Map types control the look of a game assets surface and how it reacts to light. There are many different types of texture map, we will look at the most common ones used in the Standard shader in this article.
Placing Texture Maps
When you have created your standard shader material in the inspector it has different slots in which to place your textures we will look at some of the main slots and what they do. To add a texture you can either drag the texture from your project window into the slots or select the target icon next to the slot windows of each texture type.
For this article we will demonstrate what the texture types achieve on this Art Deco Chair model. It currently has a standard shader material attached to it.
Diffuse / Albedo Map
In games a Diffuse Map means the base colour texture, in recent versions of Unity this is called the Albedo map.
This map generally only represents the base colours. It does not control lighting effects, it is asthough you have coloured the model with a paint brush.
A normal map is an image that stores a direction at each pixel. These directions are called normals.
The image has red, green, and blue channels and they control the direction of each pixel's normal. A normal map is used to fake high-resolution details on a low-resolution model.
Unity also allows you to add detail normal maps or a secondary normal map over the top of the first. In this example we have used it to indent the ivory inlay on the chair.
Ambient Occlusion Map
An Ambient Occlusion (AO) map creates soft shadowing, as if the model was lit without a direct light source, like on a cloudy day. It shadows where objects meet like in the groove of the chair or where the cushions meet. This can be done in Unity in realtime, but this requires a relativley new garphics card and can use a lot of computing power.
With these three texture types added to the standard material you can easily get great effects.