Unfamiliar graphics settings

[Hrothgar Óhreinsaður]

I noticed these graphics settings in the Perfected DOOM 3 mod: SSAO, SSIL, and Vignetting, and I'm unfamiliar with them, so I googled them, but the results I read may as well have been in Chinese. Can anyone give me an idea what these settings actually do?

[Bolkonsky]

SSAO
Stands for "Screen Space Ambient Occlusion" and is a pixel shader. Basically, in a nutshell, with this enabled what you'll notice is that objects can cast shadows upon themselves.

SSIL
No clue what it stands for, it's similar to SSAO though.

http://enbdev.com/ss_ssao_en.htm

Vignette
Should have no performance impact, it's basically a small black border around the screen for cinematic purposes. Here's an example:
http://www.dunbardigital.com/blog/bl...vignette-2.jpg