Anti-aliasing plays a crucial role in enhancing the visual appeal of your games. Its purpose is simple — to eliminate the jagged edges that often appear in games. However, the technicalities can be quite complex. In this article, we will demystify the various anti-aliasing options commonly found in games, helping you achieve the optimal balance between image quality and performance for your gaming PC.
Understanding Anti-Aliasing
Image used with permission by OnSpec Electronic, Inc.
Before we delve into anti-aliasing, let’s first discuss aliasing. Aliasing occurs when a curved line is displayed on a grid of square pixels. This is a consequence of the limitations of computer graphics, as each pixel can only represent a single color at a time. Anti-aliasing techniques aim to smoothen these jagged edges.
Aliasing can be observed not only in games but also in photo editing apps. For example, the image below from Destiny 2 exhibits aliasing, where the railing covers multiple square pixels, resulting in a jagged line where one pixel ends and the next one begins.
Image used with permission by OnSpec Electronic, Inc.
Anti-aliasing is designed to mitigate or eliminate these jagged edges. Many techniques exist to achieve this goal. In fact, you likely encounter some form of anti-aliasing in your daily life, even if you’re not a gamer or photo editor. For instance, your web browser employs anti-aliasing for rendering text.
Varieties of Anti-Aliasing
Two different types of anti-aliasing in Forza Horizon 5. FXAA on the left, MSAA on the right. Image used with permission by OnSpec Electronic, Inc.
While numerous anti-aliasing techniques exist, they can be broadly categorized into two primary approaches. The first approach is supersampling, where the anti-aliasing technique renders the image at a higher resolution and then downsamples it to smooth out rough edges. The second approach involves algorithms that analyze nearby pixels and intelligently estimate where the additional detail should be placed.
The following are some of the commonly encountered anti-aliasing techniques used in games today:
Supersample Anti-Aliasing (SSAA)
Image used with permission by OnSpec Electronic, Inc.
Supersample Anti-Aliasing, or SSAA, is the most fundamental form of anti-aliasing. It works by rendering the image at a higher resolution and then downsampling it to fit the native resolution. This process involves averaging the colors near the edges to eliminate jaggedness. Despite offering the best anti-aliasing results, SSAA is also the most demanding in terms of performance, as it effectively renders the image at a higher resolution. Consequently, SSAA is not always available in modern PC games due to its performance impact.
Multisample Anti-Aliasing (MSAA)
Image used with permission by OnSpec Electronic, Inc.
Multisample Anti-Aliasing, or MSAA, is a less computationally intensive variation of SSAA. Instead of sampling every pixel, MSAA selectively targets areas where aliasing is likely to occur, such as edges. By reducing the number of samples, MSAA saves computing resources. In most scenes, adjacent pixels often have the same color, eliminating the need for extensive anti-aliasing processing. Although less demanding than SSAA, MSAA still places a burden on your hardware.
Fast Approximate Anti-Aliasing (FXAA)
Image used with permission by OnSpec Electronic, Inc.
Fast Approximate Anti-Aliasing, or FXAA, is a post-process form of anti-aliasing. Unlike other techniques that modify the rendering, FXAA employs an algorithm to clean up jagged edges after rendering. This approach provides significant performance benefits compared to MSAA and SSAA but may result in slightly reduced image quality. FXAA uses a high contrast filter to identify edges, samples those edges, and blends them together. However, since it does not average unique colors like SSAA and MSAA, FXAA can sometimes produce slightly blurry edges.
Temporal Anti-Aliasing (TAA)
Image used with permission by OnSpec Electronic, Inc.
Temporal Anti-Aliasing, or TAA, is similar to FXAA and operates as a post-process technique. TAA samples each pixel in a frame, but unlike FXAA, it samples different locations within each frame and blends those samples with past frames. By leveraging temporal data, TAA reduces the blurriness commonly associated with FXAA. TAA is foundational to Nvidia’s Deep Learning Super Sampling (DLSS) technology and plays a crucial role in delivering high-quality results in features like Temporal Super Resolution (TSR) and AMD’s FidelityFX Super Resolution 2.0 (FSR). However, TAA has its drawbacks, such as ghosting, where previous samples persist in the new frame, resulting in a blurred effect.
Subpixel Morphological Anti-Aliasing (SMAA)
Image used with permission by OnSpec Electronic, Inc.
Subpixel Morphological Anti-Aliasing, or SMAA, is similar to FXAA but leverages edge detection and applies blurring specifically to pixels along sharp edges. The main distinction is that SMAA takes multiple samples along the edges, utilizing more GPU resources compared to FXAA. SMAA strikes a balance between image quality and performance, offering better results than FXAA without the performance requirements of MSAA or SSAA. However, in recent years, TAA has gained more popularity due to its ability to achieve a similar balance with superior results.
Enabling Anti-Aliasing in Games
You can find anti-aliasing settings in the graphics options of most games. It may be listed as “Anti-Aliasing” or the specific type of anti-aliasing (FXAA, MSAA, etc.). The settings are mostly self-explanatory, except for the factor. Certain techniques, such as MSAA, may be accompanied by a number indicating the level of anti-aliasing quality (e.g., MSAA 4x offers better quality than MSAA 2x).
Image used with permission by OnSpec Electronic, Inc.
If you wish to apply anti-aliasing universally, you can use your graphics card software. For Nvidia users, navigate to the Nvidia Control Panel and access the Manage 3D settings. By default, the Anti-aliasing mode setting is set to “Application-controlled.” You have three options:
- Off: Disables anti-aliasing by default in games.
- Enhance the application setting: Enables further anti-aliasing beyond what is provided by the game (useful in cases where a game has its own anti-aliasing toggle).
- Override any application setting: Allows you to set a custom anti-aliasing level based on the factor specified in the Anti-aliasing setting section.
Additionally, you can enable FXAA in the Nvidia Control Panel. Since FXAA is a post-process form of anti-aliasing, you can apply it to any game either as a standalone anti-aliasing solution or in conjunction with in-game settings.
Image used with permission by OnSpec Electronic, Inc.
For AMD Radeon users, you can set up anti-aliasing in Radeon Software. Head to Settings > Graphics and click on the Advanced dropdown. The anti-aliasing settings in Radeon Software are similar to Nvidia’s options, allowing you to turn it off, enhance it, or override it. Radeon Software offers additional tools for tailoring the type of anti-aliasing you want to apply, including Multisample (MSAA) and Morphological Anti-Aliasing (MLAA).
Remember to experiment with different anti-aliasing techniques and settings to find the right balance between visual quality and performance for your specific gaming setup.
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