What no Quincunx anti aliasing
Quincunx anti aliasing works by using 5 samples per pixel in the following configuration:
B C
*--------*
| A
| *
|
*--------*
D E
A is the center of the pixel that you would normally draw. It has a weight of 1/2.
B,C,D,E are offset from the center by half a pixel and each having a weighting of 1/8.
The weights of all the samples add up to 1.0 but the center has the heaviest contribution to the final image.
In shadertoy, quincunx AA means that you have to do 5 times as much rendering per pixel, but
in real rendering situations, you can achieve quincunx by doing two full screen renders.
The first render renders the screen with an offset of half a pixel (-0.5,-0.5) and the second render
uses the results of that first render to get the corner pixels to mix into the center pixel.
The benefit of doing this is that those corner pixels can be shared by all the pixels that use them
which makes it so you are basically doing 2x super sampling AA, but you get benefits closer to 5x!
https://www.techpowerup.com/forums/threads/different-types-of-aa.149319/