Launch the game once, and set your graphics options other than resolution. Now quit.
Go to <gameDir>\Program\Bin. Open user.ini. Find these lines:
DesiredFOV=85.000000
DefaultFOV=85.000000
Change the values to set your FOV to your preference. I recommend 95.43 for 16:10 resolutions and 101.4 for 16:9 resolutions.
Now open the main game .ini file. It should be named something like tribesv.ini (in the demo it's tribesv_demo2_en.ini). Look for these lines:
FullscreenViewportX=1024
FullscreenViewportY=768
Change them to set your resolution.
This game is Hor+, dependant on your FOV setting.
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Another way to set up WS is to edit the "TribesGUIState.ini" file in the "Tribes Vengeance\Program\bin\" folder.
by default these lines are present:
ScreenResolutionChoices=640x480
ScreenResolutionChoices=800x600
ScreenResolutionChoices=1024x768
ScreenResolutionChoices=1280x1024
ScreenResolutionChoices=1600x1200
You can add any further resolutions you wish to use underneath these (i.e. ScreenResolutionChoices=1680x1050).
These choices then appear in the in-game graphics settings menu, just as all the others.
FOV changes are still advisable in addition to this. (without this, the game adjusts to widescreen by cropping top and bottom)