Shader "Custom/GaoSiMoHu"
{
 Properties
 {
 _MainTex ("Texture", 2D) = "white" {}
 _BlurSize("Blur size",Float)=1.0
 }
 SubShader
 {
 ZTest Always
 cull off
 ZWrite off

 CGINCLUDE//這個可以使其他pass塊都可以使用，而不用在兩個pass里都寫，減少了寫的次數
 sampler2D _MainTex;
 half4 _MainTex_TexelSize;
 float _BlurSize;
 struct v2f{
  float4 pos:SV_POSITION;
  half2 uv[5]:TEXCOORD0;
 };
 fixed4 fragBlur(v2f i):SV_Target{
  float weight[3]={
  0.4026,
  0.2442,
  0.0545
  };

  fixed3 sum = tex2D(_MainTex,i.uv[0]).rgb * weight[0];

  for(int it = 1; it < 3; it++){
  sum += tex2D(_MainTex,i.uv[it]).rgb * weight[it];
  sum += tex2D(_MainTex,i.uv[2 * it]).rgb * weight[it];
  }

  return fixed4(sum,1.0);
 }
 ENDCG

 Pass{
  NAME "GAUSSIAN_BLUR_VERTICAL"http://這個pass的唯一名字，可以在其他地方調用，usepass + 名字
  CGPROGRAM

  #pragma vertex vertlurVertical
  #pragma fragment fragBlur
  #include "UnityCG.cginc"
  
  v2f vertlurVertical(appdata_img v){
  v2f o;
  o.pos = UnityObjectToClipPos(v.vertex);
  half2 uv = v.texcoord;
  o.uv[0]=uv;
  o.uv[1]=uv + float2(0.0,_MainTex_TexelSize.y * 1.0) * _BlurSize;
  o.uv[2]=uv - float2(0.0,_MainTex_TexelSize.y * 1.0) * _BlurSize;
  o.uv[3]=uv + float2(0.0,_MainTex_TexelSize.y * 2.0) * _BlurSize;
  o.uv[4]=uv - float2(0.0,_MainTex_TexelSize.y * 2.0) * _BlurSize;

  return o;
  }
  ENDCG
 }

 Pass{
  NAME "GAUSSIAN_BLUR_HORIZONTAL"
  CGPROGRAM
  #pragma vertex vertlurHorizontal
  #pragma fragment fragBlur
  #include "UnityCG.cginc"

  v2f vertlurHorizontal(appdata_img v){
  v2f o;
  o.pos = UnityObjectToClipPos(v.vertex);
  half2 uv = v.texcoord;
  o.uv[0]=uv;
  o.uv[1]=uv + float2(0.0,_MainTex_TexelSize.x * 1.0) * _BlurSize;
  o.uv[2]=uv - float2(0.0,_MainTex_TexelSize.x * 1.0) * _BlurSize;
  o.uv[3]=uv + float2(0.0,_MainTex_TexelSize.x * 2.0) * _BlurSize;
  o.uv[4]=uv - float2(0.0,_MainTex_TexelSize.x * 2.0) * _BlurSize;

  return o;
  }
  ENDCG
 }
 }
}