Unity Shader模糊效果

原理:对uv采样进行偏离，然后平均化
实现如下：

Shader "Blur"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0
		[Toggle]_BlurToggle("ToggleBlur",Range(0,1)) = 0
		_BlurSize("BlurSize",Range(0,0.1)) = 0


    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard fullforwardshadows

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex;

        struct Input
        {
            float2 uv_MainTex;
        };
		half _BlurSize;
        half _Glossiness;
        half _Metallic;
		half _BlurToggle;
        fixed4 _Color;

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void surf (Input IN, inout SurfaceOutputStandard o)
        {
            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, IN.uv_MainTex);
			fixed4 offset1 =  tex2D (_MainTex, IN.uv_MainTex + float2(0,_BlurSize));
			fixed4 offset2 = tex2D (_MainTex, IN.uv_MainTex + float2(_BlurSize,0));
			fixed4 offset3 = tex2D (_MainTex, IN.uv_MainTex + float2(_BlurSize,_BlurSize));
			fixed4 offsetColor = (c + offset1 +offset2 +offset3 )/4;
			fixed4 color = lerp(c,offsetColor,step(0.5,_BlurToggle));
            o.Albedo = color.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}