ABSTRACT
In this chapter, the authors discuss geometric postprocess antialiasing (GPAA), which is an alternative approach that operates on an aliased image and applies the antialiasing post-step using geometry information provided directly by the rendering engine. Additionally, the authors discuss geometry buffer antialiasing (GBAA), which is based on a similar idea, but is implemented by storing geometry information to an additional buffer. Two geometric antialiasing methods are discussed: The first method operates entirely in a postprocess step and is called geometric postprocessing antialiasing (GPAA). The second method is more similar to traditional multisample antialiasing (MSAA) in that it lays down the required information during main scene rendering and does the smoothing in a final resolve pass. The main difference between GPAA and GBAA lies in performance characteristics and engine integration. An optimization for GPAA is to prefilter the mesh geometry and only draw lines for edges that are deemed necessary to antialias.
