FXAA

FXAA, short for Fast Approximate Anti-Aliasing, is a post-processing anti-aliasing algorithm developed by Timothy Lottes at NVIDIA. It is designed to reduce jagged edges in real-time rendered images with a low performance cost by operating on the final color buffer rather than the scene geometry.

It runs as a screen-space post-process pass. The technique detects edges by examining contrast in luminance and color values and then applies a directional, multi-sample blur along those edges to smooth jaggies. Because it operates after shading and lighting are computed, it does not require multi-sample anti-aliasing buffers or changes to geometry.

Advantages include fast performance and broad compatibility, making FXAA widely available in game engines and graphics APIs. However, it can blur fine textures and small details, and may introduce color bleeding or halo-like artifacts on some edges, especially at high contrast or with text rendering. It is also sensitive to parameter settings and may interact with transparent surfaces or motion.

FXAA has been implemented as a standard option in many engines, GPUs, and graphics frameworks, and is commonly used as a low-cost alternative when traditional MSAA is impractical. It is often discussed alongside other post-processing anti-aliasing techniques such as SMAA and temporal anti-aliasing methods.