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Unsure where to post this, but…
If you look at the following short clip from GTA V you can see a band of visual distortion surrounding the player avatar as it moves. The distortion is there also if you keep the player still and pan the camera. I'm not a developer (I know a little C++, but that's it), so apologies if this is a stupid question, but what causes it?
https://photos.app.goo.gl/h889qW9mhNQ4Zcmh9
It's a bit hard to tell for sure from that clip, but it seems consistent with artifacts that often come from "temporal antialiasing" https://de45xmedrsdbp.cloudfront.net/Resources/files/TemporalAA_small-59732822.pdf . The idea is that the current frame uses information from previous frames in order to smooth out flickeriness and jagged edges of sub-pixel details that come from taking too few samples. The problem with this approach is that it doesn't make sense in situations where previous frames don't actually provide any information – for instance, when the camera moves and reveals something behind a character that wasn't visible at all in the previous frame. There are a lot of ways to combat this issue, but none of them work perfectly in all situations. In the best case, the algorithm will fall back to FXAA (or some variant) in situations like this. Often, though, instead you get things like weird motion trails or extreme aliasing that traces the silhouette of the character.
Thanks for the detailed reply. Makes me wonder whether the brain might process visual information in roughly the same way:
I'm not sure if everyone sees it, but if I walk past a tree trunk about ten feet away in low light (dusk) and look at the space next to the trunk I see a filmy disturbance in the light information. Maybe photoreceptors have biochemical ‘switch’ lag and the light revealed by the moving tree is overlayed by residue from the previous ‘frame’?
I have to admit that before your reply I was tending to think the filmy tree aura described above, in light of its similarity to the phenomenon in GTA V, was further evidence for the ‘life is a simulation’ hypothesis.
