * weight; } } fixed4 frag(v2f IN) : SV_Target { half4 sum = half4(0,0,0,0); // #define GRABPIXEL(weight, kernelx) (tex2D(_MainTex, half2(IN.texcoord.x + _MainTex_TexelSize.x * kernelx*_Size, IN.texcoord.y)) + _TextureSampleAdd) * weight  // sum += GrabPixel(IN, 0.05, -4.0); // sum += GrabPixel(IN, 0.09, -3.0); // sum += GrabPixel(IN, 0.12, -2.0); // sum += GrabPixel(IN, 0.15, -1.0); // sum += GrabPixel(IN, 0.18, 0.0); // sum += GrabPixel(IN, 0.15, +1.0); // sum += GrabPixel(IN, 0.12, +2.0); // sum += GrabPixel(IN, 0.09, +3.0); // sum += GrabPixel(IN, 0.05, +4.0); for(int i=0;i<9;i++){  sum += GrabPixel(IN, 1.0/9, i-4.0); } // half4 sumy = half4(0,0,0,0); // for(int i=0;i<15;i++){ // sumy += GrabPixely(IN, 1.0/15, i-7.0); // } // half4 sum = (sumx + sumy) * 0.5; // sum += GrabPixel(IN, 0.01, -9.0); // sum += GrabPixel(IN, 0.02, -8.0); // sum += GrabPixel(IN, 0.03, -7.0); // sum += GrabPixel(IN, 0.04, -6.0); // sum += GrabPixel(IN, 0.05, -5.0); // sum += GrabPixel(IN, 0.06, -4.0); // sum += GrabPixel(IN, 0.07, -3.0); // sum += GrabPixel(IN, 0.08, -2.0); // sum += GrabPixel(IN, 0.09, -1.0); // sum += GrabPixel(IN, 0.10, 0.0); // sum += GrabPixel(IN, 0.09, +1.0); // sum += GrabPixel(IN, 0.08, +2.0); // sum += GrabPixel(IN, 0.07, +3.0); // sum += GrabPixel(IN, 0.06, +4.0); // sum += GrabPixel(IN, 0.05, +5.0); // sum += GrabPixel(IN, 0.04, +6.0); // sum += GrabPixel(IN, 0.03, +7.0); // sum += GrabPixel(IN, 0.02, +8.0); // sum += GrabPixel(IN, 0.01, +9.0); sum = sum * IN.color; sum.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect); #ifdef UNITY_UI_ALPHACLIP clip (sum.a - 0.001); #endif return sum; // float distance = _Distance; // fixed4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color /= 9;  // color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);  // #ifdef UNITY_UI_ALPHACLIP // clip (color.a - 0.001); // #endif // return color; } ENDCG } Pass { Name "FrontBlurVer" CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma target 2.0 #include "UnityCG.cginc" #include "UnityUI.cginc" #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 };  fixed4 _Color; fixed4 _TextureSampleAdd; float4 _ClipRect; v2f vert(appdata_t IN) { v2f OUT; UNITY_SETUP_INSTANCE_ID(IN); UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT); OUT.worldPosition = IN.vertex; OUT.vertex = UnityObjectToClipPos(OUT.worldPosition); OUT.texcoord = IN.texcoord;  OUT.color = IN.color * _Color; return OUT; } sampler2D _MainTex; float4 _MainTex_TexelSize; float _Size; half4 GrabPixel(v2f i, float weight, float kernely){ if (_Size <= 1 || weight == 0){  return tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size)) * weight; }else{  half4 sum = half4(0,0,0,0);  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.2))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.4))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.6))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*0.8))*0.2;  sum += tex2D(_MainTex, half2(i.texcoord.x, i.texcoord.y + _MainTex_TexelSize.y*kernely*_Size*1.0))*0.2;  return (sum + _TextureSampleAdd) * weight; } } fixed4 frag(v2f IN) : SV_Target { half4 sum = half4(0,0,0,0);  // #define GRABPIXEL(weight, kernely) (tex2D(_MainTex, half2(IN.texcoord.x, IN.texcoord.y + _MainTex_TexelSize.y * kernely*_Size)) + _TextureSampleAdd) * weight  // sum += GrabPixel(IN, 0.05, -4.0); // sum += GrabPixel(IN, 0.09, -3.0); // sum += GrabPixel(IN, 0.12, -2.0); // sum += GrabPixel(IN, 0.15, -1.0); // sum += GrabPixel(IN, 0.18, 0.0); // sum += GrabPixel(IN, 0.15, +1.0); // sum += GrabPixel(IN, 0.12, +2.0); // sum += GrabPixel(IN, 0.09, +3.0); // sum += GrabPixel(IN, 0.05, +4.0); for(int i=0;i<9;i++){  sum += GrabPixel(IN, 1.0/9, i-4.0); } // sum += GrabPixel(IN, 0.01, -9.0); // sum += GrabPixel(IN, 0.02, -8.0); // sum += GrabPixel(IN, 0.03, -7.0); // sum += GrabPixel(IN, 0.04, -6.0); // sum += GrabPixel(IN, 0.05, -5.0); // sum += GrabPixel(IN, 0.06, -4.0); // sum += GrabPixel(IN, 0.07, -3.0); // sum += GrabPixel(IN, 0.08, -2.0); // sum += GrabPixel(IN, 0.09, -1.0); // sum += GrabPixel(IN, 0.10, 0.0); // sum += GrabPixel(IN, 0.09, +1.0); // sum += GrabPixel(IN, 0.08, +2.0); // sum += GrabPixel(IN, 0.07, +3.0); // sum += GrabPixel(IN, 0.06, +4.0); // sum += GrabPixel(IN, 0.05, +5.0); // sum += GrabPixel(IN, 0.04, +6.0); // sum += GrabPixel(IN, 0.03, +7.0); // sum += GrabPixel(IN, 0.02, +8.0); // sum += GrabPixel(IN, 0.01, +9.0); sum = sum * IN.color; sum.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect); #ifdef UNITY_UI_ALPHACLIP clip (sum.a - 0.001); #endif return sum; // float distance = _Distance; // fixed4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x + distance, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y - distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x - distance, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color += (tex2D(_MainTex, half2(IN.texcoord.x, IN.texcoord.y + distance)) + _TextureSampleAdd) * IN.color; // color /= 9;  // color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);  // #ifdef UNITY_UI_ALPHACLIP // clip (color.a - 0.001); // #endif // return color; } ENDCG } }}

