Combine texture with texture already combained in alpha layer.

Hi

Looking around the internet, I found this particular shader that I need to change a little to get it to work as I need, and I need a little help.

Code (CSharp):

1. Shader "Custom/Map Borders" ////////// Shader renamed
2. {
3.     Properties
4.     {
5.         _Color("Mask Color", Color) = (1, 1, 1, 1) ////////// _Color property added to this shader
6.         _MainTex("Base Texture (RGB)", 2D) = "white" {}
7.     _Mask("Culling Mask", 2D) = "white" {}
8.     _Cutoff("Alpha cutoff", Range(0,1)) = 0.1
9.     }
10.         SubShader
11.     {
12.         Tags{ "Queue" = "Transparent" }
13.         Cull Off ////////// I added this line to have the both sides of my plane mesh visible
14.         Lighting Off
15.         ZWrite Off
16.         Blend SrcAlpha OneMinusSrcAlpha
17.         AlphaTest GEqual[_Cutoff]
18.         Pass
19.     {
20.         SetTexture[_Mask]{
21.         constantColor[_Color]
22.         Combine texture * constant ////////// The alpha component of the _Color property defines the Culling Mask opacity (depending on the distance between the player and the grid)
23.     }
24.         SetTexture[_MainTex]{ combine texture, previous }
25.     }
26.     }
27. }

With this shader, I get a texture combined with an alpha, like if it was in a Mask Layer in photoshop:

The thing, is that I need a new MainTex (so the old one could be something like _MaskTex) that can go as a usual standard material, and layered above, this 2 layers of Masked Textures.

I am sorry if my explanation of what I want is not the best I can write, and less with so little experience touching shader scripts. Any help is appreciated.

Thanks for the attention.