Learn antialiasing techniques in computer graphics (last part)

Learn antialiasing techniques in computer graphics (last part)
Techniques of treatment of AMD aliasing MLAA Through four previous articles, we have the technology to learn about advanced anti-aliasing in computer graphics, and two well-known companies as NVIDIA and AMD have the technology quite similar, the only other way that called only, it is compared with Adaptive AA TAAA, which is the CSAA and EQAA. But apart from similar technology, the company has also developed his own techniques as a way to increase competitive advantage. The last part of the series "Understanding antialiasing techniques in computer graphics" will introduce the special technology of AMD / ATi and nVIDIA shortly.   - The technology of AMD's own antialiasing Temporary aliasing (Temporal AA - TAA) Along with the launch of the Radeon X800. ATI (this time) has introduced a new antialiasing technique called antialiasing temporary (TAA). TAA is essentially based on MSAA, but use a trick to double the number of MSAA samples using two samples of MSAA but with a different pixel frame. This is based on the characteristics of the human eye: once the number of frames per second (frames per second, or FPS for short) exceeds 60, the human eye will not be able to distinguish the difference between 2 frames the continuous, so ATI has relied on this feature to carry double the number of MSAA samples. Subscribe to the example above, we have a frame (frame 1) and the second frame (frame 2) in succession, the graphics card will conduct took two samples of the frame 1 (green) and two samples of the frame Figure 2 (blue) and 4 apply this sample to a common frame. The results that we have 4x MSAA graphics cards only work with 2xMSAA shoulder normally. Similarly 4xMSAA normal quality 8xMSAA using TAA. However, TAA is not without drawbacks. First, V-sync * must be turned on and then, the machine must be strong enough to maintain the frame 60, if the frame rate fall below 60, TAA will be disabled.   This principle is quite simple and effective, but also disadvantages uncomfortable. Therefore, TAA was eliminated in the ATI Catalyst driver version some time later.   * V-sync (sync frame rate to refresh the screen): This is a feature FPS maximum limit equal to the refresh of the screen, for example, your screen is the Refresh Rate is 60Hz, when V-sync enabled, the maximum would be 60 FPS.   Custom antialiasing (Custom Filter Anti-Aliasing - CFAA or also known as EDAA) Introduced with ATi Radeon HD 2900XT, CFAA is an antialiasing technique that not only takes samples inside the pixel, but also take the form outside that pixel. This means that samples can be taken within a certain radius that is central to the original pixel. When introduced, ATI offers 3 filters (filter) that CFAA Narrow, Wide and Edge-Detect.   Narrow and Wide radius here is compared with pixel sampling, and Edge-Detect filters to apply the algorithm to detect edges of a graphic object and focus the aliasing in the area.     Edge-Detect is easy to see how the CFAA most effective, because it can identify the edges and the edges of this process, which is the object contains the most jagged, but it's also the worst for love algorithms for handling more complex. The filter radius, effective only negligible compared to the traditional MSAA, so AMD has put two filters from the Radeon HD 6000 series.     Also on the frame after zooming up to 4x As mentioned in the previous technique EQAA only for high-end Radeon HD 6900, so alongside technical CFAA will be quite consistent with the Radeon HD 6800 or less, as it provides better image quality compared with traditional MSAA, but not too heavy compared to EQAA.   Antialiasing morphology (Morphological Anti-Aliasing - MLAA) Antialiasing morphology (MLAA) is technically completely new antialiasing, was introduced with the Radeon HD 6800. It has a completely different approach with the previous technique, MLAA is post-processing techniques (post-processing). It does not expedite the process and then color the pixel output to the screen as the previous technique, which handle only frame after it has been finalized. The principle works as follows: MLAA will analyze a frame, define the edges as well as the spectrum of the frame, after identifying the particular object, it will proceed to blur the edges by means of color mixing. MLAA similar to reduce aliasing filters in Adobe Photoshop.   