Just a simple question. I was experimenting and learning the uses of Object Space Normals versus the more appropriated Tangent Space technique, and got curious about if when using Object Space does it override vertex lighting entirely and use the pixel color of the texture to decide lighting? If that is what is happening, how expensive is it to render objects that way? If I understand it vertex lighting is standard in game rendering because its the cheapest way to determine light values.
Just want to make sure I’m understanding how Object Space interprets lighting.