FSAA/FAA Performance
Parhelia's main Antialiasing method is FAA, but is does have a fallback Supersampling mode. We'll take a look at the performance of both, once again using SS:SE's Citadel demo, without Anisotropic filtering.
| 640x480 | 800x600 | 1024x768 | 1280x1024 | 1600x1200 |
| None | 60.9 | 60 | 59.4 | 47.9 | 34.8 |
| 4X SSAA | 38.2 | 26.7 | 18.4 | 14.9 | 15.2 |
| 16X FAA | 59.7 | 59.5 | 54.9 | 42.2 | 30.5 |
| Diff from None | 640x480 | 800x600 | 1024x768 | 1280x1024 | 1600x1200 |
| 4X SSAA | -37% | -56% | -69% | -69% | -56% |
| 16X FAA | -2% | -1% | -8% | -12% | -12% |
As we can see the 4X Super-sampling FSAA is accounting for roughly the type of performance hit we would expect, being fairly large. In the worst case the Super-sample AA is taking 69%. FAA, on the other hand, is offering far better performance in this title, although it has seen larger performance drops in other titles used in this review.
FAA/FSAA Quality
Here are some sampling images using FAA/FSAA.
The first image is a 640x480 screen shot doubled in size to highlight the edges more. The second image is a close up, four times its initial size.
Looking at the close-up image of the 4X SSAA shot shows a number of intermediate colour samples that is consistent with an ordered grid 4X implementation.
The screenshot with FAA enabled shows that it clearly offers much better edge AA on the edges it applies to, and the close up shot shows the many intermediate colour samples in the inner square. However in this instance we can clearly see that it's not applying extra samples around the outer square, whereas the SSAA shot is and so would a Multisampling implementation.
FAA is also known to have issues operating with Stencil Buffers in place. Below is a screenshot of the 'Fablemark' demo which makes use of stencil buffers.
FAA Off FAA On
