Unity3D Shader：高斯模糊

C#代码：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;


public class GaoSiMouHu : MonoBehaviour {
    //高斯模糊 正态分布
    public Material mat;


    public float radio=1f;//半径


    public int downSample = 1;//分辨率进行缩放


    public int iteration = 1;//迭代次数


    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        RenderTexture rt1 = RenderTexture.GetTemporary(source.width >> downSample, source.height >> downSample, 0, source.format);
        RenderTexture rt2 = RenderTexture.GetTemporary(source.width >> downSample, source.height >> downSample, 0, source.format);
        Graphics.Blit(source, rt1);


        for (int i = 0; i < iteration; i++)
        {
            mat.SetVector("_Offset", new Vector4(0, radio, 0, 0));
            Graphics.Blit(rt1, rt2, mat);


            mat.SetVector("_Offset", new Vector4(radio, 0, 0, 0));
            Graphics.Blit(rt2, rt1, mat);


        }
        Graphics.Blit(rt1, destination);


        RenderTexture.ReleaseTemporary(rt1);
        RenderTexture.ReleaseTemporary(rt2);
    }

}

Shader代码：

Shader "Unlit/Test"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100


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;
float4 uv01:TEXCOORD1;
float4 uv23:TEXCOORD2;
float4 uv45:TEXCOORD3;
};


sampler2D _MainTex;
float4 _MainTex_TexelSize;
float4 _Offset;


v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv =v.vertex.xy;
_Offset*=_MainTex_TexelSize.xyxy;
o.uv01=v.vertex.xyxy+_Offset.xyxy*float4(1,1,-1,-1);
o.uv23=v.vertex.xyxy+_Offset.xyxy*float4(1,1,-1,-1)*2.0;
o.uv45=v.vertex.xyxy+_Offset.xyxy*float4(1,1,-1,-1)*3.0;
return o;
}

fixed4 frag (v2f i) : SV_Target
{
// sample the texture
fixed4 col =fixed4(0,0,0,0);//正态分布，权值线性变化
col+=0.4*tex2D(_MainTex,i.uv);
col+=0.15*tex2D(_MainTex,i.uv01.xy);
col+=0.15*tex2D(_MainTex,i.uv01.zw);
col+=0.10*tex2D(_MainTex,i.uv23.xy);
col+=0.10*tex2D(_MainTex,i.uv23.zw);
col+=0.05*tex2D(_MainTex,i.uv45.xy);
col+=0.05*tex2D(_MainTex,i.uv45.zw);


return col;
}
ENDCG
}
}

}