FMAA, Fast Mixed Anti-aliasing is a collection of a few antialiasing algorithms:
- Temporal Antialiasing (TAA) – takes 66% of the time of Unity’s built-in TAA. Always combines two frames: current frame and one previous frame.
- Edge Antialiasing (EAA) – very simple algorithm that blurs edges.
- FXAA – well-known NVIDIA Timothy Lottes’s algorithm. Included just as a valuable addition so that it doesn’t have to be downloaded separately.
TAA algorithm thanks to jittering camera positon is capable of alleviating sub-pixel aliasing.
EAA and FXAA are post-processors that simply blur hard edges.
The two categories, temporal and post-processors, are orthogonal to each other and complement each other nicely. It is best to use a combination of either TAA+EAA or TAA+FXAA. The former will be faster while the latter will result in top-notch antialiasing solution that should be efficient enough not to take more than 1 ms on PS4 in full HD.
TAA and EAA both work on mobile systems that support OpenGL ES 3.0. FXAA is not supported on mobiles.
Screenshots
FMAA test scene.
FMAA interface.
FMAA – no AA.
FMAA – TAA + EAA.
FMAA – TAA + FXAA.
Interface
The package comes with one script FMAA.cs. It exposes the following properties:
- Temporal – turn on/off Temporal Antialiasing.
- Temporal Per Pixel Offset – sometimes just jittering camera’s position might not be enough if used sample coordinates happen to align with jagged geometry in screen space. In that case some additional, ideally per-pixel, offset can help. That is what this option does.
- Temporal MRT Optimization – when turned on Unity will use multi-render target feature to make temporal antialiasing faster. This option gives around 20% speed boost.
- Edge Blur – turn on/off Edge Antialiasing.
- FXAA – turn on/off FXAA.
The remaining options are slots for AA shaders’ materials. A test scene shows how this should be configured.
Examples
In folder FMAA/Assets/BlossomGames/FMAA/Test you can find test scene that has a main camera with FMAA script attached. That is a good start to experiment.