The scrolling system starts with the declaration of a couple of properties, which will allow the user of this shader to increase or decrease the speed of the scrolling effect itself. At their core, they are float values being passed from the material's Inspector tab to the surface function of the shader. For more information on shader properties, see Chapter 2, Creating Your First Shader.
Once we have these float values from the material's Inspector tab, we can use them to offset our UV values in the shader.
To begin this process, we first store the UVs in a separate variable called scrolledUV. This variable has to be float2/fixed2 because the UV values are being passed to us from the Input structure:
struct Input { float2 ...
