【011-Shader-高斯模糊】

// 高斯模糊
/**
3*3 高斯矩阵 col/16
float3X3 rot = {
    
    
    1,2,1,
    2,4,2,
    1,2,1,
}

把某一个像素的相邻像素和自身按照比例进行了混合，用新的值代替原像素
**/
Shader "Hidden/11-BlurShader"
{
    
    
    Properties
    {
    
    
        _MainTex ("Texture", 2D) = "white" {
    
    }
    }
    SubShader
    {
    
    
        // No culling or depth
        Cull Off ZWrite Off ZTest Always
        Blend SrcAlpha OneMinusSrcAlpha 

        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;
            };

            v2f vert (appdata v)
            {
    
    
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            sampler2D _MainTex;
            float4 _MainTex_TexelSize;

            /**

            要获取像素点周围的所有像素

            3*3 高斯矩阵 col/16
            float3X3 rot = {
    
    
                1,2,1,
                2,4,2,
                1,2,1,
            }
            
            **/
            fixed4 frag (v2f i) : SV_Target
            {
    
    
                fixed4 col = tex2D(_MainTex, i.uv);

                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(-1,-1))*1;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(0,-1))*2;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(1,-1))*1;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(-1,0))*2;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(0,0))*4;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(1,0))*2;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(-1,1))*1;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(0,1))*2;
                col+= tex2D(_MainTex,i.uv + _MainTex_TexelSize.xy*fixed2(1,1))*1;
                
                col = col/16;

                return col;
            }
            ENDCG
        }
    }
}