Shader "Unlit/MoveLightImage"
{
 Properties
 {
 //主紋理
 _MainTex ("Texture", 2D) = "white" {}
 //燈光紋理
 _LightTex("Light Texture",2D)="white"{}
 //遮罩紋理
 _MaskTex("Mask Texture",2D)="white"{}
 }
 SubShader
 {
 Tags {"Queue"="Transparent" "RenderType"="Transparent" }
 LOD 100
 //透明混合
 Blend SrcAlpha OneMinusSrcAlpha

 Pass
 {
 CGPROGRAM
 #pragma vertex vert
 #pragma fragment frag
 // make fog work
 #pragma multi_compile_fog
 
 #include "UnityCG.cginc"

 struct appdata
 {
 float4 vertex : POSITION;
 float2 uv : TEXCOORD0;
 };

 struct v2f
 {
 float2 uv : TEXCOORD0;
 UNITY_FOG_COORDS(1)
 float4 vertex : SV_POSITION;
 };

 sampler2D _MainTex;
 float4 _MainTex_ST;
 sampler2D _LightTex;
 sampler2D _MaskTex;
 fixed4 _Color;

 v2f vert (appdata v)
 {
 v2f o;
 o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
 o.uv = TRANSFORM_TEX(v.uv, _MainTex);
 UNITY_TRANSFER_FOG(o,o.vertex);
 return o;
 }
 
 fixed4 frag (v2f i) : SV_Target
 {
 //燈光貼圖 取一半U(xiǎn)V
 float2 uv=i.uv*0.5;
 //不斷改變uv的x軸，讓他往x軸方向移動(dòng),_Time為shader的時(shí)間函數(shù)，會(huì)一直執(zhí)行
 uv.x+=-_Time.y*0.4;
 //取燈光貼圖的alpha值,黑色為0，白色為1 
 fixed lightTexA=tex2D(_LightTex,uv).a;
 //獲取遮罩貼圖的alpha值，黑色為0，白色為1 這里的uv和上面的uv是調(diào)用的不一樣的函數(shù)
 fixed maskA=tex2D(_MaskTex,i.uv).a;

 //主紋理+燈光貼圖*遮罩貼圖 簡單原理任何數(shù)*0為0 這樣就避免了遮罩外出現(xiàn)不協(xié)調(diào)燈光貼圖
 fixed4 col = tex2D(_MainTex, i.uv)+lightTexA*maskA*0.6;
 // apply fog
 UNITY_APPLY_FOG(i.fogCoord, col); 
 return col;
 }
 ENDCG
 }
 }
}