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What Is Anti-Aliasing? 7 Interesting Facts

What Is Anti-Aliasing

What is anti-aliasing and does it really improve graphics quality? It’s not uncommon for video game graphics to vary depending on the display resolution, shadow quality, drawing distance special effect, and the antialiasing effect.

If you have played any games and tried to change their graphics settings, I am sure you will come across the anti-aliasing tab, but have you ever wondered what difference this setting makes? Let me help you understand this concept.

The concept of anti-aliasing did not emerge from the gaming industry it has been around since the 1960s. Since the resolution of the displays back then used to be very low, jagged lines and blurry images were considered the standard.

The technique has been developing ever since and today, anti-aliasing is an essential part of creating realistic digital images and audio recordings. It is used in a variety of applications, from video games to movies and television. As technology continues to evolve, so too will the techniques used for anti-aliasing.

1. What Is Anti-Aliasing?

In digital graphics, anti-aliasing is a technique used to smooth out the edges of graphics or text by blending the colours of pixels that fall on the edge. The goal is to create a smoother, more natural-looking edge that creates an image with less pixelated edges and better image quality.

2. Needs

The need for anti-aliasing arises because computer displays and other digital output devices are made up of discrete pixels. Each pixel can only display a single colour, and these colours are arranged in a grid pattern. When graphics or text are displayed on a digital screen, the edges of the objects may not align perfectly with the pixel grid, causing jagged edges to appear.

2.1. Gradient Of Colours

Anti-aliasing works by calculating the colours of neighbouring pixels that fall on the edge of an object or text and blending those colours with the colours of nearby pixels. This creates a gradient of colours that makes the edge appear smoother and more natural. The amount of blending or smoothing that is applied depends on the specific anti-aliasing algorithm used and the display’s resolution.

2.2. High-Quality Graphics

Anti-aliasing is an essential technique for producing high-quality digital graphics and text, particularly in video games, where blurred edges can be distracting and can reduce immersion in the game world. While different anti-aliasing settings have different strengths and weaknesses, the goal is always the same: to produce smooth, natural-looking graphics that are easy on the eyes.

The result is a more visually pleasing image that appears less pixelated and more realistic. Anti-aliasing is used in a variety of digital graphics applications, including video games, computer graphics, and digital typography.

3. “Jaggies” Explained

While playing beautiful open-world games, one of the main focuses of the games is their graphics. Sometimes if you look closely enough, you can see some jagged edges or a staircase-like pattern around the edges or characters or scenery, these are the jaggies.

Jaggies, also known as aliasing, are visual artifacts that occur when there is a lack of smoothness in the edges of an image or graphic. They are caused by a low resolution or the inability of the display device to render curved lines and other diagonal lines and edges smoothly, resulting in jagged or staircase-like edges.

3.1.  Causes

  • When an image is displayed on a low-resolution device or is zoomed in, the edges of the entire image or graphic may appear jagged because there are not enough pixels to represent the smooth curve or diagonal line. The display device will try to approximate the curve or line by using the pixels available, resulting in jagged edges or a staircase-like effect.
  • Additionally, digital images are created using raster graphics, which are made up of a grid of pixels. When an image is resized or scaled, the pixels may be stretched or compressed, leading to a loss of image quality and the appearance of jaggies.
  • Another factor that can contribute to jaggies is the way that graphics are rendered. For example, if a graphic is not properly anti-aliased, the edge pixels may not blend seamlessly with the background, resulting in a jagged edge.
  • Pixels are the smallest entities of a display, every single pixel represents a colour. To show an image on the display all the pixels light up with their attributed colours. Pixels are generally square so it is easy for them to display horizontal or vertical lines, but the difficulty arises when they have to display a diagonal or a curved line. Square pixels cannot exactly represent a curve which causes the jaggies.

To fix all of the issues mentioned above, anti-aliasing as a concept was born.

4. Types Of Anti-Aliasing

There are two broad categories of anti-aliasing techniques: Spatial anti-aliasing and post-processing anti-aliasing.

Both are directed toward producing clearer pictures but Spatial anti-aliasing is more hardware-focused while post-processing anti-aliasing is more software-based.

4.1. Spatial Anti-Aliasing

Display resolution refers to the number of pixels that can be displayed on a screen, expressed as the number of pixels in the horizontal and vertical directions. In other words, the display resolution is the measure of how many individual dots thin lines, or pixels that make up an image are displayed on a screen.

