ABSTRACT
The use of antialiasing techniques is crucial when producing high quality graphics. Up to now, multisampling antialiasing (MSAA) has remained the most advanced solution, offering superior results in real time. However, there are important drawbacks to the use of MSAA in certain scenarios. First, the increase in processing time it consumes is not negligible at all. Further, limitations of MSAA include the impossibility, in a wide range of platforms, of activating multisampling when using multiple render targets (MRT), on which fundamental techniques such as deferred shading [Shishkovtsov 05, Koonce 07] rely. Even on platforms where MRT and MSAA can be simultaneously activated (i.e., DirectX 10), implementation of MSAA is neither trivial nor cost free [Thibieroz 09]. Additionally, MSAA poses a problem for the current generation of consoles. In the case of the Xbox 360, memory constraints force the use of CPU-based tiling techniques in case high-resolution frame buffers need to be used in conjunction with MSAA; whereas on the PS3 multisampling is usually not even applied. Another drawback of MSAA is its inability to smooth nongeometric edges, such as those resulting from the use of alpha testing, frequent when rendering vegetation. As a result, when using MSAA, vegetation can be antialiased only if alpha to coverage is used. Finally, multisampling requires extra memory, which is always a valuable resource, especially on consoles.
