Created a simple PairCondition class for pairing inputs together

[greenstack]

I found myself wanting to be able to pair inputs and check which "side" of the inputs was down, so I put this together. I designed it to depend on other conditions, and based on which condition is met, output -1, 0, or 1.

I was wondering how having both conditions held should react - should they cancel out or should the developer be able to specify a direction that behavior? I think the latter would be good but wanted to put that up for discussion here.

[Apostolique]

What is your use case for this? Is it like a joystick where you can move left or right or anywhere in between?

I had started something similar #13.

[greenstack]

It's similar to #13, yes. Here's are a sample use cases in my project:

WeaponSwap = new PairCondition
(
    new AnyCondition(
        new KeyboardCondition(Keys.A),
        new GamePadCondition(GamePadButton.LeftShoulder, playerIndex)
    ),
    new AnyCondition(
        new KeyboardCondition(Keys.S),
        new GamePadCondition(GamePadButton.RightShoulder, playerIndex)
    )
);

In this case, this is to let the player switch weapons quickly, left or right or up and down.

It's not quite the same as mapping a joystick to an input, but more mapping two related inputs to a single condition. I was inspired by this axis pairs feature from a library for another game framework to make it a bit easier to figure out which "direction" a condition was pointing in.