Distinguish the edge of the object (left), then proceed to mix colors to reduce aliasing (right) In fact, MLAA works quite well, providing image quality roughly equivalent to the SSAA (antialiasing technique first but the best image quality) but the level of work for the graphics card is only comparable with Edge-Detect CFAA. Overall, it provides the best image quality of the antialiasing technique that is not too heavy. But, as said, no technique is perfect, too MLAA. Do background principles of their treatment, MLAA will remove "aliasing" in all subjects independently, this including text, objects on-screen HUD (ammo, armor ...) are dimmed go, very annoying, especially with small size text.   Zoom in one frame does not turn on antialiasing (StarCraft 2) MLAA is currently only available in the Radeon HD 6000, but with Catalyst driver 2.11 onwards, the Radeon HD 5000 series has also been supported.     - NVIDIA Quincunx antialiasing techniques Quincunx is introduced along with the third generation Geforce cards (launched 2001). Quincunx antialiasing principles used quite strange, it does not get around the pixel samples which creates a copy of the current frame, the direction of 45 degrees clockwise, counterclockwise, so that each pixel will have 4 corners next pixel copies, making blurring the color between the original pixel and the neighboring pixels, creating aliasing blurring effect. Although NVIDIA introduced effective Quincunx antialiasing equivalent to setting 2xAA 4xAA only, but in fact, this approach only makes the dim picture becomes quite annoying, and nature is not eliminate the aliasing really like the technology mentioned in previous post.   So from birth onwards NVIDIA Geforce 4 left Quincunx by Geforce 4 onwards was strong enough to shoulder the MSAA.     As shown above, we see the original black pixel, the pixel offset red copy a 45 degree angle with the original pixel, from which the black pixel is surrounded by 4 pixel red and blur effect, reducing reduce aliasing.   Antialiasing estimates Fast (Fast approximate Anti-Aliasing - FXAA) FXAA is your answer for nVIDIA ATi MLAA. Similarly MLAA, FXAA also a technical background processing. FXAA will find and identify objects independently and apply a softening filter to reduce the contrast between the object with the surrounding environment, resulting objects will reduce aliasing. The difference is FXAA will find the level of contrast in each pixel is MLAA will find the contrast in each pattern (pattern), so generally more effective FXAA MLAA.   Epilogue 5 parts of the series "Understanding antialiasing techniques in computer graphics" recently gave us a lot about anti-aliasing techniques. First principle is simple, but there are many approaches, offer several different results. Each approach has advantages and disadvantages of their own.     The first thing we learned after this series is in the mode, MSAA selection remains the most basic. Despite the technical improvements of the MSAA as CSAA, EQAA and Edge-Detect CFAA can help improve antialiasing more or less, but still MSAA mode provides image quality equal to the best performance. The sample covered edge-detect or hard to bring all the difference that the user can distinguish, unless we stop the game and use the magnifying glass to zoom out.   The second thing is: MSAA antialiasing will not be able to lie on still objects throughout, and we need to have an optimal method to handle aliasing for transparent objects on still. NVIDIA AMD has more in this array, adaptive anti-aliasing NVIDIA TrSSAA passed.   So why, why MLAA and FXAA? They work fairly well, reducing most of aliasing. Also we MSAA independent, can operate in parallel to increase processing efficiency. MLAA and FXAA generally quite effective, but they also handle all the teeth on 2D objects on screen are not related, for example the subtitle text in the game, which makes some users uncomfortable.   There are many anti-aliasing techniques like article said, so the choice that best suits you? Through practice, the regime MSAA 4x antialiasing is relatively balanced, providing beautiful images, but not too heavy for your computer. For Nvidia users also have the option was TrSSAA to minimize aliasing to remain transparent. AMD hopes to upgrade ADAA (Adaptive AA) for all Radeon users will not lose to Nvidia users.   In summary, through this series, we had learned the principles of anti-aliasing technique is, including what kinds of technical as well as the two companies renowned as AMD and Nvidia. We also know the advantages and disadvantages of each type and level of efficiency. And we all know the role of anti-aliasing technique in the computer game is important how the antialiasing using a technique that images in the game becomes more smooth and realistic, less rugged than .   Tom's Hardware Reference ...


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