Inject VR support into some flat UE games

[frostworx]

By using #264 in combination with #265 it is possible to inject real VR support into several flat UE4 games.
Looks like most UE4 games, which were built with OpenVR (so those which ship "Engine/Binaries/ThirdParty/OpenVR")
can be played in real VR (in game menus won't be compatible though).
The current (wip & offline) implementation of above features already works as expected, but enabling VR mode, by calling the corresponding commands in the injected UE4 console is not properly working (yet).
Depending on the list of possibly VR-able games with might or might not be worth the effort to fully implement this without requiring any user-interaction.

No idea if there's an easy (automated) way to find all (non-vr) games on steam which ship "Engine/Binaries/ThirdParty/OpenVR"
(f.e. looks like steamdb doesn't help here), so no idea yet which games can be "VR-ed".

At least the following games (random order) could maybe (don't own them all yet and haven't tested them all) be made to work:

• https://store.steampowered.com/app/329200/Astray/
• https://store.steampowered.com/app/314000/Pool_Nation_FX_Lite/
• https://store.steampowered.com/app/1239050/Mists_of_Aiden/
• https://store.steampowered.com/app/750130/The_Sinking_City/ (above injection not required - the game accepts the '-vr' command line parameter!)
• https://store.steampowered.com/app/996580/Spyro_Reignited_Trilogy/
• https://store.steampowered.com/app/622020/ATV_Drift__Tricks/
• https://store.steampowered.com/app/417430/Moto_Racer__4/
• https://store.steampowered.com/app/558260/Gravel/
• https://store.steampowered.com/app/597820/BIOMUTANT/ (above injection can't open the UE4 console in the current version, a different injection I found somewhere can, but doesn't react to UE4 console VR commands - so this might be possible later(?))

There are also some games, which shipped "Engine/Binaries/ThirdParty/OpenVR"
before and can be reactivated by using an older steam depot:

• https://store.steampowered.com/app/514900/observer/ (see here)
• https://store.steampowered.com/app/1678090/Dark_Home/ (https://steamdb.info/patchnotes/7047777/)
• https://store.steampowered.com/app/1506640/Hatchpunk/
  ( dotnet DepotDownloader.dll -app 1506640 -depot 1506641 -manifest 2972482185570779622 -username XXX -password YYY ) - just bought it. quick test: injection works and in game vr view is correct - keyboard input didn't react anymore after enabling VR - probably can be resetted with an other ue4 command.

Feel free to search and report more possible compatible games!

[frostworx]

The UE4 console commands required to VR a flat game are basically (might be improvable):

vr.bEnableHMD 1
vr.bEnableStereo 1
vr.HeadTracking.ResetPosition

(depending on the game the commands need to be applied while in game-play and don't work or might even crash when called from the main game menu)

[frostworx]

If this does work it would be pretty easy to add customized vr-autostart scripts to the corresponding games.

So add to the game command line parameters either via
-exec=/path/to/vr-autostartscripts
or raw via
-ExecCmds=vr.bEnableHMD 1, vr.bEnableStereo 1, vr.HeadTracking.ResetPosition

[frostworx]

Looks like there is not much interest in this....
Anyway:
executing a console command (script) directly via command line probably can't work, as the console itself is injected into the game after the game was executed

For the same reason, I'm not sure if there's even a possibility to start a script automatically on game start (using [SystemSettings] commands in Engine.ini probably won't work)

What definitely does work is at least the following:

• automatically create a console command script stl-vr-patch with above vr commands and place it into $GAMEDIRECTORY/Binaries
• automatically add that script to the editor menu, so it can be easily edited from there
• create/edit Input.ini and add

[/Script/Engine.Console]
HistoryBuffer=exec stl-vr-patch

The user starts the game regularly then, but can easily enable VR by

• opening the console
• starting exec stl-vr-patch by selecting it from the console history

[frostworx]

The rest could be automated (maybe optionally) as well by sending following keys to the game window

• tilde/backtick/grave to open the use console
• cursor up top select exec stl-vr-patch from the console history
• return
  -> profit

[frostworx]

Initially I had problems with sending tilde reliably to the game window, therefore the HistoryBuffer idea.
This is working now, so the Input.ini functions are no longer needed.

[frostworx]

Partly added in release v6.13
"might expand depending on feedback"