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IDProjectCategoryView StatusLast Update
0005520The Dark ModGraphicspublic28.03.2021 20:28
ReporterJudith Assigned To 
Status newResolutionopen 
Platformx64OSWindowsOS Version7
Summary0005520: FOV: Find a way to correct the distortion
DescriptionThe pincusion distortion in TDM is huge. Even at fairly narrow FOV of 70, you can see objects getting stretched and looking much bigger than in the center. It's even more visible with FOV 80 or higher. In most games (and with widescreen resolutions), the effect much less severe, typically until FOV is like 110-120 and higher.
Steps To ReproduceLook at any object that is in the center of the screen, then rotate the camera so it's at one of the corners.
TagsNo tags attached.




03.02.2021 11:28


Clipboard02.jpg (541,429 bytes)


03.02.2021 19:39

developer   ~0013626



04.02.2021 17:53

administrator   ~0013637

Last edited: 04.02.2021 17:53

View 2 revisions

"In most games the effect much less severe, typically until FOV is like 110-120 and higher."

I guess that's because most games measure horizontal FOV.
As far as I remember, TDM measures some weird quantity which is neither horizontal nor vertical FOV, but something connected to virtual 640x480 screen.

If you really want to check if TDM distortion is more severe, you should ensure that actual FOV is the same, because numbers give you wrong impression.


07.02.2021 10:40

developer   ~0013662

Just looked it up in the code to have a reference point. An FOV setting of 90 actually results in horizontal FOV of 106 and vertical FOV of 74 (on a 16:9 resolution).

An FOV setting of 75 would give horizontal FOV of 91 and vertical FOV of 60 (again, for a 16:9 resolution).


28.03.2021 19:25

developer   ~0013817

Yeah I think the original FOV is calculated by 4:3 aspect.

Maybe this is something to look into?


28.03.2021 20:05

developer   ~0013818

I think the quick (initial) fix would be to set the default FOV to 75. That value is much closer to the typical horizontal FOV value of 90 and already significantly reduces the problem. Adding barrel distortion is not without its own side effects. If the issue is still more pronounced in TDM than in other games at comparable FOV values, I'd like to understand why, first :)


28.03.2021 20:28

developer   ~0013819

I wonder if we can summon Tels to discuss what he did with r_fovRatio and see if there is some disconnect that happened either after it's removal or moving to Standalone or 64-bit.

I can artificially correct this by issue setting a lower fov and then noclipping backward from the target scene so I imagine a proper fix might include a z axis adjustment to the camera too.

Issue History

Date Modified Username Field Change
03.02.2021 11:28 Judith New Issue
03.02.2021 11:28 Judith File Added: Clipboard02.jpg
03.02.2021 19:39 nbohr1more Note Added: 0013626
04.02.2021 17:53 stgatilov Note Added: 0013637
04.02.2021 17:53 stgatilov Note Edited: 0013637 View Revisions
07.02.2021 10:40 cabalistic Note Added: 0013662
28.03.2021 19:25 AluminumHaste Note Added: 0013817
28.03.2021 20:05 cabalistic Note Added: 0013818
28.03.2021 20:28 nbohr1more Note Added: 0013819