Display resolution is typically expressed in two numbers, such as 1920 x 1080, where the first number (1920) refers to the number of pixels in the horizontal direction and the second number(1080) refers to the number of pixels in the vertical direction.

Higher display resolutions generally result in sharper and more detailed images, as there are more pixels available to display information. However, higher resolutions also require more processing power and can result in reduced performance on lower-end hardware.

4.1.1. To Make Spatial Anti-Aliasing Work Us

  • Need a fragmented picture that is of a lower resolution.
  • Render that image in a higher resolution.
  • Colour samples of the extra pixels (new pixels that weren’t present in the low-resolution image) are captured at the high resolution.
  • The high-resolution image is reduced to its initial size, and a new colour is applied to each pixel that is averaged from the sampled pixels.

By performing these steps we can create a low-resolution image with the colour accuracy of a higher-resolution image.

5. Types Of Spatial Anti-Aliasing

5.1. Supersampling Anti-Aliasing (SSAA)

One of the earliest anti-aliasing techniques was supersampling anti-aliasing, which makes use of the procedure explained. SSAA is excellent for processing photorealistic pictures because it gives them a softer appearance that makes them seem more realistic. It’s also known as “full-scene anti-aliasing” (FSAA) and it is a film-style technique.

Some of its demerits included softening of vertical or horizontal lines, so anything sharp would appear slightly smeared. Before the jaggies can be smoothed, the complete image must be processed by SSAA (hence the term “full-scene”). Because PC games need to be rendered in real-time, SSAA needs a lot of computing power to run at speeds fast enough for gaming. Which is why it is not used for gaming anymore.

5.2. Multisample Anti-Aliasing (MSAA)

Multisample Anti-Aliasing (MSAA) is a technique used in computer graphics to reduce the jagged edges (aliasing) that occur when rendering 3D scenes. It works by taking multiple samples of each pixel and then averaging the colour values of those samples. The resulting colour is then used for the final rendering of that pixel.

MSAA works by dividing each pixel into multiple sub-pixels, typically 2x, 4x, or 8x. For each sub-pixel, the graphics card calculates the colour of the scene as if the sub-pixel was the center of a tiny camera. The colours from all the sub-pixels are then blended to form the final pixel colour.

The primary benefit of MSAA is that it provides a smooth and realistic appearance to the 3D scene. This is especially important in areas that require you to sharpen the graphics of the scene with fine details, such as text, wireframes, or small objects.

MSAA is not without its drawbacks, however. It can be quite resource-intensive, as it requires multiple calculations for each pixel. It can also introduce a slight blur to the image, which can be noticeable in certain situations. Additionally, MSAA may not be effective in eliminating all forms of aliasing, especially in cases of complex geometries or sub-pixel details.

Overall, MSAA is a powerful tool for improving the visual quality of 3D graphics and is commonly used in modern video games and other real-time applications.

5.3. CSAA And EQAA

CSAA (Coverage Sample Anti-Aliasing) and EQAA (Enhanced Quality Anti-Aliasing) are both advanced anti-aliasing techniques used in computer graphics to improve image quality by reducing blur edges, or aliasing using proprietary technology.

CSAA is an evolution of MSAA that was introduced by NVIDIA. It works by taking samples of pixel coverage in addition to colour samples. By using the coverage samples, CSAA can more accurately determine the edge of an object and create a smoother transition between the object and the background. This results in a more realistic and visually appealing image with fewer jagged edges.

EQAA, on the other hand, is a technique developed by AMD. It combines MSAA with a process called “edge detection” to more accurately identify the edges of objects in a scene. This allows EQAA to apply more effective anti-aliasing to those edges, resulting in a smoother, more natural-looking image. EQAA also offers variable levels of anti-aliasing to be applied in different areas of the image, depending on the complexity of the geometry, resulting in an optimized performance-to-quality ratio.

Both CSAA and EQAA are more advanced forms of anti-aliasing than MSAA and can offer superior results with less performance impact. However, they are proprietary technologies developed by NVIDIA and AMD respectively, and may not be available on all hardware or supported by all software applications.

6. Post-Process Anti-Aliasing

After the render, post-process anti-aliasing blurs each individual pixel. The GPU locates a polygon’s border by contrasting the colours of two adjacent pixels. If coloured pixels in the two images resemble one another, they likely came from the same polygon.

Since misaligned pixels, one of the main causes of jagged edges, are removed by the blurring method, it is efficient.

This method has the significant drawback of making the picture a little bit too blurry, which can be detrimental to games with dynamic lighting or detailed features.

This approach is more popular among gamers due to its quick speed and minimal processing requirements.

