Axis values support for network diffs

[paul-hansen]

We used the network diffing functionality of this library for our game jam game: https://prawl.itch.io/stellar-squeezebox which overall turned out great and it was really helpful for getting something off the ground quick!

Unfortunately, gamepad support was really lacking when diffing actions with a couple major issues:

A. There is no support for axis data for ActionDiff
B. If you use an axis as a button (e.g. turn left) you can't set a deadzone or it stops being recognized on the server. Example:
SingleAxis::negative_only(GamepadAxisType::LeftStickX, 0.1).with_deadzone(deadzone) Was user error. See comment

I'd like to contribute towards this, so if you have any thoughts about how you want this to work let me know. (I'll probably taking a few days to relax now that the jam is over, so might be a bit)

[alice-i-cecile]

Oh awesome, I'm really glad this worked out! I'm leaning towards "refactor to use traits and split apart axes and button more clearly" (#321) first: ultimately I think our data model is flawed in messy ways that come out here.

Would be very happy to pair on that though if you're up for it.

[paul-hansen]

Discovered that problem B was mostly user error. .with_deadzone() shouldn't be used with SingleAxis::negative_only instead I should have been adjusting the threshold value passed to SingleAxis::negative_only which needed to be negative. I think this would have caused issues under non-networked use too. I should have made a minimal repo to test and would have caught this, was just lazy after cramming for the jam.
Gamepads are working for our game now! Just have to treat everything as a button since there isn't axis data in actiondiffs.

[TimJentzsch]

Discovered that problem B was mostly user error. .with_deadzone() shouldn't be used with SingleAxis::negative_only instead I should have been adjusting the threshold value passed to SingleAxis::negative_only which needed to be negative. I think this would have caused issues under non-networked use too. I should have made a minimal repo to test and would have caught this, was just lazy after cramming for the jam. Gamepads are working for our game now! Just have to treat everything as a button since there isn't axis data in actiondiffs.

Is this behavior documented properly?
Might be worth it to open up a doc issue for this in case that others might run into the same problem :)

[paul-hansen]

It kind of is, but you have to think about what it's saying and already understand what the values on SingleAxis mean.

Creates a SingleAxis with the axis_type and negative_low set to threshold.

Positive values will not trigger the input.

Source

Could probably be improved to help avoid it being a footgun.