Currently two of the most popular PPAA (post-process anti-aliasing) algorithms are:
1. SMAA is an algorithm based on MLAA but with a number of innovations and improvements, and with a number of quality/performance presets. It implements advanced pattern recognition and local contrast adaptation, and the more expensive variations use temporal super-sampling to reduce temporal instability and improve quality. The SMAA algorithm version referenced in this document is the latest public code v2.7.
2. FXAA is a much faster effect. However, FXAA has simpler colour discontinuity shape detection, causing substantial (frequently unwanted) image blurring. It also has fairly limited kernel size by default, so it doesn't sufficiently anti-alias longer edge shapes, while increasing the kernel size impacts performance significantly. FXAA algorithm version referenced in this document is latest public code v3.8.
In this sample we introduce a new technique called Conservative Morphological Anti-Aliasing (CMAA). CMAA addresses two requirements that are currently not addressed by existing techniques:
1. To run efficiently on low-medium range GPU hardware, such as integrated GPUs, while providing a quality anti-aliasing solution. A budget under 3ms was used as a guide when developing the technique at a resolution of 1600x900 running on a 15watt, 4th Generation Intel® Core processor.
2.To be minimally invasive so it can be acceptable as a replacement to 2xMSAA in a wide range of applications, including worst case scenarios such as text, repeating patterns, certain geometries (power lines, mesh fences, foliage), and moving images.
CMAA is positioned between FXAA and SMAA 1x in computation cost (1.0-1.2x the cost of default FXAA 3.8 and 0.55-0.75x the cost of SMAA 1x). Compared to FXAA 3.8, CMAA provides significantly better image quality and temporal stability as it correctly handles edge lines up to 64 pixels long and is based on an algorithm that only handles symmetrical discontinuities in order to avoid unwanted blurring (thus being more conservative). When compared to SMAA 1x it will provide less anti-aliasing as it handles fewer shape types but also causes less blurring, shape distortion, and has more temporal stability (is less affected by small frame-to-frame image changes).
CMAA has four basic logical steps (not necessarily matching the order in the implementation):
1. Image analysis for colour discontinuities (afterwards stored in a local compressed 'edge' buffer). The method used is not unique to CMAA.
2. Extracting locally dominant edges with a small kernel. (Unique variation of existing algorithms).
3. Handling of simple shapes. Not particularly unique.
4. Handling of symmetrical long edge shape. (Unique take on the original MLAA shape Handling algorithm.)
