Ported trigger_userinput from Momentum Mod

[Nbc66]

This PR Ports the trigger_momentum_userinput trigger from Momentum Mod from mom_triggers.cpp

this allows you to check if a user has:

• Pressed a button
• is holding a button
• has released a button

the fgd should look like this:

@SolidClass base(Trigger) = trigger_userinput : "Trigger that fires on user KeyPress if inside trigger."
[
    output OnKeyPressed(void) : "Fires when the desired key is pressed"
    output OnKeyHeld(void) : "Fires every tick while the desired key is held"
    output OnKeyReleased(void) : "Fires when the desired key is released"
    lookedkey(choices) : "Key that fires" : "Forward" =
    [
        0 : "Forward"
        1 : "Back"
        2 : "Move Left"
        3 : "Move Right"
        4 : "Jump"
        5 : "Duck"
        6 : "Attack"
        7 : "Attack 2"
        8 : "Reload"    
    ]
]

PR Checklist

• My PR follows all guidelines in the CONTRIBUTING.md file
• My PR targets a develop branch OR targets another branch with a specific goal in mind

[meatspace]

oh yeah one thing i forgot mapbase has that momentum doesnt is a third tertiary attack, idk if its possible to add easily but might be cool

[Blixibon]

I think this trigger would be welcome in Mapbase overall, but I'm uncertain of the way it was implemented.

While you're free to address or respond to the points I raised, I'm interested enough that I would be alright with fixing this up myself in the future if you would prefer to move on from this.

[Blixibon]

I'm curious why this uses its own separate enum instead of allowing mappers to check button bits directly, but that's a question for Momentum Mod more-so than for this PR.

While I would prefer to keep functionality the same between the way it works in Mapbase and the way it works in Momentum Mod, I think it would make sense to allow for explicit button bits, especially if this may get extended to other buttons like +attack3. Perhaps there could be an alternate keyvalue to handle that.

[samisalreadytaken]

I don't think there is any need for parity with another mod for such a stupid simple entity. If this entity is to be added, the empty base class and this enum should be removed. I suppose keeping this separate would make changes to the order of IN_BUTTONS enum not break this entity, but that's really unlikely.

"Key" name is usually used for keyboard keys instead of player input buttons. "OnKey" outputs don't make much sense. "lookedkey" also sounds weird.

It seems more appropriate to have this as a point entity or an extension for game_ui instead of limiting it to a trigger. Mappers looking for something like this would certainly want to use it without a trigger.

[Nbc66]

Yeah i agree this pr just ports what Momentum Mod did i can modify this pr to make it be a point entity that just checks the players input or be an extension of game_ui

If there is anything else you guys would like me to do pls feel free to write it here

[Nbc66]

I don't think there is any need for parity with another mod for such a stupid simple entity. If this entity is to be added, the empty base class and this enum should be removed. I suppose keeping this separate would make changes to the order of IN_BUTTONS enum not break this entity, but that's really unlikely.

"Key" name is usually used for keyboard keys instead of player input buttons. "OnKey" outputs don't make much sense. "lookedkey" also sounds weird.

It seems more appropriate to have this as a point entity or an extension for game_ui instead of limiting it to a trigger. Mappers looking for something like this would certainly want to use it without a trigger.

also I just realized that this trigger works with multiple people unlike the game_ui entity which is needed for each player on a map

if you got any code suggestions pls feel free to write em here