How to account for tiling in shader uv coords?

I have a fragment shader that looks like

     Properties {
      _Color ("Color", Color) = (1,1,1,1)
      _MainTex ("Main Tex (RGBA)", 2D) = "white" {}
      _Progress ("Progress", Range(0.0,1.0)) = 0.0
     }
      
     SubShader {
     Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
     //ZTest Always - testing this to remove always ontop
     Blend SrcAlpha OneMinusSrcAlpha
     Pass {
      
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             #include "UnityCG.cginc"
              
             uniform sampler2D _MainTex;
             uniform float4 _Color;
             uniform float _Progress;
             uniform float4 _MainTex_ST;
              
             struct v2f {
                 float4 pos : POSITION;
                 float2 uv : TEXCOORD0;
             };
              
             v2f vert (appdata_base v)
             {
                 v2f o;
                 o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
                 o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
              
                 return o;
             }
              
             half4 frag( v2f i ) : COLOR
             {
                 half4 color = tex2D( _MainTex, i.uv);
                 if(i.uv.x > (1.0 - _Progress))
                 {
                     if(color.a != 0)
                     {
                         color.a = 1;
                     }
                 }else
                 {
                     color.a = 0;
                 }
                 
                 return tex2D(_MainTex, i.uv) * color * _Color;
             }
              
             ENDCG
         }
     }

Its point is to allow only showing the specified progress of whatever it's on.

If I tile the texture, when I access the uv's coords, it only returns the coords within 1 element of the tile. But I want them in terms of the entire width of the billboard I'm tiling the texture on. Is there a way to do this?