Conformal perspective as an option in TDM?

[peter_spy]

Even if we take the different way of measuring FOV for TDM, we can visually pinpoint values that feel more or less natural.

IMO, with FOV 70 things start to look like player is having a zoom lens, which makes for very claustrophobic and uneasy feeling. But even if I start from that, the amount of stretching is substantial.

FOV 70:

FOV 80:

FOV 90:

[Xolvix]

The only issue I have with upping the FOV in some games is that it can narrow the things in direct sight, which may or may not "cramp" the main areas of interest even if you are getting more peripheral imagery. Having said that, it seems like different engines can have different effects when high FOVs come into play. I have found that I need at least a 90 FOV (actual, horizontal 90 FOV) at a minimum before I'm happy, but even then I've noticed some games with an FOV of 90 seem fine while others feel like I'm too zoomed in.

For example, Deus Ex 1 has a default FOV of 75 intended for a 4:3 monitor. When running on 16:9 the various FOV calculators will suggest a new FOV of 90 to compensate, which is correct. But for some reason in Prey 2017, 90 FOV feels a little too claustrophobic whereas Deus Ex seems OK. What's more annoying is I didn't give a shit about running Prey with 90 FOV, but now that I'm aware of how FOV can differ, it's starting to annoy me! Ignorance really was bliss, so I upped it just a bit to 94 until that feeling went away.

[Xolvix]

Another trick I read somewhere - if you want to know whether a game's FOV is comparable with the FOV you expect, you can try this technique (only for first-person games):

(1) Set the game's FOV to 90
(2) Find two relatively long walls that join into a 90 degree corner and back yourself into the corner, facing out
(3) If the game is correctly using 90 horizontal FOV, you should only be able to have one of the walls on the screen at any given moment.

At a listed FOV of 90 in the menu, The Dark Mod fails the test which means it's not actually 90 degrees. I've also found that GZDoom, EDuke32, Quakespasm and Yamagi Quake II also have this "issue", except that their FOVs are either intended for a 4:3 base and scaled in the engine, or there's a config setting that auto-scales the FOV as intended for the new resolution. In most cases the "correct" FOV is 105 or 106, but not all games support such FOVs and often stretch too much, whereas these source ports seem to work fine.

[peter_spy]

Maybe TDM simply has a 4:3 ratio resized and stretched to avoid pillarboxing?

[nbohr1more]

I wonder if this new "FovoTec" thing:

https://www.pcgamer.com/first-person-shooters-have-been-getting-perspective-wrong-all-along/

is just a Conformal perspective design being sold as something new?

Anyone better than I at interpreting the study paper:

https://psyarxiv.com/7xack/

?

[lowenz]

You have good memory, nbohr!

[stgatilov]

I think this can be implemented as postprocessing shader which takes a part of traditional render and bends it to get conformal projection.

I.e. when conformat projection is enabled:

1. Find minimum FOV so that camera view contains the whole thing visible in conformal projection
2. Render everything with traditional camera and this larger FOV
3. During tonemap, compute texcoords to sample input from using some nontrivial formula

Of course, step 3 will stretch or bend the pixel-perfect render in pretty weird and non-uniform way, so perhaps it would look blurry by 1 pixel in the middle, perhaps it would have aliasing near boundaries.

But it will achieve the desired effect with very little intervention into rendering.

[lowenz]

What if we can add some sort of supersampling (and automatically disabling MSAA) before? With a clear disclaimer about performance hit/fall.

Or add FXAA/SMAA as a global option (in mutual exclusion with MSAA) as last step.

*Conformal Perspective option ON -> no MSAA + optional SSAA + frame correction + optional FXAA/SMAA

*Linear Perspective + optional MSAA or FXAA/SMAA (as now, just add FXAA/SMAA)

Edited April 8, 2023 by lowenz