PlayStation 1-style graphics - video settings of Psilosybil
Soon to be in the demo build is this new video settings menu and demo screen, displaying what the game can do in terms of reconstructing that nostalgic crappiness of the original Sony Playstation. And also the freedom to disable any part of it, because some people are just nauseated by this kind of things and that's ok.
Game demo is here: https://cancrizans.itch.io/psilosybil
All of these effects are achieved through specially written shaders, image effect shaders, and RenderTexture juggling.
Video mode means the game can run at either full resolution, or at 320p (a decent compromise) either with or without what is now a very sophisticated analog composite filter that I promise I won't touch the code of anymore.
When playing at 320p, you can choose whether to stretch to your screen size or update to the largest integer multiple. Without the video filter, you may prefer integer upscaling so as to keep pixels sharp and square and avoid funky h-lines. Uneven pixels are really not noticeable at all with the analog filter instead, so you can stretch away.
Vertex jitter simulates the original popping polygons of the PSX, which were due to multiple sources of limited precision in the hardware - the one that matters for all PS1 games is that there is no sub-pixel precision for vertices, so they move by popping in place from pixel to pixel, carrying along the entire triangle in sudden snaps. Due to the resolution being high-ish, I've found that going just a little beyond the realistic one-pixel snap gives a nice nostalgic crunchiness.
Texture swim is a simulation of the PS1 affine texture mapping, which was a crude approximation of the true perspective mapping that you get if you disable it. (You can see that when it's active, the lines of the tiles in the yellow-white flooring appear parallel, while with correct perspective they converge to a vanishing point). Usually in the game I model and design levels taking this effect into account so as to minimize nausea, as they used to do back in the day, so it's typically not as strong as in this scene which is meant to emphasize it.