FXAA - what is it? Smoothing method. Anti-aliasing in games

Has already passed the time when the games impressed solely with their gameplay: the player long ago became demanding and, in particular, demanding the quality of the picture presented on the screen. However, few people know that to ensure a high degree of quality today, many game developers use FXAA anti-aliasing. What it is - today is not known to all gamers, so many people are wondering whether it is worth including this function at all.

The predominant majority of players are well aware of what the so-called staircases are at the edges of the objects, as well as how to solve this problem by using "anti-aliansing" or simply "smoothing".

What is anti-aliasing?

Smoothing is a good thing, as the perception of the picture increases significantly, and in modern realities those games in which it is not used ultimately turn out to be booed. At the same time, it is unsatisfactory how FXAA is anti-aliasing. What it is, many users may not even be interested, but in fact it is the implementation that affects the quality of the final picture.

Bad implementation often proves that the target equipment has insufficient processing power. Of course, in favorable conditions there are those people who prefer to play on PC, since in this case the capacity of the equipment directly depends on the material capabilities of its owner, however the console players are often satisfied with the gameplay, as the quality of graphics in the majority of cases on computers is much Is better compared to what graphics console games have. However, each person chooses where and on what to play.

What is FXAA?

It should be noted right away that the FXAA smoothing technology has been used for a long time already by game players. What it is, then did not yet know, but its first use is found in the MMO Age of Conan, as well as in the world-famous shooter FEAR. In these games, however, only the original version of this smoothing was used, which at the time was not the most Productive solution.

In our time, the games use a slightly different FXAA format. What it is? It stands for Fast approximate Anti-Aliasing, which is a more efficient solution than traditional MSAA technology. This is a single-pass pixel shader, by which the resulting frame is computed during the post-processing phase. This shader was created as a faster solution, which is less demanding memory in comparison with the above, but for its advantages the technology pays for accuracy of work, as well as quality. Seeing this, many may find that technology is irrelevant. Actually this is not true.

What are the advantages of this method?

Anti-aliasing FXAA features a number of advantages, including improved anti-aliasing of so-called subpixels and speculators. In the official document, the developer of this technology, Timothy Lotts, says that his product with medium quality settings implements post-processing of frames with a resolution of 1920x1200 based on the GTX 480 with a speed of less than one millisecond.

The main advantages of FXAA smoothing are what kind of subpixel smoothing algorithm is used here that works more efficiently compared to the MLAA algorithm, which is quite enough for the equipment running at DirectX9 level. That is, in this case, post-processing is performed in one pass, and the most interesting is complete independence from the GPU Compute API used. However, there is one disadvantage here - developers must incorporate this technology into various games. At the same time, traditional anti-aliasing technologies work or, conversely, can not work at the driver level. Thus, while programmers will use the method of exponential smoothing in their engines and at the same time they will not use the FXAA code in their engines, it will be impossible to achieve the desired effect, since it was impossible to include the code from the outside until recently.

How was the problem solved?

Over time, it was decided to initially enter the FXAA code into the d3d.dl library, resulting in the possibility of flexible results tuning through various configuration files, as well as enabling or disabling FXAA using the [Pause] button. This set of files is initially copied to the directory where the executable file of the DX9 application is present, and this application will pick up the library where the necessary code is present at the start. In this case, since the developer of the technology for implementing this code in the library initially took care that the results of the work were placed on the log, users actively began to identify bugs in the work of this technology, which were quickly corrected. Over time, there were also "injections" with code for DirectX 10 and 11 formats.

How to check?

The most obvious way to determine the effect of using the method of exponential smoothing and FXAA, is possible in the game World of Tanks.

If FXAA anti-aliasing is not used, explicit "escalators" begin to appear, and although the tank models may be large enough and also have decent detail, the artifacts are very noticeable, and in particular for various thin objects. The technology of built-in anti-aliasing tries to somehow lubricate the edges of objects, but it does it quite mediocre, not to mention the fact that in some places the picture can be blurred.

What are the changes?

After the FXAA tool is turned on, the result becomes obvious: the artifacts completely disappear, however, some blurring of the picture appears. In addition, there is also a unique version of FXAA Sharpen. The developer of the technology in one version added a sharpness filter, which was taken from MPC-HC, and the final result turned out to be quite decent: the blurring completely disappears, the textures get even sharper in comparison with the original, and the "ladder", despite the use of this Filter, are almost completely absent. Now you know what FXAA is in games like World of Tanks. Due to the fact that the authors initially did not plan such a sharpness of the texture, it could slightly "knock out" the towers, but in the gameplay it is almost invisible.

Productivity here practically does not decrease. Of course, the World of Tanks engine works in a somewhat surprising way, so the bursts or, conversely, the performance drops can eventually manifest themselves literally from nothing.

NoAA, SMAA or FXAA

If you compare the modes "noAA" or SMAA and "FXAA Sharpen", then the picture significantly changes for the better in the latter case. The only exception here is the used sharpening filter, which overly thin lines narrows even more, in particular, this is especially noticeable in the hanging artillery sight. In this case, the number of frames per second in the FXAA variant significantly exceeds the previous version.

During long tests, it was determined that when using FXAA, the performance drops by approximately 10-12%, whereas in the case of using the MSAA 4x smoothing method, the quality of which competes to date with FXAA technology, there is a drop in performance By 50% or more.

Update

In 2011, there was also a customized version of the injection, which included all of the above options FXAA and their advantages. In this assembly there was a fairly large number of filters, among which is:

• Blur.
• Vignetting.
• Saturation with color.
• Sepia.
• And many others.

All this is easily configured through a single file, and the most useful in this case: the settings can be easily changed even during the game, you just need to minimize the application, open the settings editor, deploy the application and enjoy the new settings without having to restart the application. Thus, it turned out to completely eliminate the bleakness of the activation of the sharpening filter, providing a clearer picture, in which there are no "blades" of blurring and high quality of textures is achieved.