Gaming BotW shader study

[cal64]

Hello! I've been trying to figure out how the ground coloring part of the Thunder Helm (seen during the Vah Naboris pursuit part) effect was pulled off.
I've got a bunch of theories, but nothing too concrete, so I figured I'd ask for some help!

Any OpenGL wizards willing to help on This one?

Thanks for reading!

 

[cal64]

Alright, figured I'd elaborate a bit. Here's what I've thought of so far:

-The effect is done in post-processing using a get-world-coorinates-from-depth-buffer trick
-It may also be done using a method similar to the one used for volume shadows, with extra steps to "cut out" characters from the stencil buffer

Here's the problem, however:
The effect seems to get more and more pixelated as it goes further along in depth.
I still thought of a bunch of ways to make the above-mentionned methods work with this constraint, but at this point I figured I'd just ask for advice.