When the Standard Shader is used from the Inspector of a material, the process behind texture mapping is completely transparent to developers. If we want to understand how it works, it's necessary to take a closer look at TexturedShader. From the Properties section, we can see that the Albedo (RGB) texture is actually referred to in the code as _MainTex:
_MainTex ("Albedo (RGB)", 2D) = "white" {}
In the CGPROGRAM section, this texture is defined as sampler2D, the standard type for 2D textures:
sampler2D _MainTex;
The following line shows a struct called Input. This is the input parameter for the surface function and contains a packed array called uv_MainTex:
struct Input {
float2 uv_MainTex;
};
Every time the surf() function ...