6.1. Types Of Post-Process Anti-Aliasing

6.1.1. Fast Approximate Anti-Aliasing and Morphological Anti-Aliasing

Fast approximate anti-aliasing is a fast and efficient anti-aliasing technique that uses a single-pass algorithm to apply anti-aliasing to the entire image. FXAA works by detecting high-contrast edges in the image and blurring them slightly to reduce the appearance of rough edges and flickering.

FXAA is relatively easy to implement and has low-performance overhead, making it popular for use in games and real-time applications.

Morphological anti-aliasing is a more advanced anti-aliasing technique that uses a morphological filter to smooth out jagged edges and reduce aliasing artifacts. MLAA works by analyzing the texture of the image and identifying areas where jagged edges are likely to occur. It then applies a morphological anti-aliasing filter that blurs the edges slightly, creating a smoother appearance.

MLAA can be more effective than FXAA in reducing aliasing artifacts, but it can also be more computationally expensive.

Both Fast approximate anti-aliasing and Morphological anti-aliasing are post-process anti-aliasing settings, meaning they are applied after the image has been rendered. This allows them to be applied to a wide range of rendering pipelines, and they can be easily combined with other post-processing effects such as bloom, depth of field, and motion blur. MLAA was developed by AMD while FXAA was Nvidia’s creation.

6.1.2. Temporal Anti-Aliasing (TXAA)

TXAA (Temporal Anti-Aliasing) is a specific anti-aliasing technique used in computer graphics that provides a high-quality anti-aliasing solution with a minimal performance impact.

TXAA works by taking multiple samples of the scene over time and combining them to create a smoother and more natural-looking image. The technique combines multisampling with a temporal filter to reduce the appearance of jagged edges and flickering while maintaining the sharpness and clarity of the image.

TXAA uses a combination of edge detection and temporal filtering to identify high-contrast edges and smooth out any jaggedness or aliasing artifacts that may occur along these edges. It also includes a motion vector technique that allows it to better handle fast-moving objects in the scene, reducing the appearance of motion blur and jaggies.

One advantage of TXAA over other anti-aliasing methods is its ability to reduce shimmering and temporal aliasing artifacts, which can occur in fast-moving scenes or areas with complex geometry. It can also be used in combination with other post-processing effects, such as depth of field and motion blur.

TXAA is primarily used in NVIDIA graphics cards and is supported by some game engines integrated graphics and rendering software. It can provide a significant improvement in image quality compared to other anti-aliasing techniques but may require higher hardware specifications due to its more intensive processing requirements.

6.1.3. Enhanced Subpixel Morphological Anti-Aliasing (SMAA)

Spatial and post-process anti-aliasing are combined in SMAA. The same blurring technique used by MLAA and FXAA is employed to smooth the pixels, and supersampling is also used to sharpen the entire picture. With even less computing capacity needed when using SMAA, you can achieve image quality that is comparable to or better than MLAA/FXAA. It has gamers pumped up.

SMAA is a popular post-process anti-aliasing technique used to create smoother and more natural-looking images. It provides a good balance between performance and image quality, making it a popular choice for games and real-time applications.

7. What’s The Best Type Of Anti-Aliasing?

As seen above there are many types of anti-aliasing and different methods have separate requirements and specific outcomes. You’re probably wondering which method will fit your need the best, in the end, it comes down to the balance of image quality and performance of the system.

Currently, the popular anti-aliasing method is FXAA. The fast processing times and the clear and precise images make FXAA the best of both worlds.

There are many different variations of the main types, and all of them have their unique advantages and drawbacks. For example, Sub-Pixel Morphological Anti-Aliasing, or SMAA, combines aspects of FXAA as well multiple techniques such as MSAA.

If you’re looking for a more cinematic experience and have the resources to process the higher requirements then TXAA will be a better choice. TXAA can recreate photorealistic images very well and help with increasing the depth of the virtual environment created by the game.

8. Conclusion

Gaming visuals have always depended heavily on anti-aliasing. Anti-aliasing has met the challenge of producing a smoother, more attractive visual improvement with each major graphical advancement in video games.

Whatever kind of anti-aliasing you decide on for a project, it’ll probably appear better than it would without it. Anti-aliasing is a delicate and practical method for giving your game the finishing touch it was missing.

Being a game developer and actively worrying about what anti-aliasing method to use is surprisingly low on the list of priorities, despite its widespread use and importance within the gaming industry. A variety of hardware components carry out the bulk of the job, and game hardware can choose the one that is most effective for your game.

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