描边轮廓Shader,有懂shader的进

Shader "Esfog/OutLine/Mix"
{
Properties
{
_MainTex ("Base (RGB)", 2D) = "white" {}
}
SubShader
{
Tags { "RenderType"="Opaque" }
Pass
{
CGPROGRAM
#pragma vertex vert_img
#pragma fragment frag
#include "UnityCG.cginc"
uniform sampler2D _MainTex;
uniform sampler2D _OcclusionTex;
uniform sampler2D _StretchTex;
float4 frag(v2f_img i):COLOR
{
float4 srcCol = tex2D(_MainTex,i.uv);
float4 occlusionCol = tex2D(_OcclusionTex,i.uv);
float4 stretchCol = tex2D(_StretchTex,i.uv);
float occlusionTotal = occlusionCol.r + occlusionCol.g + occlusionCol.b;
float stretchTotal = stretchCol.r + stretchCol.g + stretchCol.b;
if(occlusionTotal <0.01f&&stretchTotal>0.01f)
{
return float4(stretchCol.rgb,srcCol.a);
}
else
{
return srcCol;
}
}
ENDCG
}
}
FallBack "Diffuse"
}
这个shader 最终进行描边，但是一旦unity开了抗锯齿，描边就会颠倒
后面写文章的博主提供了一段代码
#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
uv.y = 1-uv.y;
#endif
不知道该怎么加进去，求教