Unity shader学习之屏幕后期处理效果之均值模糊

均值模糊，也使用卷积来实现，之不过卷积中每个值均相等，且相加等于1。

代码如下，

子类：

 using UnityEngine;

 public class MeanBlurRenderer : PostEffectRenderer
 {
     protected override string ShaderName
     {
         get { return "Custom/Mean Blur"; }
     }
 }

MeanBlurRenderer

shader

 Shader "Custom/Mean Blur"
 {
     Properties
     {
         _MainTex("Main Texture", 2D) = "white" {}
     }

     SubShader
     {
         Pass
         {
             Cull Off
             ZWrite Off
             ZTest Always

             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag

             sampler2D _MainTex;
             float4 _MainTex_TexelSize;

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

             struct v2f
             {
                 float4 pos : SV_POSITION;
                 float2 uv[] : TEXCOORD0;
             };

             v2f vert(appdata v)
             {
                 v2f o;
                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(-, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(-, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, );
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(-, -);
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, -);
                 o.uv[] = v.uv + _MainTex_TexelSize.xy * float2(, -);
                 return o;
             }

             fixed4 frag(v2f i) : SV_TARGET
             {
                 float4 col = float4(, , , );
                 for(int k = ; k < ; k++)
                 {
                     float4 tex = tex2D(_MainTex, i.uv[k]);
                     col += tex;
                 }
                 return col * 0.1111;
             }

             ENDCG
         }
     }

     Fallback Off
 }

效果，左边为正常，右边为均值模糊：