This is sort of working backwards but I have an existing rgb texture, a leaf scan with alpha.
I want to use this on a gameObject.
Normally I assume you would use as simple geometry as possible, a quad, and then use a Stencil shader referencing the alpha channel of the texture.
But don’t I also need to create both UV and Normal maps?
How would I create these if all I have is the RGB texture?
Apply it to a plane in Unity. If the texture doesn’t work correctly, UVs will be needed. Apply it to a Plane in 3D package, including the alpha. Export/import into Unity.
If you want a normal map - the simplest process is to convert the rgb into a grey scale image and save as a separate file (leaf_normal). Unity will convert it to a normal map when you apply it to the normal map slot in the shader. This is not the most accurate process to generate a normal map - but it is the quickest.