How it works...

Unity has made the task of getting your shader environment up and running very easy for you. It is simply a matter of a few clicks and you are good to go. There are a lot of elements working in the background with regard to the Surface Shader itself. Unity has taken the Cg shader language and made it more efficient to write by doing a lot of the heavy Cg code lifting for you. The Surface Shader language is a more component-based way of writing shaders. Tasks such as processing your own texture coordinates and transformation matrices have already been done for you, so you don't have to start from scratch any more. In the past, we would have to start a new shader and rewrite a lot of code over and over again. As you gain more experience with Surface Shaders, you will naturally want to explore more of the underlying functions of the Cg language and how Unity is processing all of the low-level graphics processing unit (GPU) tasks for you.

All the files in a Unity project are referenced independently from the folder that they are in. We can move shaders and materials from within the editor without the risk of breaking any connection. Files, however, should never be moved from outside the editor as Unity will not be able to update their references.

So, by simply changing the shader's path name to a name of our choice, we have got our basic diffuse shader working in the Unity environment, with lights and shadows and all that, just by changing one line of code!