[Bug] Post-processing issues, more info needed

[emoose]

Seen a lot of mentions about post-processing being broken when resolution is changed, not sure if anyone has tried making a comparison with them though (other than comparisons between PS2 & 720p HD collection).

Does anyone know any spot in the game where post-processing becomes noticeably different at different resolutions?

In RenderDoc I noticed they're creating some blurred render target buffers, looks like the resolution of those are being scaled with the game res though, eg. at 2560x1440 it creates 1280x720/640x360 buffers, while at 1920x1080 it creates 960x540/480x270:

eg at 2560x1440 game res:

vs 1920x1080:

Very similar results there, though the 640x360 buffer maybe ends up being slightly sharper because of the increased res, or possibly there could be something in whatever shader applies these blur buffers which ends up resizing them.

[KoKlusz]

I and others have posted some comparison shots in the Resetera PC thread when arguing about it, as I don't have Master Collection yet my MGS3 shots here are from emulated PS2 and PS3 versions respectively

https://www.resetera.com/threads/metal-gear-solid-master-collection-vol-1-pc-performance-thread.777830/page-4#post-113927486

Master collection on PC acts the same according to these shots (those were taken with the older resolution mod IIRC)

https://www.resetera.com/threads/metal-gear-solid-master-collection-vol-1-pc-performance-thread.777830/page-5#post-113929823
https://www.resetera.com/threads/metal-gear-solid-master-collection-vol-1-pc-performance-thread.777830/page-5#post-113930342

And finally Master Collection (also with the older mod) vs PS2 at native res

https://www.resetera.com/threads/metal-gear-solid-master-collection-vol-1-pc-performance-thread.777830/page-6#post-113950025

In general the entire intro to MGS3 is a good example of that, cutscenes in the first chapter of MGS2 as well. In MGS2 the spotlight in the arena when you fight the first boss cast fake volumetric god rays which scale with resolution to IIRC.

MGS2 in general has a bunch of post process effects broken in every version after PS2, this video goes into some detail about it
https://www.youtube.com/watch?v=fLrcDoJt9_E

[s-ilent]

Scaling with the game resolution is kind of the problem. If you set the HD fix to run at roughly PS2 resolution, you can see effects like depth of field and bloom reappear closer to how they were in the PS2 release.

PCSX2 Software mode	HD fix at PS2-like res	HD fix at 4k

The PS2 version runs at something like 448x512, so even a 2x2 box blur covers a lot of area. The scale of the blurring, however, doesn't seem to have been changed in the HD collection. As the blur is the same size, it covers less screen area, which would account for many missing effects. For 720p, having the bloom and blur be half-res still provides some effect (but looks noticeably different), and once you go up to 1080p and onwards it's basically gone or hard to see. The in-game bloom and other blur effects are less affected because they run at a fractional resolution, but that only scales so far.

In modern games, this problem is typically handled by doing blurring through a gaussian pyramid (as far as I know) which looks roughly the same at different resolutions. Maybe it's possible to get the game to do a few more downsampling passes for the bloom? Though, that doesn't address the depth of field effect...