Okay so I’ve built my model in my 3D package (a simple room). I’ve unwrapped it, textured it and got everything into Unity. Great.
When texturing I followed a lot of the performance and optimization recommendations, hence, it’s one material and just one big texture, a texture atlas.
So umm, how do map slots work with just one material?
For instance, I want the walls to have some specularity to them, but I don’t the carpet to be shiny. Likewise, I want a normal map on the carpet, but not on the walls.
How can you apply different effects like that when you’re only working with one material and one texture?
You can just build specular and normal atlas-maps that are aligned with your main color texture.
For the spec atlas you would color the un-shiny carpet sections of the spec atlas black, for instance. Same with the normal map, the sections that you want un-normalled you would color flat, which typically in Photoshop, for instance, would be R 127, G 127 B 255. (or 127,127,127 if you’re using greyscale bump maps).
For an example, look at the buildings_a and building_a_bump texture atlases from the Bootcamp demo.
That’s not possible, you must use specific materials in this scenario. Still, texture atlas will reduce overhead. Use same materials where it’s possible.