Adding Properties to my Custom Terrain Shader in the Texture selection

Hi guys, I've made a custom terrain shader for unity and I want to have add custom values to the texture selection menu for my shader. The one problem is I can't find how unity added in the metallic property to its default shader setup for the terrain.

Unity's default



Mine



How do I put in a property like the metallic property so it shows up when you are adding textures.


** I realize now that is probably more about editor scripting. If a moderator sees this please move it for me.

 

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