Anti-aliasing

For people that hate pixels


Anti-aliasing (AA) aims to lower the amount of jagged and pixelated edges in the game. Aliasing occurs when continuous objects such as a line are displayed on a screen made up of a finite number of pixels. Instead of a smooth line one gets one with a stair-like patten. AA solves this by smoothing out the line by filling in the surrounding pixels. It makes it harder to notice the pixelated edges but also reduces contrast and makes the image more blurry.

Hardware

Techniques that demand or use some form of hardware for AA.

CSAA - Coverage-Sampled Anti-Aliasing - 2006 / EQAA - Enhanced Quality Anti-Aliasing - 2010

Variations of MSAA from Nvidia and AMD. It adds coverage samples to better detect if a primitive touch a pixel.

MSAA - Multi-Sampling Anti-Aliasing - 1999

Each pixel contain N subsample points. If a primitive touch any subsample point it will run the pixel shader. The result is then stored in each of the subsample the primitive was touching. So the z-buffer and the render target need to store N data per pixel. The final step is the resolve step that downsample all the data back to a single pixel. The simplest way is to average all subsamples in a pixel.

SSAA - Super Sampling Anti-Aliasing

The image is rendered into a frame buffer at a higher resolution then the one being displayed. The image is then down sampled to the desired display resolution.

Post-processing

Techniques that post-process the image. For people that enjoy writing shaders.

ATAA - Adaptive Temporal Antialiasing - 2018

TXAA - Temporal Anti-Aliasing - 2012

SMAA - Subpixel Morphological Anti-Aliasing - 2011

FXAA - Fast Approximate Anti-Aliasing- 2011

DLAA - Directionally Localized Anti Aliasing - 2011

MLAA - Morphological Anti-Aliasing - 2009

G-Buffer

Techniques used with deferred rendering and use a geometry buffer to work.

AGAA - Aggregate G-Buffer Anti-Aliasing - 2015

GBAA - Geometry Buffer Antialiasing - 2011

Reference

Aliasing in computer graphics - 2020

Research impact retrospective: MLAA from 2009 to 2017 - 2017

Anti-aliased Alpha Test: The Esoteric Alpha To Coverage - 2017

Road to Anti-Aliasing in BRE: Aliasing and Anti-Aliasing - 2016

A Temporal stable Distance to Edge Anti-Aliasing Technique for GCN architecture - 2015

Diving into Anti-Aliasing - 2014

Applying Sampling Theory To Real-Time Graphics - 2012

Anti-Aliasing Methods in CryENGINE 3 - 2011

Digital Foundry: The Future of Anti-Aliasing - 2011

Filtering Approaches for Real-Time Anti-Aliasing - 2011

So Many AA Techniques, So Little Time - 2011

Toms hardware: Anti-Aliasing Analysis - 2011

Recipe for antialiasing as a post - 2011