Glossary 3D Game Graphics / Term
Explaining this completely would mean explaining the whole mathematical sampling theory. It boils down to this. To recover a signal, or image, you need a minimum of samples to be able to give a realistic representation of the image. The problems start with texture maps being either too close or too far away from the viewpoint. If the polygon is far away you only have a limited number of points to show the texture map, so logically you have to drop a lot of the real pixels of your texture map. This creates some sort of interlace effect : one line is shown and one is not. This can result in weird patterns appearing, and makes the texture map look completely different from the real one. A similar problem if the polygon is close to you. You need more info than there is resulting in the generation of random noise (meaningless values). Most of the time the last problem is solved by MIP-Mapping while the other is solved by the anti-aliasing.
Another point where anti-aliasing is used is with straight lines. If you draw a straight line (under an angle) using a paint program and you zoom in, you will discover that the line looks like a stairway. To remove this and make the line look like a line points in different colors are added to the side of the line to make it look more like a real line. Most of the time it is this kind of Anti-Aliasing they are talking about.
Permanent link Anti-Aliasing - Creation date 2020-06-21