Minecraft wiki entry for Light, associated text: Ambient occlusion is responsible for adding shading to an ordinary texture. It is a layer of translucent textures, on top of the normal textures. Overlaying these AO textures onto a texture is called AO mapping. There are about five AO texture patterns used in Minecraft's smooth lighting, excluding flips and rotations, and only three patterns algorithmically. Strictly speaking, it's probably more than that. That's when the intensity changes with the brightness level. But they are solved by tint.