What is antialiasing and how it works

Antialiasing is a term that all PC gamers have read and heard thousands of times, everyone knows that it improves graphic quality by decreasing sawtooth but few users really understand how it works. We have prepared this article to explain in a simple way what antialiasing is and how it works.

How does a screen work and what is aliasing?

To understand the operation of antialiasing, we have to be clear about how a screen works, the screens are made up of millions of pixels, these are nothing more than small dots that light up in a certain color and the set of all of them forms the image we see. The problem with this arises when we want to represent something that is not a straight line, for example a curve. When drawing it on the screen there will be many imperfections due to the way the screens work, the following image illustrates it perfectly.

As we can see, it is impossible to draw a curved line on a screen made up of pixels, since the pixels have to be completely illuminated, that is, we cannot turn on one part of a pixel and turn off the other. This phenomenon gives rise to the aliasing that causes that aspect of saw teeth that you have surely seen many times in games, so that you have it clear we put an image on you. It is a very extreme example but it will serve so that everyone understands it perfectly.

An example less extreme we see it in the following image:

What is antialiasing and different types?

Once we have understood what aliasing is , we can already understand what antialiasing is , as its name indicates, you will be thinking that it is something that tries to avoid sawtooth in the images represented on the screens. That's right, antialiasing can be defined as a set of techniques to avoid the effects of aliasing and obtain finer and closer to perfection surfaces. There are various antialiasing techniques, but all of them can be grouped into two fundamental groups, the oversampling techniques and the post-processing techniques.

What graphic card should i buy? The best on the market 2017

In the case of oversampling anti - aliasing, what is done is to render the image at a higher resolution than that of the monitor and then reduce it and adjust it to the screen resolution, which is greatly improved image quality and teeth saw are greatly reduced to the point of being imperceptible. You will be thinking that this is fantastic because we have removed the problem of aliasing, the problem with these oversampling techniques is that they consume a large amount of resources on our PC and make games go slower, something that nobody likes.

Examples of anti-aliasing by oversampling are SSAA and MSAA, the first of which renders the entire image at a resolution higher than that of the screen while the second only does it at the edges of the objects, therefore the impact of SSAA on performance it is far superior, meaning it is much slower than MSAA. Other examples of oversampling antialiases are CSAA and EQAA that consume even less resources than MSAA.

If we apply antialliasing by oversampling to the first image of the post we have the following result:

In the case of a game we will see something like this:

Secondly, we have post-processing antialiasing techniques, these what they do is slightly blur the image to hide the saw teeth, this technique is applied once the image has been rendered and the impact on performance is minimal. The problem with these techniques is that the image is slightly blurred so it loses sharpness, something quite common in current games.

An example of post-processing antialiasing is FXAA, what this technique does is detect the edges of the images once they are already rendered and apply a blur filter to the edges. It is much faster than oversampling antialiasing so it was thought to replace them, the problem is that it worsens the image quality by reducing its sharpness and makes some textures look flat.

Soon after, other post-processing antialiasing techniques emerged that achieve better image quality than FXAA, these are SMAA, and TXAA. In reality the TXAA combines post-processing and oversampling techniques so it is between the two groups in image quality and performance.

Here ends our post on antialiasing, if you have any questions you can leave a comment. Remember to share this post with your friends on social networks if it has been useful to you, it is something that helps us a lot. As always, we recommend reading our guide to the best graphics cards on the market.