里面分了两个Pass来计算，这样算出的效果会好很多，然后里面试了跟多的计算，越多的分层，那么得到的效果也越高，也意味着更加的不流畅。将shader放到一个新建的材质球上，然后把材质拖到Image组件的Material属性栏上就可以了。

看看效果：

然后说第二个方式，它是将背景都给模糊的效果。

Shader "Custom/BackBlur"{ Properties {  [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {} _Color ("Main Color", Color) = (1,1,1,1)  _Size ("Size", Range(0, 20)) = 1 } Category {    // We must be transparent, so other objects are drawn before this one.   Tags {  "Queue"="Transparent"  "IgnoreProjector"="True"  "RenderType"="Transparent" "PreviewType" = "Plane" "CanUseSpriteAtlas" = "True" }     SubShader {     // Horizontal blur    GrabPass {          Tags { "LightMode" = "Always" }    }    Pass {    Tags { "LightMode" = "Always" }     Name "BackBlurHor"    CGPROGRAM     #pragma vertex vert     #pragma fragment frag     #pragma fragmentoption ARB_precision_hint_fastest     #include "UnityCG.cginc"      struct appdata_t {      float4 vertex : POSITION;      float2 texcoord : TEXCOORD0;  float4 color : COLOR;    };      struct v2f {      float4 vertex : POSITION;      float4 uvgrab : TEXCOORD0;  float4 color : COLOR;    };     v2f vert (appdata_t v) {      v2f o;      o.vertex = UnityObjectToClipPos(v.vertex);      #if UNITY_UV_STARTS_AT_TOP      float scale = -1.0;      #else      float scale = 1.0;      #endif      o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;      o.uvgrab.zw = o.vertex.zw;   o.color = v.color;     return o;     }      sampler2D _GrabTexture;     float4 _GrabTexture_TexelSize;  float4 _MainTex_TexelSize;    float _Size;    uniform float4 _Color;    // static float GaussianKernel[9] = {    //  0.05, 0.09, 0.12,    //  0.15, 0.18, 0.15,    //  0.12, 0.09, 0.05    // };    // static float GaussianKernel[19] = {    //  0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09,    //  0.1,    //  0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01,    // };    // static float GaussianKernelD[19] = {    //  -9.0, -8.0, -7.0, -6.0, -5.0, -4.0, -3.0, -2.0, -1.0,    //  0.0,    //  +1.0, +2.0, +3.0, +4.0, +5.0, +6.0, +7.0, +8.0, +9.0,    // };    half4 GrabPixel(v2f i, float weight, float kernelx){     if (i.uvgrab.x == 0 && i.uvgrab.y == 0){      kernelx = 0;     }     return tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x*kernelx*_Size, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w))) * weight;    }    half4 frag( v2f i ) : COLOR {      half4 sum = half4(0,0,0,0);     // #define GRABPIXEL(weight, kernelx) tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx*_Size, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w))) * weight          sum += GrabPixel(i, 0.05, -4.0);     sum += GrabPixel(i, 0.09, -3.0);     sum += GrabPixel(i, 0.12, -2.0);     sum += GrabPixel(i, 0.15, -1.0);     sum += GrabPixel(i, 0.18, 0.0);     sum += GrabPixel(i, 0.15, +1.0);     sum += GrabPixel(i, 0.12, +2.0);     sum += GrabPixel(i, 0.09, +3.0);     sum += GrabPixel(i, 0.05, +4.0);     // sum += GrabPixel(i, 0.01, -9.0);     // sum += GrabPixel(i, 0.02, -8.0);     // sum += GrabPixel(i, 0.03, -7.0);     // sum += GrabPixel(i, 0.04, -6.0);     // sum += GrabPixel(i, 0.05, -5.0);     // sum += GrabPixel(i, 0.06, -4.0);     // sum += GrabPixel(i, 0.07, -3.0);     // sum += GrabPixel(i, 0.08, -2.0);     // sum += GrabPixel(i, 0.09, -1.0);     // sum += GrabPixel(i, 0.10, 0.0);     // sum += GrabPixel(i, 0.09, +1.0);     // sum += GrabPixel(i, 0.08, +2.0);     // sum += GrabPixel(i, 0.07, +3.0);     // sum += GrabPixel(i, 0.06, +4.0);     // sum += GrabPixel(i, 0.05, +5.0);     // sum += GrabPixel(i, 0.04, +6.0);     // sum += GrabPixel(i, 0.03, +7.0);     // sum += GrabPixel(i, 0.02, +8.0);     // sum += GrabPixel(i, 0.01, +9.0);     float4 col5 = tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uvgrab));  float decayFactor = 1.0f;  if (i.uvgrab.x == 0 && i.uvgrab.y == 0){  decayFactor = 0;  }  sum = lerp(col5, sum, decayFactor) * i.color * _Color;      return sum;     }     ENDCG    }    // Vertical blur    GrabPass {           Tags { "LightMode" = "Always" }    }    Pass {     Tags { "LightMode" = "Always" }    Name "BackBlurVer"    CGPROGRAM     #pragma vertex vert     #pragma fragment frag     #pragma fragmentoption ARB_precision_hint_fastest     #include "UnityCG.cginc"      struct appdata_t {      float4 vertex : POSITION;      float2 texcoord: TEXCOORD0;   float4 color : COLOR;    };      struct v2f {      float4 vertex : POSITION;      float4 uvgrab : TEXCOORD0;   float4 color : COLOR;    };      v2f vert (appdata_t v) {      v2f o;      o.vertex = UnityObjectToClipPos(v.vertex);      #if UNITY_UV_STARTS_AT_TOP      float scale = -1.0;      #else      float scale = 1.0;      #endif      o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;      o.uvgrab.zw = o.vertex.zw;   o.color = v.color;     return o;     }      sampler2D _GrabTexture;     float4 _GrabTexture_TexelSize;     float _Size;    uniform float4 _Color;    half4 GrabPixel(v2f i, float weight, float kernely){     if (i.uvgrab.x == 0 && i.uvgrab.y == 0){      kernely = 0;     }     return tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _GrabTexture_TexelSize.y*kernely*_Size, i.uvgrab.z, i.uvgrab.w))) * weight;    }     half4 frag( v2f i ) : COLOR {     half4 sum = half4(0,0,0,0);      // #define GRABPIXEL(weight,kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely*_Size, i.uvgrab.z, i.uvgrab.w))) * weight       sum += GrabPixel(i, 0.05, -4.0);     sum += GrabPixel(i, 0.09, -3.0);     sum += GrabPixel(i, 0.12, -2.0);     sum += GrabPixel(i, 0.15, -1.0);     sum += GrabPixel(i, 0.18, 0.0);     sum += GrabPixel(i, 0.15, +1.0);     sum += GrabPixel(i, 0.12, +2.0);     sum += GrabPixel(i, 0.09, +3.0);     sum += GrabPixel(i, 0.05, +4.0);     // sum += GrabPixel(i, 0.01, -9.0);     // sum += GrabPixel(i, 0.02, -8.0);     // sum += GrabPixel(i, 0.03, -7.0);     // sum += GrabPixel(i, 0.04, -6.0);     // sum += GrabPixel(i, 0.05, -5.0);     // sum += GrabPixel(i, 0.06, -4.0);     // sum += GrabPixel(i, 0.07, -3.0);     // sum += GrabPixel(i, 0.08, -2.0);     // sum += GrabPixel(i, 0.09, -1.0);     // sum += GrabPixel(i, 0.10, 0.0);     // sum += GrabPixel(i, 0.09, +1.0);     // sum += GrabPixel(i, 0.08, +2.0);     // sum += GrabPixel(i, 0.07, +3.0);     // sum += GrabPixel(i, 0.06, +4.0);     // sum += GrabPixel(i, 0.05, +5.0);     // sum += GrabPixel(i, 0.04, +6.0);     // sum += GrabPixel(i, 0.03, +7.0);     // sum += GrabPixel(i, 0.02, +8.0);     // sum += GrabPixel(i, 0.01, +9.0);  float4 col5 = tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uvgrab));  float decayFactor = 1.0f;  if (i.uvgrab.x == 0 && i.uvgrab.y == 0){  decayFactor = 0;  }  sum = lerp(col5, sum, decayFactor) * i.color * _Color;      return sum;     }     ENDCG    }  }  } }

计算是一样的，不过这个相对来说要慢，毕竟是将整个屏幕那来计算的，肯定会慢很多。用法也一样，shader放到一个新建的材质球上，然后将材质球拖到一个Image组件的Material属性栏中即可，这里你可以调整Image的宽高，这样可以指定模糊那一块区域了。

看效果：